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1.
Diego Rubolini Maria Romano Roberta Martinelli Barbara Leoni Nicola Saino 《Behavioral ecology and sociobiology》2006,59(4):549-560
Mothers may profoundly affect offspring phenotype and performance by adjusting egg components, including steroid hormones.
We studied the effects of elevated prenatal testosterone (T) exposure in the ring-necked pheasant on the expression of a suite
of male and female traits, including perinatal response to stress, immune response, growth, and secondary sexual traits. Prenatal
T levels were increased by injecting the yolk of unincubated eggs with physiological doses of the hormone. Yolk T injection
resulted in a reduced length of male tarsal spurs, a trait which positively predicts male success in intra- and intersexual
selection and viability, whereas no direct effect on male wattle characteristics or plumage traits of either sex was observed.
Female spur length was also negatively affected by T, but to a lesser extent than in males. In addition, the covariation between
male secondary sexual traits, which are reliable quality indicators, differed between T and control males, suggesting that
the manipulation may have altered the assessment of overall male quality by other males and females. In conclusion, the negative
effects of elevated yolk T on spur length, a trait which positively predicts male fitness, coupled with the lack of effects
on growth or other traits in both sexes, provided limited evidence for mothers being subjected to a trade-off between positive
and negative consequences of yolk T deposition on offspring traits and suggest that directional selection for reduced yolk
T levels may occur in the ring-necked pheasant. 相似文献
2.
Increased egg estradiol concentration feminizes digit ratios of male pheasants (<Emphasis Type="Italic">Phasianus colchicus</Emphasis>) 总被引:1,自引:0,他引:1
The length ratio between individual digits differs between males and females in humans, other mammals, lizards, and one bird
species. Sexual dimorphism in digit ratios and variation among individuals of the same sex may depend on differential exposure
to androgens and estrogens during embryonic life. Organizational effects of sex hormones could cause the observed correlations
between digit ratios and diverse phenotypic traits in humans. However, no study has investigated experimentally the effect
of prenatal estrogens on digit ratios. We analyzed the effect of estradiol injection in ring-necked pheasant (Phasianus colchicus) eggs on digit ratios. Males from control eggs had higher ratios between the second or third and the fourth digit of the
right foot compared to females. Estradiol-treated eggs produced males with lower (feminized) right foot second to fourth digit
ratio. Thus, we provided the first experimental evidence that prenatal exposure to physiologically high estrogen levels affects
bird digit ratios. 相似文献
3.
Roberto Ambrosini Diego Rubolini Nicola Saino 《Behavioral ecology and sociobiology》2014,68(8):1367-1377
Adaptive strategies of sex allocation functioning to increase fitness, including strategic allocation of sex in relation to birth order and sex composition of the progeny, have frequently been explored, but the development of a statistical framework for these analyses has lagged behind. In this paper, we contribute to filling this gap by devising a method for analyzing sex sequences based on a proper parameterization of generalized linear mixed models (GLMMs). The method is highly flexible and can be easily extended to investigate sequences of traits or events or other longitudinal data. As a worked example, we focus on the analysis of sex sequences of offspring produced by females in a single reproductive event and develop a method that allows analyzing simultaneously sequences of different length (e.g., clutches of different size) and sequences with missing data, as may frequently happen in “real-world” data sets. Different patterns of allocation among traits or events along the sequence were investigated, and a real data base of sex sequences of eclectus parrots (Eclectus roratus) fledglings produced by different females was analyzed. A tutorial for running the analyses with the R or the SAS software is provided in the Electronic Supplementary Material. 相似文献
4.
