Parental overproduction is hypothesized to hedge against uncertainty over food availability and stochastic death of offspring, and to improve brood fitness. Understanding the evolution of overproduction requires quantifying its benefits to parents across a wide range of ecological conditions, which has rarely been done. Using a multiple hypotheses approach and 30 years of data, we evaluated the benefits of overproduction in the Blue-footed booby, a seabird that lays up to three eggs asynchronously, resulting in an aggressive brood hierarchy that facilitates the death of last-hatched chicks under low food abundance. Results support the resource-tracking hypothesis, as low prey abundance (estimated from sea surface temperature and chlorophyll-a concentration) led to rapid brood reduction. The insurance hypothesis was supported in broods of three, where last-hatched chicks’ survival increased after a sibling’s death. Conversely, in broods of two, results suggested that parents abandoned last-hatched chicks following first-hatched chicks’ deaths. No direct evidence supported the facilitation hypothesis: presence of a last-hatched chick during development did not enhance its sibling’s fitness in the short or long term. The value of last-hatched offspring to parents, as “extra” or “insurance” varied with indices of food abundance, brood size, and parental age. Ninety percent of overproduction benefit came from enabling parents to capitalize on favorable conditions by fledging additional offspring. Our study provides insight into the forces driving overproduction, explaining the adaptiveness of this apparently wasteful behavior and allowing us to better predict how overproduction’s benefits might be modified by ocean warming.
{"title":"Parental overproduction allows siblicidal bird to adjust brood size to climate-driven prey variation","authors":"Iván Bizberg-Barraza, Cristina Rodríguez, Hugh Drummond","doi":"10.1093/beheco/arae007","DOIUrl":"https://doi.org/10.1093/beheco/arae007","url":null,"abstract":"Parental overproduction is hypothesized to hedge against uncertainty over food availability and stochastic death of offspring, and to improve brood fitness. Understanding the evolution of overproduction requires quantifying its benefits to parents across a wide range of ecological conditions, which has rarely been done. Using a multiple hypotheses approach and 30 years of data, we evaluated the benefits of overproduction in the Blue-footed booby, a seabird that lays up to three eggs asynchronously, resulting in an aggressive brood hierarchy that facilitates the death of last-hatched chicks under low food abundance. Results support the resource-tracking hypothesis, as low prey abundance (estimated from sea surface temperature and chlorophyll-a concentration) led to rapid brood reduction. The insurance hypothesis was supported in broods of three, where last-hatched chicks’ survival increased after a sibling’s death. Conversely, in broods of two, results suggested that parents abandoned last-hatched chicks following first-hatched chicks’ deaths. No direct evidence supported the facilitation hypothesis: presence of a last-hatched chick during development did not enhance its sibling’s fitness in the short or long term. The value of last-hatched offspring to parents, as “extra” or “insurance” varied with indices of food abundance, brood size, and parental age. Ninety percent of overproduction benefit came from enabling parents to capitalize on favorable conditions by fledging additional offspring. Our study provides insight into the forces driving overproduction, explaining the adaptiveness of this apparently wasteful behavior and allowing us to better predict how overproduction’s benefits might be modified by ocean warming.","PeriodicalId":8840,"journal":{"name":"Behavioral Ecology","volume":"14 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139666771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Skye D Fissette, Tyler J Buchinger, Sonam Tamrakar, Anne M Scott, Weiming Li
The sensory trap model of signal evolution suggests that males manipulate females into mating using traits that mimic cues used in a nonsexual context. Despite much empirical support for sensory traps, little is known about how females evolve in response to these deceptive signals. Female sea lamprey (Petromyzon marinus) evolved to discriminate a male sex pheromone from the larval odor it mimics and orient only towards males during mate search. Larvae and males release the attractant 3-keto petromyzonol sulfate (3kPZS), but spawning females avoid larval odor using the pheromone antagonist, petromyzonol sulfate (PZS), which larvae but not males, release at higher rates than 3kPZS. We tested the hypothesis that migratory females also discriminate between larval odor and the male pheromone and orient only to larval odor during anadromous migration, when they navigate within spawning streams using larval odor before they begin mate search. In-stream behavioral assays revealed that, unlike spawning females, migratory females do not discriminate between mixtures of 3kPZS and PZS applied at ratios typical of larval versus male odorants. Our results indicate females discriminate between the sexual and nonsexual sources of 3kPZS during but not outside of mating and show sensory traps can lead to reliable sexual communication without females shifting their responses in the original context.
