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Kelly MBJ, Khan MK, Wierucka K, Jones BR, Shofner R, Derkarabetian S, Wolff JO. Dynamic evolution of locomotor performance independent of changes in extended phenotype use in spiders. Proc Biol Sci 2023; 290:20232035. [PMID: 37876190 PMCID: PMC10598421 DOI: 10.1098/rspb.2023.2035] [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: 05/03/2023] [Accepted: 10/06/2023] [Indexed: 10/26/2023] Open
Abstract
Many animals use self-built structures (extended phenotypes) to enhance body functions, such as thermoregulation, prey capture or defence. Yet, it is unclear whether the evolution of animal constructions supplements or substitutes body functions-with disparate feedbacks on trait evolution. Here, using brown spiders (Araneae: marronoid clade), we explored if the evolutionary loss and gain of silken webs as extended prey capture devices correlates with alterations in traits known to play an important role in predatory strikes-locomotor performance (sprint speed) and leg spination (expression of capture spines on front legs). We found that in this group high locomotor performance, with running speeds of over 100 body lengths per second, evolved repeatedly-both in web-building and cursorial spiders. There was no correlation with running speed, and leg spination only poorly correlated, relative to the use of extended phenotypes, indicating that web use does not reduce selective pressures on body functions involved in prey capture and defence per se. Consequently, extended prey capture devices serve as supplements rather than substitutions to body traits and may only be beneficial in conjunction with certain life-history traits, possibly explaining the rare evolution and repeated loss of trapping strategies in predatory animals.
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Affiliation(s)
- Michael B. J. Kelly
- Evolutionary Biomechanics, Zoological Institute and Museum, University of Greifswald, Loitzer Strasse 26, 17489 Greifswald, Germany
- School of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Md Kawsar Khan
- School of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195 Berlin, Germany
| | - Kaja Wierucka
- School of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
- Behavioural Ecology and Sociobiology Unit, German Primate Center - Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany
| | - Braxton R. Jones
- School of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
- School of Biological Sciences, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Ryan Shofner
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences E26, University of New South Wales, Sydney 2052, Australia
| | - Shahan Derkarabetian
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Jonas O. Wolff
- Evolutionary Biomechanics, Zoological Institute and Museum, University of Greifswald, Loitzer Strasse 26, 17489 Greifswald, Germany
- School of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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Hayashi T, Hayashi K, Hayashi N, Hayashi F. Optimal pit site selection in antlion larvae: the relationship between prey availability and pit maintenance costs. J ETHOL 2022. [DOI: 10.1007/s10164-022-00767-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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3
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Lim W, Kang C. Spider behaviours increase trap efficacy. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03189-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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4
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Convergent evolution of antlions and wormlions: similarities and differences in the behavioural ecology of unrelated trap-building predators. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-021-03106-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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5
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Klokočovnik V, Devetak D. Efficiency of antlion trap design and larval behavior in capture success. Behav Ecol 2021. [DOI: 10.1093/beheco/arab124] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Traps constructed by an animal reduce the amount of energy required to seek prey. The main risk of trap-building predators is the greater uncertainty of encountering prey, owing to their immobility. Sometimes environmental characteristics do not allow them to build efficient traps, resulting in lower capture success. We observed prey escape, capture success, and behavior of two antlion species, Cueta lineosa, a habitat specialist, and Myrmeleon hyalinus, a generalist, building geometrically different traps. The traps of C. lineosa are elaborate and deep, consisting of two inverted cones, while M. hyalinus builds simple inverted cones. Prey escape was observed from traps with antlion larvae present and from artificially constructed traps without antlions. We used a 3D printer to create a replica model of both trap types, pressing the model onto the substrate surface to create a trap. The C. lineosa artificial trap slowed prey escape more effectively than the simpler artificial trap of M. hyalinus. Prey escape time was four times longer for two ant species and three times longer for woodlice from C. lineosa traps. Escape time also decreased with increasing prey length. We also found behavioral differences between these two antlion species. The behavior of M. hyalinus is much more efficient in catching prey than that of C. lineosa. The results indicate that both species are efficient trap-building predators; however, it appears that capture success depends not only on trap design but also on larval behavior.
