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Ferrari A, Tacconi G, Polidori C. Subtle morphological changes in the visual and antennal sensory system of bees and wasps across an urbanisation gradient. Sci Rep 2024; 14:8960. [PMID: 38637599 PMCID: PMC11026482 DOI: 10.1038/s41598-024-58804-2] [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: 01/09/2024] [Accepted: 04/03/2024] [Indexed: 04/20/2024] Open
Abstract
Increased temperature and fragmentation of green spaces in urban areas could drive variations in functional traits of insects. Such morphological shifts may occur for sensory systems, which were previously reported to be prone to change with habitat characteristics in non-urban contexts. Here, we measured traits related to the visual and antennal sensory systems in the bees Halictus scabiosae and Osmia cornuta and the wasp Polistes dominula along an urbanisation gradient within Milan (Italy). We hypothesised that fragmentation could filter for better visual properties, and that higher temperature could filter for fewer thermoreceptors and more olfactory hairs. While controlling for body size, results show subtle but appreciable responses to urbanisation in one or more traits in all species, though not always supporting our hypotheses. O. cornuta shows marginally higher ommatidia density and smaller ommatidia diameter (associated with better visual resolution) in more fragmented sites, as well as marginally fewer thermoreceptors in hotter sites, in agreement with our two predictions. On the other hand, H. scabiosae has marginally smaller antennae and P. dominula has smaller eyes at warmer locations, and the wasp also has smaller antennae and 9th flagellomeres in more fragmented areas. Perhaps higher temperatures accelerate development of sensory system at higher speed than the rest of body in these two species. Our results represent the first evidence of urbanisation effects on the visual and antennal sensory systems of bees and wasps and underline how such effects may involve a much broader bouquet of traits then previously observed.
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Affiliation(s)
- Andrea Ferrari
- Department of Environmental Science and Policy (ESP), University of Milan, Via Celoria 26, 20133, Milan, Italy.
| | - Greta Tacconi
- Department of Environmental Science and Policy (ESP), University of Milan, Via Celoria 26, 20133, Milan, Italy
| | - Carlo Polidori
- Department of Environmental Science and Policy (ESP), University of Milan, Via Celoria 26, 20133, Milan, Italy
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2
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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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3
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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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4
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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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5
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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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6
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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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7
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Jones BM, Seymoure BM, Comi TJ, Loew ER. Species and sex differences in eye morphometry and visual responsivity of two crepuscular sweat bee species ( Megalopta spp., Hymenoptera: Halictidae). Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Visually dependent dim-light foraging has evolved repeatedly, broadening the ecological niches of some species. Many dim-light foraging lineages evolved from diurnal ancestors, requiring immense visual sensitivity increases to compensate for light levels a billion times dimmer than daylight. Some taxa, such as bees, are anatomically constrained by apposition compound eyes, which function well in daylight but not in starlight. Even with this constraint, the bee genus Megalopta has incredibly sensitive eyes, foraging in light levels up to nine orders of magnitude dimmer than diurnal relatives. Despite many behavioural studies, variation in visual sensitivity and eye morphometry has not been investigated within and across Megalopta species. Here we quantify external eye morphology (corneal area and facet size) for sympatric species of Megalopta, M. genalis and M. amoena, which forage during twilight. We use electroretinograms to show that males, despite being smaller than females, have equivalent visual sensitivity and increased retinal responsivity. Although males have relatively larger eyes compared with females, corneal area and facet size were not correlated with retinal responsivity, suggesting that males have additional non-morphological adaptations to increase retinal responsiveness. These findings provide the foundation for future work into the neural and physiological mechanisms that interface with morphology to influence visual sensitivity, with implications for understanding niche exploitation.