{"title":"Sensory trap leads to reliable communication without a shift in nonsexual responses to the model cue","authors":"Skye D Fissette, Tyler J Buchinger, Sonam Tamrakar, Anne M Scott, Weiming Li","doi":"10.1093/beheco/arae006","DOIUrl":"https://doi.org/10.1093/beheco/arae006","url":null,"abstract":"The sensory trap model of signal evolution suggests that males manipulate females into mating using traits that mimic cues used in a nonsexual context. Despite much empirical support for sensory traps, little is known about how females evolve in response to these deceptive signals. Female sea lamprey (Petromyzon marinus) evolved to discriminate a male sex pheromone from the larval odor it mimics and orient only towards males during mate search. Larvae and males release the attractant 3-keto petromyzonol sulfate (3kPZS), but spawning females avoid larval odor using the pheromone antagonist, petromyzonol sulfate (PZS), which larvae but not males, release at higher rates than 3kPZS. We tested the hypothesis that migratory females also discriminate between larval odor and the male pheromone and orient only to larval odor during anadromous migration, when they navigate within spawning streams using larval odor before they begin mate search. In-stream behavioral assays revealed that, unlike spawning females, migratory females do not discriminate between mixtures of 3kPZS and PZS applied at ratios typical of larval versus male odorants. Our results indicate females discriminate between the sexual and nonsexual sources of 3kPZS during but not outside of mating and show sensory traps can lead to reliable sexual communication without females shifting their responses in the original context.","PeriodicalId":8840,"journal":{"name":"Behavioral Ecology","volume":"14 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139667021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Miraim Benita, Ariel Menahem, Inon Scharf, Daphna Gottlieb
Temporal niche segregation is a way to reduce competition over shared resources. Species with overlapping spatial niches often show plasticity and can use different activity times to minimize competition with and disturbance by other species. In many granivores, especially those living in their food resources, there is low competition over food, but other selective forces can drive distinct temporal activity times. Reproductive interference, that is, the interaction between individuals of different species during mate acquisition, can be such a driving force. Reproductive interference is a strong driving force for niche segregation between the co-occurring flour beetles Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae). Nevertheless, most studies on Tribolium spp. evaluated other selective forces, such as resource competition, which are potentially weaker. Here, we aimed to characterize the species’ peak activity time and its plasticity when exposed to a possible reproductive interference cue. We used a synthetic aggregative pheromone, shared by both species, as a cue for potential reproductive interference. We compared temporal niche plasticity between the sexes because reproductive interference is known mainly to reduce the female’s fitness. We found that both species’ activity times were hard-wired to an endogenous clock and that the sexes differed in their peak activity time and activity level. However, once exposed to the aggregation pheromone, only females shifted their activity time to match that of conspecific males, hence expressing more plasticity than the males to reduce Reproductive interference. These findings suggest an important role of the aggregation pheromone in the process of niche segregation.
{"title":"Inter- and intraspecific female behavioral plasticity drive temporal niche segregation in two Tribolium species","authors":"Miraim Benita, Ariel Menahem, Inon Scharf, Daphna Gottlieb","doi":"10.1093/beheco/arad116","DOIUrl":"https://doi.org/10.1093/beheco/arad116","url":null,"abstract":"Temporal niche segregation is a way to reduce competition over shared resources. Species with overlapping spatial niches often show plasticity and can use different activity times to minimize competition with and disturbance by other species. In many granivores, especially those living in their food resources, there is low competition over food, but other selective forces can drive distinct temporal activity times. Reproductive interference, that is, the interaction between individuals of different species during mate acquisition, can be such a driving force. Reproductive interference is a strong driving force for niche segregation between the co-occurring flour beetles Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae). Nevertheless, most studies on Tribolium spp. evaluated other selective forces, such as resource competition, which are potentially weaker. Here, we aimed to characterize the species’ peak activity time and its plasticity when exposed to a possible reproductive interference cue. We used a synthetic aggregative pheromone, shared by both species, as a cue for potential reproductive interference. We compared temporal niche plasticity between the sexes because reproductive interference is known mainly to reduce the female’s fitness. We found that both species’ activity times were hard-wired to an endogenous clock and that the sexes differed in their peak activity time and activity level. However, once exposed to the aggregation pheromone, only females shifted their activity time to match that of conspecific males, hence expressing more plasticity than the males to reduce Reproductive interference. These findings suggest an important role of the aggregation pheromone in the process of niche segregation.","PeriodicalId":8840,"journal":{"name":"Behavioral Ecology","volume":"44 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139509626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cultural evolution facilitates behavioural adaptation in many species. The pace of cultural evolution can be accelerated by population turnover where newcomers (immigrants or juvenile recruits) introduce adaptive cultural traits into their new group. However, where newcomers are naïve to the challenges of their new group, population turnover could potentially slow the rate of cultural evolution. Here, we model cultural evolution with population turnover and show that even if turnover results in the replacement of experienced individuals with naïve ones, turnover can still accelerate cultural evolution if (a) the rate of social learning is more than twice as fast as the turnover rate and (b) newcomers are more likely to learn socially than behaviourally conservative existing group members. Although population turnover is a relatively simple factor, it is common to all animal societies and variation in the turnover rate may potentially play an important role in explaining variation in the occurrence and rates of adaptive cultural evolution across species.
