Pub Date : 2023-12-15DOI: 10.1007/s00265-023-03417-4
Brandon A. Güell, Karen M. Warkentin
Abstract
Phyllomedusid treefrogs hatch prematurely to escape egg predation, but escape success varies among species. Snake attacks elicited 55% less escape hatching in spontaneously hatching Agalychnis spurrelli than in less developed A. callidryas. Agalychnis callidryas use their vestibular system and, secondarily, their lateral line to sense physical disturbances that cue hatching. Since A. spurrelli develop faster, we hypothesized that heterochronic shifts in the onset timing of vestibular mechanosensory function, relative to hatching ability, might explain their lower escape response to mechanosensory cues. To test this, we compared onset timings of hypoxia- and mechanosensory-cued hatching (MCH) and vestibular mechanosensory function in developmental series of both species. Across species, most sibships began responding to each cue at the same developmental stage and vestibular function development, measured by the vestibulo-ocular reflex (VOR), was similar. These results demonstrate that low escape-hatching success in A.spurrelli is not caused by a delay in the onset of vestibular mechanosensory function. MCH onset in A. spurrelli was associated with VOR, but with a higher threshold than in A. callidryas. The absence of MCH before strong vestibular function suggests multimodal mechanosensing may not contribute to antipredator responses of A. spurrelli embryos. Our observations of higher escape success of larger clutches in snake attacks and hatching complications in flooded A. spurrelli suggest that differences in clutch and egg capsule structure may contribute directly to species differences in escape-hatching success. Moreover, hatching complications in A. spurrelli may select against false alarms, increasing the stringency of hatching decision rules.
Significance statement
Hatching is an essential life-stage transition during development. For some species, it also functions as an effective defense against egg-stage risks. However, the causes for variation in environmentally cued hatching responses are poorly understood. We assessed why two closely related treefrogs exhibit different escape-hatching responses to snake attacks. Comparing the onset of induced-hatching responses and vestibular function in Agalychnis callidryas and A. spurrelli revealed that the primary mechanism for mechanosensing and its developmental timing are conserved within this group, but the sensory function threshold for behavioral response differs. It also revealed that egg-clutch properties, including egg-clutch size and individual egg structure, affect the escape-hatching response. This motivates further research assessing the role of egg-clutch properties and their biomechanics in embryo escape-hatching responses.
摘要叶绿体树蛙过早孵化以躲避卵的捕食，但不同物种的躲避成功率不同。蛇的攻击导致自发孵化的Agalychnis spurrelli的逃逸孵化率比发育较差的Agalychnis callidryas低55%。茧蛙利用前庭系统，其次是侧线来感知提示孵化的物理干扰。由于马氏茧蝶的发育速度较快，我们推测，相对于孵化能力而言，前庭机械感觉功能的开始时间的异时性变化可能是它们对机械感觉线索的逃逸反应较低的原因。为了验证这一观点，我们比较了缺氧和机械感觉诱导孵化（MCH）的起始时间，以及两个物种发育序列中前庭机械感觉功能的起始时间。在不同的物种中，大多数同胞在相同的发育阶段开始对每种提示做出反应，而通过前庭眼反射（VOR）测量的前庭功能发育也很相似。这些结果表明，马刺秧鸡逃逸孵化成功率低并不是因为前庭机械感觉功能的起始延迟造成的。马刺蛙的 MCH 起始与 VOR 有关，但阈值比马刺蛙高。在强大的前庭功能之前没有 MCH 的现象表明，多模式机械感应可能不会对 A. spurrelli 胚胎的反捕食者反应做出贡献。我们的观察结果表明，在蛇的攻击下，较大的卵团的逃逸成功率较高，而在淹水的马刺秧鸡中，孵化并发症较多，这表明卵团和卵囊结构的差异可能直接导致了逃逸-孵化成功率的物种差异。此外，水刺蛇的孵化并发症可能会选择性地避免错误警报，从而提高孵化决策规则的严格程度。对某些物种而言，孵化也是抵御卵期风险的有效防御手段。然而，人们对环境暗示孵化反应差异的原因知之甚少。我们评估了为什么两种亲缘关系很近的树蛙对蛇的攻击表现出不同的逃逸-孵化反应。比较Agalychnis callidryas和A. spurrelli的诱导孵化反应开始时间和前庭功能发现，机械感应的主要机制及其发育时间在该类群中是一致的，但行为反应的感觉功能阈值却不同。研究还发现，卵螯的特性，包括卵螯的大小和单个卵的结构，会影响逃逸-孵化反应。这促使我们进一步研究评估卵离合器特性及其生物力学在胚胎逃逸-孵化反应中的作用。
{"title":"To hatch and hatch not: does heterochrony in onset of vestibular mechanosensing explain species differences in escape-hatching success of Agalychnis embryos in snake attacks?","authors":"Brandon A. Güell, Karen M. Warkentin","doi":"10.1007/s00265-023-03417-4","DOIUrl":"https://doi.org/10.1007/s00265-023-03417-4","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Phyllomedusid treefrogs hatch prematurely to escape egg predation, but escape success varies among species. Snake attacks elicited 55% less escape hatching in spontaneously hatching <i>Agalychnis spurrelli</i> than in less developed <i>A. callidryas</i>. <i>Agalychnis callidryas</i> use their vestibular system and, secondarily, their lateral line to sense physical disturbances that cue hatching. Since <i>A. spurrelli</i> develop faster, we hypothesized that heterochronic shifts in the onset timing of vestibular mechanosensory function, relative to hatching ability, might explain their lower escape response to mechanosensory cues. To test this, we compared onset timings of hypoxia- and mechanosensory-cued hatching (MCH) and vestibular mechanosensory function in developmental series of both species. Across species, most sibships began responding to each cue at the same developmental stage and vestibular function development, measured by the vestibulo-ocular reflex (VOR), was similar. These results demonstrate that low escape-hatching success in <i>A.</i> <i>spurrelli</i> is not caused by a delay in the onset of vestibular mechanosensory function. MCH onset in <i>A. spurrelli</i> was associated with VOR, but with a higher threshold than in <i>A. callidryas.</i> The absence of MCH before strong vestibular function suggests multimodal mechanosensing may not contribute to antipredator responses of <i>A. spurrelli</i> embryos. Our observations of higher escape success of larger clutches in snake attacks and hatching complications in flooded <i>A. spurrelli</i> suggest that differences in clutch and egg capsule structure may contribute directly to species differences in escape-hatching success. Moreover, hatching complications in <i>A. spurrelli</i> may select against false alarms, increasing the stringency of hatching decision rules.</p><h3 data-test=\"abstract-sub-heading\">Significance statement</h3><p>Hatching is an essential life-stage transition during development. For some species, it also functions as an effective defense against egg-stage risks. However, the causes for variation in environmentally cued hatching responses are poorly understood. We assessed why two closely related treefrogs exhibit different escape-hatching responses to snake attacks. Comparing the onset of induced-hatching responses and vestibular function in <i>Agalychnis callidryas</i> and <i>A. spurrelli</i> revealed that the primary mechanism for mechanosensing and its developmental timing are conserved within this group, but the sensory function threshold for behavioral response differs. It also revealed that egg-clutch properties, including egg-clutch size and individual egg structure, affect the escape-hatching response. This motivates further research assessing the role of egg-clutch properties and their biomechanics in embryo escape-hatching responses.</p>","PeriodicalId":8881,"journal":{"name":"Behavioral Ecology and Sociobiology","volume":"51 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138688003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-14DOI: 10.1007/s00265-023-03408-5
Bojun Yi, Song Wang, Tao Sun, Ruoshuang Liu, Michael J. Lawes, Li Yang, Xuefeng Liu, Yifeng Li, Chengming Huang, Qihai Zhou, Penglai Fan
Abstract
