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Kittelmann M, McGregor AP. Looking across the gap: Understanding the evolution of eyes and vision among insects. Bioessays 2024; 46:e2300240. [PMID: 38593308 DOI: 10.1002/bies.202300240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/29/2024] [Accepted: 03/05/2024] [Indexed: 04/11/2024]
Abstract
The compound eyes of insects exhibit stunning variation in size, structure, and function, which has allowed these animals to use their vision to adapt to a huge range of different environments and lifestyles, and evolve complex behaviors. Much of our knowledge of eye development has been learned from Drosophila, while visual adaptations and behaviors are often more striking and better understood from studies of other insects. However, recent studies in Drosophila and other insects, including bees, beetles, and butterflies, have begun to address this gap by revealing the genetic and developmental bases of differences in eye morphology and key new aspects of compound eye structure and function. Furthermore, technical advances have facilitated the generation of high-resolution connectomic data from different insect species that enhances our understanding of visual information processing, and the impact of changes in these processes on the evolution of vision and behavior. Here, we review these recent breakthroughs and propose that future integrated research from the development to function of visual systems within and among insect species represents a great opportunity to understand the remarkable diversification of insect eyes and vision.
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Affiliation(s)
- Maike Kittelmann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
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2
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Paukner D, Wildenberg GA, Badalamente GS, Littlewood PB, Kronforst MR, Palmer SE, Kasthuri N. Synchrotron-source micro-x-ray computed tomography for examining butterfly eyes. Ecol Evol 2024; 14:e11137. [PMID: 38571794 PMCID: PMC10985371 DOI: 10.1002/ece3.11137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 11/30/2023] [Accepted: 01/09/2024] [Indexed: 04/05/2024] Open
Abstract
Comparative anatomy is an important tool for investigating evolutionary relationships among species, but the lack of scalable imaging tools and stains for rapidly mapping the microscale anatomies of related species poses a major impediment to using comparative anatomy approaches for identifying evolutionary adaptations. We describe a method using synchrotron source micro-x-ray computed tomography (syn-μXCT) combined with machine learning algorithms for high-throughput imaging of Lepidoptera (i.e., butterfly and moth) eyes. Our pipeline allows for imaging at rates of ~15 min/mm3 at 600 nm3 resolution. Image contrast is generated using standard electron microscopy labeling approaches (e.g., osmium tetroxide) that unbiasedly labels all cellular membranes in a species-independent manner thus removing any barrier to imaging any species of interest. To demonstrate the power of the method, we analyzed the 3D morphologies of butterfly crystalline cones, a part of the visual system associated with acuity and sensitivity and found significant variation within six butterfly individuals. Despite this variation, a classic measure of optimization, the ratio of interommatidial angle to resolving power of ommatidia, largely agrees with early work on eye geometry across species. We show that this method can successfully be used to determine compound eye organization and crystalline cone morphology. Our novel pipeline provides for fast, scalable visualization and analysis of eye anatomies that can be applied to any arthropod species, enabling new questions about evolutionary adaptations of compound eyes and beyond.
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Affiliation(s)
- Dawn Paukner
- Department of NeurobiologyUniversity of ChicagoChicagoIllinoisUSA
- Argonne National LaboratoryLemontIllinoisUSA
- Department of Organismal Biology and AnatomyUniversity of ChicagoChicagoIllinoisUSA
| | - Gregg A. Wildenberg
- Department of NeurobiologyUniversity of ChicagoChicagoIllinoisUSA
- Argonne National LaboratoryLemontIllinoisUSA
| | - Griffin S. Badalamente
- Department of NeurobiologyUniversity of ChicagoChicagoIllinoisUSA
- Department of ZoologyThe Old Schools, University of CambridgeCambridgeUK
| | | | | | - Stephanie E. Palmer
- Department of Organismal Biology and AnatomyUniversity of ChicagoChicagoIllinoisUSA
- Department of PhysicsUniversity of ChicagoChicagoIllinoisUSA
| | - Narayanan Kasthuri
- Department of NeurobiologyUniversity of ChicagoChicagoIllinoisUSA
- Argonne National LaboratoryLemontIllinoisUSA
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3
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Chapman KE, Smith MT, Gaston KJ, Hempel de Ibarra N. Bumblebee nest departures under low light conditions at sunrise and sunset. Biol Lett 2024; 20:20230518. [PMID: 38593853 PMCID: PMC11003773 DOI: 10.1098/rsbl.2023.0518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/07/2024] [Indexed: 04/11/2024] Open
Abstract
Only a few diurnal animals, such as bumblebees, extend their activity into the time around sunrise and sunset when illumination levels are low. Low light impairs viewing conditions and increases sensory costs, but whether diurnal insects use low light as a cue to make behavioural decisions is uncertain. To investigate how they decide to initiate foraging at these times of day, we observed bumblebee nest-departure behaviours inside a flight net, under naturally changing light conditions. In brighter light bees did not attempt to return to the nest and departed with minimal delay, as expected. In low light the probability of non-departures increased, as a small number of bees attempted to return after spending time on the departure platform. Additionally, in lower illumination bees spent more time on the platform before flying away, up to 68 s. Our results suggest that bees may assess light conditions once outside the colony to inform the decision to depart. These findings give novel insights into how behavioural decisions are made at the start and the end of a foraging day in diurnal animals when the limits of their vision impose additional costs on foraging efficiency.
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Affiliation(s)
- Katherine E. Chapman
- Centre for Research in Animal Behaviour, Psychology, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Michael T. Smith
- Department of Computer Science, University of Sheffield, Sheffield, UK
| | - Kevin J. Gaston
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, UK
| | - Natalie Hempel de Ibarra
- Centre for Research in Animal Behaviour, Psychology, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
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4
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Moradinour Z, Wiklund C, Miettinen A, Gérard M, Baird E. Exposure to elevated temperature during development affects eclosion and morphology in the temperate Pieris napi butterfly (Lepidoptera: Pieridae). J Therm Biol 2023; 118:103721. [PMID: 38016229 DOI: 10.1016/j.jtherbio.2023.103721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 09/29/2023] [Accepted: 09/29/2023] [Indexed: 11/30/2023]
Abstract
Global warming has been identified as one of the main drivers of population decline in insect pollinators. One aspect of the insect life cycle that would be particularly sensitive to elevated temperatures is the developmental transition from larva to adult. Temperature-induced modifications to the development of body parts and sensory organs likely have functional consequences for adult behaviour. To date, we have little knowledge about the effect of sub-optimal temperature on the development and functional morphology of different body parts, particularly sensory organs, in ectothermic solitary pollinators such as butterflies. To address this knowledge gap, we exposed the pupae of the butterfly Pieris napi to either 23 °C or 32 °C and measured the subsequent effects on eclosion, body size and the development of the wings, proboscis, eyes and antennae. In comparison to individuals that developed at 23 °C, we found that exposure to 32 °C during the pupal stage increased mortality and decreased time to eclose. Furthermore, both female and male butterflies that developed at 32 °C were smaller and had shorter proboscides, while males had shorter antennae. In contrast, we found no significant effect of rearing temperature on wing and eye size or wing deformity. Our findings suggest that increasing global temperatures and its corresponding co-stressors, such as humidity, will impact the survival of butterflies by impairing eclosion and the proper development of body and sensory organs.
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Affiliation(s)
| | | | - Arttu Miettinen
- Institute for Biomedical Engineering, University and ETH Zurich, 8092, Zurich, Switzerland; Swiss Light Source, Paul Scherrer Institute, 5234, Villigen, Switzerland; Department of Physics, University of Jyvaskyla, 40014, Jyvaskyla, Finland
| | - Maxence Gérard
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm, Sweden
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5
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Perez M, Bagheri ZM, Brown C, Ogawa Y, Partridge JC, Hemmi JM. Contrast sensitivity, visual acuity and the effect of behavioural state on optokinetic gain in fiddler crabs. J Exp Biol 2023; 226:jeb245799. [PMID: 37732387 DOI: 10.1242/jeb.245799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 09/14/2023] [Indexed: 09/22/2023]
Abstract
Most animals rely on visual information for a variety of everyday tasks. The information available to a visual system depends in part on its spatial resolving power and contrast sensitivity. Because of their competing demands for physical space within an eye, these traits cannot simultaneously be improved without increasing overall eye size. The contrast sensitivity function is an integrated measure of visual performance that measures both resolution and contrast sensitivity. Its measurement helps us identify how different species have made a trade-off between contrast sensitivity and spatial resolution. It further allows us to identify the evolutionary drivers of sensory processing and visually mediated behaviour. Here, we measured the contrast sensitivity function of the fiddler crab Gelasimus dampieri using its optokinetic responses to wide-field moving sinusoidal intensity gratings of different orientations, spatial frequencies, contrasts and speeds. We further tested whether the behavioural state of the crabs (i.e. whether crabs are actively walking or not) affects their optokinetic gain and contrast sensitivity. Our results from a group of five crabs suggest a minimum perceived contrast of 6% and a horizontal and vertical visual acuity of 0.4 cyc deg-1 and 0.28 cyc deg-1, respectively, in the crabs' region of maximum optomotor sensitivity. Optokinetic gain increased in moving crabs compared with restrained crabs, adding another example of the importance of naturalistic approaches when studying the performance of animals.
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Affiliation(s)
- Monika Perez
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
| | - Zahra M Bagheri
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
- The UWA Oceans Institute, the University of Western Australia, Perth, WA 6009, Australia
| | - Courtney Brown
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
| | - Yuri Ogawa
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
| | - Julian C Partridge
- The UWA Oceans Institute, the University of Western Australia, Perth, WA 6009, Australia
| | - Jan M Hemmi
- School of Biological Sciences, the University of Western Australia, Perth, WA 6009, Australia
- The UWA Oceans Institute, the University of Western Australia, Perth, WA 6009, Australia
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Jie VW, Miettinen A, Baird E. Novel Methodology for Localizing and Studying Insect Dorsal Rim Area Morphology in 2D and 3D. INSECTS 2023; 14:670. [PMID: 37623380 PMCID: PMC10455470 DOI: 10.3390/insects14080670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/25/2023] [Accepted: 07/27/2023] [Indexed: 08/26/2023]
Abstract
Polarized light-based navigation in insects is facilitated by a polarization-sensitive part of the eye, the dorsal rim area (DRA). Existing methods to study the anatomy of the DRA are destructive and time-consuming. We presented a novel method for DRA localization, dissection, and measurement using 3D volumetric images from X-ray micro-computed tomography in combination with 2D photographs. Applying the method on size-polymorphic buff-tailed bumblebees, Bombus terrestris, we found that the DRA was easily obtainable from photographs of the dorsal eye region. Allometric analysis of the DRA in relation to body size in B. terrestris showed that it increased with the body size but not at the same rate. By localizing the DRA of individual bumblebees, we could also perform individual-level descriptions and inter-individual comparisons between the ommatidial structures (lens, crystalline cones, rhabdoms) of three different eye regions (DRA, non-DRA, proximate to DRA). One feature distinct to the bumblebee DRA was the smaller dimension of the crystalline cones in comparison to other regions of the eye. Using our novel methodology, we provide the first individual-level description of DRA ommatidial features and a comparison of how the DRA varies with body size in bumblebees.