In avian species, maternal provisioning to the eggs is predicted to be more valuable for the offspring under adverse environmental conditions and intense sibling competition. However, studies manipulating both the amount of maternal pre-hatching resources and the harshness of post-hatching environment have seldom been performed to date. In this experimental study of Barn Swallow (Hirundo rustica) nestlings, we tested the consequences of a reduction in the albumen content of the eggs for fitness-related offspring traits, while performing an unbalanced partial cross-fostering soon after hatching, either increasing or decreasing brood size by one nestling. By molecular sexing of the chicks, we additionally tested for sex-specific sensitivity of individual nestlings to experimental treatments and to sex ratio variation in nestmates. We predicted that chicks hatching from albumen-deprived eggs should suffer more than control chicks from the harsher rearing conditions of enlarged broods. However, although albumen removal depressed chick body mass, chicks hatching from control eggs did not fare better than those hatching from eggs with reduced albumen content in enlarged vs. reduced broods. Albumen removal had sex-specific effects on immunity, with males, but not females, hatching from eggs with reduced albumen content showing a lower T-cell-mediated immune response than controls, suggesting that the two sexes were differentially susceptible to resource deprivation during early ontogeny. In addition, both immune response and chick body mass at age 7 days, when maximum growth rate is attained, declined with an increasing proportion of male nestmates. The effect of brood size manipulation on chick body mass at age 12 days, when peak body mass is attained, was also found to depend on brood sex composition, in that an increase in the proportion of male nestmates depressed offspring body mass in reduced broods, while the reverse was true in enlarged broods. On the whole, these findings suggest that sex differences may exist in environmental sensitivity and patterns of resource allocation among different body functions, and that brood size variation and sex composition may affect offspring fitness-related traits. 相似文献
5.
Paolo Galeotti Fabio Pupin Diego Rubolini Roberto Sacchi Pietro A. Nardi Mauro Fasola 《Behavioral ecology and sociobiology》2007,61(5):711-718
Sperm competition models predict that males should adjust their sperm expenditure according to the risk and/or intensity of
sperm competition. In this paper, we analysed copulatory behaviour of both sexes and sperm expenditure in relation to female
mating status (virgin or mated) in the freshwater crayfish Austropotamobius italicus, a species where males have been reported to feed on and remove sperm laid by other males. The same females were allowed
to be inseminated sequentially by two males, and we compared the sexual behaviours of partners between the first (virgin females)
and the second mating (mated females). We found that female resistance did not differ between the first and the second mating,
nor males refused or took more time to mount a mated female. However, when mating with a mated female, males reached an effective
copulation position significantly later. This occurred because second-mating males removed, by eating, all or most spermatophores
previously deposited by first males. As removal was often incomplete, this resulted in a larger amount of sperm being deposited
on female ventral parts after the second mating, although second males did not allocate more sperm to mated females than first
males did. Thus, the peculiar mode of sperm competition, where males remove previously deposited sperm, and the consequent
predictable strong last male prevalence in paternity likely led to the observed lack of adjustment of sperm expenditure to
female mating status in this species. 相似文献
6.
Parolini Marco Sturini Michela Maraschi Federica Profumo Antonella Costanzo Alessandra Caprioli Manuela Rubolini Diego Ambrosini Roberto Canova Luca 《Environmental science and pollution research international》2021,28(13):15828-15837
Environmental Science and Pollution Research - Trace elements are widespread contaminants that can potentially threaten ecosystems and human health. Considering their distribution and toxicity,... 相似文献
7.
Paolo Galeotti Diego Rubolini Fabio Pupin Roberto Sacchi Mauro Fasola 《Behavioral ecology and sociobiology》2008,62(11):1739-1745
Asymmetry in traits of sexual relevance may impair copulation behaviour and sexual performance of males, ultimately resulting
in a fitness cost. Freshwater crayfish males use chelae, a sexually selected trait, to secure and position the female prior
to and during mating. Thus, a relatively large chelae asymmetry, resulting from accidental loss and regeneration of one cheliped
after autotomy, could have great consequences for male sexual behaviour. We studied copulatory behaviour and sperm expenditure
of males paired to a mated female in Austropotamobius italicus, a freshwater crayfish species where both male and female mate multiply and where last-mating males are able to actively
remove previously deposited sperm. We aimed at assessing whether male sperm removal and expenditure varied according to sperm
allocated by first-mating males, and according to copulation behaviour and phenotypic traits (carapace length, chelae length
and relative chelae asymmetry) of second-mating males. Second-mating males did not adjust their ejaculate size in relation
to first-mating male ejaculate, nor to the first-mating male’s sperm removed. Moreover, the amount of sperm removed by second-mating
males increased with increasing first-mating males ejaculate size, and first-mating male sperm remaining after removal did
not correlate with the original first-mating male ejaculate size. Interestingly, the amount of sperm removed by second-mating
males decreased with increasing relative chelae asymmetry, while increasing with male body size. However, second-mating (but
not first-mating) asymmetric-clawed males produced larger ejaculates than symmetric-clawed ones. Importantly, the proportion
of second-mating male sperm remaining after the two matings did not vary with relative chelae asymmetry nor with body size
of second-mating males. Thus, small, asymmetric-clawed crayfish males appear to adopt sperm allocation tactics that allow
them to fully compensate for their inferior sperm removal ability. 相似文献
8.
