Sex‐specific paternal age effects on offspring quality in Drosophila melanogaster. (22nd March 2023) - Aguilar, Prem
Abstract: Advanced paternal age has been repeatedly shown to modulate offspring quality via male‐ and/or female‐driven processes, and there are theoretical reasons to expect that some of these effects can be sex‐specific. For example, sex allocation theory predicts that, when mated with low‐condition males, mothers should invest more in their daughters compared to their sons. This is because male fitness is generally more condition‐dependent and more variable than female fitness, which makes it less risky to invest in female offspring. Here, we explore whether paternal age can affect the quality and quantity of offspring in a sex‐specific way using Drosophila melanogaster as a model organism. In order to understand the contribution of male‐driven processes on paternal age effects, we also measured the seminal vesicle size of young and older males and explored its relationship with reproductive success and offspring quality. Older males had lower competitive reproductive success, as expected, but there was no difference between the offspring sex ratio of young and older males. However, we found that paternal age caused an increase in offspring quality (i.e., offspring weight), and that this increase was more marked in daughters than sons. We discuss different male‐ and female‐driven processes that may explain such sex‐specific paternal age effects. Abstract : We explored the effect of paternal age on offspring quality using Drosophila melanogaster . Older fathers produced heavier, higher quality offspring, particularly daughters. However, we did not detect any influence of paternal age on the ratio of offspring sexes. Further analysis revealed that the improvement in offspring quality was not due to differences in seminal vesicle size. We discuss our findings by considering the potential role of both male‐ and female‐driven processes in shaping paternal age effects.