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Affiliation(s)
- Vun Wen Jie
- Department of Zoology, Stockholm University, 11418 Stockholm, Sweden;
| | - Arttu Miettinen
- Department of Physics, University of Jyvaskyla, 40014 Jyvaskyla, Finland;
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Emily Baird
- Department of Zoology, Stockholm University, 11418 Stockholm, Sweden;
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7
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Bertrand OJN, Sonntag A. The potential underlying mechanisms during learning flights. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023:10.1007/s00359-023-01637-7. [PMID: 37204434 DOI: 10.1007/s00359-023-01637-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/20/2023]
Abstract
Hymenopterans, such as bees and wasps, have long fascinated researchers with their sinuous movements at novel locations. These movements, such as loops, arcs, or zigzags, serve to help insects learn their surroundings at important locations. They also allow the insects to explore and orient themselves in their environment. After they gained experience with their environment, the insects fly along optimized paths guided by several guidance strategies, such as path integration, local homing, and route-following, forming a navigational toolkit. Whereas the experienced insects combine these strategies efficiently, the naive insects need to learn about their surroundings and tune the navigational toolkit. We will see that the structure of the movements performed during the learning flights leverages the robustness of certain strategies within a given scale to tune other strategies which are more efficient at a larger scale. Thus, an insect can explore its environment incrementally without risking not finding back essential locations.
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Affiliation(s)
- Olivier J N Bertrand
- Neurobiology, Bielefeld University, Universitätstr. 25, 33615, Bielefeld, NRW, Germany.
| | - Annkathrin Sonntag
- Neurobiology, Bielefeld University, Universitätstr. 25, 33615, Bielefeld, NRW, Germany
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8
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Bartholomée O, Dwyer C, Tichit P, Caplat P, Baird E, Smith HG. Shining a light on species coexistence: visual traits drive bumblebee communities. Proc Biol Sci 2023; 290:20222548. [PMID: 37040802 PMCID: PMC10089714 DOI: 10.1098/rspb.2022.2548] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023] Open
Abstract
Local coexistence of bees has been explained by flower resource partitioning, but coexisting bumblebee species often have strongly overlapping diets. We investigated if light microhabitat niche separation, underpinned by visual traits, could serve as an alternative mechanism underlying local coexistence of bumblebee species. To this end, we focused on a homogeneous flower resource-bilberry-in a heterogeneous light environment-hemi-boreal forests. We found that bumblebee communities segregated along a gradient of light intensity. The community-weighted mean of the eye parameter-a metric measuring the compromise between light sensitivity and visual resolution-decreased with light intensity, showing a higher investment in light sensitivity of communities observed in darker conditions. This pattern was consistent at the species level. In general, species with higher eye parameter (larger investment in light sensitivity) foraged in dimmer light than those with a lower eye parameter (higher investment in visual resolution). Moreover, species realized niche optimum was linearly related to their eye parameter. These results suggest microhabitat niche partitioning to be a potential mechanism underpinning bumblebee species coexistence. This study highlights the importance of considering sensory traits when studying pollinator habitat use and their ability to cope with changing environments.
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Affiliation(s)
- Océane Bartholomée
- Centre for Environmental and Climate Science, Lund University, Lund 22362, Sweden
| | - Ciara Dwyer
- Centre for Environmental and Climate Science, Lund University, Lund 22362, Sweden
| | - Pierre Tichit
- Department of Biology, Lund University, Lund 22362, Sweden
- Department of Zoology, Stockholm University, Stockholm 10691, Sweden
| | - Paul Caplat
- Centre for Environmental and Climate Science, Lund University, Lund 22362, Sweden
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, BT9 5DL UK
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm 10691, Sweden
| | - Henrik G Smith
- Centre for Environmental and Climate Science, Lund University, Lund 22362, Sweden
- Department of Biology, Lund University, Lund 22362, Sweden
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9
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Tan C, Cai X, Luo Z, Li Z, Xiu C, Chen Z, Bian L. Visual acuity of Empoasca onukii (Hemiptera, Cicadellidae). INSECTS 2023; 14:370. [PMID: 37103185 PMCID: PMC10145553 DOI: 10.3390/insects14040370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 06/19/2023]
Abstract
Empoasca onukii is a common tea plant pest with a preference for the color yellow. Past work has shown that host leaf color is a key cue for habitat location for E. onukii. Before studying the effect of foliage shape, size, or texture on habitat localization, it is necessary to determine the visual acuity and effective viewing distance of E. onukii. In this study, a combination of 3D microscopy and X-ray microtomography showed that visual acuity did not significantly differ between females and males, but there were significant differences in the visual acuity and optical sensitivity among five regions of E. onukii's compound eyes. The dorsal ommatidia had the highest visual acuity at 0.28 cycles per degree (cpd) but the lowest optical sensitivity (0.02 μm2sr), which indicated a trade-off between visual resolution and optical sensitivity for E. onukii. The visual acuity determined from the behavioral experiment was 0.14 cpd; E. onukii exhibited low-resolution vision and could only distinguish the units in a yellow/red pattern within 30 cm. Therefore, visual acuity contributes to the limited ability of E. onukii to distinguish the visual details of a distant target, which might be perceived as a lump of blurred color of intermediate brightness.
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Affiliation(s)
- Chang Tan
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Xiaoming Cai
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Zongxiu Luo
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Zhaoqun Li
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Chunli Xiu
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Zongmao Chen
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
| | - Lei Bian
- Tea Research Institute, Chinese Academy of Agricultural Science, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, 9 Meiling South Road, Xihu District, Hangzhou 310008, China
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Karbassioon A, Yearlsey J, Dirilgen T, Hodge S, Stout JC, Stanley DA. Responses in honeybee and bumblebee activity to changes in weather conditions. Oecologia 2023; 201:689-701. [PMID: 36790571 PMCID: PMC10038957 DOI: 10.1007/s00442-023-05332-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 02/01/2023] [Indexed: 02/16/2023]
Abstract
Insect pollination, and in particular pollination by bees, is a highly valued ecosystem service that ensures plant reproduction and the production of high-quality crops. Bee activity is known to be influenced by the weather, and as the global climate continues to change, the flying frequency and foraging behaviour of bees may also change. To maximise the benefits of pollination in a changing world, we must first understand how current weather conditions influence the activity of different bee species. This is of particular interest in a country such as Ireland where inclement weather conditions are nominally sub-optimal for foraging. We observed honeybee (Apis mellifera) and buff-tailed bumblebee (Bombus terrestris) activity across a variety of weather conditions at seven apple orchards to determine how four weather variables (temperature, relative humidity, solar radiation, wind) influenced the flight activity of each species. Each orchard contained three honeybee and three bumblebee colonies, and so we were able to observe a colony of each species concurrently in the same weather conditions. Overall, honeybees were more sensitive to changes in weather than bumblebees and could be more predisposed to future changes in within-day weather conditions. Our results indicate bumblebees could compensate for low honeybee activity in inclement conditions, which supports the theory that pollinator diversity provides resilience. This may be particularly important in management of pollinators in crops that flower in the spring when weather is more variable, and to allow varied responses to global climate change.
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Affiliation(s)
- Arrian Karbassioon
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, Ireland.
- UCD Earth Institute, University College Dublin, Dublin, Ireland.
| | - Jon Yearlsey
- UCD Earth Institute, University College Dublin, Dublin, Ireland
- School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
| | - Tara Dirilgen
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, Ireland
- UCD Earth Institute, University College Dublin, Dublin, Ireland
| | - Simon Hodge
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, Ireland
- UCD Earth Institute, University College Dublin, Dublin, Ireland
- School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Jane C Stout
- School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Dara A Stanley
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, Ireland
- UCD Earth Institute, University College Dublin, Dublin, Ireland
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11
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Jonsson T. Micro-CT and deep learning: Modern techniques and applications in insect morphology and neuroscience. FRONTIERS IN INSECT SCIENCE 2023; 3:1016277. [PMID: 38469492 PMCID: PMC10926430 DOI: 10.3389/finsc.2023.1016277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 01/06/2023] [Indexed: 03/13/2024]
Abstract
Advances in modern imaging and computer technologies have led to a steady rise in the use of micro-computed tomography (µCT) in many biological areas. In zoological research, this fast and non-destructive method for producing high-resolution, two- and three-dimensional images is increasingly being used for the functional analysis of the external and internal anatomy of animals. µCT is hereby no longer limited to the analysis of specific biological tissues in a medical or preclinical context but can be combined with a variety of contrast agents to study form and function of all kinds of tissues and species, from mammals and reptiles to fish and microscopic invertebrates. Concurrently, advances in the field of artificial intelligence, especially in deep learning, have revolutionised computer vision and facilitated the automatic, fast and ever more accurate analysis of two- and three-dimensional image datasets. Here, I want to give a brief overview of both micro-computed tomography and deep learning and present their recent applications, especially within the field of insect science. Furthermore, the combination of both approaches to investigate neural tissues and the resulting potential for the analysis of insect sensory systems, from receptor structures via neuronal pathways to the brain, are discussed.
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Affiliation(s)
- Thorin Jonsson
- Institute of Biology, Karl-Franzens-University Graz, Graz, Austria
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12
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Fitzgerald JL, Ogilvie JE, CaraDonna PJ. Ecological Drivers and Consequences of Bumble Bee Body Size Variation. ENVIRONMENTAL ENTOMOLOGY 2022; 51:1055-1068. [PMID: 36373400 DOI: 10.1093/ee/nvac093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Indexed: 06/16/2023]
Abstract
Body size is arguably one of the most important traits influencing the physiology and ecology of animals. Shifts in animal body size have been observed in response to climate change, including in bumble bees (Bombus spp. [Hymenoptera: Apidae]). Bumble bee size shifts have occurred concurrently with the precipitous population declines of several species, which appear to be related, in part, to their size. Body size variation is central to the ecology of bumble bees, from their social organization to the pollination services they provide to plants. If bumble bee size is shifted or constrained, there may be consequences for the pollination services they provide and for our ability to predict their responses to global change. Yet, there are still many aspects of the breadth and role of bumble bee body size variation that require more study. To this end, we review the current evidence of the ecological drivers of size variation in bumble bees and the consequences of that variation on bumble bee fitness, foraging, and species interactions. In total we review: (1) the proximate determinants and physiological consequences of size variation in bumble bees; (2) the environmental drivers and ecological consequences of size variation; and (3) synthesize our understanding of size variation in predicting how bumble bees will respond to future changes in climate and land use. As global change intensifies, a better understanding of the factors influencing the size distributions of bumble bees, and the consequences of those distributions, will allow us to better predict future responses of these pollinators.
