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Caroline Gilbert - One of the best experts on this subject based on the ideXlab platform.
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local weather and body condition influence habitat use and movements on land of Molting female southern elephant seals mirounga leonina
Ecology and Evolution, 2018Co-Authors: Laureline L Chaise, Iris Prinet, Camille Toscani, Susan L Gallon, William D Paterson, Dominic J Mccafferty, Marc Thery, Andre Ancel, Caroline GilbertAbstract:Southern elephant seals (Mirounga leonina) are known to move and aggregate while Molting, but little is known about their behavior on land during this time. In this study, 60 adult females were monitored (23 with GPS tags) during four Molting seasons, between 2012 and 2016 at Kerguelen Archipelago, Indian Ocean. Population surveys were recorded each year (N = 230 daily counts), and habitat use was analyzed in relation to the stage of the Molt and local weather. Based on stage of Molt, habitat use, and movements on land, we classified the Molt of elephant seals into three phases: (1) a "search phase" at the initial stage of Molt when grass and wallow habitats were used and characterized by greater mean distances travelled on land per day compared with the two other phases; (2) a "resident phase": during initial and mid-stage of Molt when animals were found in grass and wallow habitats but with less distance moved on land; and (3) a "termination phase" at the final stage of Molt where grass and beach habitats were occupied with no change in distances. Windchill and solar radiation influenced individual distances moved per day (mean 590 ± 237.0 m) at the mid- and final stage of Molt such that animals travelled greater distances on days of low windchill or high solar radiation. Individual variation in distance moved and relative habitat use were also linked to body mass index (BMI) at arrival on the colony, as females with higher BMI moved less and preferred beach habitat. Moreover, the individual rate of Molt increased with the use of wallows. Aggregation rate tended to be negatively correlated with distances moved. We therefore suggest that individuals face an energetic trade-off while Molting, balancing energy expenditure between movement and thermoregulation.
Anne Peters - One of the best experts on this subject based on the ideXlab platform.
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no evidence for an adaptive role of early Molt into breeding plumage in a female fairy wren
Behavioral Ecology, 2020Co-Authors: Sergio Nolazco, Michelle L Hall, Sjouke A Kingma, Kaspar Delhey, Anne PetersAbstract:The evolution of ornaments as sexually selected signals is well understood in males, but female ornamentation remains understudied. Fairy wrens offer an excellent model system, given their complex social structure and mating systems, and the diversity of female ornamentation. We investigated whether early Molt into ornamental breeding plumage plays an adaptive role in females of the monogamous purple-crowned fairy wren Malurus coronatus, the only fairy wren known to have female seasonal plumage. Using 6 years of monitoring, we found that the timing of female Molt was similar to males, but there was no evidence for assortative mating. Like males (previous study), older and dominant individuals acquired their breeding plumage earlier; however, in contrast to males, early Molt did not seem to be costly since unfavorable environmental conditions or previous reproductive effort did not delay Molt. Early female Molt was not associated with any indicator of reproductive quality nor did it attract additional offspring care by their partners. We also found no association between early Molt and the likelihood of acquiring a dominant (breeding) position or with the presence or proximity to same-sex rivals. Our study results, which are similar to previous findings in conspecific males, suggest that directional selection for early Molt might be relaxed in this species, in contrast to other genetically polygamous fairy wrens in which early Molt predicts extrapair mating success in males. However, the finding that Molt timing is status dependent raises the possibility that other attributes of the ornament may fulfill an adaptive function in females.
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no fitness benefits of early Molt in a fairy wren relaxed sexual selection under genetic monogamy
Behavioral Ecology, 2017Co-Authors: Marie Fan, Michelle L Hall, Sjouke A Kingma, Kaspar Delhey, Lisa M Mandeltort, Nataly Hidalgo Aranzamendi, Anne PetersAbstract:The evolution of male ornamentation has long been the focus of sexual selection studies. However, evidence is accumulating that sexually selected traits can also be lost, although the process is ill-understood. In male fairy-wrens (Malurus spp.), early Molt into the seasonal breeding plumage is critical for obtaining extra-pair paternity (EPP), which reaches very high levels in these socially monogamous songbirds. A notable exception is the purple-crowned fairy-wren, Malurus coronatus, which, like its congeners, breeds cooperatively, but where EPP is very rare. Nevertheless, males develop a conspicuous seasonal breeding plumage at highly variable times. Based on 6 years of Molt data collected for 137 individuals, we investigated the adaptive significance of pre-breeding Molt timing as a sexual signal under (near) genetic monogamy. Molt timing varied between and within individuals with age and climate: Molt was completed earlier in older males and after wetter years. Despite its potential to act as a sexual signal of male quality, fitness benefits and costs of early Molt appear limited: Molt timing did not correlate with 1) the likelihood of gaining a breeding position; 2) female mate preference (EPP/cuckoldry, divorce); 3) female reproductive investment (breeding timing, clutch size, number of clutches); 4) breeding performance (hatching success, fledging success, fledgling survival, annual reproductive success); and 5) male survival. However, although Molt timing did not predict which subordinates would become breeders, breeders Molted earlier than subordinates. The lack of EPP in this species might imply relaxed sexual selection on early Molt with potential to lead to trait disappearance.
