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James AO, Bentz AB. Predicting yolk testosterone allocation using ecological contexts and species-specific traits. J Anim Ecol 2024. [PMID: 39302064 DOI: 10.1111/1365-2656.14185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 08/28/2024] [Indexed: 09/22/2024]
Abstract
The prenatal transfer of testosterone (T) from mother to offspring is an important source of phenotypic plasticity. In birds, exposure to ecologically relevant stimuli, such as social competition or an attractive mate, can cause females to deposit more T into their egg yolks. Exposure to elevated yolk T can modify the expression of several fitness-related traits in offspring (e.g. growth, immune function, secondary sex traits and behaviour). Despite some of these changes being potentially adaptive, not all studies find that yolk T levels change in response to ecologically relevant stimuli. This heterogeneity is currently unexplained, limiting our ability to predict inter-generational responses to ecological change. Here, we performed a systematic literature search and found 119 observations across 39 wild species that measured inter-female variation in yolk T allocation in response to various stimuli. We used boosted regression trees, a form of machine learning, to examine whether species-specific traits or variation in study-level variables could explain variation in yolk T allocation (i.e. statistically significant vs. non-significant responses). We found that both species-specific traits and study-level variables are important predictors of significant changes in yolk T levels. Geographic range (latitude and longitude), evolutionary distinctiveness, longevity, egg mass relative to female mass, sociality, migration status and time to fledge were among the top 10 most influential predictors of the 48 examined. We also found that studies measuring or manipulating social stimuli (e.g. competition and breeding density) or breeding date were more likely to detect changes in yolk T allocation compared with studies examining other ecological contexts. Overall, these data provide several testable hypotheses concerning yolk T allocation and its adaptive value across species and contexts. Additionally, these findings can help us predict how ecological changes will affect hormonal responses in females that can shape future generations.
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Affiliation(s)
- Anna O James
- School of Biological Sciences, University of Oklahoma, Norman, Oklahoma, USA
| | - Alexandra B Bentz
- School of Biological Sciences, University of Oklahoma, Norman, Oklahoma, USA
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2
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Fortuna R, Paquet M, Biard C, Élard L, Ferreira AC, Leroux-Coyaux M, Parenteau C, Silva LR, Théron F, Covas R, Doutrelant C. Egg components and offspring survival vary with group size and laying order in a cooperative breeder. Oecologia 2023; 202:129-142. [PMID: 37148378 DOI: 10.1007/s00442-023-05379-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 04/25/2023] [Indexed: 05/08/2023]
Abstract
Prenatal resource allocation to offspring can be influenced by maternal environment and offspring value, and affect offspring survival. An important pathway for flexible maternal allocation is via egg components such as nutrients and hormones. In cooperative breeders, females with helpers may increase resource allocation to eggs-'differential allocation'-or reduce it-'load-lightening'. Yet, helper effects on egg composition have been poorly studied. Moreover, it is unknown how helpers' presence modulates laying order effects on egg content and survival. Here, we investigated how maternal allocation varied with group size and laying order in the cooperatively breeding sociable weaver (Philetairus socius). We estimated interactive effects of helpers and laying order on allocation to egg mass, yolk nutrients-yolk mass, proteins, lipids, carotenoids, vitamin A and vitamin E-and hormones-testosterone, androstenedione, and corticosterone. Results concurred with the 'differential allocation' predictions. Females with more helpers produced later-laid eggs with heavier yolks and more lipids, and laid eggs overall richer in lipids. Proteins, antioxidants, and hormones were not found to vary with helper number. We then analyzed how helper number modulated laying order effects on survival. Females with more helpers did not specifically produce later-laid eggs with higher survival, but eggs laid by females with more helpers were overall more likely to fledge. These findings show that some egg components (yolk mass, lipids) can positively vary according to females' breeding group size, which may improve offspring fitness.
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Affiliation(s)
- Rita Fortuna
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal.
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4099-002, Porto, Portugal.