The age and parity of female primates could reflect their physical condition and reproductive experience. Consequently, the individual age-parity dependent condition of mothers and the survival of their offspring represents a fitness tradeoff. This reproductive tradeoff is expressed in the individual birth sex ratio, offspring mortality and interbirth interval (IBI). Maternal antenatal and postnatal investment hypotheses predict that more female offspring are produced by experienced mothers in poor condition (Trivers-Willard hypothesis), and that offspring mortality decreases and IBI shortens with parity (targeted reproductive effort hypothesis). Here we test the latter predictions in captive populations of the endangered Francois’ langur (Trachypithecus francoisi), using long-term demographic and reproductive data from 21 Chinese zoos and three breeding centers. In these captive populations, birth sex ratio changed slightly from male-biased to female-biased as parity increased above five offspring in experienced mothers, consistent with the Trivers-Willard hypothesis. Although mortality of male offspring was greater than female offspring, overall offspring mortality did not vary with maternal parity. There was no significant difference in duration of postnatal care or IBI between male and female offspring. However, IBI for both female and male offspring shortened overall with increasing parity, as predicted by the targeted reproductive effort hypothesis. Females with more reproductive experience that produce more female offspring are critical to captive breeding programs that aim to increase the overall viable population size of this endangered species.
Significance statement
For primates with a slow life-history, it is important to understand how mothers age and parity affects their reproductive fitness. We investigated maternal investment strategies of captive Francois’ langurs, specifically the effect of age and parity on the birth sex ratio, offspring mortality and interbirth interval. Mothers relied more on parity (i.e., their experience) to adjust the birth sex ratio, and had more sons in the first few parities. Mothers also spent significantly less time taking care of offspring as their reproductive experience increased and physical condition was likely declining. Thus, Francois’ langurs are able to adjust their investment in reproduction as they become more experienced (greater parity) to optimize reproductive fitness.
{"title":"Maternal parity influences the birth sex ratio and birth interval of captive Francois’ langur (Trachypithecus francoisi)","authors":"Bojun Yi, Song Wang, Tao Sun, Ruoshuang Liu, Michael J. Lawes, Li Yang, Xuefeng Liu, Yifeng Li, Chengming Huang, Qihai Zhou, Penglai Fan","doi":"10.1007/s00265-023-03408-5","DOIUrl":"https://doi.org/10.1007/s00265-023-03408-5","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The age and parity of female primates could reflect their physical condition and reproductive experience. Consequently, the individual age-parity dependent condition of mothers and the survival of their offspring represents a fitness tradeoff. This reproductive tradeoff is expressed in the individual birth sex ratio, offspring mortality and interbirth interval (IBI). Maternal antenatal and postnatal investment hypotheses predict that more female offspring are produced by experienced mothers in poor condition (Trivers-Willard hypothesis), and that offspring mortality decreases and IBI shortens with parity (targeted reproductive effort hypothesis). Here we test the latter predictions in captive populations of the endangered Francois’ langur (<i>Trachypithecus francoisi</i>), using long-term demographic and reproductive data from 21 Chinese zoos and three breeding centers. In these captive populations, birth sex ratio changed slightly from male-biased to female-biased as parity increased above five offspring in experienced mothers, consistent with the Trivers-Willard hypothesis. Although mortality of male offspring was greater than female offspring, overall offspring mortality did not vary with maternal parity. There was no significant difference in duration of postnatal care or IBI between male and female offspring. However, IBI for both female and male offspring shortened overall with increasing parity, as predicted by the targeted reproductive effort hypothesis. Females with more reproductive experience that produce more female offspring are critical to captive breeding programs that aim to increase the overall viable population size of this endangered species.</p><h3 data-test=\"abstract-sub-heading\">Significance statement</h3><p>For primates with a slow life-history, it is important to understand how mothers age and parity affects their reproductive fitness. We investigated maternal investment strategies of captive Francois’ langurs, specifically the effect of age and parity on the birth sex ratio, offspring mortality and interbirth interval. Mothers relied more on parity (i.e., their experience) to adjust the birth sex ratio, and had more sons in the first few parities. Mothers also spent significantly less time taking care of offspring as their reproductive experience increased and physical condition was likely declining. Thus, Francois’ langurs are able to adjust their investment in reproduction as they become more experienced (greater parity) to optimize reproductive fitness.</p>","PeriodicalId":8881,"journal":{"name":"Behavioral Ecology and Sociobiology","volume":"20 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138632140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-14DOI: 10.1007/s00265-023-03386-8
Michelle Beyer, Kardelen Özgün Uludag, Maylis Lailler, Jonas O. Wolff, Monika J. B. Eberhard, Tomer J. Czaczkes, Cristina Tuni
Abstract
Mate search is challenging for solitary species. Trails represent a particularly potent, target-oriented means for finding mates, as trail-following increases encounter rates between individuals compared to random search. Embedding directionality information into the trail allows individuals to follow trails correctly to the source. Yet, directionality remains poorly understood. Spiders deposit trails during locomotion consisting of silk lines and substrate-borne chemicals. We conducted multiple experiments to test whether female silk trails convey directionality information, whether directionality is chemically or structurally encoded and depends on female phenotype. We also examined whether males interact with silk in a way that suggests information gathering. We exposed males of the cursorial spider Pisaura mirabilis to female trails deposited unidirectionally and scored their trail-following direction (i.e., same as or opposite to the females’). Tests were repeated after washing trails with a solvent to remove putative chemicals and by sourcing silk from females of different feeding regimes. While we found little evidence for male directional trail-following, we did find that unwashed trails were more likely to be followed than washed trails. Similarly, trails of relatively larger females were more likely to be followed correctly than those of smaller females. Males extensively probed and pulled on silk lines with their appendages, suggesting the gathering of chemical and tactile information. Taken together, results suggest that directional trail-following is selected only under specific contexts in this species. Chemical attributes of trails may convey information on female quality, with directional trail-following reflecting male mate choice in a system characterized by costly male nuptial gifts.
