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Oro D, Waldrep C, Bertolero A, Genovart M. Drivers of resource allocation for breeding under variable environments in a bet hedger. Ecol Evol 2023; 13:e10485. [PMID: 37693935 PMCID: PMC10483097 DOI: 10.1002/ece3.10485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 08/14/2023] [Accepted: 08/18/2023] [Indexed: 09/12/2023] Open
Abstract
The evolutionary theory of life histories predicts that there is a trade-off between survival and reproduction: since adult survival in long-lived organisms is high, then breeding investment is more variable and more dependent on conditions (e.g. food availability and individual experience). Clutch features influence fitness prospects, but how a bet hedger builds its clutch in temporally varying environments is quite unknown. Using 27-year data on 2847 clutches of known-age breeders, we analyse how Audouin's gulls (Larus audouinii), a species showing a combination of conservative and adaptive bet-hedging breeding strategies, can allocate energy by laying clutches and eggs of different sizes. Results show that both food availability and age influenced clutch size and total egg volume in a clutch. Interestingly, we found an interaction between food and age on egg parameters: total volume in two-egg clutches, laid mostly by younger breeders, did not significantly change with food availability and the quadratic pattern in clutch size over the range of ages was less marked as long as food conditions became harsher. With increased food, females invested more by building larger first eggs, whereas they were more conservative on second and third eggs. Furthermore, asymmetries in egg volume within three-egg clutches increased with food availability for old females. Egg size profiles of two-egg clutches suggest that gulls should exhibit progressive reduction of the size of the third egg before shifting to a two-egg clutch size. Food availability influenced all parameters studied, whereas age affected the amount of energy allocated for producing eggs (their size and number) but not the way of allocating those energies (i.e. asymmetries within the clutch). Despite the range of factors affecting the clutch, results suggest that females can allocate the amount of resources in a clutch optimally to increase their fitness under variable environments via bet-hedging.
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Affiliation(s)
- Daniel Oro
- Centre d'Estudis Avançats de Blanes – CEAB (CSIC)BlanesSpain
| | - Cassidy Waldrep
- Centre d'Estudis Avançats de Blanes – CEAB (CSIC)BlanesSpain
- Department of BiologyMiami UniversityOxfordOhioUSA
- Department of BiologyUniversity of SaskatchewanSaskatoonCanada
| | - Albert Bertolero
- Associació Ornitològica Picampall de les Terres de l'Ebre, La GaleraAmpostaSpain
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Brood sex ratio variation in a colonial raptor, the Eleonora's falcon, Falco eleonorae. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Tompkins EM, Anderson DJ. Breeding responses to environmental variation are age- and trait-dependent in female Nazca boobies. Ecology 2021; 102:e03457. [PMID: 34166542 DOI: 10.1002/ecy.3457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 12/04/2020] [Accepted: 04/05/2021] [Indexed: 12/17/2022]
Abstract
Age and environment are important determinants of reproductive parameters in long-lived organisms. These factors may interact to determine breeding responses to environmental change, yet few studies have examined the environmental dependence of aging patterns across the entire life span. We do so, using a 20-yr longitudinal data set of reproductive phenotypes in long-lived female Nazca boobies (Sula granti), a monogamous seabird breeding in the eastern tropical Pacific. Young and old females may suffer from inexperience and senescence, respectively, and/or practice reproductive restraint. Breeding performance (for breeding participation, breeding date, clutch size, egg volume, and offspring production) was expected to be lower in these age classes, particularly under environmental challenge, in comparison with middle-aged breeders. Sea surface temperature anomalies (SSTA) represented interannual variation in the El Niño-Southern Oscillation (ENSO) and were one proxy for environmental quality (a population count of clutch initiations was a second). Although only females lay eggs, both sexes care for eggs and nestlings, and the male partner's age, alone or in interaction with female age, was evaluated as a predictor of breeding performance. Middle-aged females performed better than young and old birds for all reproductive traits. Pairing with a young male delayed breeding (particularly for old females) and reduced clutch size, and pairing with an old male reduced offspring production. Challenging environments increased age effects on breeding probability and breeding date across young to middle ages and for offspring production across middle to old ages. However, important exceptions to the predicted patterns for clutch size and fledging success across young to middle ages suggested that trade-offs between fitness components may complicate patterns of trait expression across the life span. Relationships between breeding participation, environment, and individual quality and/or experience in young females may also contribute to unexpected patterns for clutch size and fledging success, traits expressed only in breeders. Finally, independent of age, breeding responses of female Nazca boobies to the ENSO did not follow expectations derived from oceanic forcing of primary productivity. During El Niño-like conditions, egg-laying traits (clutch size, breeding date) improved, but offspring production declined, whereas La Niña-like conditions were "poor" environments throughout the breeding cycle.
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Affiliation(s)
- Emily M Tompkins
- Biology Department, Wake Forest University, Winston-Salem, North Carolina, USA
| | - David J Anderson
- Biology Department, Wake Forest University, Winston-Salem, North Carolina, USA
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HEALTH STATUS OF NAZCA BOOBIES ( SULA GRANTI) ON DAPHNE MAJOR ISLAND IN THE GALÁPAGOS DETERMINED BY HEMATOLOGY, BIOCHEMISTRY, AND PHYSICAL EXAMINATION. J Zoo Wildl Med 2021; 52:671-679. [PMID: 34130410 DOI: 10.1638/2020-0136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/26/2021] [Indexed: 11/21/2022] Open
Abstract
Island species are particularly vulnerable to environmental disturbances and introduced pathogens. Conducting health assessments of wild populations in the Galápagos improves the ability of wildlife managers and veterinarians to detect deteriorations in health status. Seabirds in particular are useful species to monitor due to their colonial breeding and wide migration range. Nazca boobies (Sula granti) in a breeding colony at Daphne Major (n = 30) were given physical examinations, and blood samples were collected for hematology and biochemistry using an iSTAT Portable Clinical Analyzer. Female boobies had longer wing length than males, as well as lower blood urea nitrogen, creatinine, and white blood cell counts. This could be attributed to sexual dimorphism or differences in foraging and mating strategies between the sexes. The time between capture and blood collection had a significant inverse relationship on plasma sodium, potassium, hemoglobin, anion gaps, and lymphocyte counts, suggesting that blood sampling in Nazca boobies should be done in less than 5 m to avoid the impacts of stress on hematological parameters. This is the first health assessment on the breeding colony of Nazca boobies at Daphne Major, and the results can inform future monitoring in this species as well as other sulids.
