Biology subjects

Winder, L. A.

Publications and source records attributed to Winder, L. A..

3 recordsLinked to original sources

bioRxiv2025

Examining the genetic and phenotypic correlation between survival and fecundity in a wild bird

There is intraspecific variation in reproduction and survival, which has been hypothesised to be the result of trade-offs in investment. However, we lack compelling evidence that trade- offs drive variation within species, perhaps because genetic trade-offs are masked by environmental variation. We used a long-term dataset of breeding records for a closed population of house sparrows (Passer domesticus) and its associated pedigree to separate the genetic and environmental covariance between fecundity and survival. We measured age-specific changes in reproductive outputs and estimated the heritability of both offspring production and survival in multivariate animal models. Our results show no evidence for survival costs to reproductive output. Nor did we find evidence that individuals fecundity and survival are correlated either the genetic or permanent environment level. Our findings show no evidence that variation in fecundity is driven by the offspring-production/survival trade-off. Instead, our results show that individuals are only somewhat consistent in their reproductive output, and suggest this is a possible mechanism why selection cannot act on individual quality.

evolutionary biology↗

bioRxiv2024

Separating the genetic and environmental drivers of body temperature during the development of endothermy in an altricial bird

When altricial birds hatch, they are unable to regulate their own temperature, but by the time they fledge they are thermally independent. Early-life conditions have been shown to be an important factor contributing to an individuals performance in adult life. However, it is currently unknown to what extent body temperature during endothermy development is driven by genetic variation or by the early environment. We use thermal images of cross-fostered house sparrows (Passer domesticus) throughout the nestling period to separate genetic and environmental drivers of body temperature. Our results show small heritability of body temperature. We further found that there are effects from the natal environment which carry over into the late nestling stage. A correlation between early to the mid-nestling period was explained by the natal environment and during this period body temperature and growth follow independent developmental trajectories. Furthermore, higher body temperature is under viability selection independent of body mass. We, therefore, demonstrate the natal environment influences future offspring phenotype in a novel measure; body temperature. Our study provides the first study into the environmental and genetic drivers of body temperature variation in a wild bird, furthering our understanding of how an individuals traits evolve.

evolutionary biology↗

bioRxiv2022

The optimal clutch size revisited: separating individual quality from the costs of reproduction

Life-history theory, central to our understanding of diversity in morphology, behaviour and senescence, describes how traits evolve through the optimisation of trade-offs in investment. Despite considerable study, there is only minimal support for trade-offs within species between the two traits most closely linked to fitness - reproductive effort and survival - questioning the theorys general validity. We used a meta-analysis to separate the effects of individual quality (positive survival/reproduction correlation) from the costs of reproduction (negative survival/reproduction correlation) using studies of reproductive effort and parental survival in birds. Experimental enlargement of brood size caused reduced parental survival. However, the effect size of brood size manipulation was small and opposite to the effect of phenotypic quality, as we found that individuals that naturally produced larger clutches also survived better. The opposite effects on parental survival in experimental and observational studies of reproductive effort provides the first meta-analytic evidence for theory suggesting that quality differences mask trade-offs. Fitness projections using the overall effect size revealed that reproduction presented negligible costs, except when reproductive effort was forced beyond the maximum level observed within species, to that seen between species. We conclude that there is little support for the most fundamental life-history trade-off, between reproductive effort and survival, operating within a population. We suggest that within species, the fitness landscape of the reproduction-survival trade-off is flat until it reaches the boundaries of the between-species fast-slow life-history continuum. Our results provide a quantitative explanation as to why the costs of reproduction are not apparent and why variation in reproductive effort persists within species.

evolutionary biology↗