Culling-Induced Changes in Badger (Meles meles) Behaviour, Social Organisation and the Epidemiology of Bovine Tuberculosis

In the UK, attempts since the 1970s to control the incidence of bovine tuberculosis (bTB) in cattle by culling a wildlife host, the European badger (Meles meles), have produced equivocal results. Culling-induced social perturbation of badger populations may lead to unexpected outcomes. We test predictions from the ‘perturbation hypothesis’, determining the impact of culling operations on badger populations, movement of surviving individuals and the influence on the epidemiology of bTB in badgers using data dervied from two study areas within the UK Government's Randomised Badger Culling Trial (RBCT). Culling operations did not remove all individuals from setts, with between 34–43% of badgers removed from targeted social groups. After culling, bTB prevalence increased in badger social groups neighbouring removals, particularly amongst cubs. Seventy individual adult badgers were fitted with radio-collars, yielding 8,311 locational fixes from both sites between November 2001 and December 2003. Home range areas of animals surviving within removed groups increased by 43.5% in response to culling. Overlap between summer ranges of individuals from Neighbouring social groups in the treatment population increased by 73.3% in response to culling. The movement rate of individuals between social groups was low, but increased after culling, in Removed and Neighbouring social groups. Increased bTB prevalence in Neighbouring groups was associated with badger movements both into and out of these groups, although none of the moving individuals themselves tested positive for bTB. Significant increases in both the frequency of individual badger movements between groups and the emergence of bTB were observed in response to culling. However, no direct evidence was found to link the two phenomena. We hypothesise that the social disruption caused by culling may not only increase direct contact and thus disease transmission between surviving badgers, but may also increase social stress within the surviving population, causing immunosuppression and enhancing the expression of disease

Mother-male bond, but not paternity, influences male-infant affiliation in wild crested macaques

In promiscuous primates, interactions between adult males and infants have rarely been investigated. However, recent evidence suggests that male affiliation towards infants has an influence on several aspects of the infants’ life. Furthermore, affiliations may be associated with male reproductive strategy. In this study, we examined which social factors influenced male-infant affiliation initiated by either male or infant, in wild crested macaques (Macaca nigra). We combined behavioral data and genetic paternity analysis from 30 infants living in three wild groups in Tangkoko Reserve, Indonesia. Our results indicate that adult males and infants do not interact at random, but rather form preferential associations. The social factors with the highest influence on infant-initiated interactions were male rank and male association with the infant’s mother. While infants initiated affiliations with males more often in the absence of their mothers, adult males initiated more affiliations with infants when their mothers were present. Furthermore, males initiated affiliations more often when they were in the same group at the time the infant was conceived, when they held a high dominance rank or when they had a close relationship with the mother. Interestingly, paternity did not affect male-infant affiliation despite being highly skewed in this species. Overall, our results suggest that adult males potentially associate with an infant to secure future mating with the mother. Infants are more likely to associate with a male to receive better support, suggesting a strategy to increase the chance of infant survival in a primate society with high infant mortality

Disease: A Hitherto Unexplored Constraint on the Spread of Dogs (Canis lupus familiaris) in Pre-Columbian South America

Although debate continues, there is agreement that dogs (Canis lupus familiaris) were first domesticated in Eurasia, spreading from there to other parts of the world. However, while that expansion already extended as far as Europe, China, and North America by the early Holocene, dogs spread into (and south of) the tropics only much later. In South America, for example, the earliest well attested instances of their presence do not reach back much beyond 3000 cal. BC, and dogs were still absent from large parts of the continent – Amazonia, the Gran Chaco, and much of the Southern Cone – at European contact. Previous explanations for these patterns have focused on cultural choice, the unsuitability of dogs for hunting certain kinds of tropical forest prey, and otherwise unspecified environmental hazards, while acknowledging that Neotropical lowland forests witness high rates of canine mortality. Building on previous work in Sub-Saharan Africa (Mitchell 2015) and noting that the dog’s closest relatives, the grey wolf (C. lupus) and the coyote (C. latrans), were likewise absent from South and most of Central America in Pre- Columbian times, this paper explores instead the possibility that infectious disease constrained the spread of dogs into Neotropical environments. Four diseases are considered, all likely to be native and/or endemic to South America: canine distemper, canine trypanosomiasis, canine rangeliosis, and canine visceral leishmaniasis caused by infection with Leishmania amazonensis and L. colombiensis. The paper concludes by suggesting ways in which the hypothesis that disease constrained the expansion of dogs into South America can be developed further