Animals of many species advertise their quality as competitors and mates using a wide array of behavioral displays and elaborate ornaments (Johnstone, 1996). In many species, stronger competition among males for access to mating opportunities favors the development of colorful ornaments in males exclusively (Andersson, 1994;Emlen & Oring, 1977). In females, adaptive benefits of ornament expression may be reduced when opportunities to mate are not limited and the benefits of advertising condition do not offset the costs of producing and carrying conspicuous signaling traits-particularly as investment in fecundity can be compromised in the process

Multigenerational effects can have important and sex-dependent effects on offspring. Sex allocation theory predicts that females should differentially invest in sons and daughters depending on sex-specific fitness returns and costs of investment. Maternal stress-relevant (glucocorticoid) hormones may be one mechanism driving this effect. We investigated how maternal stress hormones differentially affected sons and daughters by manipulating levels of the glucocorticoid, corticosterone (CORT), in gravid female eastern fence lizards (Sceloporus undulatus) and quantifying reproductive investment and sex ratio of resulting clutches, and the mass, snout-vent length, and body condition of sons versus daughters at hatching. We found no effect of maternal CORT-treatment on the number or size of eggs laid or on the sex ratio of resulting offspring, but sons of CORT-treated mothers were shorter, lighter, and of poorer body condition at hatching than were sons of control mothers. We found no difference in size or condition of daughters with maternal treatment. Our results suggest that maternal stress, mediated by elevations in maternal CORT concentrations, can have sex-specific effects on offspring manifesting as lower investment in sons.

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The gut microbiome can influence host fitness and, consequently, the ecology and evolution of natural populations. Microbiome composition can be driven by environmental exposure but also by the host's genetic background and phenotype.To contrast environmental and genetic effects on the microbiome we leverage preserved specimens of eastern fence lizards from allopatric lineages east and west of the Mississippi River but reared in standardized conditions. Bacterial composition was indistinguishable between lineages but responded significantly to host age-a proxy for environmental exposure. This was accompanied by a continuous decrease in bacterial diversity in both lineages, partially driven by decreasing evenness seen only in western lizards. These findings indicate that longer exposure to a homogeneous habitat may have a depreciating effect on microbiome diversity in eastern fence lizards, a response shared by both lineages. We highlight the importance of such effects when extrapolating patterns from laboratory experiments to the natural world.

The gut microbiome can influence host fitness and, consequently, the ecology and evolution of natural populations. Microbiome composition can be driven by environmental exposure but also by the host's genetic background and phenotype. To contrast environmental and genetic effects on the microbiome we leverage preserved specimens of eastern fence lizards from allopatric lineages east and west of the Mississippi River but reared in standardized conditions. Bacterial composition was indistinguishable between lineages but responded significantly to host age -- a proxy for environmental exposure. This was accompanied by a continuous decrease in bacterial diversity in both lineages, partially driven by decreasing evenness seen only in western lizards. These findings indicate that longer exposure to a homogeneous habitat may have a depreciating effect on microbiome diversity in eastern fence lizards, a response shared by both lineages. We highlight the importance of such effects when extrapolating patterns from laboratory experiments to the natural world.