Kinship and its consequences in the cooperatively breeding southern pied babbler Turdoides bicolor

Includes abstract.Includes bibliographical references (p. 119-132).Cooperative breeding occurs when more than two individuals help to raise offspring that are not their own, and has been the focus of empirical and theoretical research for over forty years. Of central importance to this work are the fitness costs and benefits of helping, and the factors limiting the reproduction of helpers. To understand these, the genetic relationship between individuals must be known. In this thesis, I use genetic and observational data to explore kinship between individuals in groups of wild Southern Pied Babblers Turdoides bicolor

Kinship, dear enemies, and costly combat:The effects of relatedness on territorial overlap and aggression in a cooperative breeder

Many species maintain territories, but the degree of overlap between territories and the level of aggression displayed in territorial conflicts can vary widely, even within species. Greater territorial overlap may occur when neighboring territory holders are close relatives. Animals may also differentiate neighbors from strangers, with more familiar neighbors eliciting less‐aggressive responses during territorial conflicts (the “dear enemy” effect). However, research is lacking in how both kinship and overlap affect territorial conflicts, especially in group‐living species. Here, we investigate kinship, territorial overlap, and territorial conflict in a habituated wild population of group‐living cooperatively breeding birds, the southern pied babbler Turdoides bicolor. We find that close kin neighbors are beneficial. Territories overlap more when neighboring groups are close kin, and these larger overlaps with kin confer larger territories (an effect not seen for overlaps with unrelated groups). Overall, territorial conflict is costly, causing significant decreases in body mass, but conflicts with kin are shorter than those conducted with nonkin. Conflicts with more familiar unrelated neighbors are also shorter, indicating these neighbors are “dear enemies.” However, kinship modulates the “dear enemy” effect; even when kin are encountered less frequently, kin elicit less‐aggressive responses, similar to the “dear enemy” effect. Kin selection appears to be a main influence on territorial behavior in this species. Groups derive kin‐selected benefits from decreased conflicts and maintain larger territories when overlapping with kin, though not when overlapping with nonkin. More generally, it is possible that kinship extends the “dear enemy” effect in animal societies

Immune genotypes, immune responses, and survival in a wild bird population

ACKNOWLEDGEMENTS We thank the Tsawout and Tseycum bands for allowing us to conduct research on Mandarte Island, and to the many contributors to long-term monitoring, especially L. Keller, P. Nietlisbach, and J. Krippel. We also thank C. Ritland, A. Miscampbell, and G. Huber for their assistance in the laboratory. All work was conducted under permit of the Canadian Wildlife Service and UBC Animal Care Committee. Funding Information: This study was generously supported by the Natural Sciences and Engineering Research Council of Canada via a Post‐doctoral Fellowship award to MJNF (PDF‐2014–454522) and a Discovery Grant to EAMS.Peer reviewedPublisher PD

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Data from: Sex differences in the drivers of reproductive skew in a cooperative breeder

Many cooperatively breeding societies are characterized by high reproductive skew, such that some socially dominant individuals breed, while socially subordinate individuals provide help. Inbreeding avoidance serves as a source of reproductive skew in many high-skew societies, but few empirical studies have examined sources of skew operating alongside inbreeding avoidance, or compared individual attempts to reproduce (reproductive competition) with individual reproductive success. Here we use long-term genetic and observational data to examine factors affecting reproductive skew in the high-skew cooperatively breeding southern pied babbler (Turdoides bicolor). When subordinates can breed, skew remains high, suggesting factors additional to inbreeding avoidance drive skew. Subordinate females are more likely to compete to breed when older or when ecological constraints on dispersal are high, but heavy subordinate females are more likely to successfully breed. Subordinate males are more likely to compete when they are older, during high ecological constraints, or when they are related to the dominant male, but only the presence of within-group unrelated subordinate females predicts subordinate male breeding success. Reproductive skew is not driven by reproductive effort, but by forces such as intrinsic physical limitations and intra-sexual conflict (for females), or female mate choice, male mate-guarding and potentially reproductive restraint (for males). Ecological conditions or ‘outside options’ affect the occurrence of reproductive conflict, supporting predictions of recent synthetic skew models. Inbreeding avoidance together with competition for access to reproduction may generate high skew in animal societies, and disparate processes may be operating to maintain male vs. female reproductive skew in the same species

The Cost of being alone : the fate of floaters in a population of cooperatively breeding pied babblers