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Affiliation(s)
- Vesna Klokočovnik
- Faculty of Natural Sciences and Mathematics, Department of Biology, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia
| | - Dušan Devetak
- Faculty of Natural Sciences and Mathematics, Department of Biology, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia
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Büsse S, Büscher TH, Heepe L, Gorb SN, Stutz HH. Sand-throwing behaviour in pit-building antlion larvae: insights from finite-element modelling. J R Soc Interface 2021; 18:20210539. [PMID: 34520690 DOI: 10.1098/rsif.2021.0539] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Sandy pitfall traps of antlions are elaborate constructions to capture prey. Antlions exploit the interactions between the particles in their habitat and build a stable trap. This trap is close to the unstable state; prey items will slide towards the centre-where the antlion ambushes-when entering the trap. This is efficient but requires permanent maintenance. According to the present knowledge, antlions throw sand, mainly to cause sandslides towards the centre of the pit. We hypothesized that: (i) sand-throwing causes sandslides towards the centre of the pit and (ii) sand-throwing constantly maintains the pitfall trap and thus keeps its efficiency high. Using laboratory experiments, as well as finite-element analysis, we tested these hypotheses. We show, experimentally and numerically, that sand that accumulates at the centre of the pit will be removed continuously by sand-throwing, this maintenance is leading to slope condition close to an unstable state. This keeps the slope angle steep and the efficiency of the trap constant. Furthermore, the resulting sandslides can relocate the trapped prey towards the centre of the pit. This study adds further insights from specific mechanical properties of a granular medium into the behavioural context of hunting antlion larvae.
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Affiliation(s)
- Sebastian Büsse
- Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Kiel, Germany
| | - Thies H Büscher
- Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Kiel, Germany
| | - Lars Heepe
- Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Kiel, Germany
| | - Stanislav N Gorb
- Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Kiel, Germany
| | - Hans Henning Stutz
- Department of Engineering, Geotechnical Engineering, Aarhus University, Aarhus, Denmark
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Urban Pit-Building Insects Are Attracted to Walls for Multiple Reasons. BIOLOGY 2021; 10:biology10070635. [PMID: 34356490 PMCID: PMC8301029 DOI: 10.3390/biology10070635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/22/2021] [Accepted: 07/03/2021] [Indexed: 11/17/2022]
Abstract
Simple Summary Wormlions are small fly larvae that dig pit-traps in loose soil to hunt ants and other prey. Their natural habitat is caves, but they are also abundant in Mediterranean cities below man-made shelters, even in thin layers of soil. They are especially common next to building walls. First, we show that wormlions are indeed closer to walls than expected by chance. Next, we tested several explanations for this observation: the possible effect of soil depth, soil particle size, shade, and prey abundance. We could not find a single explanation for the wormlion’s proximity to walls, and in each site, a different set of explanations held true. The final step was to conduct an experiment. We placed wormlions on clear sand either in the center or next to the wall and observed whether they moved after a day. Those placed in the center moved over longer distances, and we interpret this result to indicate that those adjacent to the wall are more satisfied with their location. Our study provides an example for how animals take advantage of human-made changes in the habitat and prosper in urban habitats. Abstract Whereas most animals find urban habitats to be inferior to natural habitats, some “urban specialist” species thrive there. Wormlions present such an example. Common in Mediterranean cities, they cluster in thin layers of loose soil below man-made shelters. Wormlions are fly larvae that dig pit-traps in loose soil and hunt small arthropods. Our first aim was to determine whether wormlion pits accumulate next to walls. Wormlion pits were indeed closer to walls than expected by chance at most of the study sites. We examined possible factors behind this apparent preference, combining field observations and experiments, laboratory work, and theoretical analysis. We examined the effect of soil depth, particle size, shade, and prey abundance. Each factor provided a partial explanation for the wormlions’ proximity to walls, but none provided an overall explanation. We developed a spatially explicit simulation model, demonstrating under which conditions wall-adjacent positions are favored. Finally, we created artificial microhabitats, and placed wormlions either in the center or next to the wall. The wormlions in the center moved over longer distances than those next to the wall and did so more in the wall’s direction. The abundance of walls may help to explain the success of wormlions in urban habitats.