{"title":"Population turnover, behavioural conservatism, and rates of cultural evolution","authors":"Mark Dyble, Alberto J C Micheletti","doi":"10.1093/beheco/arae003","DOIUrl":"https://doi.org/10.1093/beheco/arae003","url":null,"abstract":"Cultural evolution facilitates behavioural adaptation in many species. The pace of cultural evolution can be accelerated by population turnover where newcomers (immigrants or juvenile recruits) introduce adaptive cultural traits into their new group. However, where newcomers are naïve to the challenges of their new group, population turnover could potentially slow the rate of cultural evolution. Here, we model cultural evolution with population turnover and show that even if turnover results in the replacement of experienced individuals with naïve ones, turnover can still accelerate cultural evolution if (a) the rate of social learning is more than twice as fast as the turnover rate and (b) newcomers are more likely to learn socially than behaviourally conservative existing group members. Although population turnover is a relatively simple factor, it is common to all animal societies and variation in the turnover rate may potentially play an important role in explaining variation in the occurrence and rates of adaptive cultural evolution across species.","PeriodicalId":8840,"journal":{"name":"Behavioral Ecology","volume":"84 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139496640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Laura Gangoso, Duarte S Viana, Marina Merchán, Jordi Figuerola
Intraspecific phenotypic variability is key to respond to environmental changes and anomalies. However, documenting the emergence of behavioral diversification in natural populations has remained elusive due to the difficulty of observing such phenomenon at the right time and place. Here, we investigated how the emergence of a new trophic strategy in a population subjected to high fluctuations in the availability of its main trophic resource (migrating songbirds) affected the breeding performance, population structure, and population fitness of a specialized color polymorphic predator, the Eleonora’s falcon from the Canary Islands. Using long-term data (2007-2022), we found that the exploitation of an alternative prey (a local petrel species) was associated with the growth of a previously residual falcon colony. Pairs in this colony laid earlier and raised more fledglings than in the other established colonies. The specialization on petrels increased over time, independently of annual fluctuations in prey availability. Importantly, however, the positive effect of petrel consumption on productivity was stronger in years with lower food availability. This trophic diversification was further associated with the genetically-determined color morph, with dark individuals preying more frequently on petrels than pale ones, which might promote the long-term maintenance of genotypic and phenotypic diversity. We empirically demonstrate how the emergence of an alternative trophic strategy can buffer populations against harsh environmental fluctuations by stabilizing their productivity.