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Affiliation(s)
- Jacquelyn L Fitzgerald
- Plant Biology and Conservation, Northwestern University, Evanston, IL 60201, USA
- Chicago Botanic Garden, Negaunee Institute for Plant Conservation Science & Action, Glencoe, IL 60022, USA
- Rocky Mountain Biological Laboratory, Crested Butte, CO 81224, USA
| | - Jane E Ogilvie
- Rocky Mountain Biological Laboratory, Crested Butte, CO 81224, USA
| | - Paul J CaraDonna
- Plant Biology and Conservation, Northwestern University, Evanston, IL 60201, USA
- Chicago Botanic Garden, Negaunee Institute for Plant Conservation Science & Action, Glencoe, IL 60022, USA
- Rocky Mountain Biological Laboratory, Crested Butte, CO 81224, USA
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13
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Chapman KE, Cozma NE, Hodgkinson AB, English R, Gaston KJ, Hempel de Ibarra N. Bumble bees exploit known sources but return with partial pollen loads when foraging under low evening light. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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14
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Bar-Shai N, Motro U, Shmida A, Bloch G. Earlier Morning Arrival to Pollen-Rewarding Flowers May Enable Feral Bumble Bees to Successfully Compete with Local Bee Species and Expand Their Distribution Range in a Mediterranean Habitat. INSECTS 2022; 13:816. [PMID: 36135517 PMCID: PMC9503872 DOI: 10.3390/insects13090816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 08/30/2022] [Accepted: 09/02/2022] [Indexed: 06/16/2023]
Abstract
During recent decades, bumble bees (Bombus terrestris) have continuously expanded their range in the Mediterranean climate regions of Israel. To assess their potential effects on local bee communities, we monitored their diurnal and seasonal activity patterns, as well as those of native bee species in the Judean Hills. We found that all bee species tend to visit pollen-providing flowers at earlier times compared to nectar-providing flowers. Bumble bees and honey bees start foraging at earlier times and colder temperatures compared to other species of bees. This means that the two species of commercially managed social bees are potentially depleting much of the pollen, which is typically non-replenished, before most local species arrive to gather it. Taking into consideration the long activity season of bumble bees in the Judean hills, their ability to forage at the low temperatures of the early morning, and their capacity to collect pollen at early hours in the dry Mediterranean climate, feral and range-expanding bumble bees potentially pose a significant competitive pressure on native bee fauna. Their effects on local bees can further modify pollination networks, and lead to changes in the local flora.
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Affiliation(s)
- Noam Bar-Shai
- Department of Ecology, Evolution and Behavior, The A. Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Jerusalem Botanical Garden, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Uzi Motro
- Department of Ecology, Evolution and Behavior, The A. Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Department of Statistics, The Hebrew University of Jerusalem, Jerusalem 91905, Israel
- The Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Avishai Shmida
- Department of Ecology, Evolution and Behavior, The A. Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Guy Bloch
- Department of Ecology, Evolution and Behavior, The A. Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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15
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Stöckl A, Grittner R, Taylor G, Rau C, Bodey AJ, Kelber A, Baird E. Allometric scaling of a superposition eye optimizes sensitivity and acuity in large and small hawkmoths. Proc Biol Sci 2022; 289:20220758. [PMID: 35892218 PMCID: PMC9326294 DOI: 10.1098/rspb.2022.0758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Animals vary widely in body size within and across species. This has consequences for the function of organs and body parts in both large and small individuals. How these scale, in relation to body size, reveals evolutionary investment strategies, often resulting in trade-offs between functions. Eyes exemplify these trade-offs, as they are limited by their absolute size in two key performance features: sensitivity and spatial acuity. Due to their size polymorphism, insect compound eyes are ideal models for studying the allometric scaling of eye performance. Previous work on apposition compound eyes revealed that allometric scaling led to poorer spatial resolution and visual sensitivity in small individuals, across a range of insect species. Here, we used X-ray microtomography to investigate allometric scaling in superposition compound eyes-the second most common eye type in insects-for the first time. Our results reveal a novel strategy to cope with the trade-off between sensitivity and spatial acuity, as we show that the eyes of the hummingbird hawkmoth retain an optimal balance between these performance measures across all body sizes.
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Affiliation(s)
- Anna Stöckl
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Rebecca Grittner
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Gavin Taylor
- Institute for Globally Distributed Open Research and Education (IGDORE), Ribeirão Preto, Brazil
| | - Christoph Rau
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Andrew J. Bodey
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Almut Kelber
- Department of Biology, Lund University, Lund, Sweden
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm, Sweden
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16
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Guiraud M, Roper M, Wolf S, Woodgate JL, Chittka L. Discrimination of edge orientation by bumblebees. PLoS One 2022; 17:e0263198. [PMID: 35709295 PMCID: PMC9202920 DOI: 10.1371/journal.pone.0263198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 06/01/2022] [Indexed: 11/19/2022] Open
Abstract
Simple feature detectors in the visual system, such as edge-detectors, are likely to underlie even the most complex visual processing, so understanding the limits of these systems is crucial for a fuller understanding of visual processing. We investigated the ability of bumblebees (Bombus terrestris) to discriminate between differently angled edges. In a multiple-choice, “meadow-like” scenario, bumblebees successfully discriminated between angled bars with 7° differences, significantly exceeding the previously reported performance of eastern honeybees (Apis cerana, limit: 15°). Neither the rate at which bees learned, nor their final discrimination performance were affected by the angular orientation of the training bars, indicating a uniform performance across the visual field. Previous work has found that, in dual-choice tests, eastern honeybees cannot reliably discriminate between angles with less than 25° difference, suggesting that performance in discrimination tasks is affected by the training regime, and doesn’t simply reflect the perceptual limitations of the visual system. We used high resolution LCD monitors to investigate bumblebees’ angular resolution in a dual-choice experiment. Bumblebees could still discriminate 7° angle differences under such conditions (exceeding the previously reported limit for Apis mellifera, of 10°, as well as that of A. cerana). Bees eventually reached similar levels of accuracy in the dual-choice experiment as they did under multiple-choice conditions but required longer learning periods. Bumblebees show impressive abilities to discriminate between angled edges, performing better than two previously tested species of honeybee. This high performance may, in turn, support complex visual processing in the bumblebee brain.
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Affiliation(s)
- Marie Guiraud
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
- * E-mail:
| | - Mark Roper
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
- Drone Development Lab, Ben Thorns Ltd, Colchester, United Kingdom
| | - Stephan Wolf
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Joseph L. Woodgate
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Lars Chittka
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
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17
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High-speed imaging of light-induced photoreceptor microsaccades in compound eyes. Commun Biol 2022; 5:203. [PMID: 35241794 PMCID: PMC8894348 DOI: 10.1038/s42003-022-03142-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 02/09/2022] [Indexed: 11/09/2022] Open
Abstract
Inside compound eyes, photoreceptors contract to light changes, sharpening retinal images of the moving world in time. Current methods to measure these so-called photoreceptor microsaccades in living insects are spatially limited and technically challenging. Here, we present goniometric high-speed deep pseudopupil (GHS-DPP) microscopy to assess how the rhabdomeric insect photoreceptors and their microsaccades are organised across the compound eyes. This method enables non-invasive rhabdomere orientation mapping, whilst their microsaccades can be locally light-activated, revealing the eyes' underlying active sampling motifs. By comparing the microsaccades in wild-type Drosophila's open rhabdom eyes to spam-mutant eyes, reverted to an ancestral fused rhabdom state, and honeybee's fused rhabdom eyes, we show how different eye types sample light information. These results show different ways compound eyes initiate the conversion of spatial light patterns in the environment into temporal neural signals and highlight how this active sampling can evolve with insects' visual needs.
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18
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Ravi S, Siesenop T, Bertrand OJ, Li L, Doussot C, Fisher A, Warren WH, Egelhaaf M. Bumblebees display characteristics of active vision during robust obstacle avoidance flight. J Exp Biol 2022; 225:274096. [PMID: 35067721 PMCID: PMC8920035 DOI: 10.1242/jeb.243021] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 01/18/2022] [Indexed: 11/20/2022]
Abstract
Insects are remarkable flyers and capable of navigating through highly cluttered environments. We tracked the head and thorax of bumblebees freely flying in a tunnel containing vertically oriented obstacles to uncover the sensorimotor strategies used for obstacle detection and collision avoidance. Bumblebees presented all the characteristics of active vision during flight by stabilizing their head relative to the external environment and maintained close alignment between their gaze and flightpath. Head stabilization increased motion contrast of nearby features against the background to enable obstacle detection. As bees approached obstacles, they appeared to modulate avoidance responses based on the relative retinal expansion velocity (RREV) of obstacles and their maximum evasion acceleration was linearly related to RREVmax. Finally, bees prevented collisions through rapid roll manoeuvres implemented by their thorax. Overall, the combination of visuo-motor strategies of bumblebees highlights elegant solutions developed by insects for visually guided flight through cluttered environments.
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Affiliation(s)
- Sridhar Ravi
- Department of Neurobiology and Center of Excellence Cognitive Interaction Technology (CITEC), Bielefeld University, 33619 Bielefeld, Germany,School of Engineering and Information Technology, University of New South Wales, Canberra, ACT 2600, Australia,Author for correspondence ()
| | - Tim Siesenop
- Department of Neurobiology and Center of Excellence Cognitive Interaction Technology (CITEC), Bielefeld University, 33619 Bielefeld, Germany
| | - Olivier J. Bertrand
- Department of Neurobiology and Center of Excellence Cognitive Interaction Technology (CITEC), Bielefeld University, 33619 Bielefeld, Germany
| | - Liang Li
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, University of Konstanz, 78464 Konstanz, Germany,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464 Konstanz, Germany,Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Charlotte Doussot
- Department of Neurobiology and Center of Excellence Cognitive Interaction Technology (CITEC), Bielefeld University, 33619 Bielefeld, Germany
| | - Alex Fisher
- School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
| | - William H. Warren
- Department of Cognitive, Linguistic & Psychological Sciences, Brown University, Providence, RI 02912, USA
| | - Martin Egelhaaf
- Department of Neurobiology and Center of Excellence Cognitive Interaction Technology (CITEC), Bielefeld University, 33619 Bielefeld, Germany
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19
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Tichit P, Zhou T, Kjer HM, Dahl VA, Dahl AB, Baird E. InSegtCone: interactive segmentation of crystalline cones in compound eyes. BMC ZOOL 2022; 7:10. [PMID: 37170292 PMCID: PMC10127308 DOI: 10.1186/s40850-021-00101-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 12/14/2021] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Understanding the diversity of eyes is crucial to unravel how different animals use vision to interact with their respective environments. To date, comparative studies of eye anatomy are scarce because they often involve time-consuming or inefficient methods. X-ray micro-tomography (micro-CT) is a promising high-throughput imaging technique that enables to reconstruct the 3D anatomy of eyes, but powerful tools are needed to perform fast conversions of anatomical reconstructions into functional eye models.
