Reciprocal preening and food sharing in colour-polymorphic nestling barn owls.

Barn owl (Tyto alba) siblings preen and offer food items to one another, behaviours that can be considered prosocial because they benefit a conspecific by relieving distress or need. In experimental broods, we analysed whether such behaviours were reciprocated, preferentially exchanged between specific phenotypes, performed to avoid harassment and food theft or signals of hierarchy status. Three of the results are consistent with the hypothesis of direct reciprocity. First, food sharing was reciprocated in three-chick broods but not in pairs of siblings, that is when nestlings could choose a partner with whom to develop a reciprocating interaction. Second, a nestling was more likely to give a prey item to its sibling if the latter individual had preened the former. Third, siblings matched their investment in preening each other. Manipulation of age hierarchy showed that food stealing was directed towards older siblings but was not performed to compensate for a low level of cooperation received. Social behaviours were related to melanin-based coloration, suggesting that animals may signal their propensity to interact socially. The most prosocial phenotype (darker reddish) was also the phenotype that stole more food, and the effect of coloration on prosocial behaviour depended upon rank and sex, suggesting that colour-related prosociality is state dependent

Genome sequencing and functional characterization of the non-pathogenic Klebsiella pneumoniae KpGe bacteria.

Klebsiella pneumoniae is an extensively studied human pathogen responsible for a wide variety of infections. Dictyostelium discoideum is a model host organism employed to study many facets of the complex interactions between phagocytic cells and bacteria. Historically, a non-pathogenic strain of K. pneumoniae has been used to feed Dictyostelium amoebae, and more recently to study cellular mechanisms involved in bacterial recognition, ingestion and killing. Here we provide the full genome sequence and functional characterization of this non-pathogenic KpGe strain

Nocturnal, diurnal and bimodal patterns of locomotion, sibling interactions and sleep in nestling Barn Owls

Temporal variation in physical activity is mainly determined by the day-night cycle. While this may be true for diurnal species whose vision at night is often poor, the situation might be more complex in nocturnal animals as many such species can see both in the dark and in the daylight. We examined in Barn Owl (Tyto alba) nestlings whether temporal variation of behavioural activities and sleep is shaped by parental feeding visits occurring during the first part of the night and the extent to which they also occur during daylight hours. We measured several behaviours in 280 individuals from 90 broods recorded in 4 years. Parental feeding visits progressively declined in frequency from the beginning to the end of the night, and a number of offspring behaviours followed the same pattern of activity (feeding, vocalization and self-preening). Surprisingly, nestlings were awake not only at sunset, but also at sunrise. Several behaviours (locomotion, wing flapping and sibling interactions, such as pecking and allopreening among nestlings) showed peaks of activity at sunset and sunrise, suggesting that they were performed for other reasons than to interact with parents. Allopreening was performed more often during the day than at night. We conclude that although adult Barn Owls are nocturnal, nestlings display a complex temporal pattern of activity that is governed not only by feeding but also by other unknown factors