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal.
- Centre d'Ecologie Fonctionnelle et Evolutive, CEFE, CNRS, Univ Montpellier, EPHE, IRD, 34293, Montpellier, France.
- Centre for Biodiversity Dynamics, Institutt for Biologi, NTNU, Trondheim, Norway.
| | - Matthieu Paquet
- Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, 75007, Uppsala, Sweden
- Institute of Mathematics of Bordeaux, University of Bordeaux, CNRS, Bordeaux INP, Talence, France
| | - Clotilde Biard
- Sorbonne Université, UPEC, CNRS, IRD, INRA, Institut d'Écologie et des Sciences de l'Environnement de Paris, IEES, 75005, Paris, France
| | - Loïc Élard
- Sorbonne Université, UPEC, CNRS, IRD, INRA, Institut d'Écologie et des Sciences de l'Environnement de Paris, IEES, 75005, Paris, France
| | - André C Ferreira
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
- Centre d'Ecologie Fonctionnelle et Evolutive, CEFE, CNRS, Univ Montpellier, EPHE, IRD, 34293, Montpellier, France
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Mathieu Leroux-Coyaux
- Sorbonne Université, UPEC, CNRS, IRD, INRA, Institut d'Écologie et des Sciences de l'Environnement de Paris, IEES, 75005, Paris, France
| | - Charline Parenteau
- Centre d'Etudes Biologiques de Chizé, CNRS-La Rochelle Université, Villiers-en-Bois, France
| | - Liliana R Silva
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Franck Théron
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
- Centre d'Ecologie Fonctionnelle et Evolutive, CEFE, CNRS, Univ Montpellier, EPHE, IRD, 34293, Montpellier, France
| | - Rita Covas
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
- DST-NRF Centre of Excellence, FitzPatrick Institute, University of Cape Town, Cape Town, South Africa
| | - Claire Doutrelant
- Centre d'Ecologie Fonctionnelle et Evolutive, CEFE, CNRS, Univ Montpellier, EPHE, IRD, 34293, Montpellier, France
- DST-NRF Centre of Excellence, FitzPatrick Institute, University of Cape Town, Cape Town, South Africa
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3
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Bebbington K, Fairfield EA, Spurgin LG, Kingma SA, Dugdale H, Komdeur J, Richardson DS. Joint care can outweigh costs of nonkin competition in communal breeders. Behav Ecol 2017; 29:169-178. [PMID: 29622934 PMCID: PMC5873242 DOI: 10.1093/beheco/arx137] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 09/04/2017] [Accepted: 10/06/2017] [Indexed: 01/21/2023] Open
Abstract
Competition between offspring can greatly influence offspring fitness and parental investment decisions, especially in communal breeders where unrelated competitors have less incentive to concede resources. Given the potential for escalated conflict, it remains unclear what mechanisms facilitate the evolution of communal breeding among unrelated females. Resolving this question requires simultaneous consideration of offspring in noncommunal and communal nurseries, but such comparisons are missing. In the Seychelles warbler Acrocephalus sechellensis, we compare nestling pairs from communal nests (2 mothers) and noncommunal nests (1 mother) with singleton nestlings. Our results indicate that increased provisioning rate can act as a mechanism to mitigate the costs of offspring rivalry among nonkin. Increased provisioning in communal broods, as a consequence of having 2 female parents, mitigates any elevated costs of offspring rivalry among nonkin: per-capita provisioning and survival was equal in communal broods and singletons, but lower in noncommunal broods. Individual offspring costs were also more divergent in noncommunal broods, likely because resource limitation exacerbates differences in competitive ability between nestlings. It is typically assumed that offspring rivalry among nonkin will be more costly because offspring are not driven by kin selection to concede resources to their competitors. Our findings are correlational and require further corroboration, but may help explain the evolutionary maintenance of communal breeding by providing a mechanism by which communal breeders can avoid these costs.