{"title":"A new trophic specialization buffers a top predator against climate-driven resource instability","authors":"Laura Gangoso, Duarte S Viana, Marina Merchán, Jordi Figuerola","doi":"10.1093/beheco/arae005","DOIUrl":"https://doi.org/10.1093/beheco/arae005","url":null,"abstract":"Intraspecific phenotypic variability is key to respond to environmental changes and anomalies. However, documenting the emergence of behavioral diversification in natural populations has remained elusive due to the difficulty of observing such phenomenon at the right time and place. Here, we investigated how the emergence of a new trophic strategy in a population subjected to high fluctuations in the availability of its main trophic resource (migrating songbirds) affected the breeding performance, population structure, and population fitness of a specialized color polymorphic predator, the Eleonora’s falcon from the Canary Islands. Using long-term data (2007-2022), we found that the exploitation of an alternative prey (a local petrel species) was associated with the growth of a previously residual falcon colony. Pairs in this colony laid earlier and raised more fledglings than in the other established colonies. The specialization on petrels increased over time, independently of annual fluctuations in prey availability. Importantly, however, the positive effect of petrel consumption on productivity was stronger in years with lower food availability. This trophic diversification was further associated with the genetically-determined color morph, with dark individuals preying more frequently on petrels than pale ones, which might promote the long-term maintenance of genotypic and phenotypic diversity. We empirically demonstrate how the emergence of an alternative trophic strategy can buffer populations against harsh environmental fluctuations by stabilizing their productivity.","PeriodicalId":8840,"journal":{"name":"Behavioral Ecology","volume":"20 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139496575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Meng-Han Joseph Chung, Megan L Head, Rebecca J Fox, Michael D Jennions
Past reproductive effort allows males to assess their ability to acquire mates, but it also consumes resources that can reduce their future competitive ability. Few studies have examined how a male’s reproductive history affects his subsequent mate choice; and, to date, no study has determined the relative contribution of past mating behavior and past ejaculate production because these two forms of investment are naturally highly correlated. Here, we disentangled the relative effects of past mating behavior and past ejaculate production in mosquitofish (Gambusia holbrooki) by experimentally preventing some males from ejaculating when trying to mate. We assessed the effect of mating behavior on mate choice by comparing males that had previously been with or without access to females and male rivals for 8 and 16 weeks; and assessed the effect of ejaculation on mate choice by comparing males that either could or could not ejaculate when they had access to females for 16 weeks. Reproductive treatment did not affect male attractiveness, but it did affect male mate choice. Somewhat surprisingly, in 5 of the 6 treatment-age at testing combinations, males preferred a female in the vicinity of a male rival over a solitary female. This preference was marginally stronger for males that had previously engaged in mating behavior but was unaffected by past ejaculate production. We discuss the potential benefits to males of associating with another male when seeking mates. This is the first study to quantify the relative influence of pre- and post-copulatory reproductive investment on male mate choice.
{"title":"Effects of past mating behavior versus past ejaculation on male mate choice and male attractiveness","authors":"Meng-Han Joseph Chung, Megan L Head, Rebecca J Fox, Michael D Jennions","doi":"10.1093/beheco/arae002","DOIUrl":"https://doi.org/10.1093/beheco/arae002","url":null,"abstract":"Past reproductive effort allows males to assess their ability to acquire mates, but it also consumes resources that can reduce their future competitive ability. Few studies have examined how a male’s reproductive history affects his subsequent mate choice; and, to date, no study has determined the relative contribution of past mating behavior and past ejaculate production because these two forms of investment are naturally highly correlated. Here, we disentangled the relative effects of past mating behavior and past ejaculate production in mosquitofish (Gambusia holbrooki) by experimentally preventing some males from ejaculating when trying to mate. We assessed the effect of mating behavior on mate choice by comparing males that had previously been with or without access to females and male rivals for 8 and 16 weeks; and assessed the effect of ejaculation on mate choice by comparing males that either could or could not ejaculate when they had access to females for 16 weeks. Reproductive treatment did not affect male attractiveness, but it did affect male mate choice. Somewhat surprisingly, in 5 of the 6 treatment-age at testing combinations, males preferred a female in the vicinity of a male rival over a solitary female. This preference was marginally stronger for males that had previously engaged in mating behavior but was unaffected by past ejaculate production. We discuss the potential benefits to males of associating with another male when seeking mates. This is the first study to quantify the relative influence of pre- and post-copulatory reproductive investment on male mate choice.","PeriodicalId":8840,"journal":{"name":"Behavioral Ecology","volume":"7 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139496013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many entomopathogenic fungi cause infections that kill their insect host. Little is understood about changes in the reproductive investment that occur during an infection by a lethal disease over the waning life of an insect. Life history theory suggests the host will respond by investing resources into fighting the disease or increasing reproduction. Here, we investigate how the reproductive life of adult house flies, Musca domestica, is impacted by its host-specific fungal pathogen, Entomophthora muscae. Specifically, we test how the week-long infection alters the mating behavior of virgin adult male house flies. We find that the pathogen significantly decreases male libido; an effect which grows stronger over the course of the infection. Furthermore, females were significantly less likely to choose an infected male, reducing male mating success. Additionally, we assessed sperm viability to understand the reproductive costs for monandrous females to mate with infected males. Analyses revealed that sperm quality decreases as early as three days post-infection. These results show that E. muscae, which can have a prevalence near 100% in wild populations, causes severe lifetime reproductive costs to male house flies. Understanding how host-pathogen interactions affect host life history is crucial for elucidating all the negative effects pathogen virulence exerts on hosts.
