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Gregory F Grether - One of the best experts on this subject based on the ideXlab platform.
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seasonal polyphenism in wing coloration affects species recognition in rubyspot damselflies Hetaerina spp
Journal of Evolutionary Biology, 2015Co-Authors: Jonathan P. Drury, Christopher N Anderson, Gregory F GretherAbstract:Understanding how phenotypic plasticityevolves and in turn affects thecourse of evolution is a major challenge in modern biology.By definition, biological species are reproductively isolated, but many animals fail to distinguish between conspecifics and closely related heterospecifics. In some cases,
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The Role of Wing Coloration in Sex Recognition and Competitor Recognition in Rubyspot Damselflies (Hetaerina spp.)
Ethology, 2015Co-Authors: Gregory F Grether, Jonathan P. Drury, Erin Berlin, Christopher N AndersonAbstract:The decision rules that animals use for distinguishing between conspecifics of different age and sex classes are relevant for understanding how closely related species interact in sympatry. In rubyspot damselflies (Hetaerina spp.), the red wing coloration of mature males is hypothesized to be a key trait for sex recognition and competitor recognition within species and the proximate trigger for interspecific male–male aggression. We tested this hypothesis by manipulating the wing coloration of tethered conspecific intruders and measuring the responses of territory holders of three species in the field. As predicted, covering the red spots of mature males with black ink nearly eliminated territorial responses, and in some cases, territorial holders clasped the blackened males as if they were females. Adding red spots to female wings triggered territorial responses and nearly eliminated sexual responses. Immature males with artificial red spots were attacked at the same rate as mature male intruders, and much more frequently than were immature male controls. The results varied somewhat by species. In H. titia, the only species of Hetaerina with substantial black wing pigmentation, the effects of blackening the red spots of intruders varied both geographically and seasonally. But even when blackening the red spots of male intruders did not reduce the aggressive response of H. titia territory holders, adding artificial red spots to female wings elicited aggressive responses and nearly eliminated sexual responses. The results of this study further strengthen the evidence that interspecific aggression in Hetaerina results from overlap in territorial signals and that the derived black wing pigmentation of H. titia reduces interspecific aggression.
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interspecific aggression not interspecific mating drives character displacement in the wing coloration of male rubyspot damselflies Hetaerina
Proceedings of The Royal Society B: Biological Sciences, 2014Co-Authors: Jonathan P. Drury, Gregory F GretherAbstract:Traits that mediate intraspecific social interactions may overlap in closely related sympatric species, resulting in costly between-species interactions. Such interactions have principally interested investigators studying the evolution of reproductive isolation via reproductive character displacement (RCD) or reinforcement, yet in addition to reproductive interference, interspecific trait overlap can lead to costly between-species aggression. Previous research on rubyspot damselflies (Hetaerina spp.) demonstrated that sympatric shifts in male wing colour patterns and competitor recognition reduce interspecific aggression, supporting the hypothesis that agonistic character displacement (ACD) drove trait shifts. However, a recent theoretical model shows that RCD overshadows ACD if the same male trait is used for both female mate recognition and male competitor recognition. To determine whether female mate recognition is based on male wing coloration in Hetaerina, we conducted a phenotype manipulation experiment. Compared to control males, male H. americana with wings manipulated to resemble a sympatric congener (H. titia) suffered no reduction in mating success. Thus, female mate recognition is not based on species differences in male wing coloration. Experimental males did, however, experience higher interspecific fighting rates and reduced survival compared to controls. These results greatly strengthen the case for ACD and highlight the mechanistic distinction between ACD and RCD.
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Interspecific aggression, not interspecific mating, drives character displacement in the wing coloration of male rubyspot damselflies (Hetaerina)
Proceedings. Biological sciences, 2014Co-Authors: Jonathan P. Drury, Gregory F GretherAbstract:Traits that mediate intraspecific social interactions may overlap in closely related sympatric species, resulting in costly between-species interactions. Such interactions have principally interested investigators studying the evolution of reproductive isolation via reproductive character displacement (RCD) or reinforcement, yet in addition to reproductive interference, interspecific trait overlap can lead to costly between-species aggression. Previous research on rubyspot damselflies (Hetaerina spp.) demonstrated that sympatric shifts in male wing colour patterns and competitor recognition reduce interspecific aggression, supporting the hypothesis that agonistic character displacement (ACD) drove trait shifts. However, a recent theoretical model shows that RCD overshadows ACD if the same male trait is used for both female mate recognition and male competitor recognition. To determine whether female mate recognition is based on male wing coloration in Hetaerina, we conducted a phenotype manipulation experiment. Compared to control males, male H. americana with wings manipulated to resemble a sympatric congener (H. titia) suffered no reduction in mating success. Thus, female mate recognition is not based on species differences in male wing coloration. Experimental males did, however, experience higher interspecific fighting rates and reduced survival compared to controls. These results greatly strengthen the case for ACD and highlight the mechanistic distinction between ACD and RCD.