Significance statement
In the context of male mate search, following conspecific trails increases the chances of encountering a mating partner, especially if trails provide information about the direction the conspecific went. Yet, trail directionality remains poorly understood. Female spiders deposit silk trails as they walk. We overall show that males follow trails directionally only under a specific context. Males were more likely to follow correctly when trails were unmanipulated (compared to being washed with solvents to remove chemicals) and when they were deposited by relatively larger females (compared to smaller ones). Chemical attributes of trails may potentially indicate directionality, while decoding movement direction from trails of larger females may reflect male preferences for females of higher reproductive value.
{"title":"Testing presence of directionality information in female spider silk trails through male trail-following behavior","authors":"Michelle Beyer, Kardelen Özgün Uludag, Maylis Lailler, Jonas O. Wolff, Monika J. B. Eberhard, Tomer J. Czaczkes, Cristina Tuni","doi":"10.1007/s00265-023-03386-8","DOIUrl":"https://doi.org/10.1007/s00265-023-03386-8","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Mate search is challenging for solitary species. Trails represent a particularly potent, target-oriented means for finding mates, as trail-following increases encounter rates between individuals compared to random search. Embedding directionality information into the trail allows individuals to follow trails correctly to the source. Yet, directionality remains poorly understood. Spiders deposit trails during locomotion consisting of silk lines and substrate-borne chemicals. We conducted multiple experiments to test whether female silk trails convey directionality information, whether directionality is chemically or structurally encoded and depends on female phenotype. We also examined whether males interact with silk in a way that suggests information gathering. We exposed males of the cursorial spider <i>Pisaura mirabilis</i> to female trails deposited unidirectionally and scored their trail-following direction (i.e., same as or opposite to the females’). Tests were repeated after washing trails with a solvent to remove putative chemicals and by sourcing silk from females of different feeding regimes. While we found little evidence for male directional trail-following, we did find that unwashed trails were more likely to be followed than washed trails. Similarly, trails of relatively larger females were more likely to be followed correctly than those of smaller females. Males extensively probed and pulled on silk lines with their appendages, suggesting the gathering of chemical and tactile information. Taken together, results suggest that directional trail-following is selected only under specific contexts in this species. Chemical attributes of trails may convey information on female quality, with directional trail-following reflecting male mate choice in a system characterized by costly male nuptial gifts.</p><h3 data-test=\"abstract-sub-heading\">Significance statement</h3><p>In the context of male mate search, following conspecific trails increases the chances of encountering a mating partner, especially if trails provide information about the direction the conspecific went. Yet, trail directionality remains poorly understood. Female spiders deposit silk trails as they walk. We overall show that males follow trails directionally only under a specific context. Males were more likely to follow correctly when trails were unmanipulated (compared to being washed with solvents to remove chemicals) and when they were deposited by relatively larger females (compared to smaller ones). Chemical attributes of trails may potentially indicate directionality, while decoding movement direction from trails of larger females may reflect male preferences for females of higher reproductive value.</p>","PeriodicalId":8881,"journal":{"name":"Behavioral Ecology and Sociobiology","volume":"51 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138688270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-12DOI: 10.1007/s00265-023-03411-w
Karin L. Hartman, Ing Chen, Pieter A. van der Harst, Andre E. Moura, Marlene Jahnke, Malgorzata Pilot, Raul Vilela, A. Rus Hoelzel
Abstract
Delphinids display a wide variety of social structures, in which local food availability and defensibility, sexual size dimorphism and interbirth intervals ultimately influence the role of kin within social units. Earlier studies of the social ecology of Risso’s dolphins (Grampus griseus) off Pico Island, the Azores, revealed a sexually stratified social structure, with long-term stable, strongly associated male clusters and temporally weakly associated female clusters. Here we test the predictions that inclusive fitness plays a role in social cohesion and structure and that both sexes are philopatric in this population. We found no correlation between association and relatedness for either males or females. Our results therefore do not support inclusive fitness as an explanation for the stable clusters of males, who instead associate with partners of a similar age, less likely to be kin due to a long inter-birth interval. Genetic data did not reveal clear sex-biased dispersal. We propose that unlike the pattern seen in some other dolphin species, the socio-genetic structure found in Risso’s dolphins is not associated with inclusive fitness but linked instead to the open oceanic habitat and the species’ life history traits.
Significance statement
Studying societies of wild cetaceans poses additional challenges compared to terrestrial mammals, since we can generally only observe behavior when individuals come (close) to the surface for breathing. Yet such studies can expand our knowledge on the links between ecology and social structure (e.g. the remarkable parallels between societies of sperm whales and elephants). This study makes a meaningful contribution, by establishing that the long-term stable male and temporally stable female associations found in earlier studies of Risso’s dolphins in the Azores are not based on kinship. Accordingly, despite very different ecological contexts, there are striking similarities between the male Risso’s dolphin clusters and the second-order alliances found in male Indo-Pacific bottlenose dolphins in Shark Bay, Australia. This offers great potential to enhance our understanding of drivers of male cooperation by further comparative research on two long-term studied systems.