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Devetak D, Podlesnik J, Scharf I, Klenovšek T. Fine sand particles enable antlions to build pitfall traps with advanced three-dimensional geometry. J Exp Biol 2020; 223:jeb224626. [PMID: 32561631 DOI: 10.1242/jeb.224626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/15/2020] [Indexed: 11/20/2022]
Abstract
Pit-building antlion larvae are predators that construct pitfall traps in fine sand. We used three-dimensional laser scanning and geometric morphometrics to reveal the shape of antlion pits of two antlion species, analysed the particle size composition of sands from the different natural habitats, and measured the slope angles of the pits of the two species. In most antlions, the pits are structured as a simple inverted cone, as in Myrmeleon hyalinus, studied here. The other antlion studied, Cueta lineosa, constructs a unique pit composed of two inverted truncated cones inserted into one another, which feature substantially steeper walls than the pits of any other antlion studied to date. Pit stability depends on the slope inclination, which oscillates between the maximum angle of stability and the angle of repose. The angles in C. linosa substrates were larger than those in M. hyalinus substrates. One reason for the steeper walls is the greater proportion of fine sand in the natural sand inhabited by C. lineosa However, video-recording revealed that both the natural sand of C. lineosa and the finest sand tested had a higher maximum angle of stability than any of the other substrates studied here. Furthermore, experiments with pits built in different substrates revealed that the shape of the pit is variable and depends on the structure of the sand. Myrmeleonhyalinus displayed a more flexible pit construction behaviour than C. lineosa The present demonstration of such differences in pit characteristics contributes to understanding how these two species co-exist in the same habitat.
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Affiliation(s)
- Dušan Devetak
- Department of Biology, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia
| | - Jan Podlesnik
- Department of Biology, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia
| | - Inon Scharf
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Tina Klenovšek
- Department of Biology, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia
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9
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Franks NR, Worley A, Falkenberg M, Sendova-Franks AB, Christensen K. Digging the optimum pit: antlions, spirals and spontaneous stratification. Proc Biol Sci 2020; 286:20190365. [PMID: 30900535 PMCID: PMC6452065 DOI: 10.1098/rspb.2019.0365] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Most animal traps are constructed from self-secreted silk, so antlions are rare among trap builders because they use only materials found in the environment. We show how antlions exploit the properties of the substrate to produce very effective structures in the minimum amount of time. Our modelling demonstrates how antlions: (i) exploit self-stratification in granular media differentially to expose deleterious large grains at the bottom of the construction trench where they can be ejected preferentially, and (ii) minimize completion time by spiral rather than central digging. Both phenomena are confirmed by our experiments. Spiral digging saves time because it enables the antlion to eject material initially from the periphery of the pit where it is less likely to topple back into the centre. As a result, antlions can produce their pits—lined almost exclusively with small slippery grains to maximize powerful avalanches and hence prey capture—much more quickly than if they simply dig at the pit's centre. Our demonstration, for the first time to our knowledge, of an animal using self-stratification in granular media exemplifies the sophistication of extended phenotypes even if they are only formed from material found in the animal's environment.
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Affiliation(s)
- Nigel R Franks
- 1 School of Biological Sciences, University of Bristol , 24 Tyndall Avenue, Bristol BS8 1TQ , UK
| | - Alan Worley
- 1 School of Biological Sciences, University of Bristol , 24 Tyndall Avenue, Bristol BS8 1TQ , UK
| | - Max Falkenberg
- 2 Blackett Laboratory, Imperial College London , South Kensington Campus, London SW7 2AZ , UK.,3 Centre for Complexity Science, Imperial College London , South Kensington Campus, London SW7 2AZ , UK
| | - Ana B Sendova-Franks
- 4 Department of Engineering Design and Mathematics, UWE Bristol , Frenchay Campus, Coldharbour Lane, Bristol BS16 1QY , UK
| | - Kim Christensen
- 2 Blackett Laboratory, Imperial College London , South Kensington Campus, London SW7 2AZ , UK.,3 Centre for Complexity Science, Imperial College London , South Kensington Campus, London SW7 2AZ , UK
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10
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11
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Shanas U, Gavish Y, Bernheim M, Mittler S, Olek Y, Tal A. Cascading ecological effects from local extirpation of an ecosystem engineer in the Arava desert. CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The extinction of a single species from a local community may carry little cost in terms of species diversity, yet its loss eliminates its biotic and abiotic interactions. We describe such a scenario in the Arava desert, where different cultural and law enforcement practices exclude Dorcas gazelles (Gazella dorcas (Linnaeus, 1758)) from the Jordanian side of the border while protecting their populations on the Israeli side. We found that gazelles break the soil crust, formed in desert systems after annual flooding, thereby creating patches of loose and cooler sand that are used by pit-building antlions (Neuroptera: Myrmeleontidae). When we artificially broke the soil crust on both sides of the border, we found a significant increase in antlion density in these patches, but only on the Israeli side. On the Jordanian side, where no gazelles have been observed since the early 1980s, no antlions colonized either control or manipulated plots. Additional choice/no-choice feeding experiments, in which we offered antlions to lizards and birds, revealed that the effect of humans on gazelles cascades farther, as antlions serve as a palatable food source for both groups. Thus, the human-mediated loss of nontrophic interactions between gazelles and antlions cascades to the loss of trophic interactions between antlions and their predators.