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Characterization of novel microsatellite loci for Hetaerina americana damselflies, and cross-amplification in other species
Conservation Genetics Resources, 2013Co-Authors: Christopher N Anderson, Gregory F GretherAbstract:Hetaerina damselflies are distributed throughout the neotropics. We developed eleven microsatellite loci for the damselfly Hetaerina americana . Microsatellites were tested for polymorphism on a panel of 24 individuals. The number of alleles ranged from 2 to 6, observed heterozygosity from 0.080 to 0.701, and the fixation index from −0.266 to 1.000. Cross-amplification was tested in 7 different species in the genus Hetaerina from the United States and Mexico. These microsatellite loci will be useful for studies of population structure and gene flow in H. americana .
Alex Córdoba-aguilar - One of the best experts on this subject based on the ideXlab platform.
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Damselfly (Odonata: Calopterygidae) Population Decline in an Urbanizing Watershed.
Journal of insect science (Online), 2019Co-Authors: Alex Córdoba-aguilar, Maya Rocha-ortegaAbstract:Reduction of terrestrial vegetation and degradation of water quality are among the factors driving insect population decline in growing cities. In this study, we investigated the extent of habitat deterioration, behavioral and physiological responses, and fitness of a damselfly [Hetaerina americana (F.)] population in a semitropical region in central Mexico. The study population was located in a riverine area that crosses a small urban area (Tehuixtla city). We related two habitat variables (tree/shrub covered area and numbers of wastewater outlets) to presumable damselfly responses (larval and adult abundance, duration of adults exposed directly to sunlight, lipid content and muscle mass, and egg survival) over the years 2002 and 2016. We detected a reduction in terrestrial vegetation cover, an increase in wastewater outlets, and a decrease in larval and adult abundance. Adults were more exposed to sunlight in 2016 than in 2002 and showed a reduced lipid content and muscle mass in 2016. Egg survival also decreased. Although correlative, these results suggest impairment of damselfly condition (via lipid and muscle reduction) and fitness as urbanization increases.
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Body temperature regulation is associated with climatic and geographical variables but not wing pigmentation in two rubyspot damselflies (Odonata: Calopterygidae)
Physiological Entomology, 2016Co-Authors: Miguel Rivas, Enrique Martínez-meyer, Jesús Muñoz, Alex Córdoba-aguilarAbstract:It has been proposed that wing pigmented spots function in temperature control in male calopterygids. Using two rubyspot species Hetaerina americana Fabricius and Hetaerina vulnerata Hagen in Selys, the present study investigated whether (i) wing spot size and colour-modified aspect can predict temperature gain after a cooling event; (ii) wing spot size is related to the temperature needed to fly and how long it takes to initiate flight; and (iii) wing spot size is related to seasonality and altitude. The results obtained do not support any of these relationships. The results also indicate that H. vulnerata can achieve flight at 8 °C less than H. americana. The present study further investigates whether the species differ in their latitudinal and geographical distribution, and respond differently to bioclimatic variables. The results obtained provide support for this particular hypothesis, showing that H. vulnerata inhabits higher altitudes, and is able to tolerate colder environments compared with H. americana. Wing spots in the two Hetaerina species do not help in thermoregulation, although both species show different temperature control abilities. This difference in thermoregulatory ability may enable the species to colonize different environments and reduce interspecific competition.