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Affiliation(s)
- Beryl M Jones
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Smithsonian Tropical Research Institute, Panama City, Panama
| | - Brett M Seymoure
- Smithsonian Tropical Research Institute, Panama City, Panama
- Living Earth Collaborative, Washington University in St. Louis, St. Louis, MO, USA
- Sound and Light Ecology Team, Colorado State University, Fort Collins, CO, USA
| | - Troy J Comi
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Ellis R Loew
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, USA
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8
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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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9
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Valterová I, Martinet B, Michez D, Rasmont P, Brasero N. Sexual attraction: a review of bumblebee male pheromones. ACTA ACUST UNITED AC 2020; 74:233-250. [PMID: 31442206 DOI: 10.1515/znc-2019-0003] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 07/31/2019] [Indexed: 11/15/2022]
Abstract
Males of many bumblebee species exhibit a conspicuous pre-mating behavior with two distinct behavioral components: scent marking and patrol flying. The marking pheromone is produced by the cephalic part of the labial gland (CLG). As far as is known, the CLG secretion is species specific, and it usually consists of two types of compounds: (i) straight-chain aliphatic alcohols, aldehydes or esters, and (ii) acyclic mono-, sesqui- and diterpenes (alcohols or acetates). Here, we summarize data from the literature reporting chemical composition of the CLG secretions of more than 80 bumblebee species. Similarities and differences within and between subgenera are discussed in the context of biosynthetic pathways and evolution.
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Affiliation(s)
- Irena Valterová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám 2, CZ-166 10 Prague, Czech Republic.,Faculty of Tropical AgriSciences, Czech University of Life Sciences, Kamýcká 129, CZ-165 21 Prague, Czech Republic
| | - Baptiste Martinet
- Laboratory of Zoology, Research Institute of Biosciences, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Denis Michez
- Laboratory of Zoology, Research Institute of Biosciences, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Pierre Rasmont
- Laboratory of Zoology, Research Institute of Biosciences, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Nicolas Brasero
- Laboratory of Zoology, Research Institute of Biosciences, University of Mons, Place du Parc 20, 7000 Mons, Belgium
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10
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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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11
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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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12
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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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13
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Brand P, Larcher V, Couto A, Sandoz JC, Ramírez SR. Sexual dimorphism in visual and olfactory brain centers in the perfume-collecting orchid bee Euglossa dilemma (Hymenoptera, Apidae). J Comp Neurol 2018; 526:2068-2077. [PMID: 30088672 PMCID: PMC6174972 DOI: 10.1002/cne.24483] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/08/2018] [Accepted: 05/22/2018] [Indexed: 11/07/2022]
Abstract
Insect mating behavior is controlled by a diverse array of sex‐specific traits and strategies that evolved to maximize mating success. Orchid bees exhibit a unique suite of perfume‐mediated mating behaviors. Male bees collect volatile compounds from their environment to concoct species‐specific perfume mixtures that are presumably used to attract conspecific females. Despite a growing understanding of the ecology and evolution of chemical signaling in orchid bees, many aspects of the functional adaptations involved, in particular regarding sensory systems, remain unknown. Here we investigated male and female brain morphology in the common orchid bee Euglossa dilemma Bembé & Eltz. Males exhibited increased relative volumes of the Medulla, a visual brain region, which correlated with larger compound eye size (area). While the overall volume of olfactory brain regions was similar between sexes, the antennal lobes exhibited several sex‐specific structures including one male‐specific macroglomerulus. These findings reveal sexual dimorphism in both the visual and the olfactory system of orchid bees. It highlights the tendency of an increased investment in the male visual system similar to that observed in other bee lineages, and suggests that visual input may play a more important role in orchid bee male mating behavior than previously thought. Furthermore, our results suggest that the evolution of perfume communication in orchid bees did not involve drastic changes in olfactory brain morphology compared to other bee lineages.
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Affiliation(s)
- Philipp Brand
- Department of Evolution and Ecology, Center for Population Biology, University of California, Davis, California
| | - Virginie Larcher
- Evolution Genomes Behavior and Ecology, Centre National de la Recherche Scientifique, Université Paris-Sud, IRD, Université Paris Saclay, Gif-sur-Yvette, France
| | - Antoine Couto
- Evolution Genomes Behavior and Ecology, Centre National de la Recherche Scientifique, Université Paris-Sud, IRD, Université Paris Saclay, Gif-sur-Yvette, France
| | - Jean-Christophe Sandoz
- Evolution Genomes Behavior and Ecology, Centre National de la Recherche Scientifique, Université Paris-Sud, IRD, Université Paris Saclay, Gif-sur-Yvette, France
| | - Santiago R Ramírez
- Department of Evolution and Ecology, Center for Population Biology, University of California, Davis, California
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Lecocq T, Gérard M, Maebe K, Brasero N, Dehon L, Smagghe G, Valterová I, De Meulemeester T, Rasmont P, Michez D. Chemical reproductive traits of diploid Bombus terrestris males: Consequences on bumblebee conservation. INSECT SCIENCE 2017; 24:623-630. [PMID: 26953256 DOI: 10.1111/1744-7917.12332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 01/04/2016] [Accepted: 01/31/2016] [Indexed: 06/05/2023]
Abstract
The current bumblebee decline leads to inbreeding in populations that fosters a loss of allelic diversity and diploid male production. As diploid males are viable and their offspring are sterile, bumblebee populations can quickly fall in a vortex of extinction. In this article, we investigate for the first time a potential premating mechanism through a major chemical reproductive trait (male cephalic labial gland secretions) that could prevent monandrous virgin queens from mating with diploid males. We focus our study on the cephalic labial gland secretions of diploid and haploid males of Bombus terrestris (L.). Contrary to initial expectations, our results do not show any significant differentiation of cephalic labial gland secretions between diploid and haploid specimens. Queens seem therefore to be unable to avoid mating with diploid males based on their compositions of cephalic labial gland secretions. This suggests that the vortex of extinction of diploid males could not be stopped through premating avoidance based on the cephalic labial gland secretions but other mechanisms could avoid mating between diploid males and queens.