{"title":"Kinship study reveals stable non-kin-based associations in a medium-sized delphinid","authors":"Karin L. Hartman, Ing Chen, Pieter A. van der Harst, Andre E. Moura, Marlene Jahnke, Malgorzata Pilot, Raul Vilela, A. Rus Hoelzel","doi":"10.1007/s00265-023-03411-w","DOIUrl":"https://doi.org/10.1007/s00265-023-03411-w","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Delphinids display a wide variety of social structures, in which local food availability and defensibility, sexual size dimorphism and interbirth intervals ultimately influence the role of kin within social units. Earlier studies of the social ecology of Risso’s dolphins (<i>Grampus griseus</i>) off Pico Island, the Azores, revealed a sexually stratified social structure, with long-term stable, strongly associated male clusters and temporally weakly associated female clusters. Here we test the predictions that inclusive fitness plays a role in social cohesion and structure and that both sexes are philopatric in this population. We found no correlation between association and relatedness for either males or females. Our results therefore do not support inclusive fitness as an explanation for the stable clusters of males, who instead associate with partners of a similar age, less likely to be kin due to a long inter-birth interval. Genetic data did not reveal clear sex-biased dispersal. We propose that unlike the pattern seen in some other dolphin species, the socio-genetic structure found in Risso’s dolphins is not associated with inclusive fitness but linked instead to the open oceanic habitat and the species’ life history traits.</p><h3 data-test=\"abstract-sub-heading\">Significance statement</h3><p>Studying societies of wild cetaceans poses additional challenges compared to terrestrial mammals, since we can generally only observe behavior when individuals come (close) to the surface for breathing. Yet such studies can expand our knowledge on the links between ecology and social structure (e.g. the remarkable parallels between societies of sperm whales and elephants). This study makes a meaningful contribution, by establishing that the long-term stable male and temporally stable female associations found in earlier studies of Risso’s dolphins in the Azores are not based on kinship. Accordingly, despite very different ecological contexts, there are striking similarities between the male Risso’s dolphin clusters and the second-order alliances found in male Indo-Pacific bottlenose dolphins in Shark Bay, Australia. This offers great potential to enhance our understanding of drivers of male cooperation by further comparative research on two long-term studied systems.</p>","PeriodicalId":8881,"journal":{"name":"Behavioral Ecology and Sociobiology","volume":"99 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-12DOI: 10.1007/s00265-023-03396-6
Michelle L. Beck, Kendra B. Sewall, Ҫağlar Akҫay
Abstract
In many taxa, melanin-based coloration is a signal of dominance or fighting ability and is associated with concentrations of hormones that may mediate aggressive behavior. Previous studies found that experimental manipulation of melanin-based signals can result in manipulated individuals receiving more social challenges in some but not all species. These differences could arise from mismatches between the signal, behavior, and hormone concentrations. In the present study, we experimentally manipulated the chest spotting of urban and rural male song sparrows (Melospiza melodia) following an assessment of their territorial aggression and initial concentrations of corticosterone and testosterone and then assessed their behavior and hormone concentrations 2 weeks later. We found that males generally displayed less territorial aggression in the second trial, consistent with our previous findings. Males in the enlarged treatment decreased aggression to a greater degree than those in the reduced treatment. The effect of the plumage manipulation was similar across the rural and urban habitats. Despite the changes in behavior we detected, we found no effects of the manipulation on concentrations of testosterone or corticosterone. Our results show that melanin-based spotting in male song sparrows is a signal of territorial aggression but the physiological mechanisms that mediate the relationships between chest spotting and behavior remain to be identified.
Significance statement
Many bird species use their plumage to signal their dominance status, fighting ability, or motivation during interactions with other individuals to resolve conflicts without a fight. Here, we asked whether chest spotting is a signal in territorial interactions among male song sparrows. We experimentally increased or reduced the extent of spotting in males and measured the change in their aggression. We found that reduced-spotting males showed a more moderate seasonal decrease of aggression compared to males with enlarged spotting reduced aggression, possibly because the former experienced more intrusions later on in the breeding season while the latter experienced fewer intrusions. These results are consistent with chest spotting size in song sparrows functioning as a signal of territory holding potential of the bearer.
{"title":"Experimental manipulation of chest spotting alters territorial aggression in urban and rural song sparrows","authors":"Michelle L. Beck, Kendra B. Sewall, Ҫağlar Akҫay","doi":"10.1007/s00265-023-03396-6","DOIUrl":"https://doi.org/10.1007/s00265-023-03396-6","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In many taxa, melanin-based coloration is a signal of dominance or fighting ability and is associated with concentrations of hormones that may mediate aggressive behavior. Previous studies found that experimental manipulation of melanin-based signals can result in manipulated individuals receiving more social challenges in some but not all species. These differences could arise from mismatches between the signal, behavior, and hormone concentrations. In the present study, we experimentally manipulated the chest spotting of urban and rural male song sparrows (<i>Melospiza melodia</i>) following an assessment of their territorial aggression and initial concentrations of corticosterone and testosterone and then assessed their behavior and hormone concentrations 2 weeks later. We found that males generally displayed less territorial aggression in the second trial, consistent with our previous findings. Males in the enlarged treatment decreased aggression to a greater degree than those in the reduced treatment. The effect of the plumage manipulation was similar across the rural and urban habitats. Despite the changes in behavior we detected, we found no effects of the manipulation on concentrations of testosterone or corticosterone. Our results show that melanin-based spotting in male song sparrows is a signal of territorial aggression but the physiological mechanisms that mediate the relationships between chest spotting and behavior remain to be identified.</p><h3 data-test=\"abstract-sub-heading\">Significance statement</h3><p>Many bird species use their plumage to signal their dominance status, fighting ability, or motivation during interactions with other individuals to resolve conflicts without a fight. Here, we asked whether chest spotting is a signal in territorial interactions among male song sparrows. We experimentally increased or reduced the extent of spotting in males and measured the change in their aggression. We found that reduced-spotting males showed a more moderate seasonal decrease of aggression compared to males with enlarged spotting reduced aggression, possibly because the former experienced more intrusions later on in the breeding season while the latter experienced fewer intrusions. These results are consistent with chest spotting size in song sparrows functioning as a signal of territory holding potential of the bearer.</p>","PeriodicalId":8881,"journal":{"name":"Behavioral Ecology and Sociobiology","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-12DOI: 10.1007/s00265-023-03415-6
Jessica H. Browne, Darryl T. Gwynne
Abstract
Male genitalia are rapidly evolving structures, often driven by sexual selection to increase fertilisation success. Although sexual selection on females can be strong in systems where males provide offspring care or feed their mates, sometimes resulting in the evolution of female ornamentation, there are no actual estimates of direct sexual selection on female genitalia. In a New Zealand ground weta, Hemiandrus pallitarsis (Orthoptera: Ensifera, Anostostomatidae), females possess a genitalic device (the accessory organ) that is necessary for successful copulation and the acquisition of glandular food-gifts from males. These nutritious gifts are known to result in sexual competition among females in other ensiferan species. In ground weta, the gifts are probably important in avoiding starvation during a months-long period when caring for (their lifetime production of) eggs and offspring. Here, we test the hypothesis that the accessory organ is a sexually selected device in H. pallitarsis by measuring the female Bateman gradient, Jones index, and directional sexual selection on the accessory organ. Using newly developed and characterised microsatellite loci, we analyse offspring and/or stored sperm to estimate female mating frequency for the first time in ground weta. As predicted, we found both a positive Bateman gradient and Jones index for females, and evidence of directional sexual selection on accessory organ length. Although organ length does not correlate well with female fecundity, it may increase mating success by indicating her condition and thus quality of her offspring care.
