Here, we report that breeding males showed increased prolactin levels when they were breeding independently of increases and decreases in day length. Also, we found a positive correlation (P = 0.05)

between the availability of food plants and prolactin levels. Changes in prolactin levels in opportunistically breeding species like the African striped mouse are not strictly regulated by photoperiod, but seem to respond to cues from food availability. ”
“Both mating system and diet are thought to drive inter-individual variation in bite force. Although previously published data suggest that bite force variation may be driven by variation in morphology (e.g. head morphology, body size, muscle size), age and physiology (e.g. fluctuating plasma testosterone Selleckchem Sunitinib levels) in some vertebrates, this remains untested in primates. Here, we explore the proximal determinants of bite force capacity in the grey mouse lemur Microcebus murinus. Our results show that in male grey mouse lemurs, bite force measurements are repeatable across a 1-month period. Yet, bite forces were independent of fluctuation plasma testosterone levels. Head dimensions and body mass

were all positively correlated with bite force. Among these, head width was the best predictor of bite force as has been observed for other vertebrates. Unexpectedly, age was highly significantly and positively correlated with bite force. Whereas older animals generally bit harder, the oldest buy ABT-263 age group (5.5 years) showed a decline in bite force capacity. These results suggest that bite force in the grey mouse lemur is mostly determined by morphology and age, yet is independent of variation OSBPL9 in testosterone. Future studies including a broader age range and animals of different sexes would be of interest to better understand the variation in bite force in this small lemur. ”
“In several animal species, discrete, heritable

phenotypic morphs occur in one sex only. This phenomenon is commonly observed in damselfly species where the coexistence of different female colour morphs is often explained in the context of sexual conflict. However, theories based on sexual conflict alone appear to be insufficient for explaining the inter-population variation in morph frequencies. A case in point is the widespread North American damselfly Nehalennia irene, in which one female morph occurs predominantly in populations in Western Canada, while another morph is more common in Eastern Canada. Given its large distribution range, historical events may be of particular relevance in explaining the observed spatial variation in morph frequencies in this species.