Results
We developed a computing method named InSegtCone to automatically segment the crystalline cones in the apposition compound eyes of arthropods. Here, we describe the full auto-segmentation process, showcase its application to three different insect compound eyes and evaluate its performance. The auto-segmentation could successfully label the full individual shapes of 60-80% of the crystalline cones and is about as accurate and 250 times faster than manual labelling of the individual cones.
Conclusions
We believe that InSegtCone can be an important tool for peer scientists to measure the orientation, size and dynamics of crystalline cones, leading to the accurate optical modelling of the diversity of arthropod eyes with micro-CT.
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20
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Perl CD, Johansen ZB, Moradinour Z, Guiraud M, Restrepo CE, Wen Jie V, Miettinen A, Baird E. Heatwave-Like Events During Development Are Sufficient to Impair Bumblebee Worker Responses to Sensory Stimuli. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2021.776830] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Heatwaves are increasingly common globally and are known to have detrimental impacts on animal morphology and behaviour. These impacts can be severe, especially if heatwaves occur during development, even on animals that can regulate the temperature of their developing young. The onset and duration of heatwaves are stochastic and therefore may affect all or only part of development. In the heterothermic bumblebee Bombus terrestris, elevated temperatures over the entirety of development cause morphological changes in adults, despite their capability to regulate brood temperature. However, the effects of heatwaves that occur during a short period of development are unclear. We test the impact of elevated developmental temperature during the latter fraction of development on the behaviour and morphology of adult worker B. terrestris. We show that exposure to elevated temperature over a portion of late development is sufficient to impair the initial behavioural responses of workers to various sensory stimuli. Despite this, exposure to elevated temperatures during a period of development did not have any significant impact on body or organ size. The negative effect of elevated developmental temperatures was independent of the exposure time, which lasted from 11–20 days at the end of the workers’ developmental period. Thus, heat stress in bumblebees can manifest without morphological indicators and impair critical behavioural responses to relevant sensory stimuli, even if only present for a short period of time at the end of development. This has important implications for our understanding of deleterious climactic events and how we measure indicators of stress in pollinators.
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21
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Perl CD, Johansen ZB, Jie VW, Moradinour Z, Guiraud M, Restrepo CE, Miettinen A, Baird E. Substantial variability in morphological scaling among bumblebee colonies. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211436. [PMID: 35242346 PMCID: PMC8753140 DOI: 10.1098/rsos.211436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Differences in organ scaling among individuals may play an important role in determining behavioural variation. In social insects, there are well-documented intraspecific differences in colony behaviour, but the extent that organ scaling differs within and between colonies remains unclear. Using 12 different colonies of the bumblebee Bombus terrestris, we aim to address this knowledge gap by measuring the scaling relationships between three different organs (compound eyes, wings and antennae) and body size in workers. Though colonies were exposed to different rearing temperatures, this environmental variability did not explain the differences of the scaling relationships. Two colonies had differences in wing versus antenna slopes, three colonies showed differences in wing versus eye slopes and a single colony has differences between eye versus antenna slopes. There are also differences in antennae scaling slopes between three different colonies, and we present evidence for putative trade-offs in morphological investment. We discuss the utility of having variable scaling among colonies and the implication for understanding variability in colony fitness and behaviour.
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Affiliation(s)
- C. D. Perl
- Department of Zoology, Stockholm University, Stockholm 106 91, Sweden
- Department of Biology, Lund University, Lund 223 62, Sweden
| | - Z. B. Johansen
- Department of Zoology, Stockholm University, Stockholm 106 91, Sweden
| | - V. W. Jie
- Department of Zoology, Stockholm University, Stockholm 106 91, Sweden
| | - Z. Moradinour
- Department of Zoology, Stockholm University, Stockholm 106 91, Sweden
| | - M. Guiraud
- Department of Zoology, Stockholm University, Stockholm 106 91, Sweden
| | - C. E. Restrepo
- Department of Zoology, Stockholm University, Stockholm 106 91, Sweden
| | - A. Miettinen
- Swiss Light Source, Paul Scherrer Institute, 5234 Villigen, Switzerland
- Institute for Biomedical Engineering, University and ETH Zurich, 8092 Zurich, Switzerland
| | - E. Baird
- Department of Zoology, Stockholm University, Stockholm 106 91, Sweden
- Department of Biology, Lund University, Lund 223 62, Sweden
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22
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Grittner R, Baird E, Stöckl A. Spatial tuning of translational optic flow responses in hawkmoths of varying body size. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:279-296. [PMID: 34893928 PMCID: PMC8934765 DOI: 10.1007/s00359-021-01530-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 11/12/2022]
Abstract
To safely navigate their environment, flying insects rely on visual cues, such as optic flow. Which cues insects can extract from their environment depends closely on the spatial and temporal response properties of their visual system. These in turn can vary between individuals that differ in body size. How optic flow-based flight control depends on the spatial structure of visual cues, and how this relationship scales with body size, has previously been investigated in insects with apposition compound eyes. Here, we characterised the visual flight control response limits and their relationship to body size in an insect with superposition compound eyes: the hummingbird hawkmoth Macroglossum stellatarum. We used the hawkmoths’ centring response in a flight tunnel as a readout for their reception of translational optic flow stimuli of different spatial frequencies. We show that their responses cut off at different spatial frequencies when translational optic flow was presented on either one, or both tunnel walls. Combined with differences in flight speed, this suggests that their flight control was primarily limited by their temporal rather than spatial resolution. We also observed strong individual differences in flight performance, but no correlation between the spatial response cutoffs and body or eye size.
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Affiliation(s)
- Rebecca Grittner
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Anna Stöckl
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Würzburg, Germany.
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23
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Langridge KV, Wilke C, Riabinina O, Vorobyev M, Hempel de Ibarra N. Approach Direction Prior to Landing Explains Patterns of Colour Learning in Bees. Front Physiol 2021; 12:697886. [PMID: 34955870 PMCID: PMC8692860 DOI: 10.3389/fphys.2021.697886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 11/02/2021] [Indexed: 11/18/2022] Open
Abstract
Gaze direction is closely coupled with body movement in insects and other animals. If movement patterns interfere with the acquisition of visual information, insects can actively adjust them to seek relevant cues. Alternatively, where multiple visual cues are available, an insect's movements may influence how it perceives a scene. We show that the way a foraging bumblebee approaches a floral pattern could determine what it learns about the pattern. When trained to vertical bicoloured patterns, bumblebees consistently approached from below centre in order to land in the centre of the target where the reward was located. In subsequent tests, the bees preferred the colour of the lower half of the pattern that they predominantly faced during the approach and landing sequence. A predicted change of learning outcomes occurred when the contrast line was moved up or down off-centre: learned preferences again reflected relative frontal exposure to each colour during the approach, independent of the overall ratio of colours. This mechanism may underpin learning strategies in both simple and complex visual discriminations, highlighting that morphology and action patterns determines how animals solve sensory learning tasks. The deterministic effect of movement on visual learning may have substantially influenced the evolution of floral signals, particularly where plants depend on fine-scaled movements of pollinators on flowers.
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Affiliation(s)
- Keri V. Langridge
- Department of Psychology, Centre for Research in Animal Behaviour, University of Exeter, Exeter, United Kingdom
| | - Claudia Wilke
- Department of Psychology, Centre for Research in Animal Behaviour, University of Exeter, Exeter, United Kingdom
- Department of Psychology, University of York, York, United Kingdom
| | - Olena Riabinina
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Misha Vorobyev
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Natalie Hempel de Ibarra
- Department of Psychology, Centre for Research in Animal Behaviour, University of Exeter, Exeter, United Kingdom
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24
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Moradinour Z, Wiklund C, Jie VW, Restrepo CE, Gotthard K, Miettinen A, Perl CD, Baird E. Sensory Organ Investment Varies with Body Size and Sex in the Butterfly Pieris napi. INSECTS 2021; 12:insects12121064. [PMID: 34940152 PMCID: PMC8707955 DOI: 10.3390/insects12121064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 11/16/2022]
Abstract
In solitary insect pollinators such as butterflies, sensory systems must be adapted for multiple tasks, including nectar foraging, mate-finding, and locating host-plants. As a result, the energetic investments between sensory organs can vary at the intraspecific level and even among sexes. To date, little is known about how these investments are distributed between sensory systems and how it varies among individuals of different sex. We performed a comprehensive allometric study on males and females of the butterfly Pieris napi where we measured the sizes and other parameters of sensory traits including eyes, antennae, proboscis, and wings. Our findings show that among all the sensory traits measured, only antenna and wing size have an allometric relationship with body size and that the energetic investment in different sensory systems varies between males and females. Moreover, males had absolutely larger antennae and eyes, indicating that they invest more energy in these organs than females of the same body size. Overall, the findings of this study reveal that the size of sensory traits in P. napi are not necessarily related to body size and raises questions about other factors that drive sensory trait investment in this species and in other insect pollinators in general.
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Affiliation(s)
- Zahra Moradinour
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
- Correspondence:
| | - Christer Wiklund
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Vun Wen Jie
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Carlos E. Restrepo
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Karl Gotthard
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
| | - Arttu Miettinen
- Swiss Light Source, Paul Scherrer Institute, 5234 Villigen, Switzerland;
- Department of Physics, University of Jyvaskyla, 40014 Jyvaskyla, Finland
| | - Craig D. Perl
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
- Department of Biology, Lund University, 223 62 Lund, Sweden
- School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Emily Baird
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden; (C.W.); (V.W.J.); (C.E.R.); (K.G.); (C.D.P.); (E.B.)