9.
Lorenzo Serra Simone Pirrello Manuela Caprioli Matteo Griggio Alessandro Andreotti Andrea Romano Andrea Pilastro Nicola Saino Roberto Sacchi Paolo Galeotti Mauro Fasola Fernando Spina Diego Rubolini 《Behavioral ecology and sociobiology》2012,66(5):697-709
In seasonally fluctuating environments, timing of reproduction is a crucial determinant of fitness. Studies of birds show that late breeding attempts generally result in offspring of lower reproductive value, with lower recruitment and long-term survival prospects. Several proximate mechanisms, including a seasonal decline of immune system functioning, may lead to a seasonal decline of offspring fitness. We investigated seasonal variation in offspring quality by subjecting first- and second-brood chicks of a sexually size dimorphic species, the European starling Sturnus vulgaris, to an immune challenge with a bacterial endotoxin (LPS), and evaluated their growth and physiological response in terms of total plasma antioxidant capacity (TAC), concentration of reactive oxygen metabolites and hematocrit. LPS challenge did not affect chick growth or oxidative status. However, hematocrit of second-brood chicks was higher in LPS chicks compared to controls. Body mass halfway through the rearing period (days?8–9 post-hatching), TAC and hematocrit were lower among second- vs. first-brood chicks. Interestingly, sexual dimorphism in body mass at days?8–9 post-hatching markedly differed between broods, first-brood males being 4.7% and second-brood males 22.7% heavier than their sisters, respectively. Pre-fledging mortality occurred among second-brood chicks only and was strongly female-biased. Our findings suggest that starling chicks, even if in poor conditions, are little affected by a bacterial challenge, at least in the short-term. Moreover, our study indicates that sex differences in body size, possibly mediated by sex-specific maternal investment in egg size, may heavily impact on pre-fledging survival in a different way in the course of the breeding season, resulting in sex-specific seasonal decline of offspring fitness. Finally, we suggest that levels of circulating antioxidants should be regarded among the proximate causes of the association between timing of fledging and long-term survival in avian species. 相似文献
10.
Diego Rubolini Maria Romano Roberta Martinelli Nicola Saino 《Behavioral ecology and sociobiology》2006,59(3):344-352
Androgen hormones of maternal origin contained in the eggs of avian species are considered to have positive effects on offspring
characteristics and performance. However, negative consequences have also been reported, suggesting that mothers may experience
a trade-off between beneficial and detrimental effects of egg androgens to offspring fitness. We studied the effects of elevated
yolk testosterone (T) concentration on survival, development and phenotype of male and female yellow-legged gull (Larus michahellis) chicks by injecting egg yolks with physiological doses of the hormone. Elevated yolk T resulted in a male-biased post-hatching
sex ratio, T-treated clutches producing a greater proportion of males compared to control ones at day 4 post-hatching, likely
resulting from a reduction of female embryonic survival, whereas no effect of hormone treatment on hatching success or short-term
chick survival was observed. In addition, T depressed post-hatching body mass in both sexes but had no effects on the intensity
of the cell-mediated immune response or skeletal growth. No sex differences in egg characteristics or chick phenotype were
detected. Time to hatching was not affected by T, but females originating from first laid eggs hatched earlier than males
of the same laying order, independently of hormone treatment. However, the implications of sex differences in hatching times
are unclear in the study species. Taken together, our results suggest that female yellow-legged gulls may be constrained in
transferring androgens to their eggs by negative consequences on the viability of female offspring and growth of chicks of
the two sexes. 相似文献