Research Group Space
  • Evolvability meets biogeography: evolutionary potential decreases at high and low environmental favourability
  • Transgenerational effects of sexual interactions and sexual conflict
  • Mating portfolios: bet-hedging, sexual selection and female multiple mating
  • Model Systems, Taxonomic Bias, and Sexual Selection: Beyond Drosophila
  • Maternal sexual interactions affect offspring survival and ageing
  • Fertilization success
  • Phyll nymphs
  • Thonrnydev
  • Bull ant

About this space

Evolution unfolds in an ecological theatre. The context within which selection takes place is set not only by interactions between the organisms and abiotic factors, but also by inter- and intra-specific interactions. Sexual interactions are paramount in sexually reproductive species because offspring production is contingent on access to members of the other sex and on access to the other sex’s gametes. Furthermore, variation in the numbers of offspring produced and variation in the genetic quality of the progeny depends on interactions between the sexes. For instance, it may depend on mating choice criteria or on the particular genetic compatibility between mating partners. In all, sexual interactions largely determine the fitness of individuals (and populations). This implies selection acting on sexual interaction traits (including adaptations to outcompete rivals), which in turn raises questions about the genetic variation underlying these traits and the factors that maintain such variation in the face of selection. The main interests of the research group relate broadly to the evolutionary ecology of the interactions between the sexes, and includes the study of the causes and consequences of female multiple mating (polyandry), the estimation of genetic variation (heritability, evolvability) in sexually selected traits and life-history traits, the study of coevolutionary male-female adaptations to sexual selection and sexual conflict, the study of risk-spreading behaviour in the evolution of mating systems, and the study of male-driven trans-generational effects on offspring life-histories and their consequences for the evolution of sexual conflict. The research carried out by the group is question driven and predominantly follows empirical approaches using several model systems (mainly insects and other invertebrates). There are two broad questions that we try to address: What can we learn about evolution from studying sexual interactions? What can we learn about sexual interactions from studying evolution?

Latest News

  • State Plan Excellence

    New grant from the State Plan of R&D&i of Excellence. Our understanding of the causes and consequences of sexual conflict is hampered due to a lack of knowledge on a fundamental question: Does sexual conflict underlies the structure of socio-sexual networks and the ability of individuals to shape their social environment? This project will exploit the integration of experimental evolution protocols and evolutionary thinking with social network theory to address this question.

Latest Publications

Ejaculate-mediated paternal effects: evidence, mechanisms and evolutionary implications
Evans, J. P., Wilson, A. J., Pilastro, A. & Garcia-Gonzalez, F.
Reproduction, 157: R109-R126

Despite serving the primary objective of ensuring that at least one sperm cell reaches and fertilizes an ovum, the male ejaculate (i.e. spermatozoa and seminal fluid) is a compositionally complex ‘trait’ that can respond phenotypically to subtle changes in conditions. In particular, recent research has shown that environmentally and genetically induced changes to ejaculates can have implications for offspring traits that are independent of the DNA sequence encoded into the sperm’s haploid genome. In this review, we compile evidence from several disciplines and numerous taxonomic systems to reveal the extent of such ejaculate-mediated paternal effects (EMPEs). We consider a number of environmental and genetic factors that have been shown to impact offspring phenotypes via ejaculates, and where possible we highlight the putative mechanistic pathways by which ejaculates can act as conduits for paternal effects. We also highlight how females themselves can influence EMPEs, and in some cases how maternally derived sources of variance may confound attempts to test for EMPEs. Finally, we consider a range of putative evolutionary implications of EMPEs, and suggest a number of potentially useful approaches for exploring these further. Overall our review confirms that EMPEs are both widespread and varied in their effects, although studies reporting their evolutionary effects are still in their infancy.