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Affiliation(s)
- Uri Shanas
- Department of Biology and Environment, University of Haifa–Oranim, Tivon 36006, Israel
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 31905, Israel
| | - Yoni Gavish
- School of Biology, Faculty of Biological Science, University of Leeds, Leeds LS2-9JT, United Kingdom
| | - Mai Bernheim
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 31905, Israel
| | - Shacham Mittler
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 31905, Israel
| | - Yael Olek
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 31905, Israel
| | - Alon Tal
- Department of Public Policy, Tel Aviv University, Tel Aviv 69978, Israel
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12
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Wang L, Brodbeck L, Iida F. Mechanics and energetics in tool manufacture and use: a synthetic approach. J R Soc Interface 2015; 11:20140827. [PMID: 25209405 DOI: 10.1098/rsif.2014.0827] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tool manufacture and use are observed not only in humans but also in other animals such as mammals, birds and insects. Manufactured tools are used for biomechanical functions such as effective control of fluids and small solid objects and extension of reaching. These tools are passive and used with gravity and the animal users' own energy. From the perspective of evolutionary biology, manufactured tools are extended phenotypes of the genes of the animal and exhibit phenotypic plasticity. This incurs energetic cost of manufacture as compared to the case with a fixed tool. This paper studies mechanics and energetics aspects of tool manufacture and use in non-human beings. Firstly, it investigates possible mechanical mechanisms of the use of passive manufactured tools. Secondly, it formulates the energetic cost of manufacture and analyses when phenotypic plasticity benefits an animal tool maker and user. We take a synthetic approach and use a controlled physical model, i.e. a robot arm. The robot is capable of additively manufacturing scoop and gripper structures from thermoplastic adhesives to pick and place fluid and solid objects, mimicking primates and birds manufacturing tools for a similar function. We evaluate the effectiveness of tool use in pick-and-place and explain the mechanism for gripper tools picking up solid objects with a solid-mechanics model. We propose a way to formulate the energetic cost of tool manufacture that includes modes of addition and reshaping, and use it to analyse the case of scoop tools. Experiment results show that with a single motor trajectory, the robot was able to effectively pick and place water, rice grains, a pebble and a plastic box with a scoop tool or gripper tools that were manufactured by itself. They also show that by changing the dimension of scoop tools, the energetic cost of tool manufacture and use could be reduced. The work should also be interesting for engineers to design adaptive machines.
