Distribution of Affiliative Behavior Across Kin Classes and Their Fitness Consequences in Mandrills

Multimale–multifemale primate groups are ideal models to study the impact of kinship on the evolution of sociality. Indeed, the frequent combination of female philopatry and male reproductive skew produces social systems where both maternal and paternal kin are co‐resident. Several primates are known to bias their behavior toward both maternal and paternal kin. Moreover, allocation of affiliation toward paternal kin has been shown to depend on the availability in maternal kin: Female baboons invest more in paternal kin after the loss of preferred maternal kin. Here, we examined how affiliation co‐varies across kin classes in juvenile mandrills (Mandrillus sphinx), an Old World primate living in a multimale–multifemale society. While affiliation levels observed with the mother and with maternal half‐sibs co‐varied positively, especially in young females, we found that levels of affiliation among paternal half‐sibs correlated negatively with levels of affiliation among individuals from the same matriline (distant kin), possibly as a result of kin availability. In addition, in social species, social bonds between individuals have been linked to differentiated fitness consequences: More socially integrated individuals generally enjoy higher fitness. We therefore also tested whether affiliation during early life impacts fitness. We showed that the global amount of affiliation during juvenescence translated into possible reproductive benefits: Females who were more socially integrated gave birth on average a year before females that were less socially integrated. However, age at first reproduction was not predicted by the amount of affiliation exchanged with any particular kin class. These results add to the growing body of evidence demonstrating differential investment in bonding and possible social adjustments among different kin categories and emphasizing once more the adaptive value of sociality.     

Deciphering the effect of climate warming on an emerging poplar pest using spatial extrapolation of population parameters

1. The woolly poplar aphid Phloeomyzus passerinii Signoret (Aphididae: Phloeomyzinae) is a major pest of poplar plantations. We hypothesized that recent temperature increases may have contributed to the emergence and subsequent northward expansion of outbreaks in France.
2. We reared P. passerinii at four temperatures to estimate its thermal requirements. We used experimental data to parametrize a mechanistic and temperature-driven physiologically-based demographic model. The model was used to simulate the effect of temperature on aphid dynamics and to assess the role of climate warming on the spatiotemporal dynamics of outbreaks.
3. The lower developmental threshold was estimated at 6.4 °C and the development degree-days at 171.
4. Our model supports the hypothesis that recent warming may have promoted outbreaks in northern France. During recent exceptionally warm years, more than 70% of the northern poplar area was favourable for outbreaks.
5. Our model suggests that climate warming is not the sole factor involved. The dominance of resistant poplar genotypes such as ‘Robusta’ or ‘Beaupré’ may have preserved plantations from outbreaks before 1996 in southern France and until 2000 in the central part. Other factors, including biological characteristics, biotic interactions, or precipitation should be investigated.

     

Nutritional regulation of serum osteocalcin: study in kwashiorkor

The serum levels of osteocalcin (bone gla protein) in two groups of Senegalese children, healthy controls and severely malnourished (kwashiorkor) children during nutritional rehabilitation, were measured. The serum osteocalcin of all kwashiorkor children was dramatically decreased on admission to hospital, but increased fourfold during rehabilitation. Serum osteocalcin was low in the control group. In both groups these low levels seemed to be independent of those of 1,25-dihydroxyvitamine D3 which were in the normal range. The results suggest that serum osteocalcin levels might be related to protein-energy status.