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Is allometry of sexual traits adaptive? A field test with territorial damselflies
Biological Journal of the Linnean Society, 2015Co-Authors: Rafael Bello-bedoy, Miguel Rivas, Roberto Munguía-steyer, Martín Alejandro Serrano-meneses, Isaac González-santoyo, David E. Vrech, Alex Córdoba-aguilarAbstract:Recent studies have linked static allometry of sexual traits to selective advantages, in terms of sexual selection. An underlying, yet untested, assumption is that the allometry of sexual traits confers higher mating success and/or survival. Here, we investigated whether the allometry of two sexual traits is related to male mating success and survival in two species of damselflies: wing size in Paraphlebia zoe and the red-pigmented wing spot in Hetaerina americana. We used large field-based data sets of marked-recaptured animals, in which we recorded male mating success and survival. Both sexual traits exhibited hyperallometric patterns; however, allometry was not linked to either mating success or survival. These results indicate that, at least during the period of sexual competition, allometry does not seem to be adaptive. Although our results may only apply to our damselfly study subjects (which nevertheless would require further tests in different seasons and/or study sites), our findings should encourage researchers to evaluate at least whether the assumed adaptiveness of sexual trait allometry holds for their study animals. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114, 327–334.
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The Behavioral and Physiological Ecology of Adult Rubyspot Damselflies (Hetaerina, Calopterygidae, Odonata)
Advances in the Study of Behavior, 2014Co-Authors: Alex Córdoba-aguilar, Daniel González-tokmanAbstract:Abstract We review the behavioral and physiological ecology of rubyspot damselflies before, during, and after copulation. Adult rubyspots are sexually dimorphic, with males bearing a red wing spot. For reproduction, males aggregate and defend sunny river spots in a lek fashion: they mate with passing females and take them to communal vegetation sites for oviposition. Three alternative reproductive tactics (ARTs) are used: territorial (those that defend a site), nonterritorial (those that do not defend a site), and switcher (those that can switch between the former two tactics). Males using the three ARTs differ in physiological attributes related to spot size, and flight and immune ability, which are related to male quality and condition. In general, wing spot production is costly when food is scarce and therefore large spot sizes are associated with high mating success and survival. A key inducer of sexual activities is the juvenile hormone (JH). However, high JH titers in males negatively affect their immune expression and survival. In situations of immune demand, young males may skip territorial defence, while old males keep high territorial activity, supporting a scenario of terminal investment. During copulation, rubyspot males can remove sperm from the female's sperm storage organs using two mechanisms: sensory stimulation and direct physical removal. The sensory stimulation mechanism evolved through the female's sensory bias that control egg release and fertilization. The precopulatory interaction in rubyspots can be better understood using a sexual conflict scenario where, due to intense male harassment, females have reduced control of their mating rate. This may affect female survival and energetic resources.
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Allometry of a sexual trait in relation to diet experience and alternative mating tactics in two rubyspot damselflies (Calopterygidae: Hetaerina)
Biological Journal of the Linnean Society, 2013Co-Authors: Hugo A. Álvarez, Martín Alejandro Serrano-meneses, Isidora Reyes-márquez, Jesús Guillermo Jiménez-cortés, Alex Córdoba-aguilarAbstract:Several arguments have been put forward to explain how sexual selection drives the evolution of sexual trait allometry, especially hyperallometry. The ‘positive allometry theory’ suggests that hyperallometry is a rule in all-secondary sexual traits, whereas the ‘display hypothesis’ suggests that only males in good condition will exhibit hyperallometric sexual display traits. In the present study, we investigated: (1) the condition-dependence nature (by using two diet treatments that varied in the amount of food provided to the larvae) of a sexually selected trait (wing pigmentation; WP) in recently-emerged adults of the American rubyspot damselfly, Hetaerina americana, and (2) the scaling relationship between WP and body size (wing and body length) in the rubyspot damselflies H. americana and Hetaerina vulnerata, according to alternative reproductive tactics (ARTs; territorial and nonterritorial males). First, we found support that indicated that diet positively affected WP length, although there was no significant WP allometric pattern in relation to diet regimes. Second, WP was hyperallometric in both Hetaerina species. WP size was similar between ARTs and, in H. americana (but not H. vulnerata), nonterritorial males showed steeper slopes than territorial males when wing length was used. The results obtained support the notion that sexual traits are hyperallometric, although there is no clear pattern in relation to ARTs. © 2013 The Linnean Society of London
Christopher N Anderson - One of the best experts on this subject based on the ideXlab platform.
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seasonal polyphenism in wing coloration affects species recognition in rubyspot damselflies Hetaerina spp
Journal of Evolutionary Biology, 2015Co-Authors: Jonathan P. Drury, Christopher N Anderson, Gregory F GretherAbstract:Understanding how phenotypic plasticityevolves and in turn affects thecourse of evolution is a major challenge in modern biology.By definition, biological species are reproductively isolated, but many animals fail to distinguish between conspecifics and closely related heterospecifics. In some cases,
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The Role of Wing Coloration in Sex Recognition and Competitor Recognition in Rubyspot Damselflies (Hetaerina spp.)
