Journal of Ethology最新文献

Any kind of unpredictability affects female reproduction. In fluctuating environments, the fittest genotype can change between generations, and mating with “unsuitable” males will result in reproductive failure due to their genetic or environmental factors. If females cannot discriminate the quality of mates, monandrous mating with “unsuitable” male may lead to reproductive failure. Bet-hedging polyandry hypothesis suggests that polyandry can spread such risks over multiple males and some empirical studies support this hypothesis. However, no studies have considered the effect of female condition on mating acceptance. Because polyandry accumulates the costs of mating, only high conditioned females could accept multiple mating. In this study, females were assigned to monandry (M), two mating polyandry (2P), or three mating polyandry (3P) treatments. All females were mated with three males. For females assigned to the M treatment, for the second and third matings, we removed spermatophores immediately after transfer. For 2P females, the final spermatophore was removed immediately after transfer. Geometric mean fitness across (pseudo) generations as a long-term fitness index (calculated from the egg fertilization rate and egg hatching rate) significantly increased with the number of undisturbed mates. Therefore, the bet-hedging polyandry hypothesis is again supported after adjusting for the female condition.

Abstract

Animal internal states can be expressed via social behaviors that are known to shape group dynamics (i.e., allogrooming, social play, agonistic encounters) and that can be flexibly used after experiencing negative stimuli. In extensively bred domestic species, animals are not always used to human handling, and thus also mandatory health checks can alter group dynamics. Here, we investigated possible fluctuations in social behaviors according to the presence and distance from the health check in a group of young Maremmana heifers and steers in semi-extensive conditions. We found that aggression did not change in relation to the health check. On the contrary, the time individuals spent playing and affiliating with each other drastically reduced in the day after the routinary check (Post 1, 0–24 h) if compared to days far from the event (Control): after that, it reached the highest level in the following day (Post 2, 24–48 h). This rebound effect might allow animals to compensate for the previous lack of social interactions and to restore social homeostasis. The findings suggest that social interactions in Maremmana cattle are informative about their internal states. Additionally, social play and allogrooming appear to function as coping strategies for these cattle.

Wing design in birds is the result of different and potentially opposing natural selection pressures, such as those related to migration, predator avoidance and habitat type. Sexual selection for flight performance may also shape wing design via female preferences for superior performance of flight display. The black-headed bunting Emberiza melanocephala is a polygynous species that is sexually dimorphic in both plumage colour and size. Males perform Towering song-flight, which is a physically demanding display performed only in the presence of receptive females, potentially affecting male mating success. Towering flight features could in turn be influenced by wing morphology. Thus, we studied male wingtip shape in relation to the frequency of Towering song-flights and consequently in relation to the mating success of black-headed bunting males. We found that male mating success was not related to the frequency of song-flights even though it was predicted by male wingtip shape, perhaps suggesting that the quality of Towering flights, in terms of height, steepness or duration of flight, rather than the quantity, influences male mating success.