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Affiliation(s)
- Kat Bebbington
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK.,Behavioural Ecology and Physiological Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Eleanor A Fairfield
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Lewis G Spurgin
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Sjouke A Kingma
- Behavioural Ecology and Physiological Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Hannah Dugdale
- Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Jan Komdeur
- Behavioural Ecology and Physiological Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - David S Richardson
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK.,Nature Seychelles, Mahé, Republic of Seychelles
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Bentz AB, Becker DJ, Navara KJ. Evolutionary implications of interspecific variation in a maternal effect: a meta-analysis of yolk testosterone response to competition. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160499. [PMID: 28018636 PMCID: PMC5180134 DOI: 10.1098/rsos.160499] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 11/02/2016] [Indexed: 05/02/2023]
Abstract
Competition between conspecifics during the breeding season can result in behavioural and physiological programming of offspring via maternal effects. For birds, in which maternal effects are best studied, it has been claimed that exposure to increased competition causes greater deposition of testosterone into egg yolks, which creates faster growing, more aggressive offspring; such traits are thought to be beneficial for high-competition environments. Nevertheless, not all species show a positive relationship between competitive interactions and yolk testosterone, and an explanation for this interspecific variation is lacking. We here test if the magnitude and direction of maternal testosterone allocated to eggs in response to competition can be explained by life-history traits while accounting for phylogenetic relationships. We performed a meta-analysis relating effect size of yolk testosterone response to competition with species coloniality, nest type, parental effort and mating type. We found that effect size was moderated by coloniality and nest type; colonial species and those with open nests allocate less testosterone to eggs when in more competitive environments. Applying a life-history perspective helps contextualize studies showing little or negative responses of yolk testosterone to competition and improves our understanding of how variation in this maternal effect may have evolved.
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Affiliation(s)
- Alexandra B. Bentz
- Poultry Science Department, University of Georgia, 203 Poultry Science Building, Athens, GA 30602, USA
| | - Daniel J. Becker
- Odum School of Ecology, University of Georgia, 140 E. Green Street, Athens, GA 30602, USA
| | - Kristen J. Navara
- Poultry Science Department, University of Georgia, 203 Poultry Science Building, Athens, GA 30602, USA
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5
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Riehl C, Strong MJ, Edwards SV. Inferential reasoning and egg rejection in a cooperatively breeding cuckoo. Anim Cogn 2014; 18:75-82. [PMID: 24993064 DOI: 10.1007/s10071-014-0778-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 05/06/2014] [Accepted: 06/24/2014] [Indexed: 11/30/2022]
Abstract
Inferential reasoning-associating a visible consequence with an imagined event-has been demonstrated in several bird species in captivity, but few studies have tested wild birds in ecologically relevant contexts. Here, we investigate inferential reasoning by the greater ani, a cooperatively breeding cuckoo in which several females lay eggs in one nest. Prior to laying her first egg, each female removes any eggs that have already been laid by other females in the shared nest. After laying her first egg, however, each female stops removing eggs, presumably in order to avoid accidentally rejecting her own. But are anis using inferential reasoning to track the fate of their eggs in the communal nest, or is egg ejection governed by non-cognitive determinants? We experimentally removed eggs from two-female nests after both females had laid at least one egg and used video recording to verify that both females viewed the empty nest. We waited until one female (A) laid an egg in the nest, and video recorded the behavior of the female that had not yet re-laid (B). We predicted that if capable of inferential reasoning, female B should infer that the new egg could not be her own and she should remove it. Five out of five females tested failed to make this inference, suggesting that egg removal is either determined by the female's reproductive status or by the amount of time elapsed between egg removal and re-laying. This apparent cognitive constraint may have implications for the evolutionary stability of the anis' unusual breeding system.
