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Ecogeographical rules linking climate to morphology have gained renewed interest because of climate change. Yet few studies have evaluated to what extent geographical trends ascribed to these rules have a genetic, rather than environmentally determined, basis. This applies especially to Allen's rule, which states that the relative extremity length decreases with increasing latitude. We studied leg length in the common frog (Rana temporaria) along a 1500 km latitudinal gradient utilizing wild and common garden data. In the wild, the body size-corrected femur and tibia lengths did not conform to Allen's rule but peaked at mid-latitudes. However, the ratio of femur to tibia length increased in the north, and the common garden data revealed a genetic cline consistent with Allen's rule in some trait and treatment combinations. While selection may have shortened the leg length in the north, the genetic trend seems to be partially masked by environmental effects.

When faced with the risk of predation, tadpoles of many amphibian species are known to modify their phenotype. In this work we studied the effect of an exotic species, the red swamp crayfish (Procambarus clarkii), on the phenotype of two species of amphibians with different reproduction habitats: the Iberian painted frog, Discoglossus galganoi, that normally reproduces in temporary water bodies and the common toad, Bufo bufo, that reproduces in permanent water bodies. The responses were compared with the ones shown in the presence of a native predator, dragonfly (Aeshnidae) larvae. Behaviour, growth and morphology of tadpoles were monitored in a factorial experiment with five treatments. Our results showed that only the permanent habitat species altered its behaviour and life-history traits in the presence of P. clarkii; however, this was mediated by chemical cues from consumed conspecifics. Antipredator responses of B. bufo towards the exotic crayfish were similar to the ones towards the native predator, while D. galganoi responded to the dragonfly larvae but not to P. clarkii. This may be the result of infrequent colonization events of temporary habitats by the crayfish. Therefore, the consequences of the introduction of P. clarkii might be more serious for D. galganoi and other species living in temporary habitats. Species breeding in permanent habitats, more prone to having generalized antipredator responses, may be relatively protected against this exotic crayfish although the effectiveness of these responses still needs to be tested.

Group-living sets the scene for complex social behaviours such as cooperative breeding, and exploring the factors that shape group-living is crucial in understanding these behaviours. This thesis explores the ecology of a population of the facultative cooperative breeding southern anteater-chat (Myrmecocichla formicivora), a group-living bird species endemic to southern Africa. It reveals a breeding system based around a breeding pair and up to three auxiliary males. Despite equal numbers of males and females produced as fledglings there was a surplus of adult males, which remained philopatric. Dispersal was strongly female biased. Females dispersed within their first year, they dispersed further than males, and they lost the benefits of the natal site. The sex skew in the population suggested that these factors drive differential mortality, with juvenile females having much lower annual survival than juvenile males. Adult survival was higher, with female survival only slightly lower than male survival. Dispersal distances suggested that males selected the breeding location, nearer to their natal site. There was no evidence of surplus non-breeding females. On the loss of a breeding female there was no replacement until new females entered the population, yet if a breeding male disappeared the female promptly re-paired with a male from another group. There was no indication of birds floating in the population, and if males were orphaned or widowed they joined other groups as unrelated helpers in preference to floating. There was no sign of inter-group or individual aggression among chats, and unrelated helpers were peacefully accepted into groups, suggesting mutual benefits. In fact all birds in a group helped raise offspring of the breeding pair, and groups with more helpers fledged more offspring, which implies that both direct and indirect fitness benefits can be gained through joining a group and helping. There was surprisingly little inheritance of breeding position by auxiliaries, and strikingly low levels of extra-pair paternity. This study suggests that the Southern anteater-chat group structure arises through male philopatry due to a shortage of breeding females, the benefits of remaining on the natal site and helping, and the potentially high costs of living alone.

Dispersal choice is important in understanding population structure and dynamics. Here we examine male choice in the facultative cooperative breeding southern anteater-chat Myrmecocichla formicivora based on a four year study in South Africa. The sex ratio in our study population was male biased, with many males remaining philopatric. All groups consisted of one or more adult males associated with one adult female. We found a significant positive effect of auxiliary number on group productivity (both number of young fledged, and first year survival), while controlling for potentially confounding variables (territory and breeder identity). The majority of auxiliaries, 54%, were related to both birds in the breeding pair, with another 25% related to one member of the pair, and 21% related to neither of the breeders. There was no evidence of males floating within our study population, and it appears that if males lose their family due to mortality they join other groups as unrelated non-breeding auxiliaries rather than float. No aggression was observed between individual southern anteater-chats, and unrelated group members helped rear offspring in the group they had joined. Despite the presence of, and helping by unrelated group members there was very little evidence of breeding position inheritance (1/24 auxiliaries unrelated to the breeding female) or extra-pair paternity (2.4% of fledglings). This study suggests that the southern anteater-chat group structure arises through male philopatry due to a lack of breeding females and potentially high costs of living alone.

Sex biased dispersal is a crucial factor in understanding the mechanism of family dynamics in many cooperative breeders. Female biased dispersal occurs in many cooperatively breeding birds. It is often associated with females dispersing earlier and further, and a male biased sex skew in the population. Here we investigated female dispersal in the southern anteater-chat, a facultative cooperatively breeding passerine of southern Africa. Our study population had a male biased sex skew, and females had lower annual survival than males. Dispersal was strongly female biased, with females dispersing within their first year whereas many males remained philopatric beyond the next breeding season. Breeding females were on average younger than breeding males, and also dispersed further. Each breeding group contained only one female. No females were found floating in the population, and all females were associated with one or more males in a breeding group. It appears that all females disperse in their first year directly to a breeding position. If a female disappeared in the breeding season they were not replaced until new females matured and dispersed the following season, yet if a male breeder disappeared during the breeding season he was almost immediately replaced, indicating that there are no surplus females.

We tested the cross amplification of 37 microsatellite markers for their suitability in genotyping the southern anteater-chat Myrmecocichla formicivora, an opportunistic cooperatively breeding passerine bird endemic to southern Africa. Fourteen microsatellite markers were identified as having suitable characteristics, with minor deviation from Hardy-Weinberg equilibrium and little evidence of null alleles. These 14 Primer pairs were combined in 4 multiplexes and run on 183 individual samples from our study population of southern anteater-chat on Benfontein Nature Reserve, near Kimberley in central South Africa. The loci ranged from 3-34 alleles per locus, and observed heterozygosity ranged from 0.45 -0.93. We then tested these 14 microsatellites for their use in examining paternity in a population of southern anteater-chat being studied on Benfontein Nature Reserve, near Kimberley in South Africa. Of the population of 183 individuals (the 2011 population) 93% of the offspring could be allocated a mother, 97% a father, and 87% a parent pair with 95% confidence. The remainder could be allocated at the 80% confidence level. Where mothers could be assigned from observations this was in 100% agreement with the microsatellite results, giving us good support for the accurate assignment of parentage in our population.