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Howard JL, Tompkins EM, Anderson DJ. Effects of age, sex, and ENSO phase on foraging and flight performance in Nazca boobies. Ecol Evol 2021; 11:4084-4100. [PMID: 33976796 PMCID: PMC8093656 DOI: 10.1002/ece3.7308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/15/2021] [Accepted: 01/28/2021] [Indexed: 12/02/2022] Open
Abstract
Age-related changes in survival and reproduction are common in seabirds; however, the underlying causes remain elusive. A lack of experience for young individuals, and a decline in foraging performance for old birds, could underlie age-related variation in reproduction because reproductive success is connected closely to provisioning offspring. For seabirds, flapping flight during foraging trips is physiologically costly; inexperience or senescent decline in performance of this demanding activity might cap delivery of food to the nest, providing a proximate explanation for poor breeding success in young and old age, respectively. We evaluated the hypothesis that young and old Nazca boobies (Sula granti), a Galápagos seabird, demonstrate deficits in foraging outcomes and flight performance. We tagged incubating male and female adults across the life span with both accelerometer and GPS loggers during the incubation periods of two breeding seasons (years), during the 2015 El Niño and the following weak La Niña. We tested the ability of age, sex, and environment to explain variation in foraging outcomes (e.g., mass gained) and flight variables (e.g., wingbeat frequency). Consistent with senescence, old birds gained less mass while foraging than middle-aged individuals, a marginal effect, and achieved a slower airspeed late in a foraging trip. Contrary to expectations, young birds showed no deficit in foraging outcomes or flight performance, except for airspeed (contingent on environment). Young birds flew slower than middle-aged birds in 2015, but faster than middle-aged birds in 2016. Wingbeat frequency, flap-glide ratio, and body displacement (approximating wingbeat strength) failed to predict airspeed and were unaffected by age. Sex influenced nearly all aspects of performance. Environment affected flight performance and foraging outcomes. Boobies' foraging outcomes were better during the extreme 2015 El Niño than during the 2016 weak La Niña, a surprising result given the negative effects tropical seabirds often experience during extreme El Niños.
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7
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Brandl HB, Farine DR, Funghi C, Schuett W, Griffith SC. Early-life social environment predicts social network position in wild zebra finches. Proc Biol Sci 2020; 286:20182579. [PMID: 30963840 DOI: 10.1098/rspb.2018.2579] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Early-life experience can fundamentally shape individual life-history trajectories. Previous research has suggested that exposure to stress during development causes differences in social behaviour later in life. In captivity, juvenile zebra finches exposed to elevated corticosterone levels were less socially choosy and more central in their social networks when compared to untreated siblings. These differences extended to other aspects of social life, with 'stress-exposed' juveniles switching social learning strategies and juvenile males less faithfully learning their father's song. However, while this body of research suggests that the impacts of early-life stress could be profound, it remains unknown whether such effects are strong enough to be expressed under natural conditions. Here, we collected data on social associations of zebra finches in the Australian desert after experimentally manipulating brood sizes. Juveniles from enlarged broods experienced heightened sibling competition, and we predicted that they would express similar patterns of social associations to stress-treated birds in the captive study by having more, but less differentiated, relationships. We show striking support for the suggested consequences of developmental stress on social network positions, with our data from the wild replicating the same results in 9 out of 10 predictions previously tested in captivity. Chicks raised in enlarged broods foraged with greater numbers of conspecifics but were less 'choosy' and more central in the social network. Our results confirm that the natural range of variation in early-life experience can be sufficient to predict individuals' social trajectories and support theory highlighting the potential importance of developmental conditions on behaviour.
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Affiliation(s)
- Hanja B Brandl
- 1 Institute of Zoology, Universität Hamburg , Hamburg , Germany.,2 Department of Biological Sciences, Macquarie University , Sydney , Australia.,3 School of Biological, Earth, and Environmental Sciences, University of New South Wales , Sydney, New South Wales , Australia
| | - Damien R Farine
- 4 Department of Collective Behaviour, Max Planck Institute for Ornithology , Konstanz , Germany.,5 Chair of Biodiversity and Collective Behaviour, Department of Biology, University of Konstanz , Konstanz , Germany.,6 Centre for the Advanced Study of Collective Behaviour, University of Konstanz , Konstanz , Germany.,7 Department of Zoology, Edward Grey Institute of Field Ornithology, University of Oxford , Oxford , UK
| | - Caterina Funghi
- 1 Institute of Zoology, Universität Hamburg , Hamburg , Germany.,2 Department of Biological Sciences, Macquarie University , Sydney , Australia.,3 School of Biological, Earth, and Environmental Sciences, University of New South Wales , Sydney, New South Wales , Australia
| | - Wiebke Schuett
- 1 Institute of Zoology, Universität Hamburg , Hamburg , Germany.,3 School of Biological, Earth, and Environmental Sciences, University of New South Wales , Sydney, New South Wales , Australia.,8 School of Life Sciences, University of Sussex , Brighton , UK
| | - Simon C Griffith
- 2 Department of Biological Sciences, Macquarie University , Sydney , Australia.,3 School of Biological, Earth, and Environmental Sciences, University of New South Wales , Sydney, New South Wales , Australia
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Factors affecting the reproductive performance of barbary partridges in cereal croplands of Northwestern Morocco: the role of timing of breeding and vegetation cover at fine-scale. Biologia (Bratisl) 2020. [DOI: 10.2478/s11756-019-00290-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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Champagnon J, Lebreton JD, Drummond H, Anderson DJ. Pacific Decadal and El Niño oscillations shape survival of a seabird. Ecology 2019; 99:1063-1072. [PMID: 29714830 DOI: 10.1002/ecy.2179] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 01/18/2018] [Accepted: 01/25/2018] [Indexed: 11/11/2022]
Abstract
Understanding and modeling population change is urgently needed to predict effects of climate change on biodiversity. High trophic-level organisms are influenced by fluctuations of prey quality and abundance, which themselves may depend on climate oscillations. Modeling effects of such fluctuations is challenging because prey populations may vary with multiple climate oscillations occurring at different time scales. The analysis of a 28-yr time series of capture-recapture data of a tropical seabird, the Nazca Booby (Sula granti), in the Galápagos, Ecuador, allowed us to test for demographic effects of two major ocean oscillations occurring at distinct time-scales: the inter-annual El Niño Southern Oscillation (ENSO) and inter-decadal oscillations. As expected for a tropical seabird, survival of fledgling birds was highly affected by extreme ENSO events; by contrast, neither recruitment nor breeding participation were affected by either ENSO or decadal oscillations. More interesting, adult survival, a demographic trait that canalizes response to environmental variations, was unaffected by inter-annual ENSO oscillations yet was shaped by the Pacific Decadal Oscillation and small pelagic fish regime. Adult survival decreased during oceanic conditions associated with higher breeding success, an association probably mediated in this species by costs of reproduction that reduce survival when breeding attempts end later. To our knowledge, this is the first study suggesting that survival of a vertebrate can be vulnerable to a natural multidecadal oscillation.