Significance statement
Female genitalia have largely been studied in the context of exerting selection on males, while the potential for selection on females via mate acquisition or manipulation of males is virtually unstudied. Such selection may be relevant in systems where males make investments in reproduction (offspring-care; mate-feeding), and females are subject to strong sexual selection, occasionally possessing sexual ornaments. Using microsatellite analysis of offspring and stored sperm to estimate mating frequency, we provide the first evidence of directional sexual selection on a female genital device (accessory organ) found in species of maternal care-providing ground weta. In our focal species, Hemiandrus pallitarsis, we found that females with more mates produced more offspring and females with longer accessory organs obtained more mates. These findings suggest that the female genital device is a secondary sexual trait, although may have additional mechanical functions.
{"title":"Sexual selection on a female copulatory device in an insect with nuptial gifts","authors":"Jessica H. Browne, Darryl T. Gwynne","doi":"10.1007/s00265-023-03415-6","DOIUrl":"https://doi.org/10.1007/s00265-023-03415-6","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Male genitalia are rapidly evolving structures, often driven by sexual selection to increase fertilisation success. Although sexual selection on females can be strong in systems where males provide offspring care or feed their mates, sometimes resulting in the evolution of female ornamentation, there are no actual estimates of direct sexual selection on female genitalia. In a New Zealand ground weta, <i>Hemiandrus pallitarsis</i> (Orthoptera: Ensifera, Anostostomatidae), females possess a genitalic device (the accessory organ) that is necessary for successful copulation and the acquisition of glandular food-gifts from males. These nutritious gifts are known to result in sexual competition among females in other ensiferan species. In ground weta, the gifts are probably important in avoiding starvation during a months-long period when caring for (their lifetime production of) eggs and offspring. Here, we test the hypothesis that the accessory organ is a sexually selected device in <i>H. pallitarsis</i> by measuring the female Bateman gradient, Jones index, and directional sexual selection on the accessory organ. Using newly developed and characterised microsatellite loci, we analyse offspring and/or stored sperm to estimate female mating frequency for the first time in ground weta. As predicted, we found both a positive Bateman gradient and Jones index for females, and evidence of directional sexual selection on accessory organ length. Although organ length does not correlate well with female fecundity, it may increase mating success by indicating her condition and thus quality of her offspring care.</p><h3 data-test=\"abstract-sub-heading\">Significance statement</h3><p>Female genitalia have largely been studied in the context of exerting selection on males, while the potential for selection on females via mate acquisition or manipulation of males is virtually unstudied. Such selection may be relevant in systems where males make investments in reproduction (offspring-care; mate-feeding), and females are subject to strong sexual selection, occasionally possessing sexual ornaments. Using microsatellite analysis of offspring and stored sperm to estimate mating frequency, we provide the first evidence of directional sexual selection on a female genital device (accessory organ) found in species of maternal care-providing ground weta. In our focal species, <i>Hemiandrus pallitarsis</i>, we found that females with more mates produced more offspring and females with longer accessory organs obtained more mates. These findings suggest that the female genital device is a secondary sexual trait, although may have additional mechanical functions.</p>","PeriodicalId":8881,"journal":{"name":"Behavioral Ecology and Sociobiology","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.1007/s00265-023-03412-9
Yusong Lin, Xia Qiu, Jinzhong Fu, Richard Peters, Yin Qi
Abstract
Elucidating the factors that influence the evolution of signal complexity is essential in understanding animal communication. Compared to vocal and color signals, movement-based visual signals only start to attract attention recently. In this study, we tested the social complexity (social structure promotes signal complexity) and background noise hypotheses (background noise promotes signal complexity) on the evolution of movement-based visual signal complexity. We collected display signals from twelve populations across the distribution range of the Asian agamid lizard, Phrynocephalus przewalskii. Their various components (tail coil, tail lash, body turning, and limb flapping) were quantified. Furthermore, we measured the population density and sexual size dimorphism (SSD), as estimates of social complexity, and estimate background noise using presence of plant and wind speed. We tested associations between measurements of variability in individual signal components and the overall display with estimates of social complexity and background noise using linear mixed models. We found evidence to suggest that both SSD and the noise environment impact the delivery of multiple display components, particularly the duration and maximum speed of display components. Importantly, our findings suggest that social and environmental factors do not impact males and females equally. Our data are consistent with both social complexity and background noise hypotheses, and our research provides direct evidence on the links among display complexity, social complexity, and background noise.