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25
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Jezeera MA, Tichit P, Balamurali GS, Baird E, Kelber A, Somanathan H. Spatial resolution and sensitivity of the eyes of the stingless bee, Tetragonula iridipennis. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:225-238. [PMID: 34738166 DOI: 10.1007/s00359-021-01521-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 11/28/2022]
Abstract
Stingless bees are important pollinators in the tropics. The tremendous variation in body size makes them an excellent group to study how miniaturization affects vision and visual behaviours. Using direct measurements and micro-CT, we reconstructed the eye structure, estimated anatomical spatial resolution and optical sensitivity of the stingless bee Tetragonula iridipennis. T. iridipennis is similar in size to the Australian stingless bee Tetragonula carbonaria and is smaller than honeybees. It has correspondingly small eyes (area = 0.56 mm2), few ommatidia (2451 ± 127), large inter-facet (3.0 ± 0.6°) and acceptance angles (2.8°). Theoretical estimates suggest that T. iridipennis has poorer spatial resolution (0.17 cycles degree-1) than honeybees, bumblebees, and T. carbonaria. Its optical sensitivity (0.08 µm2 sr), though higher than expected, is within the range of diurnal bees. This may provide them with greater contrast sensitivity, which is likely more relevant than the absolute sensitivity in this diurnal bee. Behaviourally determined detection thresholds for single targets using y-maze experiments were 11.5° for targets that provide chromatic contrast alone and 9.1° for targets providing chromatic and achromatic contrast. Further studies into microhabitat preferences and behaviour are required to understand how miniaturization influences its visual ecology.
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Affiliation(s)
- M Asmi Jezeera
- IISER TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India.
| | - Pierre Tichit
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden.,Department of Zoology, Stockholm University, Stockholm, Sweden
| | - G S Balamurali
- IISER TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Almut Kelber
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Hema Somanathan
- IISER TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
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26
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Rigosi E, Warrant EJ, O’Carroll DC. A new, fluorescence-based method for visualizing the pseudopupil and assessing optical acuity in the dark compound eyes of honeybees and other insects. Sci Rep 2021; 11:21267. [PMID: 34711871 PMCID: PMC8553845 DOI: 10.1038/s41598-021-00407-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/11/2021] [Indexed: 11/24/2022] Open
Abstract
Recent interest in applying novel imaging techniques to infer optical resolution in compound eyes underscores the difficulty of obtaining direct measures of acuity. A widely used technique exploits the principal pseudopupil, a dark spot on the eye surface representing the ommatidial gaze direction and the number of detector units (ommatidia) viewing that gaze direction. However, dark-pigmented eyes, like those of honeybees, lack a visible pseudopupil. Attempts over almost a century to estimate optical acuity in this species are still debated. Here, we developed a method to visualize a stable, reliable pseudopupil by staining the photoreceptors with fluorescent dyes. We validated this method in several species and found it to outperform the dark pseudopupil for this purpose, even in pale eyes, allowing more precise location of the gaze centre. We then applied this method to estimate the sampling resolution in the frontal part of the eye of the honeybee forager. We found a broad frontal acute zone with interommatidial angles below 2° and a minimum interommatidial angle of 1.3°, a broader, sharper frontal acute zone than previously reported. Our study provides a new method to directly measure the sampling resolution in most compound eyes of living animals.
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Affiliation(s)
- Elisa Rigosi
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - Eric J. Warrant
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - David C. O’Carroll
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
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27
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Muth F. Intra-specific differences in cognition: bumblebee queens learn better than workers. Biol Lett 2021; 17:20210280. [PMID: 34376073 DOI: 10.1098/rsbl.2021.0280] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Species' cognitive traits are shaped by their ecology, and even within a species, cognition can reflect the behavioural requirements of individuals with different roles. Social insects have a number of discrete roles (castes) within a colony and thus offer a useful system to determine how ecological requirements shape cognition. Bumblebee queens are a critical point in the lifecycle of their colony, since its future success is reliant on a single individual's ability to learn about floral stimuli while finding a suitable nest site; thus, one might expect particularly adept learning capabilities at this stage. I compared wild Bombus vosnesenskii queens and workers on their ability to learn a colour association and found that queens performed better than workers. In addition, queens of another species, B. insularis, a cuckoo species with a different lifecycle but similar requirements at this stage, performed equally well as the non-parasitic queens. To control for differences in foraging experience, I then repeated this comparison with laboratory-based B. impatiens and found that unmated queens performed better than workers. These results add to the body of work on how ecology shapes cognition and opens the door to further research in comparative cognition using wild bees.
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Affiliation(s)
- Felicity Muth
- Departmnet of Integrative Biology, University of Texas at Austin, TX, USA
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28
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Stankiewicz J, Webb B. Looking down: a model for visual route following in flying insects. BIOINSPIRATION & BIOMIMETICS 2021; 16:055007. [PMID: 34243169 DOI: 10.1088/1748-3190/ac1307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/09/2021] [Indexed: 06/13/2023]
Abstract
Insect visual navigation is often assumed to depend on panoramic views of the horizon, and how these change as the animal moves. However, it is known that honey bees can visually navigate in flat, open meadows where visual information at the horizon is minimal, or would remain relatively constant across a wide range of positions. In this paper we hypothesise that these animals can navigate using view memories of the ground. We find that in natural scenes, low resolution views from an aerial perspective of ostensibly self-similar terrain (e.g. within a field of grass) provide surprisingly robust descriptors of precise spatial locations. We propose a new visual route following approach that makes use of transverse oscillations to centre a flight path along a sequence of learned views of the ground. We deploy this model on an autonomous quadcopter and demonstrate that it provides robust performance in the real world on journeys of up to 30 m. The success of our method is contingent on a robust view matching process which can evaluate the familiarity of a view with a degree of translational invariance. We show that a previously developed wavelet based bandpass orientated filter approach fits these requirements well, exhibiting double the catchment area of standard approaches. Using a realistic simulation package, we evaluate the robustness of our approach to variations in heading direction and aircraft height between inbound and outbound journeys. We also demonstrate that our approach can operate using a vision system with a biologically relevant visual acuity and viewing direction.
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Affiliation(s)
- J Stankiewicz
- School of Informatics, University of Edinburgh, 10 Crichton Street, Edinburgh EH8 9AB, United Kingdom
| | - B Webb
- School of Informatics, University of Edinburgh, 10 Crichton Street, Edinburgh EH8 9AB, United Kingdom
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29
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Abstract
Most animals have at least some binocular overlap, i.e., a region of space that is viewed by both eyes. This reduces the overall visual field and raises the problem of combining two views of the world, seen from different vantage points, into a coherent whole. However, binocular vision also offers many potential advantages, including increased ability to see around obstacles and increased contrast sensitivity. One particularly interesting use for binocular vision is comparing information from both eyes to derive information about depth. There are many different ways in which this might be done, but in this review, I refer to them all under the general heading of stereopsis. This review examines the different possible uses of binocular vision and stereopsis and compares what is currently known about the neural basis of stereopsis in different taxa. Studying different animals helps us break free of preconceptions stemming from the way that stereopsis operates in human vision and provides new insights into the different possible forms of stereopsis. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Jenny C A Read
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom;
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30
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Khaldy L, Tocco C, Byrne M, Dacke M. Compass Cue Integration and Its Relation to the Visual Ecology of Three Tribes of Ball-Rolling Dung Beetles. INSECTS 2021; 12:insects12060526. [PMID: 34204081 PMCID: PMC8229028 DOI: 10.3390/insects12060526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 06/01/2021] [Accepted: 06/03/2021] [Indexed: 11/16/2022]
Abstract
To guide their characteristic straight-line orientation away from the dung pile, ball-rolling dung beetles steer according to directional information provided by celestial cues, which, among the most relevant are the sun and polarised skylight. Most studies regarding the use of celestial cues and their influence on the orientation system of the diurnal ball-rolling beetle have been performed on beetles of the tribe Scarabaeini living in open habitats. These beetles steer primarily according to the directional information provided by the sun. In contrast, Sisyphus fasciculatus, a species from a different dung-beetle tribe (the Sisyphini) that lives in habitats with closely spaced trees and tall grass, relies predominantly on directional information from the celestial pattern of polarised light. To investigate the influence of visual ecology on the relative weight of these cues, we studied the orientation strategy of three different tribes of dung beetles (Scarabaeini, Sisyphini and Gymnopleurini) living within the same biome, but in different habitat types. We found that species within a tribe share the same orientation strategy, but that this strategy differs across the tribes; Scarabaeini, living in open habitats, attribute the greatest relative weight to the directional information from the sun; Sisyphini, living in closed habitats, mainly relies on directional information from polarised skylight; and Gymnopleurini, also living in open habitats, appear to weight both cues equally. We conclude that, despite exhibiting different body size, eye size and morphology, dung beetles nevertheless manage to solve the challenge of straight-line orientation by weighting visual cues that are particular to the habitat in which they are found. This system is however dynamic, allowing them to operate equally well even in the absence of the cue given the greatest relative weight by the particular species.
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Affiliation(s)
- Lana Khaldy
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 223 62 Lund, Sweden; (C.T.); (M.D.)
- Correspondence:
| | - Claudia Tocco
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 223 62 Lund, Sweden; (C.T.); (M.D.)
- School of Animal, Plant and Environmental Sciences, University of the Witswatersrand, 1 Jan Smuts Avenue, Braamfontein, Johannesburg 2000, South Africa;
| | - Marcus Byrne
- School of Animal, Plant and Environmental Sciences, University of the Witswatersrand, 1 Jan Smuts Avenue, Braamfontein, Johannesburg 2000, South Africa;
| | - Marie Dacke
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 223 62 Lund, Sweden; (C.T.); (M.D.)
- School of Animal, Plant and Environmental Sciences, University of the Witswatersrand, 1 Jan Smuts Avenue, Braamfontein, Johannesburg 2000, South Africa;
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31
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Hall K, Robert T, Gaston KJ, Hempel de Ibarra N. Onset of morning activity in bumblebee foragers under natural low light conditions. Ecol Evol 2021; 11:6536-6545. [PMID: 34141238 PMCID: PMC8207423 DOI: 10.1002/ece3.7506] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 03/04/2021] [Accepted: 03/08/2021] [Indexed: 11/24/2022] Open
Abstract
Foraging on flowers in low light at dusk and dawn comes at an additional cost for insect pollinators with diurnal vision. Nevertheless, some species are known to be frequently active at these times. To explore how early and under which light levels colonies of bumblebees, Bombus terrestris, initiate their foraging activity, we tracked foragers of different body sizes using RFID over 5 consecutive days during warm periods of the flowering season. Bees that left the colony at lower light levels and earlier in the day were larger in size. This result extends the evidence for alloethism in bumblebees and shows that foragers differ in their task specialization depending on body size. By leaving the colony earlier to find and exploit flowers in low light, larger-sized foragers are aided by their more sensitive eyes and can effectively increase their contributions to the colony's food influx. The decision to leave the colony early seems to be further facilitated by knowledge about profitable food resources in specific locations. We observed that experience accrued over many foraging flights determined whether a bee started foraging under lower light levels and earlier in the morning. Larger-sized bees were not more experienced than smaller-sized bees, confirming earlier observations of wide size ranges among active foragers. Overall, we found that most foragers left at higher light levels when they could see well and fly faster. Nevertheless, a small proportion of foragers left the colony shortly after the onset of dawn when light levels were below 10 lux. Our observations suggest that bumblebee colonies have the potential to balance the benefits of deploying large-sized or experienced foragers during dawn against the risks and costs of foraging under low light by regulating the onset of their activity at different stages of the colony's life cycle and in changing environmental conditions.