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Affiliation(s)
- Jocelyn Champagnon
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, AP 70275, México DF, 04510, México.,CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, 1919 Route de Mende, 34293, Montpellier, France.,Institut de Recherche de la Tour du Valat, Le Sambuc, 13200, Arles, France
| | - Jean-Dominique Lebreton
- CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, 1919 Route de Mende, 34293, Montpellier, France
| | - Hugh Drummond
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, AP 70275, México DF, 04510, México
| | - David J Anderson
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, 27109, USA
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10
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Richardson J, Ross J, Smiseth PT. Food deprivation affects egg laying and maternal care but not offspring performance in a beetle. Behav Ecol 2019. [DOI: 10.1093/beheco/arz104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Individuals vary with respect to their nutritional state and such variation is an important determinant of the amount of resources individuals allocate toward reproductive functions. Currently, we have a relatively poor understanding of the downstream consequences of food deprivation on different traits associated with reproduction. Here, we address this gap by investigating how food deprivation affected different traits across the breeding cycle in the burying beetle, Nicrophorus vespilloides; a species that breeds on carcasses of small vertebrates serving as food for both parents and offspring. We found that food-deprived females took longer to start egg laying than control females, which may allow them more time to feed from the carcass. There was no difference between food-deprived and control females in the number, size, laying pattern, or hatching success of eggs, suggesting that this delay allowed females to compensate for their poor initial state. However, food-deprived females spent less time providing care, suggesting that this compensation was incomplete. Finally, we found no evidence for negative effects of food deprivation on the offspring’s growth or survival, which is surprising given that food-deprived females took longer to initiate egg laying and provided less care to their offspring. Our results highlight that food deprivation can have complex effects on parental and offspring traits, and suggest that females face a trade-off between the benefits of mitigating downstream consequences of nutritional stress and the costs associated with delaying the start of reproduction.
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Affiliation(s)
- Jon Richardson
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Jennifer Ross
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Per T Smiseth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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11
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Tompkins EM, Anderson DJ. Sex-specific patterns of senescence in Nazca boobies linked to mating system. J Anim Ecol 2019; 88:986-1000. [PMID: 30746683 DOI: 10.1111/1365-2656.12944] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 10/15/2018] [Indexed: 01/19/2023]
Abstract
Under life-history theories of ageing, increased senescence should follow relatively high reproductive effort. This expectation has rarely been tested against senescence varying between and within the two sexes, although such an approach may clarify the origins of sex-specific ageing in the context of a given mating system. Nazca boobies (Sula granti; a seabird) practise serial monogamy and biparental care. A male-biased population sex ratio results in earlier and more frequent breeding by females. Based on sex-specific reproductive schedules, females were expected to show faster age-related decline for survival and reproduction. Within each sex, high reproductive effort in early life was expected to reduce late-life performance and accelerate senescence. Longitudinal data were used to (a) evaluate the sex specificity of reproductive and actuarial senescence and then (b) test for early-/late-life fitness trade-offs within each sex. Within-sex analyses inform an interpretation of sex differences in senescence based on costs of reproduction. Analyses incorporated individual heterogeneity in breeding performance and cohort-level differences in early-adult environments. Females showed marginally more intense actuarial senescence and stronger age-related declines for fledging success. The opposite pattern (earlier and faster male senescence) was found for breeding probability. Individual reproductive effort in early life positively predicted late-life reproductive performance in both sexes and thus did not support a causal link between early-reproduction/late-life fitness trade-offs and sex differences in ageing. A high-quality diet in early adulthood reduced late-life survival (females) and accelerated senescence for fledging success (males). This study documents clear variation in ageing patterns-by sex, early-adult environment and early-adult reproductive effort-with implications for the role mating systems and early-life environments play in determining ageing patterns. Absent evidence for a disposable soma mechanism, patterns of sex differences in senescence may result from age- and condition-dependent mate choice interacting with this population's male-biased sex ratio and mate rotation.
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Affiliation(s)
- Emily M Tompkins
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina
| | - David J Anderson
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina
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12
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Mishra I, Kumar V. The quantity-quality trade-off: differential effects of daily food times on reproductive performance and offspring quality in diurnal zebra finches. J Exp Biol 2019; 222:jeb.196667. [DOI: 10.1242/jeb.196667] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 02/27/2019] [Indexed: 01/23/2023]
Abstract
Abundant food supply is crucial to reproductive performance, as shown by restricted food availability experiments, in small-sized vertebrates including birds. However, whether daily times of feeding would affect the reproduction is largely unknown. Present study investigated the effects of daily food availability times on reproductive performance and quality of eggs and offspring survivors in zebra finches (Taeniopygia guttata). To randomly paired birds kept under 12 h light per day for about 52 weeks, food availability period was restricted to 4 h in morning (FA-M) or evening (FA-E), with controls on food ad libitum; thus, daily food deprivation period began after 4 h of food in FA-M and was continuous with nighttime starvation in FA-E. Both food restrictions adversely affected reproductive health as shown by reduced sex steroids and mesotocin levels, but not general metabolism as indicated by no-difference in thyroxin and triiodothyronine levels. Food for 4 h negatively affected the reproductive performance, although with differences between FA-M and FA-E pairs. Particularly, there was delayed onset of reproduction and compromised reproductive success in FA-E, but not in FA-M pairs; conversely, the offspring health was severely compromised in FA-M, but not in FA-E pairs. Furthermore, FA-M females were in better health, implicating sex-biasness in parental food provisioning. Overall, we demonstrate trade-off of ‘quantity’ (offspring produced and/ or survived) for ‘quality’ (how good offspring were in health) in response to daily food availability times in zebra finches that much like humans are diurnal and retain the ability to reproduce throughout the year.
