Biology subjects

Cattelan, S.

Publications and source records attributed to Cattelan, S..

4 recordsLinked to original sources

bioRxiv2023

Sperm quality and function deteriorate in old males of the naturally short-lived turquoise killifish

Maximizing the life-long reproductive output would lead to the prediction that short-lived and fast aging species would undergo no - if any - reproductive senescence. Turquoise killifish (Nothobranchius furzeri) are naturally short-lived teleosts, and undergo extensive somatic aging, characterized by molecular, cellular, and organ dysfunction following the onset of sexual maturation. Here, we tested whether naturally short-lived and fast aging turquoise killifish males maximize reproduction and display minimal - if any, reproductive senescence. We analysed age-related changes in sperm traits, the proportion of fertilized eggs, as well as embryo survival. Contrary to the expectation of no reproductive aging, we found that turquoise killifish males undergo extensive reproductive aging, consisting in the age-dependent decline in sperm quality, decreased proportion of fertilized eggs and lower embryo survival. Our results indicate that male turquoise killifish do not trade-off age-dependent soma decline with life-long sustained reproductive fitness. Instead, somatic and reproductive aging appear to occur simultaneously. Our findings question generalized soma vs. reproductive senescence trade-off models and highlight the importance of integrating species-specific ecological and demographic constraints to explain observed life history traits.

evolutionary biology↗

bioRxiv2023

Sperm length evolution in relation to body mass is shaped by multiple trade-offs in tetrapods

Sperm size is highly variable across species and is influenced by various factors including fertilization mode, female reproductive traits and sperm competition. Despite considerable efforts, many questions about sperm size variation remain open. Variation in body size may affect sperm size evolution through its influence on these factors, but the extent to which sperm size variation is linked to body mass remains elusive. In this study, we use the general theory of Pareto Optimality to investigate the relationship between sperm size and body mass across tetrapods. We find that tetrapods fall within a triangular-shaped Pareto front in the trait space of body mass and sperm length suggesting that the evolution of sperm size in relation to body size is shaped by trade-offs. We then explore the three main factors predicted to influence sperm size evolution, namely sperm competition, clutch size and genome size. Our results demonstrate that body mass optimally shapes sperm size evolution in tetrapods mainly through its association with sperm competition and clutch size. Finally, we show that the triangular-shaped Pareto front is maintained when tested separately within mammals, birds, endothermic species and internal fertilizers, suggesting that similar evolutionary trade-offs characterize the evolution of sperm size in relation to body size within taxonomic/phylogenetic and functional subgroups of tetrapods. This study provides insights into the evolutionary mechanisms driving interspecific sperm size variation and highlights the importance of considering multiple trade-offs in optimizing reproductive traits.

evolutionary biology↗

bioRxiv2023

Sperm production is negatively associated with muscle and sperm telomere length in a highly polyandrous species

Life history theory suggests that aging is one of the costs of reproduction. Accordingly, a higher reproductive allocation is expected to increase the deterioration of both the somatic and the germinal lines through enhanced telomere attrition. In most species, males reproductive allocation mainly regards traits that increase mating and fertilization success, i.e. sexually selected traits. In the current study, we tested the hypothesis that a higher investment in sexually selected traits is associated with a reduced telomere length in the guppy (Poecilia reticulata), an ectotherm species characterized by strong pre- and postcopulatory sexual selection. We first measured telomere length in both the soma and the sperm over the course of guppys lifespan to see if there was any variation in telomere length associated with age. Secondly, we investigated whether a greater expression of pre- and postcopulatory sexually selected traits is linked to shorter telomere length in both the somatic and the sperm germinal lines, and in young and old males. We found that telomeres lengthened with age in the somatic tissue, but there was no age-dependent variation in telomere length in the sperm cells. Telomere length in guppies was significantly and negatively correlated with sperm production in both tissues and life stages considered in this study. Our findings indicate that telomere erosion in male guppies is more strongly associated with their reproductive investment (sperm production) rather than their age, suggesting a trade-off between reproduction and maintenance is occurring at each stage of males life in this species.

molecular biology↗

bioRxiv2022

Immediate predation risk alters the relationship between potential and realised selection on male traits in the Trinidad guppy Poecilia reticulata

Predation risk perception can alter mating behaviours in males and females, but the consequences for sexual selection remain underexplored. We have previously shown that in experimental populations of Trinidadian guppies Poecilia reticulata the opportunity for sexual selection (i.e. the variance in male reproductive fitness) was higher following exposure to a simulated risk of predation than in a no-risk condition. We build upon this result by exploring whether imminent predation risk affects: 1) the relationship between the opportunity for sexual selection and the actual strength of selection on male traits and 2) the traits contributing to male fitness, and he shape of selection on these traits. While predation risk increased the variance in male fitness, realised selection on traits remained unaffected. Pre- and postcopulatory traits follow complex patterns of nonlinear and correlational selection in both treatments. Differences in selection gradients deviate from predictions based on evolutionary responses to predation, the most notable being stronger selection on courtship rate under predation risk. Our results demonstrate that the operation of sexual selection can be altered by perception of an imminent predation risk and reinforce the notion that both trait-based and variance-based metrics should be employed for an informative quantification.

evolutionary biology↗