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Affiliation(s)
- Katie Hall
- Centre for Research in Animal Behaviour, PsychologyUniversity of ExeterExeterUK
| | - Théo Robert
- Centre for Research in Animal Behaviour, PsychologyUniversity of ExeterExeterUK
- Present address:
Centre for Behaviour and Evolution, Biosciences InstituteNewcastle UniversityNewcastle upon TyneUK
| | - Kevin J. Gaston
- Environment and Sustainability InstituteUniversity of ExeterPenrynUK
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32
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Romell J, Jie VW, Miettinen A, Baird E, Hertz HM. Laboratory phase-contrast nanotomography of unstained Bombus terrestris compound eyes. J Microsc 2021; 283:29-40. [PMID: 33822371 DOI: 10.1111/jmi.13005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/21/2021] [Indexed: 11/30/2022]
Abstract
Imaging the visual systems of bumblebees and other pollinating insects may increase understanding of their dependence on specific habitats and how they will be affected by climate change. Current high-resolution imaging methods are either limited to two dimensions (light- and electron microscopy) or have limited access (synchrotron radiation x-ray tomography). For x-ray imaging, heavy metal stains are often used to increase contrast. Here, we present micron-resolution imaging of compound eyes of buff-tailed bumblebees (Bombus terrestris) using a table-top x-ray nanotomography (nano-CT) system. By propagation-based phase-contrast imaging, the use of stains was avoided and the microanatomy could more accurately be reconstructed than in samples stained with phosphotungstic acid or osmium tetroxide. The findings in the nano-CT images of the compound eye were confirmed by comparisons with light- and transmission electron microscopy of the same sample and finally, comparisons to synchrotron radiation tomography as well as to a commercial micro-CT system were done.
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Affiliation(s)
- Jenny Romell
- Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Vun Wen Jie
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Arttu Miettinen
- Institute for Biomedical Engineering, Zurich University and ETH Zurich, Zurich, Switzerland.,Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland.,Arttu Miettinen, Department of Physics, University of Jyvaskyla, Jyvaskyla, Finland
| | - Emily Baird
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Hans M Hertz
- Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden
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33
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Duncan AB, Salazar BA, Garcia SR, Brandley NC. A Sexual Dimorphism in the Spatial Vision of North American Band-Winged Grasshoppers. Integr Org Biol 2021; 3:obab008. [PMID: 34396041 PMCID: PMC8358991 DOI: 10.1093/iob/obab008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Visual acuity (VA)-a measurement of the fineness or coarseness of vision-may vary within a species including between the biological sexes. Although numerous studies have found males with finer VA than females, relatively few have shown the opposite with females having finer vision. This is surprising because our understanding of between species differences in VA suggests that females may have finer vision than males if they 1) are larger than males, or 2) need finer vision to detect and/or discriminate between males. Here, we estimate the interommatidial angle (ΔΦ, an anatomical measurement of VA) in three species of band-winged grasshoppers in which females are both the larger sex and likely interpret visual signals (Arphia pseudonietana, Dissosteira carolina, and Spharagemon equale; total n = 98). Using a radius of curvature estimation method, we find that females have ∼19% finer estimated ΔΦ than males in the most acute region and axis of the eye, but that this dimorphism varies between species. Further visual explorations of the species showing the greatest body size dimorphism (D. carolina) suggest that this ΔΦ dimorphism is driven by females having larger eyes with more ommatidia. In contrast to many diurnal flying insects where males have finer vision to acquire mates, our study is one of the first to demonstrate a female-biased sexual dimorphism in acuity. Given 1) the number of species in which females are larger than males, and 2) the variability of mating behaviors across taxa, our results suggest that differences in VA between the sexes may be more common than currently appreciated. Resumen La agudeza visual (AV)-una medida de la finura o la dificultad visual-puede variar dentro de una especie, incluso entre los sexos biológicos. Aunque numerosos estudios han encontrado machos con una AV más fina que las hembras, relativamente pocos han demostrado lo contrario, hembras con visión más fina. Esto es sorprendente porque nuestra comprensión de diferencias entre especies en AV sugiere que las hembras pueden tener una visión más fina que los machos si 1) son más grandes que los machos, o 2) necesitan una visión más fina para detectar y/o discriminar entre los machos. Aquí, estimamos el ángulo interommatidial (ΔΦ, una medida anatómica de AV) en tres especies de saltamontes de ala de banda en las que las hembras son el sexo más grande y probablemente interpretan señales visuales (Arphia pseudonietana, Dissosteira carolina, y Spharagemon equale; total n = 98). Usando un método de estimación de radio de curvatura, encontramos que las hembras tienen un estimado ΔΦ ∼19% más fino que los machos en la región y eje más agudos del ojo, pero que este dimorfismo varía entre especies. Exploraciones visuales adicionales de la especie que muestra el mayor dimorfismo del tamaño corporal (D. carolina) sugieren que este dimorfismo de ΔΦ debe a que las hembras tienen ojos más grandes con más omatidios. En contraste con muchos insectos voladores diurnos donde los machos tienen una visión más fina para adquirir parejas, nuestro estudio es uno de los primeros en demostrar un dimorfismo sesgado por las hembras en la agudeza. Dado 1) el número de especies en las que las hembras son más grandes que los machos, y 2) la variabilidad de los comportamientos de apareamiento entre taxones, nuestros resultados sugieren que las diferencies de AV entre los sexos pueden ser más comunes de lo que se aprecia actualmente.
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Affiliation(s)
- A B Duncan
- Department of Organismal Biology and Ecology, Colorado College, 14 E, W Cache La Poudre Street, Colorado Springs, CO 80903, USA
| | - B A Salazar
- Department of Organismal Biology and Ecology, Colorado College, 14 E, W Cache La Poudre Street, Colorado Springs, CO 80903, USA
| | - S R Garcia
- Department of Biology, College of Wooster, 1189 Beall Avenue, Wooster, OH 44691, USA
| | - N C Brandley
- Department of Organismal Biology and Ecology, Colorado College, 14 E, W Cache La Poudre Street, Colorado Springs, CO 80903, USA.,Department of Biology, College of Wooster, 1189 Beall Avenue, Wooster, OH 44691, USA
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34
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Frasnelli E, Robert T, Chow PKY, Scales B, Gibson S, Manning N, Philippides AO, Collett TS, Hempel de Ibarra N. Small and Large Bumblebees Invest Differently when Learning about Flowers. Curr Biol 2020; 31:1058-1064.e3. [PMID: 33373638 DOI: 10.1016/j.cub.2020.11.062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/10/2020] [Accepted: 11/24/2020] [Indexed: 01/23/2023]
Abstract
Honeybees1 and bumblebees2 perform learning flights when leaving a newly discovered flower. During these flights, bees spend a portion of the time turning back to face the flower when they can memorize views of the flower and its surroundings. In honeybees, learning flights become longer when the reward offered by a flower is increased.3 We show here that bumblebees behave in a similar way, and we add that bumblebees face an artificial flower more when the concentration of the sucrose solution that the flower provides is higher. The surprising finding is that a bee's size determines what a bumblebee regards as a "low" or "high" concentration and so affects its learning behavior. The larger bees in a sample of foragers only enhance their flower facing when the sucrose concentration is in the upper range of the flowers that are naturally available to bees.4 In contrast, smaller bees invest the same effort in facing flowers whether the concentration is high or low, but their effort is less than that of larger bees. The way in which different-sized bees distribute their effort when learning about flowers parallels the foraging behavior of a colony. Large bumblebees5,6 are able to carry larger loads and explore further from the nest than smaller ones.7 Small ones with a smaller flight range and carrying capacity cannot afford to be as selective and so accept a wider range of flowers. VIDEO ABSTRACT.
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Affiliation(s)
- Elisa Frasnelli
- Centre for Research in Animal Behaviour, Psychology, Washington Singer Laboratories, University of Exeter, Perry Road, Exeter EX1 4QG, UK
| | - Théo Robert
- Centre for Research in Animal Behaviour, Psychology, Washington Singer Laboratories, University of Exeter, Perry Road, Exeter EX1 4QG, UK
| | - Pizza Ka Yee Chow
- Centre for Research in Animal Behaviour, Psychology, Washington Singer Laboratories, University of Exeter, Perry Road, Exeter EX1 4QG, UK
| | - Ben Scales
- Centre for Research in Animal Behaviour, Psychology, Washington Singer Laboratories, University of Exeter, Perry Road, Exeter EX1 4QG, UK
| | - Sam Gibson
- Centre for Research in Animal Behaviour, Psychology, Washington Singer Laboratories, University of Exeter, Perry Road, Exeter EX1 4QG, UK
| | - Nicola Manning
- Centre for Research in Animal Behaviour, Psychology, Washington Singer Laboratories, University of Exeter, Perry Road, Exeter EX1 4QG, UK
| | - Andrew O Philippides
- School of Engineering and Informatics, University of Sussex, Chichester Building, Falmer, Brighton BN1 9QJ, UK
| | - Thomas S Collett
- School of Life Sciences, University of Sussex, John Maynard Smith Building, Falmer, Brighton BN1 9QG, UK.
| | - Natalie Hempel de Ibarra
- Centre for Research in Animal Behaviour, Psychology, Washington Singer Laboratories, University of Exeter, Perry Road, Exeter EX1 4QG, UK.
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35
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Baird E, Tichit P, Guiraud M. The neuroecology of bee flight behaviours. CURRENT OPINION IN INSECT SCIENCE 2020; 42:8-13. [PMID: 32818691 DOI: 10.1016/j.cois.2020.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
By combining functional, ecological and evolutionary perspectives, neuroecology can provide key insights into understanding how behaviour and the underlying sensory and neural processes are shaped by ecology and evolutionary history. Bees are an ideal system for neuroecological studies because they represent a numerous and diverse insect group that inhabit a broad range of environments. Flight is central to the evolutionary success of bees and is the key to their survival and fitness but this review of recent work on fundamental flight behaviours in different species - landing, collision avoidance and speed control - reveals striking differences. We discuss the potential ecological and evolutionary drivers behind this variation but argue that to understand their adaptive value future work should include multidisciplinary approaches that integrate neuroscience, ecology, phylogeny and behaviour.