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Affiliation(s)
- I. Mishra
- Department of Zoology, University of Delhi, Delhi – 110 007, India
| | - V. Kumar
- Department of Zoology, University of Delhi, Delhi – 110 007, India
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13
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Johnston GR. The role of hatching asynchrony and sibling rivalry in pelican brood reduction. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Gregory R Johnston
- Royal Zoological Society of South Australia, Adelaide Zoo, Adelaide, SA, Australia
- College of Science and Engineering, Flinders University of South Australia, Adelaide, SA, Australia
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Gasperini S, Bonacchi A, Bartolommei P, Manzo E, Cozzolino R. Seasonal cravings: plant food preferences of syntopic small mammals. ETHOL ECOL EVOL 2017. [DOI: 10.1080/03949370.2017.1310141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Stefania Gasperini
- Fondazione Ethoikos, Convento dell’Osservanza, 53030 Radicondoli (Siena), Italy
- U.R. Ecologia Comportamentale, Etologia e Gestione della Fauna, Dipartimento di Scienze della Vita, Università di Siena, Via P.A. Mattioli 4, 53100 Siena, Italy
| | - Andrea Bonacchi
- Fondazione Ethoikos, Convento dell’Osservanza, 53030 Radicondoli (Siena), Italy
- U.R. Ecologia Comportamentale, Etologia e Gestione della Fauna, Dipartimento di Scienze della Vita, Università di Siena, Via P.A. Mattioli 4, 53100 Siena, Italy
| | - Paola Bartolommei
- Fondazione Ethoikos, Convento dell’Osservanza, 53030 Radicondoli (Siena), Italy
| | - Emiliano Manzo
- Fondazione Ethoikos, Convento dell’Osservanza, 53030 Radicondoli (Siena), Italy
| | - Roberto Cozzolino
- Fondazione Ethoikos, Convento dell’Osservanza, 53030 Radicondoli (Siena), Italy
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Taylor HR, Colbourne RM, Robertson HA, Nelson NJ, Allendorf FW, Ramstad KM. Cryptic inbreeding depression in a growing population of a long-lived species. Mol Ecol 2017; 26:799-813. [DOI: 10.1111/mec.13977] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 11/07/2016] [Accepted: 11/21/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Helen R. Taylor
- School of Biological Sciences; Victoria University of Wellington; Kelburn Parade Wellington New Zealand
| | | | | | - Nicola J. Nelson
- School of Biological Sciences; Victoria University of Wellington; Kelburn Parade Wellington New Zealand
| | - Fred W. Allendorf
- Montana Conservation Genetics Lab; University of Montana; Missoula MT USA
| | - Kristina M. Ramstad
- Department of Biology & Geology; University of South Carolina Aiken; 471 University Parkway Aiken SC USA
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Reynolds MH, Courtot KN, Berkowitz P, Storlazzi CD, Moore J, Flint E. Will the Effects of Sea-Level Rise Create Ecological Traps for Pacific Island Seabirds? PLoS One 2015; 10:e0136773. [PMID: 26398209 PMCID: PMC4580421 DOI: 10.1371/journal.pone.0136773] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 08/07/2015] [Indexed: 11/18/2022] Open
Abstract
More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross, Phoebastria immutabilis; black-footed albatross, P. nigripes; and Bonin petrel, Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of rising sea levels.
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Affiliation(s)
- Michelle H. Reynolds
- U.S. Geological Survey, Pacific Island Ecosystems Research Center, PO Box 44, Hawai‘i National Park, Hawai‘i, United States of America
- * E-mail:
| | - Karen N. Courtot
- U.S. Geological Survey, Pacific Island Ecosystems Research Center, PO Box 44, Hawai‘i National Park, Hawai‘i, United States of America
| | - Paul Berkowitz
- Hawai‘i Cooperative Studies Unit, University of Hawai‘i at Hilo, Hawai‘i National Park, Hawai‘i, United States of America
| | - Curt D. Storlazzi
- U.S. Geological Survey, Pacific Coastal and Marine Science Center, 400 Natural Bridges Drive, Santa Cruz, California, United States of America
| | - Janet Moore
- Saint Mary’s University, Halifax, Nova Scotia, Canada
| | - Elizabeth Flint
- U.S. Fish and Wildlife Service, Pacific Islands Refuges and Monuments Office, 300 Ala Moana Blvd. Suite 5–231, Honolulu, Hawai‘i, United States of America
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Davies S, Deviche P. At the crossroads of physiology and ecology: food supply and the timing of avian reproduction. Horm Behav 2014; 66:41-55. [PMID: 24727023 DOI: 10.1016/j.yhbeh.2014.04.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 04/01/2014] [Accepted: 04/05/2014] [Indexed: 01/19/2023]
Abstract
This article is part of a Special Issue “Energy Balance”. The decision of when to breed is crucial to the reproductive success and fitness of seasonally breeding birds. The availability of food for adults prior to breeding has long been thought to play a critical role in timing the initiation of seasonal reproductive events, in particular laying. However, unequivocal evidence for such a role remains limited and the physiological mechanisms by which an increase in food availability results in seasonal activation of the reproductive system are largely speculative. This lack of mechanistic information partly reflects a lack of integration of ecological and physiological approaches to study seasonal reproduction. Indeed, most work pertaining to the role of food availability for adults on the timing of avian reproduction has been ecological and has focused almost exclusively on female traits associated with reproductive timing (e.g., lay date and clutch size). By contrast, most work on the physiological bases of the relationship between food availability and the timing of reproduction has investigated male traits associated with reproductive development (e.g., reproductive hormones and gonadal development). To advance our understanding of these topics, we review the role of proximate factors including food availability, social factors, and ambient temperature in the control of breeding decisions, and discuss the role of three potential candidates (leptin, glucocorticoids, and GnIH-neuropeptide Y) that may mediate the effects of food availability on these decisions. We emphasize that future progress in this area is heavily contingent upon the use of physiology-based approaches and their integration into current ecological frameworks.