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Affiliation(s)
- Christina Riehl
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St., Cambridge, MA, 02138, USA,
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6
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Yolk contributes steroid to the multidimensional endocrine environment of embryos of Niveoscincus metallicus, a viviparous skink with a moderately complex placenta. Comp Biochem Physiol A Mol Integr Physiol 2014; 171:51-6. [DOI: 10.1016/j.cbpa.2014.02.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 02/10/2014] [Accepted: 02/14/2014] [Indexed: 02/05/2023]
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7
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Kapoor A, Lubach G, Hedman C, Ziegler TE, Coe CL. Hormones in infant rhesus monkeys' (Macaca mulatta) hair at birth provide a window into the fetal environment. Pediatr Res 2014; 75:476-81. [PMID: 24418932 PMCID: PMC3961505 DOI: 10.1038/pr.2014.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 10/04/2013] [Indexed: 11/27/2022]
Abstract
BACKGROUND It is established that maternal parity can affect infant growth and risk for several disorders, but the prenatal endocrine milieu that contributes to these outcomes is still largely unknown. Recently, it has been shown that hormones deposited in hair can provide a retrospective reflection of hormone levels while the hair was growing. Taking advantage of this finding, our study utilized hair at birth to investigate if maternal parity affected fetal hormone exposure during late gestation. METHODS Hair was collected from primiparous and multiparous mother and infant monkeys at birth and used to determine steroid hormones embedded in hair while the infant was in utero. A high-pressure liquid chromatography-triple quadrupole mass spectrometry technique was refined, which enabled the simultaneous measurement of eight hormones. RESULTS Hormone concentrations were dramatically higher in neonatal compared to maternal hair, reflecting extended fetal exposure as the first hair was growing. Further, hair cortisone was higher in primiparous mothers and infants when compared to the multiparous dyads. CONCLUSION This research demonstrates that infant hair can be used to track fetal hormone exposure and a panel of steroid hormones can be quantified from hair specimens. Given the utility in nonhuman primates, this approach can be translated to a clinical setting with human infants.
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Affiliation(s)
- Amita Kapoor
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI,Correspondence: Dr. Amita Kapoor Wisconsin National Primate Research Center, University of Wisconsin-Madison 1223 Capital Court, Rm 205, Madison, WI, 53715, U.S.A. Tel: (608) 890-4386
| | - Gabriele Lubach
- Department of Psychology, University of Wisconsin-Madison, Madison, WI,Harlow Center for Biological Psychology, University of Wisconsin-Madison, Madison, WI
| | - Curtis Hedman
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI,Wisconsin State Laboratory of Hygiene, Madison, WI
| | - Toni E. Ziegler
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI
| | - Christopher L. Coe
- Department of Psychology, University of Wisconsin-Madison, Madison, WI,Harlow Center for Biological Psychology, University of Wisconsin-Madison, Madison, WI
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8
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Paquet M, Covas R, Chastel O, Parenteau C, Doutrelant C. Maternal effects in relation to helper presence in the cooperatively breeding sociable weaver. PLoS One 2013; 8:e59336. [PMID: 23536872 PMCID: PMC3607610 DOI: 10.1371/journal.pone.0059336] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 02/15/2013] [Indexed: 11/29/2022] Open
Abstract
In egg laying species, breeding females may adjust the allocation of nutrients or other substances into eggs in order to maximise offspring or maternal fitness. Cooperatively breeding species offer a particularly interesting context in which to study maternal allocation because helpers create predictably improved conditions during offspring development. Some recent studies on cooperative species showed that females assisted by helpers produced smaller eggs, as the additional food brought by the helpers appeared to compensate for this reduction in egg size. However, it remains unclear how common this effect might be. Also currently unknown is whether females change egg composition when assisted by helpers. This effect is predicted by current maternal allocation theory, but has not been previously investigated. We studied egg mass and contents in sociable weavers (Philetairus socius). We found that egg mass decreased with group size, while fledgling mass did not vary, suggesting that helpers may compensate for the reduced investment in eggs. We found no differences in eggs' carotenoid contents, but females assisted by helpers produced eggs with lower hormonal content, specifically testosterone, androstenedione (A4) and corticosterone levels. Taken together, these results suggest that the environment created by helpers can influence maternal allocation and potentially offspring phenotypes.
