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House CM, Duffield K, Rapkin J, Sakaluk SK, Hunt J. The transfer of male cuticular hydrocarbons provides a reliable cue of the risk and intensity of sperm competition in decorated crickets. Evolution 2024; 78:1606-1618. [PMID: 38864438 DOI: 10.1093/evolut/qpae088] [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: 02/27/2024] [Revised: 05/14/2024] [Accepted: 06/10/2024] [Indexed: 06/13/2024]
Abstract
Theoretically, males should increase their ejaculate expenditure when the probability of sperm competition occurring (or risk) is high but decrease ejaculate expenditure as the number of competing ejaculates (or intensity) increases. Here we examine whether male decorated crickets (Gryllodes sigillatus) use cuticular hydrocarbons (CHCs) transferred to females by rival males at mating to assess the risk and intensity of sperm competition and adjust their ejaculate accordingly. Unmated females and those perfumed with CHCs extracted from one, three, or five males could be distinguished chemically, providing a reliable cue of the risk and intensity of sperm competition. In agreement with theory, males mating with these females increased sperm number with the risk of sperm competition and decreased sperm number with the intensity of sperm competition. Similarly, as the risk of sperm competition increased, males produced a larger and more attractive spermatophylax (an important non-sperm component of the ejaculate) but these traits did not vary with the intensity of sperm competition. Our results therefore demonstrate that both sperm and non-sperm components of the male ejaculate respond to the risk and intensity of sperm competition in different ways and that CHCs provide males with an important cue to strategically tailor their ejaculate.
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Affiliation(s)
- Clarissa M House
- School of Science, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Richmond, NSW 2753, Australia
| | - Kristin Duffield
- Crop Bioprotection Research Unit, National Centre for Agricultural Utilization Research, USDA-ARS, Peoria, IL 61604, United States
- School of Biological Sciences, Illinois State University, Normal, IL 61790, United States
| | - James Rapkin
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, United Kingdom
| | - Scott K Sakaluk
- School of Biological Sciences, Illinois State University, Normal, IL 61790, United States
| | - John Hunt
- School of Science, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Richmond, NSW 2753, Australia
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, United Kingdom
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2
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Smithson CH, Duncan EJ, Sait SM, Bretman A. Sensory perception of rivals has trait-dependent effects on plasticity in Drosophila melanogaster. Behav Ecol 2024; 35:arae031. [PMID: 38680228 PMCID: PMC11053361 DOI: 10.1093/beheco/arae031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 03/05/2024] [Accepted: 04/23/2024] [Indexed: 05/01/2024] Open
Abstract
The social environment has myriad effects on individuals, altering reproduction, immune function, cognition, and aging. Phenotypic plasticity enables animals to respond to heterogeneous environments such as the social environment but requires that they assess those environments accurately. It has been suggested that combinations of sensory cues allow animals to respond rapidly and accurately to changeable environments, but it is unclear whether the same sensory inputs are required in all traits that respond to a particular environmental cue. Drosophila melanogaster males, in the presence of rival males, exhibit a consistent behavioral response by extending mating duration. However, exposure to a rival also results in a reduction in their lifespan, a phenomenon interpreted as a trade-off associated with sperm competition strategies. D. melanogaster perceive their rivals by using multiple sensory cues; interfering with at least two olfactory, auditory, or tactile cues eliminates the extension of mating duration. Here, we assessed whether these same cues were implicated in the lifespan reduction. Removal of combinations of auditory and olfactory cues removed the extended mating duration response to a rival, as previously found. However, we found that these manipulations did not alter the reduction in lifespan of males exposed to rivals or induce any changes in activity patterns, grooming, or male-male aggression. Therefore, our analysis suggests that lifespan reduction is not a cost associated with the behavioral responses to sperm competition. Moreover, this highlights the trait-specific nature of the mechanisms underlying plasticity in response to the same environmental conditions.