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Affiliation(s)
- Thomas Lecocq
- Laboratory of Zoology, Research Institute of Biosciences, University of Mons, Mons, France
- Research Unit Animal and Functionalities of Animal Products (URAFPA), University of Lorraine - INRA, 2 Avenue de la Forêt de Haye, BP 172, F-54505, Vandoeuvre-lès-Nancy, France
| | - Maxence Gérard
- Laboratory of Zoology, Research Institute of Biosciences, University of Mons, Mons, France
| | - Kevin Maebe
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000, Ghent, Belgium
| | - Nicolas Brasero
- Laboratory of Zoology, Research Institute of Biosciences, University of Mons, Mons, France
| | - Lauren Dehon
- Laboratory of Zoology, Research Institute of Biosciences, University of Mons, Mons, France
| | - Guy Smagghe
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000, Ghent, Belgium
| | - Irena Valterová
- Academy of Sciences of the Czech Republic, Institute of Organic Chemistry and Biochemistry, Flamingovo nam 2, CZ 166 10, Prague, Czech Republic
| | | | - Pierre Rasmont
- Laboratory of Zoology, Research Institute of Biosciences, University of Mons, Mons, France
| | - Denis Michez
- Laboratory of Zoology, Research Institute of Biosciences, University of Mons, Mons, France
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15
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Somanathan H, Borges RM, Warrant EJ, Kelber A. Visual Adaptations for Mate Detection in the Male Carpenter Bee Xylocopa tenuiscapa. PLoS One 2017; 12:e0168452. [PMID: 28107354 PMCID: PMC5249068 DOI: 10.1371/journal.pone.0168452] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 12/01/2016] [Indexed: 11/18/2022] Open
Abstract
Sexual dimorphism in eye structure is attributed to sexual selection in animals that employ vision for locating mates. In many male insects, large eyes and eye regions of higher acuity are believed to facilitate the location of females. Here, we compare various features of male and female eyes in three sympatric carpenter bee species, which include two diurnal species (Xylocopa tenuiscapa and X. leucothorax) as well as a nocturnal species (X. tranquebarica). In X. tenuiscapa, males have larger eyes than females, while in the nocturnal X. tranquebarica, males have slightly smaller eyes and in X. leucothorax, the eyes are of similar size in both sexes. X. tenuiscapa males detect females by perching near nest sites (resource defence) or along fly-ways and other open areas with good visibility. Males of the other two species search for females by patrolling. We postulate that the larger eyes of male X. tenuiscapa are beneficial to their mode of mate detection since perching males may benefit from a larger visual area of high resolution detecting moving stimuli across the sky, and which may be germane to the more social and gregarious nesting behaviour of this species, compared to the other solitary bees. We tested the performance of the eyes of male X. tenuiscapa behaviourally and find that a perching male can detect a flying female at a distance of 20 m, which darkens the visual field of a single ommatidium by just 2%. This, together with the bee's high spatial resolution permits detection of moving stimuli at least as well or even better than achieved by honey bee drones.