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Affiliation(s)
- Scott Davies
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA.
| | - Pierre Deviche
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA.
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Westneat DF, Bókony V, Burke T, Chastel O, Jensen H, Kvalnes T, Lendvai ÁZ, Liker A, Mock D, Schroeder J, Schwagmeyer PL, Sorci G, Stewart IRK. Multiple aspects of plasticity in clutch size vary among populations of a globally distributed songbird. J Anim Ecol 2014; 83:876-87. [DOI: 10.1111/1365-2656.12191] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 11/20/2013] [Indexed: 12/01/2022]
Affiliation(s)
- David F. Westneat
- Department of Biology and Center for Ecology, Evolution, and Behavior; University of Kentucky; 101 Morgan Building Lexington KY 40506-0225 USA
| | - Veronika Bókony
- Department of Limnology; University of Pannonia; Pf. 158 Veszprém H-8201 Hungary
| | - Terry Burke
- Department of Genetics; University of Nottingham; NG7 2RD UK
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield S10 2TN UK
| | - Olivier Chastel
- Centre d'Etudes Biologiques de Chizé; Centre Nationale de la Recherche Scientifique; Villiers-en-Bois Beauvoir sur Niort F-79360 France
| | - Henrik Jensen
- Department of Biology; Centre for Biodiversity Dynamics; Norwegian University of Science and Technology; Trondheim NO-7491 Norway
| | - Thomas Kvalnes
- Department of Biology; Centre for Biodiversity Dynamics; Norwegian University of Science and Technology; Trondheim NO-7491 Norway
| | - Ádám Z. Lendvai
- Centre d'Etudes Biologiques de Chizé; Centre Nationale de la Recherche Scientifique; Villiers-en-Bois Beauvoir sur Niort F-79360 France
- Department of Biology; Virginia Tech; 4102 Derring Hall Blacksburg VA 24060 USA
| | - András Liker
- Department of Limnology; University of Pannonia; Pf. 158 Veszprém H-8201 Hungary
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield S10 2TN UK
| | - Douglas Mock
- Department of Biology; 730 Van Vleet Oval Norman OK 73019 USA
| | - Julia Schroeder
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield S10 2TN UK
| | | | - Gabriele Sorci
- Biogéosciences; CNRS UMR 6282; Université de Bourgogne; 6 Boulevard Gabriel Dijon F-21000 France
| | - Ian R. K. Stewart
- Department of Biology and Center for Ecology, Evolution, and Behavior; University of Kentucky; 101 Morgan Building Lexington KY 40506-0225 USA
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Kowalczyk ND, Chiaradia A, Preston TJ, Reina RD. Linking dietary shifts and reproductive failure in seabirds: a stable isotope approach. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12216] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicole D. Kowalczyk
- School of Biological Sciences Monash University Clayton Victoria3800 Australia
| | - Andre Chiaradia
- School of Biological Sciences Monash University Clayton Victoria3800 Australia
- Research Department Phillip Island Nature Parks PO Box 97Cowes Victoria3922 Australia
| | - Tiana J. Preston
- School of Biological Sciences Monash University Clayton Victoria3800 Australia
| | - Richard D. Reina
- School of Biological Sciences Monash University Clayton Victoria3800 Australia
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Wellicome TI, Danielle Todd L, Poulin RG, Holroyd GL, Fisher RJ. Comparing food limitation among three stages of nesting: supplementation experiments with the burrowing owl. Ecol Evol 2013; 3:2684-95. [PMID: 24567832 PMCID: PMC3930041 DOI: 10.1002/ece3.616] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/08/2013] [Accepted: 04/17/2013] [Indexed: 11/25/2022] Open
Abstract
Food availability is an important limiting factor for avian reproduction. In altricial birds, food limitation is assumed to be more severe during the nestling stage than during laying or incubation, but this has yet to be adequately tested. Using food-supplementation experiments over a 5-year period, we determined the degree and timing of food limitation for burrowing owls (Athene cunicularia) breeding in Canada. Burrowing owls are an endangered species and food limitation during the nestling stage could influence reproductive performance of this species at the northern extent of their range. Supplemented pairs fledged on average 47% more owlets than unfed pairs, except during a year when natural food was not limiting (i.e., a prey irruption year). The difference in fledgling production resulted from high nestling mortality in unfed broods, with 96% of all nestling deaths being attributed to food shortage. Supplemental feeding during the nestling period also increased fledgling structural size. Pairs fed from the start of laying produced the same number of hatchlings as pairs that received no supplemental food before hatch. Furthermore, pairs supplemented from egg laying to fledging and pairs supplemented during the nestling period alone had the same patterns of nestling survival, equal numbers of fledglings, and similar fledgling mass and structural size. Our results provide empirical support for the hypothesis that the nestling period is the most food-limited phase of the breeding cycle. The experimental design we introduce here could be used with other altricial species to examine how the timing of food limitation differs among birds with a variety of life-history strategies. For burrowing owls, and other species with similar life histories, long-term, large-scale, and appropriately timed habitat management increasing prey abundance or availability is critical for conservation. Our results provide empirical support for the hypothesis that the nestling period is the most food-limited phase of the breeding cycle. For burrowing owls, and other species with similar life histories, long-term, large-scale, and appropriately timed habitat management increasing prey abundance or availability is critical for conservation.