Ethology, 2015Co-Authors: Gregory F Grether, Jonathan P. Drury, Erin Berlin, Christopher N AndersonAbstract:The decision rules that animals use for distinguishing between conspecifics of different age and sex classes are relevant for understanding how closely related species interact in sympatry. In rubyspot damselflies (Hetaerina spp.), the red wing coloration of mature males is hypothesized to be a key trait for sex recognition and competitor recognition within species and the proximate trigger for interspecific male–male aggression. We tested this hypothesis by manipulating the wing coloration of tethered conspecific intruders and measuring the responses of territory holders of three species in the field. As predicted, covering the red spots of mature males with black ink nearly eliminated territorial responses, and in some cases, territorial holders clasped the blackened males as if they were females. Adding red spots to female wings triggered territorial responses and nearly eliminated sexual responses. Immature males with artificial red spots were attacked at the same rate as mature male intruders, and much more frequently than were immature male controls. The results varied somewhat by species. In H. titia, the only species of Hetaerina with substantial black wing pigmentation, the effects of blackening the red spots of intruders varied both geographically and seasonally. But even when blackening the red spots of male intruders did not reduce the aggressive response of H. titia territory holders, adding artificial red spots to female wings elicited aggressive responses and nearly eliminated sexual responses. The results of this study further strengthen the evidence that interspecific aggression in Hetaerina results from overlap in territorial signals and that the derived black wing pigmentation of H. titia reduces interspecific aggression.
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Characterization of novel microsatellite loci for Hetaerina americana damselflies, and cross-amplification in other species
Conservation Genetics Resources, 2013Co-Authors: Christopher N Anderson, Gregory F GretherAbstract:Hetaerina damselflies are distributed throughout the neotropics. We developed eleven microsatellite loci for the damselfly Hetaerina americana . Microsatellites were tested for polymorphism on a panel of 24 individuals. The number of alleles ranged from 2 to 6, observed heterozygosity from 0.080 to 0.701, and the fixation index from −0.266 to 1.000. Cross-amplification was tested in 7 different species in the genus Hetaerina from the United States and Mexico. These microsatellite loci will be useful for studies of population structure and gene flow in H. americana .
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Multiple routes to reduced interspecific territorial fighting in Hetaerina damselflies
Behavioral Ecology, 2011Co-Authors: Christopher N Anderson, Gregory F GretherAbstract:Behavioral Ecology doi:10.1093/beheco/arr013 Advance Access publication 11 March 2011 Original Article Multiple routes to reduced interspecific territorial fighting in Hetaerina damselflies Christopher N. Anderson a,b and Gregory F. Grether a Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA and b Departamento de Ecologi´a Evolutiva, Instituto de Ecologi´a, Universidad Nacional Auto´noma de Me´xico, Circuito Exterior s/n, Apdo. Postal 70-275, Me´xico, D.F. 04510, Me´xico a INTRODUCTION I n their classic review of interspecific territoriality in birds, Orians and Willson (1964) described several possible out- comes of secondary contact between formerly allopatric terri- torial species. In one scenario, the newly sympatric species initially respond aggressively to each other and defend non- overlapping territories, but interspecific aggression is selected against because the species overlap so little in resource use that the costs of defending interspecific territories outweigh the benefits. Orians and Willson predicted that this would lead to divergence in the traits used to identify conspecifics until the species no longer respond aggressively to each other. They did not consider this character displacement scenario further, however, because they were primarily concerned with cases in which interspecific territoriality is adaptive. For the most part, researchers studying interspecific territoriality have continued to focus on cases in which it seems adaptive, while those interested in character displacement have focused on the classic mechanisms described by Brown and Wilson (1956; but see Cody 1969, 1973; Gill 1974; Murray 1981; Adams 2004; Tynkkynen et al. 2005; Peiman and Robinson 2007; Grether et al. 2009). Brown and Wilson (1956) alluded to the possi- bility that interspecific fighting could cause sympatric charac- ter shifts but only to clarify that they did not intend their theory of character displacement to encompass such shifts. Address correspondence to C.N. Anderson. E-mail: cnanderson1980 @gmail.com. Received 18 September 2010; revised 21 December 2010; accepted 13 January 2011. O The Author 2011. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com Recently, it has become clear that interspecific fighting is common among closely related or phenotypically similar spe- cies (Schultz and Switzer 2001; Dijkstra et al. 2005, 2006; Tynkkynen et al. 2006; Pauers et al. 2008; Peiman and Robinson 2010). Moreover, interspecific fighting is not re- stricted to species that compete with each other for limited resources (Grether et al. 2009; Ord and Stamps 2009; Peiman and Robinson 2010). Grether et al. (2009) modeled the char- acter displacement scenario described by Orians and Willson (1964) and showed that 2 species that initially treat each other as competitors but are not in competition for a limiting re- source can diverge in agonistic signals and competitor recog- nition functions until they no longer interact aggressively. Conversely, species that do not initially recognize each other as competitors but are in competition for a limiting resource can converge in agonistic signals and competitor recognition functions until they treat each other as competitors, as sug- gested by Cody (1969, 1973). Several putative examples of both of these forms of ‘‘agonistic’’ character displacement have been reported (Tobias and Seddon 2009; Anderson and Grether 2010a), but in general, the evolutionary effects of interspecific fighting remain understudied (Grether et al. 2009; Peiman and Robinson 2010). In this paper, we further investigate recently reported cases of divergent agonistic character displacement in Hetaerina damselflies (Anderson and Grether 2010a, 2010b). We explain the specific goals of this paper after introducing the study system and the evidence for character displacement. Male Hetaerina damselflies form leks along rivers where they defend small non-resource–based mating territories. Both mating and territorial behavior typically occurs between the hours of 10:00 and 17:00; outside this period, males are Downloaded from beheco.oxfordjournals.org at University of California, Los Angeles on May 20, 2011 Interspecific territoriality may be adaptive if territories contain depletable resources that are valuable to both species, but it can also arise as a maladaptive by-product of intraspecific territoriality. In the latter scenario, sympatric species ought to diverge in ways that reduce interspecific fighting. We studied 4 Hetaerina damselfly species that can be found in sympatry in North America. Prior work showed that sympatric populations have diverged from each other in wing coloration and competitor recognition in 2 of the 4 sympatric species pairs (H. titia/H. occisa, H. titia/H. americana). Here, we show that sympatric populations of these 2 species pairs overlap completely in habitat use, and yet, interspecific territorial fights occur much less frequently than intraspe- cific fights. Experimentally manipulating the wing coloration of male H. occisa and H. americana to more closely resemble H. titia increased the rate of interspecific fights, which provides direct evidence that divergence in wing coloration is partly responsible for the low rate of interspecific fights. We found that interspecific fighting is also reduced in the other 2 species pairs (H. occisa/ H. cruentata, H. americana/H. cruentata), even though prior work showed that heterospecific territory intruders are attacked just as aggressively as conspecific territory intruders. In these cases, however, the sympatric species differ sufficiently in habitat use to reduce the interspecific encounter rate and thereby account for the reduced rate of interspecific fighting. Thus, interspecific fighting is reduced relative to intraspecific fighting in all 4 species pairs, albeit through different mechanisms. Key words: com- petitor recognition, heterospecific aggression, interspecific fighting, interspecific territoriality, species recognition. [Behav Ecol
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character displacement in the fighting colours of Hetaerina damselflies
Proceedings of The Royal Society B: Biological Sciences, 2010Co-Authors: Christopher N Anderson, Gregory F GretherAbstract:Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a pattern of character displacement (divergence in sympatry). A geographical survey of four Hetaerina damselfly species in Mexico and Texas showed evidence for character displacement in both species pairs that regularly occurs sympatrically. Hetaerina titia, a species that typically has large black wing spots and small red wing spots, shifted to having even larger black spots and smaller red wing spots at sites where a congener with large red wing spots is numerically dominant (Hetaerina americana or Hetaerina occisa). Hetaerina americana showed the reverse pattern, shifting towards larger red wing spots where H. titia is numerically dominant. This pattern is consistent with the process of agonistic character displacement, but the ontogenetic basis of the shift remains to be demonstrated.
Daniel González-tokman - One of the best experts on this subject based on the ideXlab platform.