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Affiliation(s)
- Emily Baird
- Department of Zoology, Stockholm University, Sweden; Department of Biology, Lund University, Sweden.
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36
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Tichit P, Alves-Dos-Santos I, Dacke M, Baird E. Accelerated landings in stingless bees are triggered by visual threshold cues. Biol Lett 2020; 16:20200437. [PMID: 32842893 DOI: 10.1098/rsbl.2020.0437] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Most flying animals rely primarily on visual cues to coordinate and control their trajectory when landing. Studies of visually guided landing typically involve animals that decrease their speed before touchdown. Here, we investigate the control strategy of the stingless bee Scaptotrigona depilis, which instead accelerates when landing on its narrow hive entrance. By presenting artificial targets that resemble the entrance at different locations on the hive, we show that these accelerated landings are triggered by visual cues. We also found that S. depilis initiated landing and extended their legs when the angular size of the target reached a given threshold. Regardless of target size, the magnitude of acceleration was the same and the bees aimed for the same relative position on the target suggesting that S. depilis use a computationally simple but elegant 'stereotyped' landing strategy that requires few visual cues.
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Affiliation(s)
- Pierre Tichit
- Department of Biology, Lund University, Lund 223 62, Sweden
| | | | - Marie Dacke
- Department of Biology, Lund University, Lund 223 62, Sweden
| | - Emily Baird
- Department of Biology, Lund University, Lund 223 62, Sweden.,Department of Zoology, Stockholm University, Stockholm 106 91, Sweden
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37
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Arganda S, Hoadley AP, Razdan ES, Muratore IB, Traniello JFA. The neuroplasticity of division of labor: worker polymorphism, compound eye structure and brain organization in the leafcutter ant Atta cephalotes. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:651-662. [PMID: 32506318 DOI: 10.1007/s00359-020-01423-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/23/2020] [Accepted: 05/14/2020] [Indexed: 12/24/2022]
Abstract
Our understanding of how sensory structure design is coupled with neural processing capacity to adaptively support division of labor is limited. Workers of the remarkably polymorphic fungus-growing ant Atta cephalotes are behaviorally specialized by size: the smallest workers (minims) tend fungi in dark subterranean chambers while larger workers perform tasks outside the nest. Strong differences in worksite light conditions are predicted to influence sensory and processing requirements for vision. Analyzing confocal scans of worker eyes and brains, we found that eye structure and visual neuropils appear to have been selected to maximize task performance according to light availability. Minim eyes had few ommatidia, large interommatidial angles and eye parameter values, suggesting selection for visual sensitivity over acuity. Large workers had larger eyes with disproportionally more and larger ommatidia, and smaller interommatidial angles and eye parameter values, indicating peripheral sensory adaptation to ambient rainforest light. Optic lobes and mushroom body collars were disproportionately small in minims. Within the optic lobe, lamina and lobula relative volumes increased with worker size whereas medulla volume decreased. Visual system phenotypes thus correspond to task specializations in dark or light environments and illustrate a functional neuroplasticity underpinning division of labor in this socially complex agricultural ant.
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Affiliation(s)
- Sara Arganda
- Department of Biology, Boston University, Boston, USA.
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI), Toulouse University, CNRS, UPS, 31062, Toulouse, France.
- Departamento de Biología y Geología, Física y Química Inorgánica, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Madrid, Spain.
| | | | - Evan S Razdan
- Department of Biology, Boston University, Boston, USA
| | | | - James F A Traniello
- Department of Biology, Boston University, Boston, USA
- Graduate Program for Neuroscience, Boston University, Boston, MA, 02215, USA
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38
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Comin CH, Taylor GJ, Costa LDF. Quantifying the regularity of a 3D set of points on the surface of an ellipsoidal object. Pattern Recognit Lett 2020. [DOI: 10.1016/j.patrec.2020.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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39
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Small eyes in dim light: Implications to spatio-temporal visual abilities in Drosophila melanogaster. Vision Res 2020; 169:33-40. [DOI: 10.1016/j.visres.2020.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/27/2020] [Accepted: 02/27/2020] [Indexed: 02/07/2023]
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40
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Ryan LA, Cunningham R, Hart NS, Ogawa Y. The buzz around spatial resolving power and contrast sensitivity in the honeybee, Apis mellifera. Vision Res 2020; 169:25-32. [PMID: 32145455 DOI: 10.1016/j.visres.2020.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 10/24/2022]
Abstract
Most animals rely on vision to perform a range of behavioural tasks and variations in the anatomy and physiology of the eye likely reflect differences in habitat and life history. Moreover, eye design represents a balance between often conflicting requirements for gathering different forms of visual information. The trade-off between spatial resolving power and contrast sensitivity is common to all visual systems, and European honeybees (Apis mellifera) present an important opportunity to better understand this trade-off. Vision has been studied extensively in A. mellifera as it is vital for foraging, navigation and communication. Consequently, spatial resolving power and contrast sensitivity in A. mellifera have been measured using several methodologies; however, there is considerable variation in estimates between methodologies. We assess pattern electroretinography (pERG) as a new method for assessing the trade-off between visual spatial and contrast information in A.mellifera. pERG has the benefit of measuring spatial contrast sensitivity from higher order visual processing neurons in the eye. Spatial resolving power of A.mellifera estimated from pERG was 0.54 cycles per degree (cpd), and contrast sensitivity was 16.9. pERG estimates of contrast sensitivity were comparable to previous behavioural studies. Estimates of spatial resolving power reflected anatomical estimates in the frontal region of the eye, which corresponds to the region stimulated by pERG. Apis mellifera has similar spatial contrast sensitivity to other hymenopteran insects with similar facet diameter (Myrmecia ant species). Our results support the idea that eye anatomy has a substantial effect on spatial contrast sensitivity in compound eyes.
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Affiliation(s)
- Laura A Ryan
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia.
| | - Rhianon Cunningham
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Nathan S Hart
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Yuri Ogawa
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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41
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Taylor GJ, Hall SA, Gren JA, Baird E. Exploring the visual world of fossilized and modern fungus gnat eyes (Diptera: Keroplatidae) with X-ray microtomography. J R Soc Interface 2020; 17:20190750. [PMID: 32019468 PMCID: PMC7061697 DOI: 10.1098/rsif.2019.0750] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Animal eyes typically possess specialized regions for guiding different behavioural tasks within their specific visual habitat. These specializations, and evolutionary changes to them, can be crucial for understanding an animal's ecology. Here, we explore how the visual systems of some of the smallest flying insects, fungus gnats, have adapted to different types of forest habitat over time (approx. 30 Myr to today). Unravelling how behavioural, environmental and phylogenetic factors influence the evolution of visual specializations is difficult, however, because standard quantitative techniques often require fresh tissue and/or provide data in eye-centric coordinates that prevent reliable comparisons between species with different eye morphologies. Here, we quantify the visual world of three gnats from different time periods and habitats using X-ray microtomography to create high-resolution three-dimensional models of the compound eyes of specimens in different preservation states—fossilized in amber, dried or stored in ethanol. We present a method for analysing the geometric details of individual corneal facets and for estimating and comparing the sensitivity, spatial resolution and field of view of species across geographical space and evolutionary time. Our results indicate that, despite their miniature size, fungus gnats do have variations in visual properties across their eyes. We also find some indication that these visual specializations vary across species and may represent adaptations to their different forest habitats. Overall, the findings demonstrate how such investigations can be used to study the evolution of visual specializations—and sensory ecology in general—across a range of insect taxa from different geographical locations and across time.
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Affiliation(s)
| | - Stephen A Hall
- Division of Solid Mechanics, Lund University, Lund, Sweden
| | - Johan A Gren
- Department of Geology, Lund University, Lund, Sweden
| | - Emily Baird
- Department of Biology, Lund University, Lund, Sweden.,Department of Zoology, Stockholm University, Stockholm, Sweden
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Kelber A, Somanathan H. Spatial Vision and Visually Guided Behavior in Apidae. INSECTS 2019; 10:insects10120418. [PMID: 31766747 PMCID: PMC6956220 DOI: 10.3390/insects10120418] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 11/05/2019] [Accepted: 11/21/2019] [Indexed: 01/10/2023]
Abstract
The family Apidae, which is amongst the largest bee families, are important pollinators globally and have been well studied for their visual adaptations and visually guided behaviors. This review is a synthesis of what is known about their eyes and visual capabilities. There are many species-specific differences, however, the relationship between body size, eye size, resolution, and sensitivity shows common patterns. Salient differences between castes and sexes are evident in important visually guided behaviors such as nest defense and mate search. We highlight that Apis mellifera and Bombus terrestris are popular bee models employed in the majority of studies that have contributed immensely to our understanding vision in bees. However, other species, specifically the tropical and many non-social Apidae, merit further investigation for a better understanding of the influence of ecological conditions on the evolution of bee vision.
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Affiliation(s)
- Almut Kelber
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
- Correspondence: (A.K.); (H.S.)
| | - Hema Somanathan
- IISER TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research, Maruthamala PO, Vithura, Thiruvananthapuram, Kerala 695551, India
- Correspondence: (A.K.); (H.S.)
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43
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Sumner-Rooney L, Kenny NJ, Ahmed F, Williams ST. The utility of micro-computed tomography for the non-destructive study of eye microstructure in snails. Sci Rep 2019; 9:15411. [PMID: 31659206 PMCID: PMC6817935 DOI: 10.1038/s41598-019-51909-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 10/09/2019] [Indexed: 02/02/2023] Open
Abstract
Molluscan eyes exhibit an enormous range of morphological variation, ranging from tiny pigment-cup eyes in limpets, compound eyes in ark clams and pinhole eyes in Nautilus, through to concave mirror eyes in scallops and the large camera-type eyes of the more derived cephalopods. Here we assess the potential of non-destructive micro-computed tomography (µ-CT) for investigating the anatomy of molluscan eyes in three species of the family Solariellidae, a group of small, deep-sea gastropods. We compare our results directly with those from traditional histological methods applied to the same specimens, and show not only that eye microstructure can be visualised in sufficient detail for meaningful comparison even in very small animals, but also that μ-CT can provide additional insight into gross neuroanatomy without damaging rare and precious specimens. Data from μ-CT scans also show that neurological innervation of eyes is reduced in dark-adapted snails when compared with the innervation of cephalic tentacles, which are involved in mechanoreception and possibly chemoreception. Molecular tests also show that the use of µ-CT and phosphotungstic acid stain do not prevent successful downstream DNA extraction, PCR amplification or sequencing. The use of µ-CT methods is therefore highly recommended for the investigation of difficult-to-collect or unique specimens.