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experimental manipulation of testosterone and condition during Molt affects activity and vocalizations of male blue tits
Hormones and Behavior, 2008Co-Authors: Ralf H J M Kurvers, Mark L Roberts, Scott R Mcwilliams, Anne PetersAbstract:Testosterone (T) is a key hormone regulating behavioral trade-offs in male birds, shifting investment towards sexual and competitive behaviors. However, the role of T in regulating male behavior during the Molt has received very little attention, although this is a crucial life-history stage. Since the effect of T on behavior may be condition-dependent, particularly during the costly Molt period, we studied the effects of T and condition in a two-way design. We manipulated T under two dietary regimes (standard and improved, resulting in an enhanced condition) in captive blue tits (Cyanistes caeruleus) undergoing the first pre-basic Molt. T treatment increased song frequency, indicating that song is T-dependent also at this time of year. Males on the improved diet sang less than males in relatively worse condition, providing no support for song as an indicator of male condition. T-treated males exhibited greater locomotor activity than control males, but only when fed the standard diet. Neither T- nor diet-treatment affected plumage maintenance (preening). Although T treatment resulted in a delay in Molt progress all birds completed the Molt. Taken together our results show that during the Molt male birds are sensitive to relatively small fluctuations in T. Similar to its commonly observed effects during the breeding season, T stimulated an increase in song and locomotion. While there might be some benefits associated with such T effects, these must be traded-off against costs associated with conspicuous behavior and increased Molt duration.
Michael A. Fedak - One of the best experts on this subject based on the ideXlab platform.
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Water Flux, Body Composition, and Metabolic Rate during Molt in Female Southern Elephant Seals (Mirounga leonina)
Physiological and Biochemical Zoology, 1993Co-Authors: Ian L. Boyd, Tom Arnbom, Michael A. FedakAbstract:Tritiated water dilution was used to measure changes in the proximate body composition of adult female southern elephant seals at the end of lactation and at the beginning and end of Molt. During the 72 ± 0.9 d foraging phase between lactation and Molt, seals gained 1.50 ± 0.16 kg·d⁻¹. Of the total mass gain (1065 ± 10.5 kg) 49% was water, 39% was fat, and 11% was protein. This represented an increase in total body gross energy of 2,111 ± 283 MJ throughout the foraging period. The rate of mass lost during Molt was 4.70 ± 0.21 kg· d⁻¹ comprising 49% water, 33% fat and 16% protein. Although it was impossible to measure accurately the duration of fasting during the Molt, the minimum cost of Molt was 1,631 ± 146 MJ, which was not significantly different from the energy gained between lactation and Molt. Females invested half as much in Molt as in the growth of their pups. The metabolic rate during Molt was 2.15 ± 17 W·kg1⁻¹, which was 2.8 ± 0.2 times the predicted resting metabolic rate. Water influx was greater than expected from metabolic water production, and seals had an additional water influx of 1. 75 ± 0.31 L·d⁻¹. This additional influx was negatively related to metabolic water production. There was some evidence from measurements of water influx that seals fed during Molt, but this accounted for only 11.5% of the daily energy expenditure.
Michelle L Hall - One of the best experts on this subject based on the ideXlab platform.
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no evidence for an adaptive role of early Molt into breeding plumage in a female fairy wren
Behavioral Ecology, 2020Co-Authors: Sergio Nolazco, Michelle L Hall, Sjouke A Kingma, Kaspar Delhey, Anne PetersAbstract:The evolution of ornaments as sexually selected signals is well understood in males, but female ornamentation remains understudied. Fairy wrens offer an excellent model system, given their complex social structure and mating systems, and the diversity of female ornamentation. We investigated whether early Molt into ornamental breeding plumage plays an adaptive role in females of the monogamous purple-crowned fairy wren Malurus coronatus, the only fairy wren known to have female seasonal plumage. Using 6 years of monitoring, we found that the timing of female Molt was similar to males, but there was no evidence for assortative mating. Like males (previous study), older and dominant individuals acquired their breeding plumage earlier; however, in contrast to males, early Molt did not seem to be costly since unfavorable environmental conditions or previous reproductive effort did not delay Molt. Early female Molt was not associated with any indicator of reproductive quality nor did it attract additional offspring care by their partners. We also found no association between early Molt and the likelihood of acquiring a dominant (breeding) position or with the presence or proximity to same-sex rivals. Our study results, which are similar to previous findings in conspecific males, suggest that directional selection for early Molt might be relaxed in this species, in contrast to other genetically polygamous fairy wrens in which early Molt predicts extrapair mating success in males. However, the finding that Molt timing is status dependent raises the possibility that other attributes of the ornament may fulfill an adaptive function in females.