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9
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Ibáñez-Álamo JD, De Neve L, Roldán M, Rodríguez J, Trouvé C, Chastel O, Soler M. Corticosterone levels in host and parasite nestlings: is brood parasitism a hormonal stressor? Horm Behav 2012; 61:590-7. [PMID: 22366505 DOI: 10.1016/j.yhbeh.2012.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 02/07/2012] [Accepted: 02/08/2012] [Indexed: 10/28/2022]
Abstract
Parasite chicks from non-evictor species usually try to monopolize host parental care, thereby increasing considerably the level of food competition in the nest. Here, we propose that brood parasitism is an important stressor for host and parasite nestlings and explore this hypothesis in the non-evictor great spotted cuckoo (Clamator glandarius) and its main hosts, the same-sized black-billed magpie (Pica pica) and the larger carrion crow (Corvus corone). We experimentally created 3-nestling broods of different brood compositions (only cuckoo chicks, only host chicks, or cuckoo and host chicks together) and measured baseline corticosterone levels of nestlings along their developmental period (early, middle and late). We found that brood parasitism increased corticosterone levels in magpie nestlings in the mid and late nestling period compared to those raised in unparasitized nests. Interestingly, carrion crow nestlings from parasitized nests only increased their corticosterone levels in the mid nestling period, when the competition for food with the cuckoo nestling was highest. Our results suggest that brood parasitism could be a potential physiological stressor for host nestlings, especially during the developmental stages where food requirements are highest. Conversely, cuckoo nestlings could be physiologically adapted to high competition levels since they did not show significant differences in corticosterone levels in relation to brood composition.
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Cohen RE, Wade J. Newly deposited maternal hormones can be detected in the yolks of oviductal eggs in the green anole lizard. ACTA ACUST UNITED AC 2010; 313:352-8. [PMID: 20336789 DOI: 10.1002/jez.605] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Studies often examine egg yolks after oviposition with the goal of drawing conclusions about maternal allocation of gonadal steroid hormones and how it may affect offspring development. However, these hormones might originate from a few sources, including the ovary, blood plasma, or the embryo itself. The goal of this study was to investigate whether maternal steroids can enter oviductal eggs. In Experiment 1, gravid female green anole lizards were injected with 1 microCi 3H-T. Plasma, ovarian follicles (separated into yolking and non-yolking samples), and shelled oviductal eggs were collected at times ranging from 15 min to 24 hr after treatment. Main effects of tissue, time, and an interaction between them all existed on recovered 3H-hormone corrected for tissue mass. Of particular interest, there was a decrease in plasma with coincident increase in eggs. In Experiment 2, females were injected with doses ranging from 0.01 to 0.45 microCi of 3H-T per gram body weight. Across tissues, 3H-hormone levels corrected for mass were greater with increasing doses. Values also differed among tissues and an interaction was detected. Within each dose, plasma and non-yolking follicles generally had higher concentrations of 3H-hormone than did yolking follicles and oviductal eggs. However, at and after 6 hr, eggs had higher total radioactivity levels than both yolking and non-yolking follicles had (not corrected for mass). The results indicate that steroids can cross through relatively well-formed shells before oviposition, suggesting a way in which maternal hormones might influence developmental factors after yolk deposition.
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Affiliation(s)
- Rachel E Cohen
- Department of Zoology, Michigan State University, East Lansing, Michigan 48824-1101, USA.