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The Behavioral and Physiological Ecology of Adult Rubyspot Damselflies (Hetaerina, Calopterygidae, Odonata)
Advances in the Study of Behavior, 2014Co-Authors: Alex Córdoba-aguilar, Daniel González-tokmanAbstract:Abstract We review the behavioral and physiological ecology of rubyspot damselflies before, during, and after copulation. Adult rubyspots are sexually dimorphic, with males bearing a red wing spot. For reproduction, males aggregate and defend sunny river spots in a lek fashion: they mate with passing females and take them to communal vegetation sites for oviposition. Three alternative reproductive tactics (ARTs) are used: territorial (those that defend a site), nonterritorial (those that do not defend a site), and switcher (those that can switch between the former two tactics). Males using the three ARTs differ in physiological attributes related to spot size, and flight and immune ability, which are related to male quality and condition. In general, wing spot production is costly when food is scarce and therefore large spot sizes are associated with high mating success and survival. A key inducer of sexual activities is the juvenile hormone (JH). However, high JH titers in males negatively affect their immune expression and survival. In situations of immune demand, young males may skip territorial defence, while old males keep high territorial activity, supporting a scenario of terminal investment. During copulation, rubyspot males can remove sperm from the female's sperm storage organs using two mechanisms: sensory stimulation and direct physical removal. The sensory stimulation mechanism evolved through the female's sensory bias that control egg release and fertilization. The precopulatory interaction in rubyspots can be better understood using a sexual conflict scenario where, due to intense male harassment, females have reduced control of their mating rate. This may affect female survival and energetic resources.
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SUPPORT FOR THE IMMUNOCOMPETENCE HANDICAP HYPOTHESIS IN THE WILD: HORMONAL MANIPULATION DECREASES SURVIVAL IN SICK DAMSELFLIES
Evolution; international journal of organic evolution, 2012Co-Authors: Daniel González-tokman, Roberto Munguía-steyer, Isaac González-santoyo, Fernanda Baena-díaz, Alex Córdoba-aguilarAbstract:The immunocompetence handicap hypothesis (ICHH) states that hormones enhance sexual trait expression but impair immunity. Previous tests of the ICHH have been hampered by experimental design problems. Here, we report on an experimental test of the ICHH that includes manipulations of both hormones and infections in males of the territorial damselfly, Hetaerina americana, with accurate survival measurements. We conducted a fully factorial experiment subjecting each individual to one of three topical treatments: methoprene (a juvenile hormone analog), acetone, or control, and one of three injection treatments: bacteria, PBS, or control. We measured survival of manipulated males in both the wild and in captivity. As predicted, survival was most heavily impaired in methoprene-bacteria males than in the other groups in the wild, and no survival differences emerged in captive animals. This result confirms that survival is one cost an animal pays for increased hormonal levels. This corroborates theoretical predictions of the ICHH.
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Infection effects on feeding and territorial behaviour in a predatory insect in the wild
Animal Behaviour, 2011Co-Authors: Daniel González-tokman, Alex Córdoba-aguilar, Isaac González-santoyo, Humberto Lanz-mendozaAbstract:Sick animals may change their feeding behaviour to compensate for infections. However, there is little information regarding whether infection affects (1) feeding behaviour of predators, (2) feeding behaviour using an experimental approach in the wild, (3) other costly behaviours and/or (4) physiological components of condition. We experimentally infected males of the predatory damselfly Hetaerina americana in a field experiment. We hypothesized that infection would reduce feeding behaviour. We further predicted a reduction in territorial activity, an increase in immune response (measured by the activity of phenoloxidase, PO) and a reduction of fat reserves and flight-associated muscle mass (two traits usually traded off with immune ability and territorial behaviour). We also infected males in a laboratory experiment that controlled for food supply and territorial activity, and measured the same physiological characters. Immune challenges in the field experiment unexpectedly increased feeding rate but did not change territorial activities. Muscle mass was reduced in the field but not in the laboratory, probably because of differences in the presence of energetically expensive territorial activities. In the laboratory, starvation and infection reduced PO activity and fat stores but did not affect muscle mass. Thus, our field and laboratory results support the idea that increased feeding compensates for infections in predators.
Jonathan P. Drury - One of the best experts on this subject based on the ideXlab platform.
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seasonal polyphenism in wing coloration affects species recognition in rubyspot damselflies Hetaerina spp
Journal of Evolutionary Biology, 2015Co-Authors: Jonathan P. Drury, Christopher N Anderson, Gregory F GretherAbstract:Understanding how phenotypic plasticityevolves and in turn affects thecourse of evolution is a major challenge in modern biology.By definition, biological species are reproductively isolated, but many animals fail to distinguish between conspecifics and closely related heterospecifics. In some cases,
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The Role of Wing Coloration in Sex Recognition and Competitor Recognition in Rubyspot Damselflies (Hetaerina spp.)