Significance statement
The evolution of animal signal complexity has fascinated biologists for generations. We know much about vocal and color signals; nevertheless, movement-based visual signals only start to attract attention recently. Here we tested the factors influencing the evolution of display complexity using P. przewalskii as a study system, particularly around the social complexity (social structure promotes signal complexity) and background noise hypotheses (background noise promotes signal complexity). Our data are consistent with both social complexity and background noise hypotheses and provide direct evidence on the links among movement-based visual signal complexity, social complexity, and background noise.
摘要阐明影响信号复杂性进化的因素对于理解动物交流至关重要。与声音和颜色信号相比，基于运动的视觉信号直到最近才开始受到关注。在本研究中，我们检验了社会复杂性假说（社会结构促进信号复杂性）和背景噪声假说（背景噪声促进信号复杂性）对基于运动的视觉信号复杂性进化的影响。我们收集了亚洲巨蜥（Phrynocephalus przewalskii）分布范围内12个种群的显示信号。我们对这些信号的各个组成部分（卷尾、甩尾、转体和拍肢）进行了量化。此外，我们还测量了种群密度和性别大小二态性（SSD），作为社会复杂性的估计值，并利用植物的存在和风速来估计背景噪声。我们使用线性混合模型检验了单个信号成分和整体显示的变化测量值与社会复杂性和背景噪声估计值之间的关联。我们发现，有证据表明 SSD 和噪声环境都会影响多种显示成分的传递，尤其是显示成分的持续时间和最大速度。重要的是，我们的研究结果表明，社会和环境因素对男性和女性的影响并不相同。我们的数据与社会复杂性和背景噪声假说一致，我们的研究为显示复杂性、社会复杂性和背景噪声之间的联系提供了直接证据。我们对声音和颜色信号有很多了解；然而，基于运动的视觉信号直到最近才开始引起人们的注意。在这里，我们以 P. przewalskii 为研究对象，测试了影响显示复杂性进化的因素，特别是围绕社会复杂性假说（社会结构促进信号复杂性）和背景噪声假说（背景噪声促进信号复杂性）。我们的数据与社会复杂性假说和背景噪声假说一致，并为基于运动的视觉信号复杂性、社会复杂性和背景噪声之间的联系提供了直接证据。
{"title":"Testing the factors on the evolution of movement-based visual signal complexity in an Asian agamid lizard","authors":"Yusong Lin, Xia Qiu, Jinzhong Fu, Richard Peters, Yin Qi","doi":"10.1007/s00265-023-03412-9","DOIUrl":"https://doi.org/10.1007/s00265-023-03412-9","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Elucidating the factors that influence the evolution of signal complexity is essential in understanding animal communication. Compared to vocal and color signals, movement-based visual signals only start to attract attention recently. In this study, we tested the social complexity (social structure promotes signal complexity) and background noise hypotheses (background noise promotes signal complexity) on the evolution of movement-based visual signal complexity. We collected display signals from twelve populations across the distribution range of the Asian agamid lizard, <i>Phrynocephalus przewalskii</i>. Their various components (tail coil, tail lash, body turning, and limb flapping) were quantified. Furthermore, we measured the population density and sexual size dimorphism (SSD), as estimates of social complexity, and estimate background noise using presence of plant and wind speed. We tested associations between measurements of variability in individual signal components and the overall display with estimates of social complexity and background noise using linear mixed models. We found evidence to suggest that both SSD and the noise environment impact the delivery of multiple display components, particularly the duration and maximum speed of display components. Importantly, our findings suggest that social and environmental factors do not impact males and females equally. Our data are consistent with both social complexity and background noise hypotheses, and our research provides direct evidence on the links among display complexity, social complexity, and background noise.</p><h3 data-test=\"abstract-sub-heading\">Significance statement</h3><p>The evolution of animal signal complexity has fascinated biologists for generations. We know much about vocal and color signals; nevertheless, movement-based visual signals only start to attract attention recently. Here we tested the factors influencing the evolution of display complexity using <i>P. przewalskii</i> as a study system, particularly around the social complexity (social structure promotes signal complexity) and background noise hypotheses (background noise promotes signal complexity). Our data are consistent with both social complexity and background noise hypotheses and provide direct evidence on the links among movement-based visual signal complexity, social complexity, and background noise.</p>","PeriodicalId":8881,"journal":{"name":"Behavioral Ecology and Sociobiology","volume":"53 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138569494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-06DOI: 10.1007/s00265-023-03407-6
Maria A. van Noordwijk, Laura R. LaBarge, Julia A. Kunz, Anna M. Marzec, Brigitte Spillmann, Corinne Ackermann, Puji Rianti, Erin R. Vogel, S. Suci Utami Atmoko, Michael Kruetzen, Carel P. van Schaik
Abstract
The social and mating systems of orangutans, one of our closest relatives, remain poorly understood. Orangutans (Pongo spp.) are highly sexually dimorphic and females are philopatric and maintain individual, but overlapping home ranges, whereas males disperse, are non-territorial and wide-ranging, and show bimaturism, with many years between reaching sexual maturity and attaining full secondary sexual characteristics (including cheek pads (flanges) and emitting long calls). We report on 21 assigned paternities, among 35 flanged and 15 unflanged, genotyped male Bornean orangutans (Pongo pygmaeus wurmbii), studied from 2003 to 2018 in Tuanan (Central Kalimantan, Indonesia). All 10 infants born since mid-2003 with an already identified sire were sired by flanged males. All adult males ranged well beyond the study area (c. 1000 ha), and their dominance relations fluctuated even within short periods. However, 5 of the 10 identified sires had multiple offspring within the monitored area. Several sired over a period of c. 10 years, which overlapped with siring periods of other males. The long-calling behavior of sires indicated they were not consistently dominant over other males in the area around the time of known conceptions. Instead, when they were seen in the area, the known sires spent most of their time within the home ranges of the females whose offspring they sired. Overall, successful sires were older and more often resident than others.
Significance statement
It is difficult to assess reproductive success for individuals of long-lived species, especially for dispersing males, who cannot be monitored throughout their lives. Due to extremely long interbirth intervals, orangutans have highly male-skewed operational sex ratios and thus intensive male-male competition for every conception. Paternity analyses matched 21 immature Bornean orangutans with their most likely sire (only 10 of 50 genotyped males) in a natural population. Half of these identified sires had multiple offspring in the study area spread over periods of at least 10 years, despite frequently ranging outside this area. Dominance was a poor predictor of success, but, consistent with female mating tactics to reduce the risk of infanticide, known “sires” tended to have relatively high local presence, which seems to contribute to the males’ siring success. The results highlight the importance of large protected areas to enable a natural pattern of dispersal and ranging.