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11
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Riehl C. Egg ejection risk and hatching asynchrony predict egg mass in a communally breeding cuckoo, the Greater Ani (Crotophaga major). Behav Ecol 2010. [DOI: 10.1093/beheco/arq038] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Bertin A, Richard-Yris MA, Houdelier C, Lumineau S, Möstl E, Kuchar A, Hirschenhauser K, Kotrschal K. Habituation to humans affects yolk steroid levels and offspring phenotype in quail. Horm Behav 2008; 54:396-402. [PMID: 18572170 DOI: 10.1016/j.yhbeh.2008.04.012] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 03/21/2008] [Accepted: 04/23/2008] [Indexed: 11/20/2022]
Abstract
In the field as well as in the laboratory, human-generated stress responses are reduced in adult animals previously habituated to humans in comparison to non-habituated individuals. In birds, yolk steroid levels vary with maternal environment and condition. We tested the hypothesis that the experience of female birds with humans could affect yolk steroids levels and offspring phenotype. Two groups of Japanese quail, one habituated to humans (H) and a second non-habituated (NH), were exposed daily to brief human disturbances. We analysed egg quality, offspring growth, and offspring emotional reactivity. NH females produced eggs with less androgens (testosterone and androstenedione) and more immunoreactive progesterone compared to birds habituated to humans. NH females produced eggs with less yolk, heavier shell and chicks hatching later and being smaller as compared to habituated individuals. A lower emotional reactivity was found in young of NH females compared to young of H females. Thus, human disturbance of the mother triggered different effects on chick phenotype depending on previous experience of mother birds with humans. In addition, we describe for the first time the influence of environmental stimuli on yolk immunoreactive progesterone levels. Our results show that a relatively minor difference in behavioral habituation may have substantial effects on eggs and offspring. This has obvious implications for keeping and handling laboratory animals, for conservation biology and for animal welfare.
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Affiliation(s)
- Aline Bertin
- Konrad-Lorenz-Forschungsstelle, University of Vienna, A-4645 Grünau, Austria.
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13
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Maternal investment in eggs is affected by male feet colour and breeding conditions in the blue-footed booby, Sula nebouxii. Behav Ecol Sociobiol 2008. [DOI: 10.1007/s00265-008-0620-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Schmaltz G, Quinn JS, Schoech SJ. Do group size and laying order influence maternal deposition of testosterone in smooth-billed ani eggs? Horm Behav 2008; 53:82-9. [PMID: 17942099 DOI: 10.1016/j.yhbeh.2007.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Revised: 08/17/2007] [Accepted: 09/04/2007] [Indexed: 11/28/2022]
Abstract
The avian egg contains maternal hormones that affect behavior, growth, morphology, and offspring survival. Evidence to date suggests that patterns of yolk androgen deposition could provide females with a means to manipulate sibling competition and, thereby, increase their fitness. We examined yolk testosterone (T) concentrations in eggs of the smooth-billed ani (Crotophaga ani) to understand patterns of androgen deposition in eggs of this plural-breeding joint-nesting cooperatively breeding species. We tested the hatching asynchrony adjustment hypothesis, which states that increases in yolk androgen levels over the laying sequence function to mitigate the disadvantage of being a later-hatched chick in species without adaptive brood reduction. We also investigated the effect of group size on yolk T deposition to test the hypothesis that females in multi-female groups could give a competitive edge to their own chicks by depositing higher T levels in their eggs. Predictions of the hatching asynchrony adjustment hypothesis were supported in both single- and multi-female groups as yolk testosterone levels increased from early- to late-laid eggs. This suggests that ani females can influence nestling competition and chick survival by within-clutch differential T allocation. Unexpectedly, we did not observe an effect of group size on yolk T deposition. Yolk testosterone concentrations may not be a mere reflection of a female's hormonal status as female plasma circulating levels of T did not vary in the same direction as yolk T levels. Results of this study therefore support the idea that females may adaptively manipulate chick behavior through hormonal deposition in eggs.
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Affiliation(s)
- Gregory Schmaltz
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1
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15
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Gil D. Chapter 7 Hormones in Avian Eggs: Physiology, Ecology and Behavior. ADVANCES IN THE STUDY OF BEHAVIOR 2008. [DOI: 10.1016/s0065-3454(08)00007-7] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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