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Exposure to extreme temperatures can negatively affect animal reproduction, by disrupting the ability of individuals to produce any offspring (fertility), or the number of offspring produced by fertile individuals (fecundity). This has important ecological consequences, because reproduction is the ultimate measure of population fitness: a reduction in reproductive output lowers the population growth rate and increases the extinction risk. Despite this importance, there have been no large-scale summaries of the evidence for effect of temperature on reproduction. We provide a systematic map of studies testing the relationship between temperature and animal reproduction. We systematically searched for published studies that statistically test for a direct link between temperature and animal reproduction, in terms of fertility, fecundity or indirect measures of reproductive potential (gamete and gonad traits). Overall, we collated a large and rich evidence base, with 1654 papers that met our inclusion criteria, encompassing 1191 species. The map revealed several important research gaps. Insects made up almost half of the dataset, but reptiles and amphibians were uncommon, as were non-arthropod invertebrates. Fecundity was the most common reproductive trait examined, and relatively few studies measured fertility. It was uncommon for experimental studies to test exposure of different life stages, exposure to short-term heat or cold shock, exposure to temperature fluctuations, or to independently assess male and female effects. Studies were most often published in journals focusing on entomology and pest control, ecology and evolution, aquaculture and fisheries science, and marine biology. Finally, while individuals were sampled from every continent, there was a strong sampling bias towards mid-latitudes in the Northern Hemisphere, such that the tropics and polar regions are less well sampled. This map reveals a rich literature of studies testing the relationship between t

One of the most pressing questions we face as biologists is to understand how climate change will affect the evolutionary dynamics of natural populations and how these dynamics will in turn affect population recovery. Increasing evidence shows that sexual selection favors population viability and local adaptation. However, sexual selection can also foster sexual conflict and drive the evolution of male harm to females. Male harm is extraordinarily widespread and has the potential to suppress female fitness and compromise population growth, yet we currently ignore its net effects across taxa or its influence on local adaptation and evolutionary rescue. We conducted a comparative meta-analysis to quantify the impact of male harm on female fitness and found an overall negative effect of male harm on female fitness. Negative effects seem to depend on proxies of sexual selection, increasing inversely to the female relative size and in species with strong sperm competition. We then developed theoretical models to explore how male harm affects adaptation and evolutionary rescue. We show that, when sexual conflict depends on local adaptation, population decline is reduced, but at the cost of slowing down genetic adaptation. This trade-off suggests that eco-evolutionary feedback on sexual conflict can act like a double-edged sword, reducing extinction risk by buffering the demographic costs of climate change, but delaying genetic adaptation. However, variation in the mating system and male harm type can mitigate this trade-off. Our work shows that male harm has widespread negative effects on female fitness and productivity, identifies potential mechanistic factors underlying variability in such costs across taxa, and underscores how acknowledging the condition-dependence of male harm may be important to understand the demographic and evolutionary processes that impact how species adapt to environmental change.

From inbreeding avoidance to kin-selected cooperation, social behaviours are frequently reliant on kin recognition. However, kin recognition mechanisms are costly to evolve and currently not very well understood. Recent evidence suggests that, by altering their host's odour, gut and other host-associated microorganisms may provide a promising avenue for understanding kin recognition. In Drosophila melanogaster, kin recognition can mediate mate choice, sexual conflict and larval competition/cooperation, underscoring its important functional role. As is commonly the case, kin recognition in this species depends on both familiarity (i.e. shared rearing environment) and relatedness, and seems to rely mainly on body odours determined by cuticular hydrocarbons. Here, we investigated the degree to which larval rearing environment and relatedness (full-sibs versus unrelated) determine co-variation between gut microbiota and cuticular hydrocarbons in D. melanogaster. We found that rearing environment strongly determined microbiota composition and cuticular hydrocarbon profiles, but that these effects were independent from each other. In contrast, relatedness did not influence microbiota composition, but had a strong influence on microbiota diversity, which in turn covaried significantly with cuticular hydrocarbon profiles. Our results show that, in D. melanogaster, odours may convey information about both familiarity and relatedness via an interaction between: 1) direct effects of the rearing environment on cuticular hydrocarbons and 2) indirect effects of relatedness on cuticular hydrocarbons via gut microbiota diversity.