{"title":"Reproductive success of Bornean orangutan males: scattered in time but clustered in space","authors":"Maria A. van Noordwijk, Laura R. LaBarge, Julia A. Kunz, Anna M. Marzec, Brigitte Spillmann, Corinne Ackermann, Puji Rianti, Erin R. Vogel, S. Suci Utami Atmoko, Michael Kruetzen, Carel P. van Schaik","doi":"10.1007/s00265-023-03407-6","DOIUrl":"https://doi.org/10.1007/s00265-023-03407-6","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The social and mating systems of orangutans, one of our closest relatives, remain poorly understood. Orangutans (<i>Pongo</i> spp<i>.</i>) are highly sexually dimorphic and females are philopatric and maintain individual, but overlapping home ranges, whereas males disperse, are non-territorial and wide-ranging, and show bimaturism, with many years between reaching sexual maturity and attaining full secondary sexual characteristics (including cheek pads (flanges) and emitting long calls). We report on 21 assigned paternities, among 35 flanged and 15 unflanged, genotyped male Bornean orangutans (<i>Pongo pygmaeus wurmbii</i>), studied from 2003 to 2018 in Tuanan (Central Kalimantan, Indonesia). All 10 infants born since mid-2003 with an already identified sire were sired by flanged males. All adult males ranged well beyond the study area (c. 1000 ha), and their dominance relations fluctuated even within short periods. However, 5 of the 10 identified sires had multiple offspring within the monitored area. Several sired over a period of c. 10 years, which overlapped with siring periods of other males. The long-calling behavior of sires indicated they were not consistently dominant over other males in the area around the time of known conceptions. Instead, when they were seen in the area, the known sires spent most of their time within the home ranges of the females whose offspring they sired. Overall, successful sires were older and more often resident than others.</p><h3 data-test=\"abstract-sub-heading\">Significance statement</h3><p>It is difficult to assess reproductive success for individuals of long-lived species, especially for dispersing males, who cannot be monitored throughout their lives. Due to extremely long interbirth intervals, orangutans have highly male-skewed operational sex ratios and thus intensive male-male competition for every conception. Paternity analyses matched 21 immature Bornean orangutans with their most likely sire (only 10 of 50 genotyped males) in a natural population. Half of these identified sires had multiple offspring in the study area spread over periods of at least 10 years, despite frequently ranging outside this area. Dominance was a poor predictor of success, but, consistent with female mating tactics to reduce the risk of infanticide, known “sires” tended to have relatively high local presence, which seems to contribute to the males’ siring success. The results highlight the importance of large protected areas to enable a natural pattern of dispersal and ranging.</p>","PeriodicalId":8881,"journal":{"name":"Behavioral Ecology and Sociobiology","volume":"36 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bumblebees establish annual colonies that start with the emergence of workers in spring and end with the production of sexuals, the majority of which are males, in late summer. To date, the causes responsible for the transition in the production of diploid-female offspring to haploid-male offspring during the decline phase of colonies remain elusive. Using flow cytometry, we tested whether such a caste shift is correlated with a decline in sperm number and quality (i.e., sperm viability and sperm DNA fragmentation) in the queen spermatheca over time, from mating to the emergence of the first males. We found that sperm number and viability significantly decreased, while sperm DNA fragmentation increased in the spermatheca over time. These results suggest that the shift towards male production during the decline phase of a bumblebee colony stems at least partly from a combination of a drop in sperm count and sperm quality in queens’ spermatheca.
Significance statement
In social Hymenoptera, sex determination is based on the haplodiploidy system in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid. So far, the proximal mechanisms responsible for the social transition from diploid-female egg production to haploid-male egg production remain unknown. We show that the shift towards male production during the decline phase of bumblebee colonies is associated with a reduction in the quantity and quality of the sperm stored in the queen spermatheca over time. More generally, it suggests that sperm conservation is limited and likely adapted to the relatively short lifespan of bumblebee queens, which produce small and annual colonies.
{"title":"Transition in the production of diploid-female to haploid-male eggs in bumblebee colonies: sperm quality or depletion?","authors":"Baptiste Martinet, Kimberly Przybyla, Camille Michielsens, Serge Aron","doi":"10.1007/s00265-023-03410-x","DOIUrl":"https://doi.org/10.1007/s00265-023-03410-x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Bumblebees establish annual colonies that start with the emergence of workers in spring and end with the production of sexuals, the majority of which are males, in late summer. To date, the causes responsible for the transition in the production of diploid-female offspring to haploid-male offspring during the decline phase of colonies remain elusive. Using flow cytometry, we tested whether such a caste shift is correlated with a decline in sperm number and quality (i.e., sperm viability and sperm DNA fragmentation) in the queen spermatheca over time, from mating to the emergence of the first males. We found that sperm number and viability significantly decreased, while sperm DNA fragmentation increased in the spermatheca over time. These results suggest that the shift towards male production during the decline phase of a bumblebee colony stems at least partly from a combination of a drop in sperm count and sperm quality in queens’ spermatheca.</p><h3 data-test=\"abstract-sub-heading\">Significance statement</h3><p>In social Hymenoptera, sex determination is based on the haplodiploidy system in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid. So far, the proximal mechanisms responsible for the social transition from diploid-female egg production to haploid-male egg production remain unknown. We show that the shift towards male production during the decline phase of bumblebee colonies is associated with a reduction in the quantity and quality of the sperm stored in the queen spermatheca over time. More generally, it suggests that sperm conservation is limited and likely adapted to the relatively short lifespan of bumblebee queens, which produce small and annual colonies.</p>","PeriodicalId":8881,"journal":{"name":"Behavioral Ecology and Sociobiology","volume":"15 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-30DOI: 10.1007/s00265-023-03409-4
Sergio Del Arco, Jose María Del Arco
Abstract
Past studies have revealed the benefits of rodent participation in the colonization process of oak species. Certain rodent species (Apodemus sylvaticus and Mus spretus) partially consume acorns, beginning at the basal part and preserving the embryo. Perea et al. (2011) and Yang and Yi (2012) found that during periods of abundance, the remains left after partial consumption continue to be present on the surface and are not transported to caches, given that they are perceived as leftovers. These remains, produced after several visits by the cache owner or by thieving conspecifics, also appear in the caches. If they are perceived as offal, they will not be attacked and may remain in these stores for longer periods, serving as resources for the cache builder. Our objective is to determine whether these remnants are perceived as offal by the rodent generating them or if the remains left by other rodents are considered offal. This is relevant in cases of theft, a common behavior of this species, if the thieving animals reject the remains. The results suggest that foreign remains and the rodents’ own remains are not rejected, but rather, they are consumed in preference to intact acorns. The intact acorns remain in the cache for longer periods and have a greater opportunity to germinate and emerge. Rodents prefer to consume foreign remains first. This may be due to the fact that, in case of shortage, it is considered advantageous to finish the reserves of a potential competitor before depleting one’s own reserves.