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Affiliation(s)
| | | | - Farah Ahmed
- Natural History Museum, Cromwell Road, London, UK
- Exponent International Ltd, London, UK
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Wilby D, Aarts T, Tichit P, Bodey A, Rau C, Taylor G, Baird E. Using micro-CT techniques to explore the role of sex and hair in the functional morphology of bumblebee (Bombus terrestris) ocelli. Vision Res 2019; 158:100-108. [PMID: 30826353 DOI: 10.1016/j.visres.2019.02.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 01/27/2019] [Accepted: 02/24/2019] [Indexed: 11/16/2022]
Affiliation(s)
- David Wilby
- Department of Biology, Lund University, Lund, Sweden
| | - Tobio Aarts
- Department of Biology, Lund University, Lund, Sweden; Institute for Interdisciplinary Studies, University of Amsterdam, Amsterdam, Netherlands
| | - Pierre Tichit
- Department of Biology, Lund University, Lund, Sweden
| | - Andrew Bodey
- Diamond Light Source, Oxfordshire, United Kingdom
| | | | - Gavin Taylor
- Department of Biology, Lund University, Lund, Sweden
| | - Emily Baird
- Department of Biology, Lund University, Lund, Sweden; Department of Zoology, Stockholm University, Stockholm, Sweden.
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Taylor GJ, Tichit P, Schmidt MD, Bodey AJ, Rau C, Baird E. Bumblebee visual allometry results in locally improved resolution and globally improved sensitivity. eLife 2019; 8:40613. [PMID: 30803484 PMCID: PMC6391067 DOI: 10.7554/elife.40613] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 12/23/2018] [Indexed: 12/19/2022] Open
Abstract
The quality of visual information that is available to an animal is limited by the size of its eyes. Differences in eye size can be observed even between closely related individuals, yet we understand little about how this affects vision. Insects are good models for exploring the effects of size on visual systems because many insect species exhibit size polymorphism. Previous work has been limited by difficulties in determining the 3D structure of eyes. We have developed a novel method based on x-ray microtomography to measure the 3D structure of insect eyes and to calculate predictions of their visual capabilities. We used our method to investigate visual allometry in the bumblebee Bombus terrestris and found that size affects specific aspects of vision, including binocular overlap, optical sensitivity, and dorsofrontal visual resolution. This reveals that differential scaling between eye areas provides flexibility that improves the visual capabilities of larger bumblebees. Bees fly through complex environments in search of nectar from flowers. They are aided in this quest by excellent eyesight. Scientists have extensively studied the eyesight of honeybees to learn more about how such tiny eyes work and how they process and learn visual information. Less is known about the honeybee’s larger cousins, the bumblebees, which are also important pollinators. Bumblebees come in different sizes and one question scientists have is how eye size affects vision. Bigger bumblebees are known to have bigger eyes, and bigger eyes are usually better. But which aspects of vision are improved in larger eyes is not clear. For example, does the size of a bee’s eyes affect how large their field of view is, or how sensitive they are to light? Or does it impact their visual acuity, a measurement of the smallest objects the eye can see? Scaling up an eye would likely improve all these aspects of sight slightly, but changes in a small area of the eye might more drastically improve some parts of vision. Now, Taylor et al. show that larger bumblebees with bigger eyes have better vision than their smaller counterparts. In the experiments, a technique called microtomography was used to measure the 3D structure of bumblebee eyes. The measurements were then applied to build 3D models of the bumblebee eyes, and computational geometry was used to calculate the sensitivity, acuity, and viewing direction across the entire surface of each model eye. Taylor et al. found that larger bees had improved ability to see small objects in front or slightly above them. They had a bigger area of overlap between the sight in both eyes when they looked forward and up. They were also more sensitive to light across the eye. The experiments show that improvements in eyesight with larger size are very specific and likely help larger bees to adapt to their environment. Behavioral studies could help scientists better understand how these changes help bigger bees and how the traits evolved. These findings might also help engineers trying to design miniature cameras to help small, flying autonomous vehicles navigate. Bees fly through complex environments and face challenges similar to those small flying vehicles would face. Emulating the design of bee eyes and how they change with size might lead to the development of better cameras for these vehicles.
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Affiliation(s)
| | - Pierre Tichit
- Department of Biology, Lund University, Lund, Sweden
| | - Marie D Schmidt
- Department of Biology, Lund University, Lund, Sweden.,Westphalian University of Applied Sciences, Bocholt, Germany
| | | | | | - Emily Baird
- Department of Biology, Lund University, Lund, Sweden.,Department of Zoology, Stockholm University, Stockholm, Sweden
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46
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Bagheri ZM, Jessop AL, Kato S, Partridge JC, Shaw J, Ogawa Y, Hemmi JM. A new method for mapping spatial resolution in compound eyes suggests two visual streaks in fiddler crabs. J Exp Biol 2019; 223:jeb.210195. [DOI: 10.1242/jeb.210195] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 12/01/2019] [Indexed: 11/20/2022]
Abstract
Visual systems play a vital role in guiding the behaviour of animals. Understanding the visual information animals are able to acquire is therefore key to understanding their visually-mediated decision making. Compound eyes, the dominant eye type in arthropods, are inherently low-resolution structures. Their ability to resolve spatial detail depends on sampling resolution (interommatidial angle) and the quality of ommatidial optics. Current techniques for estimating interommatidial angles are difficult, and generally require in vivo measurements. Here, we present a new method for estimating interommatidial angles based on the detailed analysis of 3D Micro-CT images of fixed samples. Using custom-made MATLAB software we determine the optical axes of individual ommatidia and project these axes into the three-dimensional space around the animal. The combined viewing directions of all ommatidia, estimated from geometrical optics, allow us to estimate interommatidial angles and map the animal's sampling resolution across its entire visual field. The resulting topographic representations of visual acuity match very closely the previously published data obtained from both fiddler and grapsid crabs. However, the new method provides additional detail that was not previously detectable and reveals that fiddler crabs, rather than having a single horizontal visual streak as is common in flat world inhabitants, likely have two parallel streaks located just above and below the visual horizon. A key advantage of our approach is that it can be used on appropriately preserved specimens allowing the technique to be applied to animals such as deep-sea crustaceans that are inaccessible or unsuitable for in vivo approaches.
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Affiliation(s)
- Zahra M. Bagheri
- School of Biological Sciences, the University of Western Australia, Perth, Australia
| | - Anna-Lee Jessop
- School of Biological Sciences, the University of Western Australia, Perth, Australia
| | - Susumu Kato
- School of Biological Sciences, the University of Western Australia, Perth, Australia
| | - Julian C. Partridge
- The UWA Oceans Institute, the University of Western Australia, Perth, Australia
| | - Jeremy Shaw
- Centre for Microscopy, Characterisation and Analysis, the University of Western Australia, Perth, Australia
| | - Yuri Ogawa
- School of Biological Sciences, the University of Western Australia, Perth, Australia
| | - Jan M. Hemmi
- School of Biological Sciences, the University of Western Australia, Perth, Australia
- The UWA Oceans Institute, the University of Western Australia, Perth, Australia
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47
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Palavalli-Nettimi R, Ogawa Y, Ryan LA, Hart NS, Narendra A. Miniaturisation reduces contrast sensitivity and spatial resolving power in ants. J Exp Biol 2019; 222:jeb.203018. [DOI: 10.1242/jeb.203018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 05/17/2019] [Indexed: 12/30/2022]
Abstract
Vision is crucial for animals to find prey, locate conspecifics, and to navigate within cluttered landscapes. Animals need to discriminate objects against a visually noisy background. However, the ability to detect spatial information is limited by eye size. In insects, as individuals become smaller, the space available for the eyes reduces, which affects the number of ommatidia, the size of the lens and the downstream information processing capabilities. The evolution of small body size in a lineage, known as miniaturisation, is common in insects. Here, using pattern electroretinography with vertical sinusoidal gratings as stimuli, we studied how miniaturisation affects spatial resolving power and contrast sensitivity in four diurnal ants that live in a similar environment but varied in their body and eye size. We found that ants with fewer and smaller ommatidial facets had lower spatial resolving power and contrast sensitivity. The spatial resolving power was maximum in the largest ant Myrmecia tarsata at 0.60 cycles per degree (cpd) compared to the ant with smallest eyes Rhytidoponera inornata that had 0.48 cpd. Maximum contrast sensitivity (minimum contrast threshold) in M. tarsata (2627 facets) was 15.51 (6.4% contrast detection threshold) at 0.1 cpd, while the smallest ant R. inornata (227 facets) had a maximum contrast sensitivity of 1.34 (74.1% contrast detection threshold) at 0.05 cpd. This is the first study to physiologically investigate contrast sensitivity in the context of insect allometry. Miniaturisation thus dramatically decreases maximum contrast sensitivity and also reduces spatial resolution, which could have implications for visually guided behaviours.
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Affiliation(s)
| | - Yuri Ogawa
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Laura A. Ryan
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Nathan S. Hart
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Ajay Narendra
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
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48
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Stöckl A, Grittner R, Pfeiffer K. The role of lateral optic flow cues in hawkmoth flight control. J Exp Biol 2019; 222:jeb.199406. [PMID: 31196978 DOI: 10.1242/jeb.199406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 06/05/2019] [Indexed: 02/02/2023]
Abstract
Flying animals require sensory feedback on changes of their body position, as well as on their distance to nearby objects. The apparent image motion, or optic flow, which is generated as animals move through the air, can provide this information. Flight tunnel experiments have been crucial for our understanding of how insects use this optic flow for flight control in confined spaces. However, previous work mainly focused on species from two insect orders: Hymenoptera and Diptera. We therefore set out to investigate if the previously described control strategies to navigate enclosed environments are also used by insects with a different optical system, flight kinematics and phylogenetic background. We tested the role of lateral visual cues for forward flight control in the hummingbird hawkmoth Macroglossum stellatarum (Sphingidae, Lepidoptera), which possess superposition compound eyes, and have the ability to hover in addition to their fast forward flight capacities. Our results show that hawkmoths use a similar strategy for lateral position control as bees and flies in balancing the magnitude of translational optic flow perceived in both eyes. However, the control of lateral optic flow on flight speed in hawkmoths differed from that in bees and flies. Moreover, hawkmoths showed individually attributable differences in position and speed control when the presented optic flow was unbalanced.
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Affiliation(s)
- Anna Stöckl
- Chair of Behavioral Physiology and Sociobiology, Würzburg University, Germany
| | - Rebecca Grittner
- Chair of Behavioral Physiology and Sociobiology, Würzburg University, Germany
| | - Keram Pfeiffer
- Chair of Behavioral Physiology and Sociobiology, Würzburg University, Germany
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