A competitive environment influences sperm production, but not testes tissue composition, in house mice
Firman, R. C., Garcia-Gonzalez, F., Simmons, L. W. & André, G.
Journal of Evolutionary Biology, 31:1647-1654
Transgenerational effects of maternal sexual interactions in seed beetles
Zajitschek, S. R. K., Dowling, D. K., Head, M. L., Rodriguez-Exposito, E. & Garcia-Gonzalez, F.
Heredity, 121: 282-291

Mating often bears large costs to females, especially in species with high levels of sexual conflict over mating rates. Given the direct costs to females associated with multiple mating, which include reductions in lifespan and lifetime reproductive success, past research focused on identifying potential indirect benefits (through increases in offspring fitness) that females may accrue. Far less attention has, however, been devoted to understanding how costs of sexual interactions to females may extend across generations. Hence, little is known about the transgenerational implications of variation in mating rates, or the net consequences of maternal sexual activities across generations. Using the seed beetle, Callosobruchus maculatus, a model system for the study of sexual conflict, we investigate the effects of mating with multiple males versus a single male, and tease apart effects due to sexual harassment and those due to mating per se, over three generations. A multigenerational analysis indicated that females that were exposed to ongoing sexual harassment and who also were permitted to mate with multiple males showed no difference in net fitness compared to females that mated just once without ongoing harassment. Intriguingly, however, females that were continually harassed, but permitted to mate just once, suffered a severe decline in net fitness compared to females that were singly (not harassed) or multiply mated (harassed, but potentially gaining benefits via mating with multiple males). Overall, the enhanced fitness in multiply mated compared to harassed females may indicate that multiple mating confers transgenerational benefits. These benefits may counteract, but do not exceed (i.e., we found no difference between singly and multiply mated females), the large transgenerational costs of harassment. Our study highlights the importance of examining transgenerational effects from an inclusive (looking at both indirect benefits but also costs) perspective, and the need to investigate transgenerational effects across several generations if we are to fully understand the consequences of sexual interactions, sexual conflict evolution, and the interplay of sexual conflict and multi-generational costs and benefits.

Indirect genetic effects—everything is special, everything is important: a comment on Bailey et al
Garcia-Gonzalez, F.
Behavioral Ecology, 29(1): 12-13
A father effect explains sex-ratio bias
Malo, A. F., Martinez-Pastor, F., Garcia-Gonzalez, F., Garde, J., Ballou, J. D. & Lacy, R. C.
Proceedings of the Royal Society of London B, 284: 20171159

Sex ratio allocation has important fitness consequences, and theory predicts that parents should adjust offspring sex ratio in cases where the fitness returns of producing male and female offspring vary. The ability of fathers to bias offspring sex ratios has traditionally been dismissed given the expectation of an equal proportion of X- and Y-chromosome-bearing sperm (CBS) in ejaculates due to segregation of sex chromosomes at meiosis. This expectation has been recently refuted. Here we used Peromyscus leucopus to demonstrate that sex ratio is explained by an exclusive effect of the father, and suggest a likely mechanism by which male-driven sex-ratio bias is attained. We identified a male sperm morphological marker that is associated with the mechanism leading to sex ratio bias; differences among males in the sperm nucleus area (a proxy for the sex chromosome that the sperm contains) explain 22% variation in litter sex ratio. We further show the role played by the sperm nucleus area as a mediator in the relationship between individual genetic variation and sex-ratio bias. Fathers with high levels of genetic variation had ejaculates with a higher proportion of sperm with small nuclei area. This, in turn, led to siring a higher proportion of sons (25% increase in sons per 0.1 decrease in the inbreeding coefficient). Our results reveal a plausible mechanism underlying unexplored male-driven sex-ratio biases. We also discuss why this pattern of paternal bias can be adaptive. This research puts to rest the idea that father contribution to sex ratio variation should be disregarded in vertebrates, and will stimulate research on evolutionary constraints to sex ratios—for example, whether fathers and mothers have divergent, coinciding, or neutral sex allocation interests. Finally, these results offer a potential explanation for those intriguing cases in which there are sex ratio biases, such as in humans.