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Affiliation(s)
- Claire H Smithson
- School of Biology, Faculty of Biological Sciences, University of Leeds, Clarendon Road, Leeds, West Yorkshire, LS2 9JT, United Kingdom
| | - Elizabeth J Duncan
- School of Biology, Faculty of Biological Sciences, University of Leeds, Clarendon Road, Leeds, West Yorkshire, LS2 9JT, United Kingdom
| | - Steven M Sait
- School of Biology, Faculty of Biological Sciences, University of Leeds, Clarendon Road, Leeds, West Yorkshire, LS2 9JT, United Kingdom
| | - Amanda Bretman
- School of Biology, Faculty of Biological Sciences, University of Leeds, Clarendon Road, Leeds, West Yorkshire, LS2 9JT, United Kingdom
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3
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Playing to the crowd: Using Drosophila to dissect mechanisms underlying plastic male strategies in sperm competition games. ADVANCES IN THE STUDY OF BEHAVIOR 2023. [DOI: 10.1016/bs.asb.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Liu J, Zhang Y, Zheng X, He XZ, Wang Q. Combined cues of male competition influence spermatozoal investment in a moth. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13554] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Junyan Liu
- School of Agriculture and Environment Massey University Palmerston North New Zealand
| | - Yujing Zhang
- Guangxi Key Laboratory of Agric‐Environment and Agric‐Products Safety National Demonstration Center for Experimental Plant Science Education College of Agriculture Guangxi University Nanning China
| | - Xia‐Lin Zheng
- Guangxi Key Laboratory of Agric‐Environment and Agric‐Products Safety National Demonstration Center for Experimental Plant Science Education College of Agriculture Guangxi University Nanning China
| | - Xiong Z. He
- School of Agriculture and Environment Massey University Palmerston North New Zealand
| | - Qiao Wang
- School of Agriculture and Environment Massey University Palmerston North New Zealand
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5
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Ratz T, Nichol TW, Smiseth PT. Parental responses to increasing levels of handicapping in a burying beetle. Behav Ecol 2019. [DOI: 10.1093/beheco/arz157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AbstractParental care is highly variable, reflecting that parents make flexible decisions about how much care to provide in response to variation in the cost and/or benefit of care. Handicapping has traditionally been used as a tool for increasing the energetic cost of care, thereby inducing a reduction in care by handicapped parents. However, recent evidence shows that handicapped parents sometimes provide more care, suggesting that handicapping can trigger terminal investment. Here, we investigate responses to different levels of handicapping in the burying beetle Nicrophorus vespilloides by comparing handicapped female parents fitted with a wide range of handicaps, as well as control females without a handicap. We found that handicapped females spent more time provisioning food and less time being absent from the crypt than control females, while there was no effect of the level of handicapping among handicapped females. We found no effect of handicapping on larval begging behavior, larval performance (mean larval mass and brood size at dispersal), or female investment in future reproduction (i.e., weight gain while breeding and life span after breeding). Our findings provide no support for the widely held assumption that handicapping simply increases the cost of care. Instead, our results are consistent with the suggestion that handicapping triggers terminal investment by suppressing the condition of parents below the threshold at which terminal investment is triggered.
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Affiliation(s)
- Tom Ratz
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas W Nichol
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Per T Smiseth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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6
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Rebar D, Barbosa F, Greenfield MD. Female reproductive plasticity to the social environment and its impact on male reproductive success. Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2661-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Dore AA, McDowall L, Rouse J, Bretman A, Gage MJG, Chapman T. The role of complex cues in social and reproductive plasticity. Behav Ecol Sociobiol 2018; 72:124. [PMID: 30100665 PMCID: PMC6060796 DOI: 10.1007/s00265-018-2539-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 06/20/2018] [Accepted: 06/22/2018] [Indexed: 01/13/2023]
Abstract
Phenotypic plasticity can be a key determinant of fitness. The degree to which the expression of plasticity is adaptive relies upon the accuracy with which information about the state of the environment is integrated. This step might be particularly beneficial when environments, e.g. the social and sexual context, change rapidly. Fluctuating temporal dynamics could increase the difficulty of determining the appropriate level of expression of a plastic response. In this review, we suggest that new insights into plastic responses to the social and sexual environment (social and reproductive plasticity) may be gained by examining the role of complex cues (those comprising multiple, distinct sensory components). Such cues can enable individuals to more accurately monitor their environment in order to respond adaptively to it across the whole life course. We briefly review the hypotheses for the evolution of complex cues and then adapt these ideas to the context of social and sexual plasticity. We propose that the ability to perceive complex cues can facilitate plasticity, increase the associated fitness benefits and decrease the risk of costly 'mismatches' between phenotype and environment by (i) increasing the robustness of information gained from highly variable environments, (ii) fine-tuning responses by using multiple strands of information and (iii) reducing time lags in adaptive responses. We conclude by outlining areas for future research that will help to determine the interplay between complex cues and plasticity.
