Reproductive biology of Gazella arabica: Predictors of offspring weight and short- and long-term offspring survival

Reproductive traits are central to organismal fitness,and so the factors influencing patterns of reproduction and offspring survival are at the heart of biology.Making use of breeding data collected over 16 years at the King Khalid Wildlife Research Centre in Saudi Arabia,we investigated the reproductive biology of Arabian gazelles Gazella arabica.Offspring survival was mainly a function of birth weight,with heavier offspring having higher survival rates than lighter offspring.However,while sons were heavier than daughters,daughters had higher survival rates.We could not find evidence that giving birth to sons negatively impacts offspring weight in the following year.We uncovered large narrow-sense heritability(h2)in offspring weight at birth,while maternal effects(m2)on birth weight were of lesser importance.However,maternal effects on offspring survival were strong until weaning age,while paternal effects dominated survival to sexual maturity and first reproduction.We propose that variation in maternal postnatal care might overshadow the effects of maternal inheritance of birth weights,while the overall strong heritability of weight at birth and the paternal effects on survival llustrates strong variance in sire fitness based on genetic quality,suggesting a role for sexual selectionbyfemalemate choiceinwildpopulations.

Predator-induced changes of male and female mating preferences: innate and learned components

While many mati ng pref ere nces have a genetic basis, the question remai ns as to whether and how learning/experience can modify individual mate choice decisions. We used wild-caught (predator-experienced) and Fi laboratory-reared (predator-naive) invasive Western mosquitofish Gambusia affinis from China to test whether mating preferences (assessed in a first mate choice test) would change under immediate predation threat. The same individuals were tested in a second mate choice test during which 1 of 3 types of animated predators was presented: 1) a co-occurring predator, 2) a co-evolved but not currently co-occurring predator, and 3) a non-piscivorous species as control. We compared preference scores derived from both mate choice tests to separate innate from experiential effects of predation. We also asked whether predator-induced changes in mating preferences would differ betwee n sexes or depend on the choosing individual's personality type and/or body size. Wild-caught fish altered their mate choice decisions most when exposed to the co-occurring predator whereas laboratory-reared individuals responded most to the co-evolved predator, suggesting that both innate mechanisms and learning effects are involved. This behavior likely reduces individuals' risk of falling victim to predation by temporarily moving away from high-quality (i.e., conspicuous) mating partners. Accordingly, effects were stronger in bolder than shyer, large- compared with small-bodied, and female compared with male focal individuals, likely because those phenotypes face an increased predation risk overall. Our study adds to the growing body of literature appreciating the complexity of the mate choice process, where an array of intrinsic and extrinsic factors interacts during decision-making.