Significance statement
Rodents participate in the acorn dissemination process by constructing surface stores (caches). The rodent species studied here partially consumes acorns, beginning with the basal part and preserving the embryo located at the apical end. These partially consumed acorn remains are considered offal and remain in the caches for longer periods, serving as reserves for the rodent. Our objective is to examine whether these acorn remains are viewed as offal by the rodents. We have found that, to the contrary, they are consumed before intact acorns. Intact acorns remain in the caches for longer periods, assuming the role of reserves and taking on a greater capacity to germinate. This species of rodent differentiates between its own remains and those of others, first consuming the foreign offal. Therefore, their own offal remains in the stores for longer periods and may potentially germinate if the embryo is preserved. This behavior has been demonstrated by this rodent species.
摘要过去的研究已经揭示了啮齿动物参与橡树物种定植过程的好处。某些啮齿类动物(针叶鼠和野鼠)部分地吃橡子，从基部开始，并保存胚胎。Perea et al.(2011)和Yang and Yi(2012)发现，在丰度期间，部分消耗后留下的残留物继续存在于地表，而不会被运送到贮藏库，因为它们被视为剩菜。这些遗骸，在贮藏物的主人或偷来的同类多次造访后产生，也出现在贮藏物中。如果它们被认为是无用的，它们将不会受到攻击，并且可能在这些存储中保留更长的时间，作为缓存构建器的资源。我们的目标是确定这些残留物是否被产生它们的啮齿动物视为内脏，或者其他啮齿动物留下的遗骸是否被视为内脏。这与偷窃有关，这是这个物种的一种常见行为，如果偷窃的动物拒绝遗体。结果表明，外来的残骸和啮齿类动物自己的残骸并没有被拒绝，相反，它们比完整的橡子更容易被吃掉。完整的橡子在贮藏物中保存的时间更长，并且有更大的机会发芽和发芽。啮齿类动物更喜欢先吃掉外国的遗骸。这可能是因为，在短缺的情况下，在耗尽自己的储备之前完成潜在竞争对手的储备被认为是有利的。啮齿动物通过建立表面贮藏(贮藏)参与橡果的传播过程。这里研究的啮齿动物部分食用橡实，从基部开始，保存位于顶端末端的胚胎。这些部分被吃掉的橡子残骸被认为是内脏，可以在贮藏物中保存更长的时间，作为啮齿动物的储备。我们的目的是检查这些橡子残骸是否被啮齿类动物视为内脏。我们发现，恰恰相反，它们在完整的橡子之前被吃掉。完整的橡子在贮藏库中保存的时间更长，承担了储备的作用，并具有更大的发芽能力。这种啮齿动物区分自己的遗体和其他动物的遗体，首先消耗外来的内脏。因此，它们自己的内脏会在储存中保存更长的时间，如果胚胎被保存下来，它们可能会发芽。这种行为已经在这种啮齿动物身上得到了证明。
{"title":"The role of partially consumed acorn remains in scatter hoards and their implications in oak colonization","authors":"Sergio Del Arco, Jose María Del Arco","doi":"10.1007/s00265-023-03409-4","DOIUrl":"https://doi.org/10.1007/s00265-023-03409-4","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Past studies have revealed the benefits of rodent participation in the colonization process of oak species. Certain rodent species (<i>Apodemus sylvaticus</i> and <i>Mus spretus</i>) partially consume acorns, beginning at the basal part and preserving the embryo. Perea et al. (2011) and Yang and Yi (2012) found that during periods of abundance, the remains left after partial consumption continue to be present on the surface and are not transported to caches, given that they are perceived as leftovers. These remains, produced after several visits by the cache owner or by thieving conspecifics, also appear in the caches. If they are perceived as offal, they will not be attacked and may remain in these stores for longer periods, serving as resources for the cache builder. Our objective is to determine whether these remnants are perceived as offal by the rodent generating them or if the remains left by other rodents are considered offal. This is relevant in cases of theft, a common behavior of this species, if the thieving animals reject the remains. The results suggest that foreign remains and the rodents’ own remains are not rejected, but rather, they are consumed in preference to intact acorns. The intact acorns remain in the cache for longer periods and have a greater opportunity to germinate and emerge. Rodents prefer to consume foreign remains first. This may be due to the fact that, in case of shortage, it is considered advantageous to finish the reserves of a potential competitor before depleting one’s own reserves.</p><h3 data-test=\"abstract-sub-heading\">Significance statement</h3><p>Rodents participate in the acorn dissemination process by constructing surface stores (caches). The rodent species studied here partially consumes acorns, beginning with the basal part and preserving the embryo located at the apical end. These partially consumed acorn remains are considered offal and remain in the caches for longer periods, serving as reserves for the rodent. Our objective is to examine whether these acorn remains are viewed as offal by the rodents. We have found that, to the contrary, they are consumed before intact acorns. Intact acorns remain in the caches for longer periods, assuming the role of reserves and taking on a greater capacity to germinate. This species of rodent differentiates between its own remains and those of others, first consuming the foreign offal. Therefore, their own offal remains in the stores for longer periods and may potentially germinate if the embryo is preserved. This behavior has been demonstrated by this rodent species.</p>","PeriodicalId":8881,"journal":{"name":"Behavioral Ecology and Sociobiology","volume":"8 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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