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Affiliation(s)
- Alice A. Dore
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ UK
| | - Laurin McDowall
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT UK
| | - James Rouse
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT UK
| | - Amanda Bretman
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT UK
| | - Matthew J. G. Gage
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ UK
| | - Tracey Chapman
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ UK
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Duffield KR, Hampton KJ, Houslay TM, Hunt J, Rapkin J, Sakaluk SK, Sadd BM. Age‐dependent variation in the terminal investment threshold in male crickets. Evolution 2018; 72:578-589. [DOI: 10.1111/evo.13443] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 01/17/2023]
Affiliation(s)
- Kristin R. Duffield
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
| | - Kylie J. Hampton
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
| | - Thomas M. Houslay
- Center for Ecology and Conservation, College of Life and Environmental Sciences University of Exeter Penryn TR10 9FE United Kingdom
| | - John Hunt
- Center for Ecology and Conservation, College of Life and Environmental Sciences University of Exeter Penryn TR10 9FE United Kingdom
- School of Science and Health and Hawkesbury Institute for the Environment, Western Sydney University Penrith NSW 2751 Australia
| | - James Rapkin
- Center for Ecology and Conservation, College of Life and Environmental Sciences University of Exeter Penryn TR10 9FE United Kingdom
| | - Scott K. Sakaluk
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
| | - Ben M. Sadd
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
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Barbosa F, Rebar D, Greenfield MD. When do trade-offs occur? The roles of energy constraints and trait flexibility in bushcricket populations. J Evol Biol 2017; 31:287-301. [PMID: 29215173 DOI: 10.1111/jeb.13221] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 11/28/2017] [Indexed: 11/28/2022]
Abstract
In many animal species, the expression of sexually selected traits is negatively correlated with traits associated with survival such as immune function, a relationship termed a 'trade-off'. But an alternative in which sexually selected traits are positively correlated with survival traits is also widespread. We propose that the nature of intertrait relationships is largely determined by overall energy expenditure, energy availability and trait flexibility, with trade-offs expected when individuals are subject to energy constraints. We tested this hypothesis in Ephippiger diurnus, a European bushcricket in which males are distinguished by two prominent sexually selected traits, acoustic calls and a large spermatophore transferred to the female at mating, and where immune function may be critical in survival. Ephippiger diurnus are distributed as small, isolated populations that are differentiated genetically and behaviourally. We analysed songs, spermatophores and the immune function in male individuals from eight populations spanning a range of song types. As predicted, we only found trade-offs in those populations that expended more energy on song and were less flexible in their ability to adjust that expenditure. Ultimately, energy constraints and resulting trade-offs may limit the evolution of song exaggeration in E. diurnus populations broadcasting long calls comprised of multiple 'syllables'.
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Affiliation(s)
- F Barbosa
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), Faculté des Sciences et Techniques, UMR 7261, Tours, France.,Department of Biology, Lake Forest College, Lake Forest, IL, USA
| | - D Rebar
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), Faculté des Sciences et Techniques, UMR 7261, Tours, France.,Department of Zoology, University of Cambridge, Cambridge, UK
| | - M D Greenfield
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), Faculté des Sciences et Techniques, UMR 7261, Tours, France
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Abstract
Although reproductive strategies can be influenced by a variety of intrinsic and extrinsic factors, life history theory provides a rigorous framework for explaining variation in reproductive effort. The terminal investment hypothesis proposes that a decreased expectation of future reproduction (as might arise from a mortality threat) should precipitate increased investment in current reproduction. Terminal investment has been widely studied, and a variety of intrinsic and extrinsic cues that elicit such a response have been identified across an array of taxa. Although terminal investment is often treated as a static strategy, the level at which a cue of decreased future reproduction is sufficient to trigger increased current reproductive effort (i.e., the terminal investment threshold) may depend on context, including the internal state of the organism or its current external environment, independent of the cue that triggers a shift in reproductive investment. Here, we review empirical studies that address the terminal investment hypothesis, exploring both the intrinsic and extrinsic factors that mediate its expression. Based on these studies, we propose a novel framework within which to view the strategy of terminal investment, incorporating factors that influence an individual's residual reproductive value beyond a terminal investment trigger - the dynamic terminal investment threshold.
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11
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Plasticity of signaling and mate choice in a trilling species of the Mecopoda complex (Orthoptera: Tettigoniidae). Behav Ecol Sociobiol 2017; 71:164. [PMID: 29104348 PMCID: PMC5655568 DOI: 10.1007/s00265-017-2381-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/28/2017] [Accepted: 09/09/2017] [Indexed: 11/13/2022]
Abstract
Abstract Males of a trilling species in the Mecopoda complex produce conspicuous calling songs that consist of two motifs: an amplitude-modulated motif with alternating loud and soft segments (AM-motif) and a continuous, high-intensity trill. The function of these song motifs for female attraction and competition between males was investigated. We tested the hypothesis that males modify their signaling behavior depending on the social environment (presence/absence of females or rival males) when they compete for mates. Therefore, we analyzed acoustic signaling of males in three different situations: (1) solo singing, (2) acoustic interaction with another male, and (3) singing in the presence of a female. In addition, the preference of females for these song motifs and further song parameters was studied in two-choice experiments. As expected, females showed a preference for conspicuous and loud song elements, but nevertheless, males increased the proportion of the AM-motif in the presence of a female. In acoustic interactions, males reduced bout duration significantly compared to both other situations. However, song bouts in this situation still overlapped more than expected by chance, which indicates intentionally simultaneous singing. A multivariate statistical analysis revealed that the proportion of the AM-motif and the duration of loud segments within the AM-motif allow a reliable prediction of whether males sing in isolation, compete with another male, or sing in the presence of a female. These results indicate that the AM-motif plays a dominant role especially in close-range courtship and that males are challenged in finding a balance between attracting females and saving energy during repeated acoustic interactions. Significance statement Males of acoustic insects often produce conspicuous calling songs that have a dual function in male-male competition and mate attraction. High signal amplitudes and signal rates are associated with high energetic costs for signal production. We would therefore predict that males adjust their signaling behavior according to their perception of the social context. Here we studied signal production and mate choice in a katydid, where males switch between loud and soft song segments in a dynamic way. Additionally, we examined the attractiveness of different song elements in female choice tests. Our results show how males of this katydid deal with the conflict of remaining attractive for females and competing with a costly signal with rivals.
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