{"title":"Low sex drive and choosy females: Fungal infections are a reproductive downfall for male house flies","authors":"Sam Edwards, Eleanor Bath, Henrik H De Fine Licht","doi":"10.1093/beheco/arae004","DOIUrl":"https://doi.org/10.1093/beheco/arae004","url":null,"abstract":"Many entomopathogenic fungi cause infections that kill their insect host. Little is understood about changes in the reproductive investment that occur during an infection by a lethal disease over the waning life of an insect. Life history theory suggests the host will respond by investing resources into fighting the disease or increasing reproduction. Here, we investigate how the reproductive life of adult house flies, Musca domestica, is impacted by its host-specific fungal pathogen, Entomophthora muscae. Specifically, we test how the week-long infection alters the mating behavior of virgin adult male house flies. We find that the pathogen significantly decreases male libido; an effect which grows stronger over the course of the infection. Furthermore, females were significantly less likely to choose an infected male, reducing male mating success. Additionally, we assessed sperm viability to understand the reproductive costs for monandrous females to mate with infected males. Analyses revealed that sperm quality decreases as early as three days post-infection. These results show that E. muscae, which can have a prevalence near 100% in wild populations, causes severe lifetime reproductive costs to male house flies. Understanding how host-pathogen interactions affect host life history is crucial for elucidating all the negative effects pathogen virulence exerts on hosts.","PeriodicalId":8840,"journal":{"name":"Behavioral Ecology","volume":"192 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139496007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alicia M Korpach, Christina M Davy, Alex M Mills, Kevin C Fraser
Timing programs in animal migrants have been selected to synchronize movements that coincide with predictable resources on the breeding and nonbreeding grounds. Migrants face potential temporal conflicts if their migration schedules benefit from synchrony to conflicting rhythms associated with annual biogeographical (circannual) cues, lunar (circalunar) cues, or individually-repeatable internal clocks. We repeat-tracked individuals of an avian lunaphilic species, Eastern Whip-poor-will (Antrostomus vociferus), for 2–3 successive autumn migrations to determine the influence of the lunar cycle, breeding location, and individual repeatability on migration timing. Almost all birds avoided departing for migration during a full moon, likely to take advantage of the bright moonlight to facilitate visual foraging and enhance pre-migration fattening. However, groups from two latitudinally-distant sampling areas adjusted their autumn departure timing differently relative to the timing of the September full moon, presumably due to differences in seasonal prey availability. Individual repeatability increased throughout autumn migration, suggesting that the factors responsible for shaping migration timing may differ for different migration stages. Our results, that lunar synchrony, local climate, and individual internal clocks appeared to account for much of the variation in migration timing in whip-poor-wills, underscore the value of measuring potentially interacting factors that shape migratory behavior at species, group, and individual levels. It remains unclear if, or how, maintaining individually-repeatable annual migration schedules provides an adaptive benefit for whip-poor-wills or other lunaphilic migrants. Further clarifying the reasons for phenotypic variation in whip-poor-will migration timing will improve predictions of their abilities to adjust migratory movements under changing environmental conditions.