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Affiliation(s)
- Troy I Wellicome
- Department of Biological Sciences, University of Alberta T6G 2E9, Edmonton, Canada ; Canadian Wildlife Service Room 200, 4999-98th Ave., T6B 2X3, Edmonton, Canada
| | - L Danielle Todd
- Department of Biology, University of Regina S4S 0A2, Regina, Canada
| | - Ray G Poulin
- Department of Biology, University of Regina S4S 0A2, Regina, Canada ; Royal Saskatchewan Museum 2340 Albert St., S4P 2V7, Regina, Canada
| | - Geoffrey L Holroyd
- Canadian Wildlife Service Room 200, 4999-98th Ave., T6B 2X3, Edmonton, Canada
| | - Ryan J Fisher
- Department of Biological Sciences, University of Alberta T6G 2E9, Edmonton, Canada
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Westneat DF, Stewart IRK, Hatch MI. Complex interactions among temporal variables affect the plasticity of clutch size in a multi-brooded bird. Ecology 2009; 90:1162-74. [PMID: 19537538 DOI: 10.1890/08-0698.1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Phenotypic plasticity is a widespread phenomenon and may have important influences on evolutionary processes. Multidimensional plasticity, in which multiple environmental variables affect a phenotype, is especially interesting if there are interactions among these variables. We used a long-term data set from House Sparrows (Passer domesticus), a multi-brooded passerine bird, to test several predictions from life-history theory regarding the shape of optimal reaction norms for clutch size. The best-fit model for variation in clutch size included three temporal variables (the order of attempt within a season, the date of those attempts, and the age of the female). Clutch size was also sensitive to the quadratics of date and female age, both of which had negative coefficients. Finally, we found that the relationship between date and clutch size became more negative as attempt order increased. These results suggest that female sparrows have a multidimensional reaction norm for clutch size that matches predictions of life-history theory but also implicates more complexity than can be captured by any single model. Analysis of the sources of variation in reaction norm height and slope was complicated by the additional environmental dimensions. We found significant individual variation in mean clutch size in all analyses, indicating that individuals differed in the height of their clutch size reaction norm. By contrast, we found no evidence of significant individual heterogeneity in the slopes of several dimensions. We assess the possible mechanisms producing this reaction norm and discuss their implications for understanding complex plasticity.
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Affiliation(s)
- David F Westneat
- Department of Biology, Center for Ecology, Evolution, and Behavior, 101 Morgan Building, University of Kentucky, Lexington, Kentucky 40506-0225, USA.
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Müller MS, Brennecke JF, Porter ET, Ottinger MA, Anderson DJ. Perinatal androgens and adult behavior vary with nestling social system in siblicidal boobies. PLoS One 2008; 3:e2460. [PMID: 18560542 PMCID: PMC2413419 DOI: 10.1371/journal.pone.0002460] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 05/06/2008] [Indexed: 11/18/2022] Open
Abstract
Background Exposure to androgens early in development, while activating adaptive aggressive behavior, may also exert long-lasting effects on non-target components of phenotype. Here we compare these organizational effects of perinatal androgens in closely related Nazca (Sula granti) and blue-footed (S. nebouxii) boobies that differ in neonatal social system. The older of two Nazca booby hatchlings unconditionally attacks and ejects the younger from the nest within days of hatching, while blue-footed booby neonates lack lethal aggression. Both Nazca booby chicks facultatively upregulate testosterone (T) during fights, motivating the prediction that baseline androgen levels differ between obligately siblicidal and other species. Methodology/Principal Findings We show that obligately siblicidal Nazca boobies hatch with higher circulating androgen levels than do facultatively siblicidal blue-footed boobies, providing comparative evidence of the role of androgens in sociality. Although androgens confer a short-term benefit of increased aggression to Nazca booby neonates, exposure to elevated androgen levels during this sensitive period in development can also induce long-term organizational effects on behavior or morphology. Adult Nazca boobies show evidence of organizational effects of early androgen exposure in aberrant adult behavior: they visit unattended non-familial chicks in the colony and direct mixtures of aggression, affiliative, and sexual behavior toward them. In a longitudinal analysis, we found that the most active Non-parental Adult Visitors (NAVs) were those with a history of siblicidal behavior as a neonate, suggesting that the tendency to show social interest in chicks is programmed, in part, by the high perinatal androgens associated with obligate siblicide. Data from closely related blue-footed boobies provide comparative support for this interpretation. Lacking obligate siblicide, they hatch with a corresponding low androgen level, and blue-footed booby adults show a much lower frequency of NAV behavior and a lower probability of behaving aggressively during NAV interactions. This species difference in adult social behavior appears to have roots in both pleiotropic and experiential effects of nestling social system. Conclusions/Significance Our results indicate that Nazca boobies experience life-long consequences of androgenic preparation for an early battle to the death.
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Affiliation(s)
- Martina S. Müller
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Julius F. Brennecke
- Cold Spring Harbor Laboratory, Watson School of Biological Sciences and Howard Hughes Medical Institute, Cold Spring Harbor, New York, United States of America
| | - Elaine T. Porter
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Mary Ann Ottinger
- Animal & Avian Sciences, University of Maryland, College Park, Maryland, United States of America
| | - David J. Anderson
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
- * E-mail:
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Wang Y, Wu Z, Lu P, Zhang F, Li Y. Breeding ecology and oviposition site selection of black-spotted pond frogs (Rana nigromaculata) in Ningbo, China. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s11515-008-0064-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Steiger S, Richter K, Müller JK, Eggert AK. Maternal nutritional condition and genetic differentiation affect brood size and offspring body size in Nicrophorus. ZOOLOGY 2007; 110:360-8. [PMID: 17702555 DOI: 10.1016/j.zool.2007.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 06/02/2007] [Accepted: 06/10/2007] [Indexed: 10/22/2022]
Abstract
In most animal species, brood size and body size exhibit some variation within and between populations. This is also true for burying beetles (genus Nicrophorus), a group in which the body size of offspring depends critically on the number of offspring competing for food due to the discrete nature of resource used for larval nutrition (vertebrate carcasses). In one species, brood size and body size are correlated with population density, and appear to be phenotypically plastic. We investigated potential proximate causes of between-population variation in brood size and body size in two species, Nicrophorus vespilloides and Nicrophorus defodiens. Our first experiment supported the notion that brood size is phenotypically plastic, because it was affected by environmental variation in adult nutritional condition. We found that the pre-breeding nutritional status of female N. vespilloides affected the number of eggs they laid, the number of surviving larvae in their broods, and the body size of their offspring. We do not know whether this plasticity is adaptive because greater offspring body size confers an advantage in contests over breeding resources, or whether starved females are constrained to produce smaller clutches because they cannot fully compensate for their poor pre-breeding nutritional status by feeding from the carcass. Our second experiment documents that brood size, specifically the infanticidal brood-size adjustment behavior, has undergone genetic differentiation between two populations of N. defodiens. Even under identical breeding conditions with identical numbers of first-instar larvae, females descended from the two populations produced broods of different size with corresponding differences in offspring body size.