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no fitness benefits of early Molt in a fairy wren relaxed sexual selection under genetic monogamy
Behavioral Ecology, 2017Co-Authors: Marie Fan, Michelle L Hall, Sjouke A Kingma, Kaspar Delhey, Lisa M Mandeltort, Nataly Hidalgo Aranzamendi, Anne PetersAbstract:The evolution of male ornamentation has long been the focus of sexual selection studies. However, evidence is accumulating that sexually selected traits can also be lost, although the process is ill-understood. In male fairy-wrens (Malurus spp.), early Molt into the seasonal breeding plumage is critical for obtaining extra-pair paternity (EPP), which reaches very high levels in these socially monogamous songbirds. A notable exception is the purple-crowned fairy-wren, Malurus coronatus, which, like its congeners, breeds cooperatively, but where EPP is very rare. Nevertheless, males develop a conspicuous seasonal breeding plumage at highly variable times. Based on 6 years of Molt data collected for 137 individuals, we investigated the adaptive significance of pre-breeding Molt timing as a sexual signal under (near) genetic monogamy. Molt timing varied between and within individuals with age and climate: Molt was completed earlier in older males and after wetter years. Despite its potential to act as a sexual signal of male quality, fitness benefits and costs of early Molt appear limited: Molt timing did not correlate with 1) the likelihood of gaining a breeding position; 2) female mate preference (EPP/cuckoldry, divorce); 3) female reproductive investment (breeding timing, clutch size, number of clutches); 4) breeding performance (hatching success, fledging success, fledgling survival, annual reproductive success); and 5) male survival. However, although Molt timing did not predict which subordinates would become breeders, breeders Molted earlier than subordinates. The lack of EPP in this species might imply relaxed sexual selection on early Molt with potential to lead to trait disappearance.
Sjouke A Kingma - One of the best experts on this subject based on the ideXlab platform.
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no evidence for an adaptive role of early Molt into breeding plumage in a female fairy wren
Behavioral Ecology, 2020Co-Authors: Sergio Nolazco, Michelle L Hall, Sjouke A Kingma, Kaspar Delhey, Anne PetersAbstract:The evolution of ornaments as sexually selected signals is well understood in males, but female ornamentation remains understudied. Fairy wrens offer an excellent model system, given their complex social structure and mating systems, and the diversity of female ornamentation. We investigated whether early Molt into ornamental breeding plumage plays an adaptive role in females of the monogamous purple-crowned fairy wren Malurus coronatus, the only fairy wren known to have female seasonal plumage. Using 6 years of monitoring, we found that the timing of female Molt was similar to males, but there was no evidence for assortative mating. Like males (previous study), older and dominant individuals acquired their breeding plumage earlier; however, in contrast to males, early Molt did not seem to be costly since unfavorable environmental conditions or previous reproductive effort did not delay Molt. Early female Molt was not associated with any indicator of reproductive quality nor did it attract additional offspring care by their partners. We also found no association between early Molt and the likelihood of acquiring a dominant (breeding) position or with the presence or proximity to same-sex rivals. Our study results, which are similar to previous findings in conspecific males, suggest that directional selection for early Molt might be relaxed in this species, in contrast to other genetically polygamous fairy wrens in which early Molt predicts extrapair mating success in males. However, the finding that Molt timing is status dependent raises the possibility that other attributes of the ornament may fulfill an adaptive function in females.
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no fitness benefits of early Molt in a fairy wren relaxed sexual selection under genetic monogamy
Behavioral Ecology, 2017Co-Authors: Marie Fan, Michelle L Hall, Sjouke A Kingma, Kaspar Delhey, Lisa M Mandeltort, Nataly Hidalgo Aranzamendi, Anne PetersAbstract:The evolution of male ornamentation has long been the focus of sexual selection studies. However, evidence is accumulating that sexually selected traits can also be lost, although the process is ill-understood. In male fairy-wrens (Malurus spp.), early Molt into the seasonal breeding plumage is critical for obtaining extra-pair paternity (EPP), which reaches very high levels in these socially monogamous songbirds. A notable exception is the purple-crowned fairy-wren, Malurus coronatus, which, like its congeners, breeds cooperatively, but where EPP is very rare. Nevertheless, males develop a conspicuous seasonal breeding plumage at highly variable times. Based on 6 years of Molt data collected for 137 individuals, we investigated the adaptive significance of pre-breeding Molt timing as a sexual signal under (near) genetic monogamy. Molt timing varied between and within individuals with age and climate: Molt was completed earlier in older males and after wetter years. Despite its potential to act as a sexual signal of male quality, fitness benefits and costs of early Molt appear limited: Molt timing did not correlate with 1) the likelihood of gaining a breeding position; 2) female mate preference (EPP/cuckoldry, divorce); 3) female reproductive investment (breeding timing, clutch size, number of clutches); 4) breeding performance (hatching success, fledging success, fledgling survival, annual reproductive success); and 5) male survival. However, although Molt timing did not predict which subordinates would become breeders, breeders Molted earlier than subordinates. The lack of EPP in this species might imply relaxed sexual selection on early Molt with potential to lead to trait disappearance.
