Adoption in African wild dogs, Lycaon pictus

Parental care of unrelated young is occasionally misdirected and maladaptive from an individual fitness perspective (e.g. interspecific brood parasitism). Alternatively, adults may'adopt'dependent young and gain direct benefits irrespective of the degree of relatedness. For social species whose fitness is partially a function of group size, direct benefits of increasing group size may provide a mechanism favouring adoption independently of the inclusive fitness consequences. African wild dogs. Lycaon pictus , are social carnivores for which group size has been positively crrelated with reproductive success and competitive ability. Co-operative breeding by wild dogs has been described previously as strongly kin-selected and helpers were assumed to be invariably closely related to offspring. However, observations from this study show that the assumption that helpers are related to those they help is not always valid. A minimum of 25% of study area packs ( n =12) contained nonbreeding adults that provided parental care for unrelated pups. Costs of adopting unrelated weaned wild dog pups are slight or nonexistent except for delayed costs due to later potential conflict with mature same-sex adoptees over access to mates. Immediate and delayed direct benefits identified here are associated with increasing group size and may indicate important mechanisms underlyig adoption and the evolution of helping behaviour in wild dogs.     

Birth and simultaneous rearing of two litters in a pack of captive African wild dogs (Lycaon pictus)

Two female African wild dogs (Lycaon pictus) in a pack of 10 animals at the Bronx Zoo gave birth to litters of nine and seven pups within a 2‐day period. Two pups from the litter of seven died before they were 2 weeks old, but the other 14 survived past weaning. Litter size, sex ratio, and pup developmental stages were all consistent with data obtained from other captive‐ and wild‐born litters. Both dams were very attentive to their litters, and during the pups' first 2 weeks spent >90% of their time in the dens with the pups. By 2 days after birth and during their first 2 weeks of life, the pups spent 86% of their time in a nursing position. Before parturition and during the first week post‐partum, one of the dams (DAL) was clearly dominant to the other (WHI). However, the females' dominance rank reversed 2 weeks post‐partum. On two occasions during the pups' first 2 weeks DAL stole and reared one of WHI's pups, but between Weeks 3 and 4 all of DAL's pups were stolen and WHI raised both litters as one until they were weaned. The pups began spending time out of their den at approximately 1 month of age. The timing of the births, the design of the wild dogs' management facility, and the presence of several dens in different enclosures within the facility all likely contributed to the successful rearing of the litters. The pups in both litters were very similar in size because of the short interval between births, so one litter did not have a competitive advantage over the other with respect to gaining access to the dam for milk. The facility's design helped mitigate aggression within the pack, and the presence of multiple dens enabled to dams to move the pups to different den sites and allowed the two females to stay visually and spatially apart from each other while remaining with the pack. Zoo Biol 0:1–17, 2006. © 2006 Wiley‐Liss, Inc.     

The effects of anthrax on endangered African wild dogs (Lycaon pictus)

African wild dogs ( Lycaon pictus ) are large, social canids formerly found throughout sub-Saharan Africa. Wild dogs are now endangered; only six nations hold populations larger than 100 individuals. Considerable evidence suggests that disease plays a central role in the regulation of some wild dog populations. In particular, it has been suggested that epizootics of rabies, canine distemper and anthrax can have strong local effects on wild dog numbers. Resolution of the regulatory importance of these diseases has been hampered by lack of data from wild populations. Here we report on an outbreak of anthrax among wild dogs in the Selous Game Reserve in southern Tanzania, describing clinical signs and diagnosis, measuring mortality, and testing for effects on hunting success and movements. Only one of five packs under study was affected. Immediate mortality was mild, with none of 18 adults (0%) and four of 24 pups (17%) dying. Mortality was significantly higher among puppies (<1 year old) than among adults. Mortality of individuals that showed signs of disease but did not die immediately was not significantly elevated over the following six months. The hunting success and movement patterns of the pack were not affected by the outbreak. Collectively, these data suggest that African wild dogs possess a degree of resistance to anthrax.     

Contact with domestic dogs increases pathogen exposure in endangered African wild dogs (Lycaon pictus)

Background

Infectious diseases have contributed to the decline and local extinction of several wildlife species, including African wild dogs (Lycaon pictus). Mitigating such disease threats is challenging, partly because uncertainty about disease dynamics makes it difficult to identify the best management approaches. Serious impacts on susceptible populations most frequently occur when generalist pathogens are maintained within populations of abundant (often domestic) “reservoir” hosts, and spill over into less abundant host species. If this is the case, disease control directed at the reservoir host might be most appropriate. However, pathogen transmission within threatened host populations may also be important, and may not be controllable by managing another host species.

Methodology/Principal Findings

We investigated interspecific and intraspecific transmission routes, by comparing African wild dogs'' exposure to six canine pathogens with behavioural measures of their opportunities for contact with domestic dogs and with other wild dogs. Domestic dog contact was associated with exposure to canine parvovirus, Ehrlichia canis, Neospora caninum and perhaps rabies virus, but not with exposure to canine distemper virus or canine coronavirus. Contact with other wild dogs appeared not to increase the risk of exposure to any of the pathogens.

Conclusions/Significance

These findings, combined with other data, suggest that management directed at domestic dogs might help to protect wild dog populations from rabies virus, but not from canine distemper virus. However, further analyses are needed to determine the management approaches – including no intervention – which are most appropriate for each pathogen.     