Ethology, 2015Co-Authors: Gregory F Grether, Jonathan P. Drury, Erin Berlin, Christopher N AndersonAbstract:The decision rules that animals use for distinguishing between conspecifics of different age and sex classes are relevant for understanding how closely related species interact in sympatry. In rubyspot damselflies (Hetaerina spp.), the red wing coloration of mature males is hypothesized to be a key trait for sex recognition and competitor recognition within species and the proximate trigger for interspecific male–male aggression. We tested this hypothesis by manipulating the wing coloration of tethered conspecific intruders and measuring the responses of territory holders of three species in the field. As predicted, covering the red spots of mature males with black ink nearly eliminated territorial responses, and in some cases, territorial holders clasped the blackened males as if they were females. Adding red spots to female wings triggered territorial responses and nearly eliminated sexual responses. Immature males with artificial red spots were attacked at the same rate as mature male intruders, and much more frequently than were immature male controls. The results varied somewhat by species. In H. titia, the only species of Hetaerina with substantial black wing pigmentation, the effects of blackening the red spots of intruders varied both geographically and seasonally. But even when blackening the red spots of male intruders did not reduce the aggressive response of H. titia territory holders, adding artificial red spots to female wings elicited aggressive responses and nearly eliminated sexual responses. The results of this study further strengthen the evidence that interspecific aggression in Hetaerina results from overlap in territorial signals and that the derived black wing pigmentation of H. titia reduces interspecific aggression.
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interspecific aggression not interspecific mating drives character displacement in the wing coloration of male rubyspot damselflies Hetaerina
Proceedings of The Royal Society B: Biological Sciences, 2014Co-Authors: Jonathan P. Drury, Gregory F GretherAbstract:Traits that mediate intraspecific social interactions may overlap in closely related sympatric species, resulting in costly between-species interactions. Such interactions have principally interested investigators studying the evolution of reproductive isolation via reproductive character displacement (RCD) or reinforcement, yet in addition to reproductive interference, interspecific trait overlap can lead to costly between-species aggression. Previous research on rubyspot damselflies (Hetaerina spp.) demonstrated that sympatric shifts in male wing colour patterns and competitor recognition reduce interspecific aggression, supporting the hypothesis that agonistic character displacement (ACD) drove trait shifts. However, a recent theoretical model shows that RCD overshadows ACD if the same male trait is used for both female mate recognition and male competitor recognition. To determine whether female mate recognition is based on male wing coloration in Hetaerina, we conducted a phenotype manipulation experiment. Compared to control males, male H. americana with wings manipulated to resemble a sympatric congener (H. titia) suffered no reduction in mating success. Thus, female mate recognition is not based on species differences in male wing coloration. Experimental males did, however, experience higher interspecific fighting rates and reduced survival compared to controls. These results greatly strengthen the case for ACD and highlight the mechanistic distinction between ACD and RCD.
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Interspecific aggression, not interspecific mating, drives character displacement in the wing coloration of male rubyspot damselflies (Hetaerina)
Proceedings. Biological sciences, 2014Co-Authors: Jonathan P. Drury, Gregory F GretherAbstract:Traits that mediate intraspecific social interactions may overlap in closely related sympatric species, resulting in costly between-species interactions. Such interactions have principally interested investigators studying the evolution of reproductive isolation via reproductive character displacement (RCD) or reinforcement, yet in addition to reproductive interference, interspecific trait overlap can lead to costly between-species aggression. Previous research on rubyspot damselflies (Hetaerina spp.) demonstrated that sympatric shifts in male wing colour patterns and competitor recognition reduce interspecific aggression, supporting the hypothesis that agonistic character displacement (ACD) drove trait shifts. However, a recent theoretical model shows that RCD overshadows ACD if the same male trait is used for both female mate recognition and male competitor recognition. To determine whether female mate recognition is based on male wing coloration in Hetaerina, we conducted a phenotype manipulation experiment. Compared to control males, male H. americana with wings manipulated to resemble a sympatric congener (H. titia) suffered no reduction in mating success. Thus, female mate recognition is not based on species differences in male wing coloration. Experimental males did, however, experience higher interspecific fighting rates and reduced survival compared to controls. These results greatly strengthen the case for ACD and highlight the mechanistic distinction between ACD and RCD.