{"title":"Lunar synchrony, geography, and individual clocks shape autumn migration timing in an avian migrant","authors":"Alicia M Korpach, Christina M Davy, Alex M Mills, Kevin C Fraser","doi":"10.1093/beheco/arae001","DOIUrl":"https://doi.org/10.1093/beheco/arae001","url":null,"abstract":"Timing programs in animal migrants have been selected to synchronize movements that coincide with predictable resources on the breeding and nonbreeding grounds. Migrants face potential temporal conflicts if their migration schedules benefit from synchrony to conflicting rhythms associated with annual biogeographical (circannual) cues, lunar (circalunar) cues, or individually-repeatable internal clocks. We repeat-tracked individuals of an avian lunaphilic species, Eastern Whip-poor-will (Antrostomus vociferus), for 2–3 successive autumn migrations to determine the influence of the lunar cycle, breeding location, and individual repeatability on migration timing. Almost all birds avoided departing for migration during a full moon, likely to take advantage of the bright moonlight to facilitate visual foraging and enhance pre-migration fattening. However, groups from two latitudinally-distant sampling areas adjusted their autumn departure timing differently relative to the timing of the September full moon, presumably due to differences in seasonal prey availability. Individual repeatability increased throughout autumn migration, suggesting that the factors responsible for shaping migration timing may differ for different migration stages. Our results, that lunar synchrony, local climate, and individual internal clocks appeared to account for much of the variation in migration timing in whip-poor-wills, underscore the value of measuring potentially interacting factors that shape migratory behavior at species, group, and individual levels. It remains unclear if, or how, maintaining individually-repeatable annual migration schedules provides an adaptive benefit for whip-poor-wills or other lunaphilic migrants. Further clarifying the reasons for phenotypic variation in whip-poor-will migration timing will improve predictions of their abilities to adjust migratory movements under changing environmental conditions.","PeriodicalId":8840,"journal":{"name":"Behavioral Ecology","volume":"18 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139496580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Claire T Hemingway, Smruti Pimplikar, Felicity Muth
Foraging theory assumes that animals assess value based on objective payoffs; however, animals often evaluate rewards comparatively, forming expectations based on recent experience. This form of evaluation may be particularly relevant for nectar foragers such as bumblebees, where individuals can visit thousands of flowers daily that vary in nectar quality. While many animals, including bees, demonstrate reference-based evaluation in experimental contexts, it is unclear whether this occurs in the wild. Here, we asked how daily experience with wildflower nectar influenced wild bumblebees’ reward evaluation. We measured the daily nectar concentration of bee-visited wildflowers (Penstemon spp.), before presenting foragers with conspecific flowers filled with a range of artificial nectar concentrations. We recorded bees’ acceptance of artificial nectar, the probability of subsequent visits to flowers on the same plant, and residence time. While bees had a minimum threshold of nectar acceptability that was unaffected by experience, when there was higher-concentration environmental nectar, they were less likely to accept lower-quality rewards on manipulated plants. Bees also visited more flowers and stayed longer on plants with higher-concentration nectar. This study shows evidence for both absolute and reference-based evaluation in wild bees and points towards differences between bees’ behavior in lab- and wild-foraging contexts.
{"title":"Wild bumblebees use both absolute and relative evaluation when foraging","authors":"Claire T Hemingway, Smruti Pimplikar, Felicity Muth","doi":"10.1093/beheco/arad112","DOIUrl":"https://doi.org/10.1093/beheco/arad112","url":null,"abstract":"Foraging theory assumes that animals assess value based on objective payoffs; however, animals often evaluate rewards comparatively, forming expectations based on recent experience. This form of evaluation may be particularly relevant for nectar foragers such as bumblebees, where individuals can visit thousands of flowers daily that vary in nectar quality. While many animals, including bees, demonstrate reference-based evaluation in experimental contexts, it is unclear whether this occurs in the wild. Here, we asked how daily experience with wildflower nectar influenced wild bumblebees’ reward evaluation. We measured the daily nectar concentration of bee-visited wildflowers (Penstemon spp.), before presenting foragers with conspecific flowers filled with a range of artificial nectar concentrations. We recorded bees’ acceptance of artificial nectar, the probability of subsequent visits to flowers on the same plant, and residence time. While bees had a minimum threshold of nectar acceptability that was unaffected by experience, when there was higher-concentration environmental nectar, they were less likely to accept lower-quality rewards on manipulated plants. Bees also visited more flowers and stayed longer on plants with higher-concentration nectar. This study shows evidence for both absolute and reference-based evaluation in wild bees and points towards differences between bees’ behavior in lab- and wild-foraging contexts.","PeriodicalId":8840,"journal":{"name":"Behavioral Ecology","volume":"77 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139375242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aneta Arct, Rafał Martyka, Szymon M Drobniak, Lars Gustafsson, Mariusz Cichoń
In birds, extrapair paternity (EPP) constitutes an alternative mating strategy, with potentially important fitness consequences for both males and females and their offspring. Several factors have been identified that can influence the occurrence of EPP, but the role of environmental variability has so far received relatively little attention. Using long-term data set from a wild population of the blue tit (Cyanistes cearuleus), we assess the importance of ambient temperature in modulating the levels of extrapair paternity. Here, we showed that the variability of local thermal conditions affects the occurrence of EPP. Specifically, we found that the probability of EPP increased with rising variability in ambient temperature experienced by females prior to egg laying. This pattern is consistent with an idea of plastic female responses to unpredictable environments. Our results suggest that extrapair mating may represent an adaptive behavioral strategy to compensate for the potential negative effects of unstable environmental conditions.
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