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Affiliation(s)
- Sandra Steiger
- Department of Ecology and Evolutionary Biology, Institute of Zoology, University of Freiburg, Hauptstrasse 1, D-79104, Freiburg, Germany.
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26
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Townsend HM, Anderson DJ. ASSESSMENT OF COSTS OF REPRODUCTION IN A PELAGIC SEABIRD USING MULTISTATE MARK-RECAPTURE MODELS. Evolution 2007; 61:1956-68. [PMID: 17683437 DOI: 10.1111/j.1558-5646.2007.00169.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We used a long-term population band-resight survey database, a parallel reproduction database, and multistate mark-recapture analysis to assess the costs of reproduction, a keystone concept of life-history evolution, in Nazca boobies (Sula granti) from Punta Cevallos, Isla Española, Galápagos, Ecuador. We used eight years of resight and breeding data to compare models that included sex- and state-specific survival probabilities and probabilities of transition between reproductive states using multistate mark-recapture models. Models that included state-specific effects were compared with models lacking such effects to evaluate costs of reproduction. The top model, optimizing the trade-off of model simplicity and fit to the data using the Akaike Information Criterion (AIC), showed evidence of a temporally varying survival cost of reproduction: nonbreeders showed higher annual survival than breeders did in some years. Because increasing investment among breeders showed no negative association with survival and subsequent breeding success, this evidence indicates a cost to both males and females of initiating, but not of continuing, a reproductive attempt. In some cases, breeders reaching the highest reproductive state (fledging an offspring) showed higher survival or subsequent breeding success than did failed breeders, consistent with differences in overall quality that promote both survival and reproduction. Although a male-biased adult sex ratio was observed in this population of Nazca boobies, models of state- and sex-specific survival and transition probabilities were not supported, indicating that males and females do not incur different costs of reproduction, and that the observed sex ratio bias is not due to sex-specific adult mortality.
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Affiliation(s)
- Howard M Townsend
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina 27109, USA.
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D'Alba L, Torres R. Seasonal Egg-Mass Variation and Laying Sequence in a Bird With Facultative Brood Reduction. ACTA ACUST UNITED AC 2007. [DOI: 10.1093/auk/124.2.643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Females may maximize their lifetime reproductive output by adjusting their investment in each breeding event to the perceived likelihood of success. The Blue-footed Booby (Sula nebouxii) is a long-lived seabird with facultative siblicide. We examined whether there is differential resource allocation to eggs with laying order and whether greater egg mass increases hatching probability, chick survival, hatching interval, and mass and size at hatching. We found that the relative investment in first and second eggs decreased as the season advanced: second eggs were slightly (1.5%) heavier than first eggs in early clutches; by contrast, first eggs were 2% heavier than second eggs in late clutches. Accordingly, hatching probability increased with laying date for first eggs and decreased for second eggs. The mass of the egg increased hatching probability, and no effect on chick survival was detected. Laying interval increased after a heavier egg was laid, and heavier eggs produced heavier hatchlings. Hatching intervals were positively related to laying intervals, but egg mass was unrelated to the length of the incubation period and the hatching interval. Our results suggest that egg mass influences embryo survival and that Blue-footed Booby females may adaptively allocate resources to eggs of different laying order according to breeding conditions.
Variación del Peso de los Huevos y Secuencia de Postura en un Ave con Reducción Facultativa de la Nidada
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Affiliation(s)
- Liliana D'Alba
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, México D.F. 4510, Mexico
| | - Roxana Torres
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, México D.F. 4510, Mexico
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Abstract
Within a single population of hawksbill sea turtles (Eretmochelys imbricata), we found a behavioral polymorphism for maternal nest site choice with respect to beach microhabitat characteristics. Some females preferred to nest in littoral forest and in places with overstory vegetation cover, and others preferred to nest in more open, deforested areas. Nest site choice was consistent within and between nesting seasons two years apart. This was not a result of females simply returning to the same location along the shoreline; beach sections used by individual turtles varied between seasons. Nest site choice was not influenced by changes in beach environment (e.g., beach width and foliage cover) or by changes in females' reproductive output (e.g., clutch size), suggesting that fidelity to particular microhabitats is a major determinant of the observed nesting patterns. Because hawksbills exhibit temperature-dependent sex determination, if the behavioral polymorphism in nest site choice has a genetic basis, as is plausible, then this would have implications for sex ratio evolution and offspring survival. By taking an individual-based approach to the study of maternal behavior we reveal previously overlooked individual variation and hope to provide some impetus for more detailed studies of nest site choice.
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Affiliation(s)
- Stephanie J Kamel
- Department of Zoology, University of Toronto, 25 Harbord Street, Toronto, Ontario M5S 3G5, Canada.
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Velando A, Beamonte-Barrientos R, Torres R. Pigment-based skin colour in the blue-footed booby: an honest signal of current condition used by females to adjust reproductive investment. Oecologia 2006; 149:535-42. [PMID: 16821015 DOI: 10.1007/s00442-006-0457-5] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Accepted: 05/02/2006] [Indexed: 10/24/2022]
Abstract
In monogamous species, the value of present reproduction is affected by the current condition of the mate, and females may use male ornaments to evaluate his condition and adjust their level of investment according. Many animals display colour in fleshy structures which may be accurate indicators of quality due to their potentially rapid response to changes in condition. Here we show that in the blue-footed booby, Sula nebouxii, male foot colour is structurally (collagen arrays) and pigment based. In 48 h foot colour became duller when males were food deprived and brighter when they were re-fed with fresh fish. Variation of dietary carotenoids induced comparable changes in cell-mediated immune function and foot colour, suggesting that carotenoid-pigmentation reveals the immunological state of individuals. These results suggest that pigment-based foot colour is a rapid honest signal of current condition. In a second experiment, we found that rapid variation in male foot colour caused parallel variation in female reproductive investment. One day after the first egg was laid we captured the males and modified the foot colour of experimental males with a non-toxic and water resistant duller blue intensive make-up, mimicking males in low condition. Females decreased the size of their second eggs, relative to the second egg of control females, when the feet of their mates were experimentally duller. Since brood reduction in this species is related to size differences between brood mates at hatching, by laying lighter second eggs females are facilitating brood reduction. Our data indicate that blue-footed booby females are continuously evaluating their mates and can perform rapid adjustments of reproductive investment by using dynamic sexual traits. We suggest that this fine-tuned adjustment may be widespread in socially monogamous animals.
