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Bodyweight is an important health and welfare indicator for captive non-human primates (NHPs). Bodyweight can be measured during routine handling procedures, which cause stress. Alternatively, animals can be trained to step onto a scale, but training success varies greatly between individuals. Being able to weigh animals regularly without having to handle or train them is thus desirable for monitoring animal health and welfare. This study investigates the utility, ie the participation, reliability and time investment, of voluntary weighing in captive NHPs living in large social groups. Subjects of the study were 92 rhesus macaques (Macaca mulatta) housed in four social groups at the Biomedical Primate Research Centre in Rijswijk, The Netherlands. A scale was placed in their home enclosure during several sessions. Individuals were unwilling to step onto an unbaited scale. When likeable food items were used to attract individuals to the scale, 68% of them stepped onto the scale. Age and dominance rank did not affect stepping onto the scale, whereas exploratory tendency and social group did. The level of agreement between bodyweight by voluntary weighing and bodyweight measured during sedation was very high. These results show that the majority of rhesus macaques in social groups can be weighed voluntarily and that voluntary weighing is reliable. When optimising and further developing the method, voluntary weighing can form a valuable tool in the captive management of NHPs.

As well as leading to a loss of biodiversity (i.e. species richness and abundance), human activities also affect ecosystem functioning. Documenting how the suite of ecological roles changes following disturbance provides a complementary source of information for conservation management. To this end, we measured mammal diversity in terms of community structure (i.e. abundance, composition and species richness) and functional diversity in three sites differing in conservation effort in a tropical rainforest in Cameroon. Results show that sites without primary or secondary conservation efforts had lower mammal abundances and an altered mammal composition but similar species richness compared to better-protected areas. In terms of functional diversity, we found more variation of traits (i.e. FDis) in the site with primary conservation and higher abundances of functionally unique species (i.e. FOri) in sites with either primary or secondary conservation efforts. We found no overall difference in the abundance of specialist and generalist species between sites (i.e. FSpe). We identified several drivers affecting abundance, species richness and functional diversity of mammal communities, although there did not appear to be a common driver affecting all mammal diversity measures in a similar way. Our results suggest that, in addition to preserving mammal abundance and community composition, conservation efforts (both primary and secondary) are able to contribute to maintaining higher levels of functional diversity compared to areas devoid of conservation. We demonstrate that functional diversity metrics can provide valuable additional information about the status of mammal communities that can be used to better inform conservation management.

The heterozygosity status of polymorphic elements of the immune system, such as the major histocompatibility complex (MHC), is known to increase the potential to cope with a wider variety of pathogens. Pre- and postcopulatory processes may regulate MHC heterozygosity. In a population where mating occurs among individuals that share identical MHC haplotypes, postcopulatory selection may disfavour homozygous offspring or ones with two MHC haplotypes identical to its mother. We tested these ideas by determining the incidence of MHC-heterozygous and MHC-homozygous individuals in a pedigreed, partially consanguineous captive rhesus monkey colony. Bayesian statistics showed that when parents share MHC haplotypes, the distribution of MHC-heterozygous and MHC-homozygous individuals significantly fitted the expected Mendelian distribution, both for the complete MHC haplotypes, and for MHC class I or II genes separately. Altogether, we found in this captive colony no evidence for postcopulatory selection against MHC-homozygous individuals. However, the distribution of paternally and maternally inherited MHC haplotypes tended to differ significantly from expected. Individuals with two MHC haplotypes identical to their mother were underrepresented and offspring with MHC haplotypes identical to their father tended to be overrepresented. This suggests that postcopulatory processes affect MHC haplotype combination in offspring, but do not prevent low MHC heterozygosity.