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Affiliation(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 Thiruvananthapuram, Kerala, India
- * E-mail:
| | - Renee Maria Borges
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India
| | - Eric J. Warrant
- Lund Vision Group, Department for Biology, Lund University, Lund, Sweden
| | - Almut Kelber
- Lund Vision Group, Department for Biology, Lund University, Lund, Sweden
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16
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Streinzer M, Huber W, Spaethe J. Body size limits dim-light foraging activity in stingless bees (Apidae: Meliponini). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:643-55. [PMID: 27495990 PMCID: PMC5023731 DOI: 10.1007/s00359-016-1118-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 07/28/2016] [Accepted: 07/29/2016] [Indexed: 12/02/2022]
Abstract
Stingless bees constitute a species-rich tribe of tropical and subtropical eusocial Apidae that act as important pollinators for flowering plants. Many foraging tasks rely on vision, e.g. spatial orientation and detection of food sources and nest entrances. Meliponini workers are usually small, which sets limits on eye morphology and thus quality of vision. Limitations are expected both on acuity, and thus on the ability to detect objects from a distance, as well as on sensitivity, and thus on the foraging time window at dusk and dawn. In this study, we determined light intensity thresholds for flight under dim light conditions in eight stingless bee species in relation to body size in a Neotropical lowland rainforest. Species varied in body size (0.8-1.7 mm thorax-width), and we found a strong negative correlation with light intensity thresholds (0.1-79 lx). Further, we measured eye size, ocelli diameter, ommatidia number, and facet diameter. All parameters significantly correlated with body size. A disproportionately low light intensity threshold in the minute Trigonisca pipioli, together with a large eye parameter P eye suggests specific adaptations to circumvent the optical constraints imposed by the small body size. We discuss the implications of body size in bees on foraging behavior.
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Affiliation(s)
- Martin Streinzer
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
- Department of Neurobiology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
| | - Werner Huber
- Department of Botany and Biodiversity Research, Faculty of Life Sciences, University of Vienna, Rennweg 14, 1030, Vienna, Austria
| | - Johannes Spaethe
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090, Vienna, Austria
- Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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17
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Marco Antonio DS, Hartfelder K. Toward an Understanding of Divergent Compound Eye Development in Drones and Workers of the Honeybee (Apis melliferaL.): A Correlative Analysis of Morphology and Gene Expression. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 328:139-156. [DOI: 10.1002/jez.b.22696] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 08/17/2016] [Accepted: 08/21/2016] [Indexed: 12/27/2022]
Affiliation(s)
- David S. Marco Antonio
- Departamento de Genética; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto SP Brazil
| | - Klaus Hartfelder
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto SP Brazil
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18
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Douglass JK, Wehling MF. Rapid mapping of compound eye visual sampling parameters with FACETS, a highly automated wide-field goniometer. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:839-851. [PMID: 27655343 DOI: 10.1007/s00359-016-1119-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/27/2016] [Accepted: 07/29/2016] [Indexed: 11/29/2022]
Abstract
A highly automated goniometer instrument (called FACETS) has been developed to facilitate rapid mapping of compound eye parameters for investigating regional visual field specializations. The instrument demonstrates the feasibility of analyzing the complete field of view of an insect eye in a fraction of the time required if using non-motorized, non-computerized methods. Faster eye mapping makes it practical for the first time to employ sample sizes appropriate for testing hypotheses about the visual significance of interspecific differences in regional specializations. Example maps of facet sizes are presented from four dipteran insects representing the Asilidae, Calliphoridae, and Stratiomyidae. These maps provide the first quantitative documentation of the frontal enlarged-facet zones (EFZs) that typify asilid eyes, which, together with the EFZs in male Calliphoridae, are likely to be correlated with high-spatial-resolution acute zones. The presence of EFZs contrasts sharply with the almost homogeneous distribution of facet sizes in the stratiomyid. Moreover, the shapes of EFZs differ among species, suggesting functional specializations that may reflect differences in visual ecology. Surveys of this nature can help identify species that should be targeted for additional studies, which will elucidate fundamental principles and constraints that govern visual field specializations and their evolution.
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Affiliation(s)
- John K Douglass
- Eglin Air Force Base, 101 W. Eglin Blvd., Eglin AFB, FL, 32542, USA.
| | - Martin F Wehling
- Eglin Air Force Base, 101 W. Eglin Blvd., Eglin AFB, FL, 32542, USA
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19
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The trap of sex in social insects: From the female to the male perspective. Neurosci Biobehav Rev 2014; 46 Pt 4:519-33. [DOI: 10.1016/j.neubiorev.2014.09.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 09/14/2014] [Accepted: 09/22/2014] [Indexed: 01/27/2023]
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