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Affiliation(s)
- Alberto Velando
- Departamento de Ecoloxía e Bioloxía Animal, Campus Lagoas-Marcosende, Universidade de Vigo, 36310, Vigo, Spain
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Humphries CA, Arevalo VD, Fischer KN, Anderson DJ. Contributions of marginal offspring to reproductive success of Nazca booby (Sula granti) parents: tests of multiple hypotheses. Oecologia 2005; 147:379-90. [PMID: 16208491 DOI: 10.1007/s00442-005-0264-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2005] [Accepted: 09/01/2005] [Indexed: 10/25/2022]
Abstract
While obligate siblicide is a phylogenetically widespread behavior, known from plants, insects, birds, and other taxa, with important implications for life history evolution, comprehensive evaluations of its costs and benefits to parents are rare. We used 12 years of breeding and band resight data to evaluate the importance of several potential benefits that marginal offspring (the usual victims of obligate siblicide) could provide to parent Nazca boobies (Sula granti), a seabird. We found no evidence for the resource-tracking hypothesis: 99.95% of two-chick broods were reduced to one chick before fledging, and the single exceptional brood probably lost one chick between fledging and independence. Behavioral observations indicated that siblicidal aggression caused most mortality of marginal chicks, and at least contributed to the remainder. We also found no evidence that marginal offspring provide a food resource for other family members. Marginal chicks benefit parents via adoption into other families, and possibly also in the context of progeny choice, but these benefits are minor compared to the insurance that marginal chicks provide against early failure of core (first-hatched) offspring. Further evaluation of the Insurance Egg Hypothesis showed that marginal and core offspring are functionally equivalent in the absence of sibling interactions, and that core offspring incur no detectable costs from behaving siblicidally. Nazca boobies are truly obligate brood reducers, with parents receiving principally insurance benefits from marginal offspring, but many birds and other taxa exhibiting persistent, unconditional sibling aggression do not exhibit universal brood reduction. Insurance is only one of several potential benefits that marginal offspring can confer on parents, and a multi-hypothesis approach to decompose the different types of benefits is required to understand the evolution of clutch size in other obligately siblicidal species.
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Ferree ED, Wikelski MC, Anderson DJ. Hormonal correlates of siblicide in Nazca boobies: support for the Challenge Hypothesis. Horm Behav 2004; 46:655-62. [PMID: 15555508 DOI: 10.1016/j.yhbeh.2004.06.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Revised: 06/21/2004] [Accepted: 06/22/2004] [Indexed: 10/26/2022]
Abstract
The androgen hormone testosterone (T) mediates vertebrate aggression in many contexts and according to the Challenge Hypothesis is up-regulated during social challenges. While originally applied to challenges experienced by breeding adults, we show for the first time that T is similarly up-regulated during deadly sibling aggression in young birds. When two nestling Nazca boobies hatch, one--usually the older chick--virtually always kills the other chick by pushing it from the nest. We compared concentrations of T, dehydroepiandrosterone (DHEA; a precursor of T), and corticosterone (Cort; a stress hormone) of chicks at various stages. T was elevated during fights in both chicks in two-chick broods, but not before and after fights, and not in chicks lacking a nest mate. DHEA was elevated 1 day after hatching and declined with age but appeared not to vary in concert with aggression. Cort did not vary across fighting and nonfighting periods. In conjunction with an earlier study [Tarlow, E.M., Wikelski, M., Anderson, D.J., 2001. Hormonal correlates of siblicide in Galapagos Nazca boobies. Horm. Behav. 40:14-20], these results indicate that T is temporarily up-regulated around the time of fights, as predicted by the Challenge Hypothesis. Our data suggest a general role for T during challenges at any time in life, not just during breeding.
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Affiliation(s)
- Elise D Ferree
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109-7325, USA
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Reynolds SJ, Schoech SJ, Bowman R. Nutritional quality of prebreeding diet influences breeding performance of the Florida scrub-jay. Oecologia 2003; 134:308-16. [PMID: 12647137 DOI: 10.1007/s00442-002-1126-y] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2002] [Accepted: 10/31/2002] [Indexed: 11/26/2022]
Abstract
Food supplementation studies of breeding birds have traditionally concentrated on energetic constraints on breeding performance. It is only recently that the nutritional quality of the prebreeding diet has also been considered influential. We examined the importance of specific nutrients in the prebreeding diet of the Florida scrub-jay ( Aphelocoma coerulescens). Birds were provided with one of two supplements (rich in protein and fat or rich in fat only) prior to breeding in 2000 and 2001 and their breeding performance, in relation to unsupplemented (control) birds, was examined. Birds receiving both supplements significantly advanced laying in both years, and increased clutch size in 2000 but not in 2001. Laying date explained variation in clutch size in birds on dietary supplements. Egg mass and volume declined with laying order, irrespective of dietary treatment, but birds on the high fat, high protein diet laid heavier third eggs than controls and this was independent of laying date. Laboratory analysis of 14 abandoned and unhatched eggs revealed that as egg mass increased so did the absolute amount of protein and water while fat content remained relatively fixed. Using these relationships between the masses of egg components and fresh egg mass, we calculated that heavier third eggs laid by birds on high fat and high protein, compared with those laid by controls, contained more water that may be fundamental to chick growth and survival. This is the first demonstration for an avian species that nutritional quality of prebreeding diet can simultaneously influence laying date, clutch size, and egg size and composition.
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