From inbreeding avoidance to kin-selected cooperation, social behaviours are frequently reliant on kin recognition. However, kin recognition mechanisms are costly to evolve and currently not very well understood. Recent evidence suggests that, by altering their host’s odour, gut and other host-associated microorganisms may provide a promising avenue for understanding kin recognition. In Drosophila melanogaster, kin recognition can mediate mate choice, sexual conflict and larval competition/cooperation, underscoring its important functional role. As is commonly the case, kin recognition in this species depends on both familiarity (i.e. shared rearing environment) and relatedness, and seems to rely mainly on body odours determined by cuticular hydrocarbons. Here, we investigated the degree to which larval rearing environment and relatedness (full-sibs vs. unrelated) determine co-variation between gut microbiota and cuticular hydrocarbons in D. melanogaster. We found that rearing environment strongly determined both microbiota and cuticular hydrocarbon composition, but that these effects were independent from each other. In contrast, relatedness did not influence microbiota composition, but had a strong influence on microbiota diversity, which in turn covaried significantly with cuticular hydrocarbon composition. Our results show that, in D. melanogaster, odours may convey information about both familiarity and relatedness via an interaction between: a) direct effects of the rearing environment on cuticular hydrocarbons and b) indirect effects of relatedness on cuticular hydrocarbons via gut microbiota diversity.

Gran part del coneixement que atresorem sobre l’evolució, i la biologia en general, descansa sobre les idees que Darwin va exposar sobre la selecció sexual fa ja cent cinquanta anys. En la seva obra The Descent of Man, and Selection in Relation to Sex, Darwin explica dos mecanismes fonamentals per entendre la competència per la reproducció: el combat per l’aparellament i l’elecció de parella. Avui dia sabem que, juntament amb aquests dos mecanismes, l’intricat camí cap a la reproducció també depèn de la competència espermàtica i de l’elecció críptica de la parella per part de les femelles. En el present text repassem el que hem après sobre aquests quatre mecanismes i discutim aspectes generals sobre els rols sexuals, la batalla evolutiva entre els sexes i la rellevància general de la selecció sexual per entendre el món natural. Després de cent cinquanta anys estudiant la selecció sexual, avui sabem que amb aquesta idea Darwin no només va completar l’esquema general de la seva Teoria de la Selecció Natural, sinó que va establir les bases del que s’ha convertit en un dels camps més complexos i estimulants en l’estudi de l’evolució. Un procés vital per entendre no només l’evolució de mascles i femelles, sinó també els processos d’especiació, la capacitat de les poblacions per adaptar-se a ambients canviants, o l’evolució de la mateixa reproducció sexual.Paraules clau: evolució, selecció sexual, comportament animal, sexes., Much of the knowledge we treasure about evolution, and biology in general, rests on Darwin’s ideas about sexual selection, put forward 150 years ago. In his work The Descent of Man, and Selection in Relation to Sex, Darwin explains two fundamental mechanisms competition for reproduction: to understand intra-sexual competition and mate choice. Today we know that, along with these two mechanisms, the intricate path to reproduction also depends on sperm competition and cryptic mate choice by females. In this text we review what we have learned about these four mechanisms and discuss general aspects of sex roles, the evolutionary battle between the sexes and the general relevance of sexual selection for understanding the natural world. After 150 years of studying sexual selection, we now know that with this idea Darwin not only completed the general outline of his Theory of Natural Selection, but laid the foundations of what has become one of the most complex and stimulating fields in the study of evolution. A vital process for understanding not only the evolution of males and females, but also speciation, the ability of populations to adapt to changing environments, or the evolution of sexual reproduction itself.Keywords: evolution, sexual selection, animal behaviour, sexes.