a b s t r a c tThe present review is based on the thesis that mate choice results from information-processing mechanisms governed by computational rules and that, to understand how females choose their mates, we should identify which are the sources of information and how they are used to make decisions. We describe mate choice as a three-step computational process and for each step we present theories and review empirical evidence. The first step is a perceptual process. It describes the acquisition of evidence, that is, how females use multiple cues and signals to assign an attractiveness value to prospective mates (the preference function hypothesis). The second step is a decisional process. It describes the construction of the decision variable (DV), which integrates evidence (private information by direct assessment), priors (public information), and value (perceived utility) of prospective mates into a quantity that is used by a decision rule (DR) to produce a choice. We make the assumption that females are optimal Bayesian decision makers and we derive a formal model of DV that can explain the effects of preference functions, mate copying, social context, and females' state and condition on the patterns of mate choice. The third step of mating decision is a deliberative process that depends on the DRs. We identify two main categories of DRs (absolute and comparative rules), and review the normative models of mate sampling tactics associated to them. We highlight the limits of the normative approach and present a class of computational models (sequential-sampling models) that are based on the assumption that DVs accumulate noisy evidence over time until a decision threshold is reached. These models force us to rethink the dichotomy between comparative and absolute decision rules, between discrimination and recognition, and even between rational and irrational choice. Since they have a robust biological basis, we think they may represent a useful theoretical tool for behavioural ecologist interested in integrating proximate and ultimate causes of mate choice.

To determine how climate factors influence age, body size and sexual size dimorphism (SSD) in the Mediterranean region, we generated data on age and body size of the European Treefrog, Hyla arborea, in three Turkish populations with a latitudinal gradient. We estimated age structure (total ), using skeletochronology. Mean body size of both sexes was smaller in a southern population (Antalya) than in northern populations (Çanakkale and Rize) with female-larger SSD in the northern populations. A positive correlation was found between age and body size in each sex of all the populations, save the Antalya females. Since amphibian growth is reduced after maturity but continues towards the asymptotic size, interpopulation size differences may partly be explained by differences in longevity with four years in Antalya and five years in the other two populations. Comparing age and body size in three Turkish populations with those in three different populations (Greece, Switzerland and Germany) from the literature, there was a trend of South-to-North increase in body size with increased latitude and decreased temperature and aridity. The same trend occurred also in age structure (e.g., age at maturity/first reproduction, longevity). These results suggest that a difference in age structure between populations is a main factor for the geographic variation in body size of this species.

Sexual size dimorphism (SSD) is often explained as the differential equilibrium between stabilizing survival selection and directional sexual/fecundity selection on the body size of males and females. Provided that survival selection is similar in both sexes, female‐biased SSD is thought to occur when fecundity selection on female body size is stronger than sexual selection on male body size. However, in animals with indeterminate growth, body size depends on several life‐history traits, thus, to understand why SSD has evolved, one should understand how it arises. We investigate SSD in the Tyrrhenian tree frog, Hyla sarda, by describing sexual dimorphism in age and growth and by assessing how body size affects their reproductive success. Females are 16% larger than males because they mature 1 year later, live 1 year longer and reach a larger asymptotic body size. Furthermore, body size correlates positively with female fecundity, but not with male mating success. These results suggest that SSD arises from differential optimal trade‐offs between the expected number of reproductive episodes (which decreases with prolonging growth) and the expected success in each reproductive episode (which increases with prolonging growth).

a b s t r a c tIn anurans, fecundity (clutch size) is the most important determinant of female reproductive success. We investigated three possible causes responsible for fecundity variation in female Italian treefrogs, Hyla intermedia, during four breeding seasons: (i) variation in morphological (body size and condition) and life-history (age) traits; (ii) variation in the tradeoff between the number and the size of eggs; (iii) seasonal effects and within-season differences in the timing of deposition. At the population level, we found no evidence for a tradeoff between the number and the size of eggs, because they both correlated positively with females' body size. Conversely, neither age nor post-spawning body condition showed any effect on female reproductive investment. Independent of body size, we found no evidence for variation in reproductive effort among different breeding seasons, but strong evidence for a decrease of clutch size and an increase of egg size with the advancing of a breeding season. To test for the functional significance of the observed temporal variation in allocation strategy, we carried out a rearing experiment in seminatural conditions on a random sample of ten clutches. The experiment showed a negative effect of clutch size and a positive effect of egg size on both tadpole growth and developmental rates, suggesting that reproductive investment, although constrained by body size, can be adjusted by females to the time of deposition to increase the chances of offspring survival.