Distemper-like disease and encephalitozoonosis in wild dogs (Lycaon pictus)

Clinical signs of a fatal disease resembling those of canine distemper were observed in two groups of captive wild dog (Lycaon pictus) pups 13 days after vaccination with a commercially available combination vaccine for dogs which contained a live attenuated strain of canine distemper virus. Histopathological examination of tissues revealed the presence of intranuclear inclusion bodies in neurons and lesions resembling canine distemper as well as colonies of an Encephalitozoon sp. in the central nervous system and kidneys. Lesions were observed in both organs which resembled those described in other species infected with Encephalitozoon cuniculi.     

Inbreeding, heterozygosity and fitness in a reintroduced population of endangered African wild dogs (Lycaon pictus)

It is crucial to understand the genetic health and implications of inbreeding in wildlife populations, especially of vulnerable species. Using extensive demographic and genetic data, we investigated the relationships among pedigree inbreeding coefficients, metrics of molecular heterozygosity and fitness for a large population of endangered African wild dogs (Lycaon pictus) in South Africa. Molecular metrics based on 19 microsatellite loci were significantly, but modestly correlated to inbreeding coefficients in this population. Inbred wild dogs with inbreeding coefficients of ??0.25 and subordinate individuals had shorter lifespans than outbred and dominant contemporaries, suggesting some deleterious effects of inbreeding. However, this trend was confounded by pack-specific effects as many inbred individuals originated from a single large pack. Despite wild dogs being endangered and existing in small populations, findings within our sample population indicated that molecular metrics were not robust predictors in models of fitness based on breeding pack formation, dominance, reproductive success or lifespan of individuals. Nonetheless, our approach has generated a vital database for future comparative studies to examine these relationships over longer periods of time. Such detailed assessments are essential given knowledge that wild canids can be highly vulnerable to inbreeding effects over a few short generations.     

Inbreeding avoidance influences the viability of reintroduced populations of African wild dogs (Lycaon pictus)

The conservation of many fragmented and small populations of endangered African wild dogs (Lycaon pictus) relies on understanding the natural processes affecting genetic diversity, demographics, and future viability. We used extensive behavioural, life-history, and genetic data from reintroduced African wild dogs in South Africa to (1) test for inbreeding avoidance via mate selection and (2) model the potential consequences of avoidance on population persistence. Results suggested that wild dogs avoided mating with kin. Inbreeding was rare in natal packs, after reproductive vacancies, and between sibling cohorts (observed on 0.8%, 12.5%, and 3.8% of occasions, respectively). Only one of the six (16.7%) breeding pairs confirmed as third-order (or closer) kin consisted of animals that were familiar with each other, while no other paired individuals had any prior association. Computer-simulated populations allowed to experience inbreeding had only a 1.6% probability of extinction within 100 years, whereas all populations avoiding incestuous matings became extinct due to the absence of unrelated mates. Populations that avoided mating with first-order relatives became extinct after 63 years compared with persistence of 37 and 19 years for those also prevented from second-order and third-order matings, respectively. Although stronger inbreeding avoidance maintains significantly more genetic variation, our results demonstrate the potentially severe demographic impacts of reduced numbers of suitable mates on the future viability of small, isolated wild dog populations. The rapid rate of population decline suggests that extinction may occur before inbreeding depression is observed.     

Evolutionary ecology meets wildlife management: artificial group augmentation in the re-introduction of endangered African wild dogs (Lycaon pictus)

As an alternative to kin selection, group augmentation theory provides a framework for evolutionary mechanisms maintaining cooperative breeding when individual fitness is positively related to group size. It is expected that a cooperator group would accept or adopt unrelated foreigners when it is below a critical threshold size and group members could thus benefit from recruiting additional helpers. In re-introduction attempts, this would allow for a group to be augmented artificially before release, which would enhance its chance to establish itself successfully in the release area. This possibility was tested using endangered African wild dogs Lycaon pictus studied in Hluhluwe-iMfolozi Park, South Africa. Here, we report on the first successful artificial integration of an unrelated adult female with her three male pups into an existing pack. In addition, post-release monitoring data are presented, including how a yearling male displaced the dominant male that adopted him as a pup, adding to the controversy over the evolutionary stability of group augmentation as a route to cooperative breeding. This study thus demonstrates how theory from evolutionary ecology can be applied to practical wildlife management, and vice versa.     

Patterns of population subdivision, gene flow and genetic variability in the African wild dog (Lycaon pictus)

African wild dogs are large, highly mobile carnivores that are known to disperse over considerable distances and are rare throughout much of their geographical range. Consequently, genetic variation within and differentiation between geographically separated populations is predicted to be minimal. We determined the genetic diversity of mitochondrial DNA (mtDNA) control region sequences and microsatellite loci in seven populations of African wild dogs. Analysis of mtDNA nucleotide diversity suggests that, historically, wild dog populations have been small relative to other large carnivores. However, population declines due to recent habitat loss have not caused a dramatic reduction in genetic diversity. We found one historical and eight recent mtDNA genotypes in 280 individuals that defined two highly divergent clades. In contrast to a previous, more limited, mtDNA analysis, sequences from these clades are not geographically restricted to eastern or southern African populations. Rather, we found a large admixture zone spanning populations from Botswana, Zimbabwe and south-eastern Tanzania. Mitochondrial and microsatellite differentiation between populations was significant and unique mtDNA genotypes and alleles characterized the populations. However, gene flow estimates (Nm) based on microsatellite data were generally greater than one migrant per generation. In contrast, gene flow estimates based on the mtDNA control region were lower than expected given differences in the mode of inheritance of mitochondrial and nuclear markers which suggests a male bias in long-distance dispersal.