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Affiliation(s)
- Liyu Wang
- Bio-Inspired Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Leonhardstrasse 27, Zurich 8092, Switzerland
| | - Luzius Brodbeck
- Bio-Inspired Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Leonhardstrasse 27, Zurich 8092, Switzerland
| | - Fumiya Iida
- Bio-Inspired Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Leonhardstrasse 27, Zurich 8092, Switzerland
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Behavioral repeatability and personality in pit-building antlion larvae under differing environmental contexts. Behav Ecol Sociobiol 2014. [DOI: 10.1007/s00265-014-1804-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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14
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Barkae ED, Golan O, Ovadia O. Dangerous neighbors: interactive effects of factors influencing cannibalism in pit-building antlion larvae. Behav Ecol 2014. [DOI: 10.1093/beheco/aru123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Dor R, Rosenstein S, Scharf I. Foraging behaviour of a neglected pit-building predator: the wormlion. Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.04.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Beponis LM, O'Dea RE, Ohl VA, Ryan MP, Backwell PRY, Binning SA, Haff TM. Cleaning Up After a Meal: The Consequences of Prey Disposal for Pit-Building Antlion Larvae. Ethology 2014. [DOI: 10.1111/eth.12257] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lucy M. Beponis
- Division of Evolution, Ecology and Genetics; Research School of Biology; The Australian National University; Canberra ACT Australia
| | - Rose E. O'Dea
- Division of Evolution, Ecology and Genetics; Research School of Biology; The Australian National University; Canberra ACT Australia
| | - Valérie-Anne Ohl
- Division of Evolution, Ecology and Genetics; Research School of Biology; The Australian National University; Canberra ACT Australia
| | - Mitchell P. Ryan
- Division of Evolution, Ecology and Genetics; Research School of Biology; The Australian National University; Canberra ACT Australia
| | - Patricia R. Y. Backwell
- Division of Evolution, Ecology and Genetics; Research School of Biology; The Australian National University; Canberra ACT Australia
| | - Sandra A. Binning
- Division of Evolution, Ecology and Genetics; Research School of Biology; The Australian National University; Canberra ACT Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies; The Australian National University; Canberra ACT Australia
| | - Tonya M. Haff
- Division of Evolution, Ecology and Genetics; Research School of Biology; The Australian National University; Canberra ACT Australia
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Klokočovnik V, Devetak D, Orlačnik M. Behavioral Plasticity and Variation in Pit Construction of Antlion Larvae in Substrates with Different Particle Sizes. Ethology 2012. [DOI: 10.1111/eth.12012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Dušan Devetak
- Faculty of Natural Sciences and Mathematics; Maribor; Slovenia
| | - Marina Orlačnik
- Faculty of Natural Sciences and Mathematics; Maribor; Slovenia
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19
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Foraging strategy switching in an antlion larva. Behav Processes 2012; 91:1-7. [PMID: 22634046 DOI: 10.1016/j.beproc.2012.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 03/10/2012] [Accepted: 04/22/2012] [Indexed: 11/20/2022]
Abstract
Antlion larvae are typically considered as trap-building predators, but some species of antlions always forage without using pits or only sometimes use pits to capture prey; they can ambush prey without pits. This study examined a species that switches its strategy between pit-trapping and ambushing and asked the mechanism behind the switching behaviour. A dynamic optimization model incorporating tradeoffs between the two strategies was built. The tradeoffs were prey capture success and predation risk (both are higher when pit-trapping). The model predicted that antlions should use the trap-building strategy when their energy status is low and should use the ambush strategy when their energy status is high. These predictions as well as an assumption (i.e., predation risk associated with pit-trapping is higher than that associated with ambushing) of the model were empirically confirmed. The results suggest that antlions flexibly switch between pit-trapping and ambushing to maximize their fitness by balancing the costs and benefits of the two strategies.
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Scharf I, Lubin Y, Ovadia O. Foraging decisions and behavioural flexibility in trap-building predators: a review. Biol Rev Camb Philos Soc 2010; 86:626-39. [PMID: 21062400 DOI: 10.1111/j.1469-185x.2010.00163.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Foraging theory was first developed to predict the behaviour of widely-foraging animals that actively search for prey. Although the behaviour of sit-and-wait predators often follows predictions derived from foraging theory, the similarity between these two distinct groups of predators is not always obvious. In this review, we compare foraging activities of trap-building predators (mainly pit-building antlions and web-building spiders), a specific group of sit-and-wait predators that construct traps as a foraging device, with those of widely-foraging predators. We refer to modifications of the trap characteristics as analogous to changes in foraging intensity. Our review illustrates that the responses of trap-building and widely-foraging predators to different internal and external factors, such as hunger level, conspecific density and predation threat are quite similar, calling for additional studies of foraging theory using trap-building predators. In each chapter of this review, we summarize the response of trap-building predators to a different factor, while contrasting it with the equivalent response characterizing widely-foraging predators. We provide here evidence that the behaviour of trap-building predators is not stereotypic or fixed as was once commonly accepted, rather it can vary greatly, depending on the individual's internal state and its interactions with external environmental factors.
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Affiliation(s)
- Inon Scharf
- Department of Biology II, Ludwig Maximilian University of Munich, Grosshadernerstr. 2, D-82152 Planegg-Martinsried, Germany.
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21
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Rao D. Experimental Evidence for the Amelioration of Shadow Competition in an Orb-Web Spider Through the ‘Ricochet’ Effect. Ethology 2009. [DOI: 10.1111/j.1439-0310.2009.01656.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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