The occurrence of group-living behaviour has often been explained by the benefits individuals receive through cooperation; including increased reproductive output, vigilance against predators, and load-lightening behaviour. However, to fully understand the benefits of group-living, it is important to quantify the costs of living alone. Here, we look at the fate of floaters (individuals who have no fixed territory and remain alone for extended periods) in a population of cooperatively breeding pied babblers Turdoides bicolor. We found that individuals spent less time foraging and more time vigilant for predators when found as a floater compared to when they were in a group. Consequently, they suffered a continuous loss of body mass, with long-term floaters suffering the highest losses. This had a long-term effect: floaters that eventually did regain a position in a group usually entered as helpers, in contrast to dispersers, who usually entered a new group as breeders. This high cost of living alone highlights the benefits of group-living and may help to understand patterns of delayed dispersal in some social species.4 page(s

Data from: Individual dispersal decisions in a cooperative breeder: ecological constraints, the benefits of philopatry, and the social queue for dominance

1. Delayed dispersal is a key step in the evolution of familial animal societies and cooperative breeding. However, no consensus has been reached on the ecological and social circumstances driving delayed dispersal. 2. Here we test predictions from the ecological constraints and benefits of philopatry hypotheses as well as the recently-proposed dual benefits hypothesis to better understand the evolution of group-living and cooperative breeding. Furthermore, we consider how individual social circumstances within groups affect dispersal decisions. 3. We examine 11 years of life-history information on a wild population of cooperatively breeding southern pied babblers (Turdoides bicolor). We investigate the effects of ecological conditions, natal-group membership and individual social context on male and female dispersal delays, disperser survival and acquisition of dominance. 4. Female dispersal decisions are generally unconstrained by ecological or social circumstances. In contrast, males disperse in response to relaxed ecological constraints, decreases in nepotistic tolerance, or when low social rank in the queue for dominance decreases their likelihood of gaining a dominant breeding position. Early dispersal by end-of-queue males often leads to a head-of-queue subordinate position in a non-natal group, thereby increasing access to dominant breeding positions. However, males and females remaining in natal groups gain benefits of philopatry via increased survival and, for head-of-queue males, very high likelihood of acquisition of a breeding position. 5. Overall, predictions from the dual benefits hypothesis best describe these results, while some predictions from each of the ecological constraints and benefits of philopatry hypotheses were supported. The benefits of living and working together (collective action benefits) in large stable groups are of central importance in shaping dispersal delays in southern pied babbler societies. In addition, position in the subordinate social queue for dominance is key in determining access to reproduction, particularly for males. This research highlights the importance of considering the costs and benefits of individual social circumstances in dispersal decisions and illustrates how the dual benefits hypothesis offers new perspectives in understanding delayed dispersal

Is sentinel behaviour safe? An experimental investigation

Sentinel behaviour, where individuals take turns to watch for danger and give alarm calls to approaching predators, has been observed in a number of animal societies. However, the evolutionary causes of this behaviour remain unclear. There are two main, competing hypotheses regarding the evolution of sentinel behaviour. The first hypothesis is that it is a cooperative behaviour, where group members benefit from the detection of danger but share the workload of acting as a sentinel. The second is that it is a safe, selfish behaviour. Under the second hypothesis, once an individual is satiated, being a sentinel is safer because sentinels can detect threats more readily and can therefore escape from predators faster. We examined whether sentinels are safer than foragers in a wild, free-living cooperative bird (the pied babbler, Turdoides bicolor) with a well-described sentinel system. We found that sentinel behaviour was costly because (1) sentinels were targeted by predators more often, (2) they were further from cover than foragers, and (3) they took longer to reach the safety of cover following a predator alarm. These results suggest that individuals do not become sentinels because it is safer. This is the first study to demonstrate that sentinels are at greater risk of predator attack than foraging group members and suggests sentinel activity may have evolved as a form of cooperative behaviour.6 page(s

Routes to breeding in cooperatively breeding pied babblers Turdoides bicolor

In cooperatively breeding and other family living species, there are often more individuals of reproductive age than available breeding positions. Asking how individuals attain reproductive status is therefore crucial if we are to understand the selection pressures that operate in these groups. Here, we present data on routes to breeding in pied babblers Turdoides bicolor, cooperatively breeding passerines from the Kalahari Desert. Individuals of both sexes remained on the natal territory into adulthood, despite being relatively unlikely to breed there. Instead, individuals seemed to use the natal territory as a base to monitor the availability of breeding positions elsewhere. Both sexes were most likely to attain breeding status by moving into vacant breeding positions on non-natal territories, although females also occasionally seized breeding positions by overthrowing breeding females on foreign territories. We discuss these patterns in the context of existing theoretical and empirical data.6 page(s