Linking female infidelity with social context

Infidelity is common among many taxa with prevailing social monogamy, but we still do not know what shapes variation in and drives the evolution of, extra-pair behaviour. Males are expected to reap fitness benefits from siring extra-pair offspring because extra-pair fathers do not expend resources on costly parental care. This is, however, not the case for females who raise the resulting extra-pair young, posing the question of why females take part in extra-pair mating. A hypothesis that recently gained traction is that the social environment might play an important role, yet this is crucially understudied.
I will aim to test whether the social context is linked to extra-pair behaviour, in House Sparrow at two closed study systems: a wild population on Lundy island, Devon, UK, and another captive population held in aviaries at Silwood park, Imperial College London. Social behaviour (in this case, social associations with member of a breeding pair, an extra-pair mate or a potential extra pair mate) will be identified through observed individually colour marked birds, and passive radio frequency identification (RFID) at feeding stations. From this data I will then construct social networks which, in their most basic form, connect nodes (individual birds) to one and other based on the binary state of associated, or not associated (i.e. through contact or presence in the same space at the same time). The identification of extra-pair fertilisation will be inferred from the genetic parentage of nestlings, where the breeding pair have been identified.
This project will reap the benefits from long-term data in the wild, where precise fitness data and a genetic pedigree allow fitness costs and benefits to be measured, and quantitative genetic analyses.

This project will seek to address the following questions;
1) Is there a specific socio-behavioural phenotype more closely associated with female EPP? (i.e. bold, shy, etc.)

2) Are the off-spring of successful EPF attempts more likely to engage in EPP? (i.e. through the inheritance of X behavioural phenotype from parents)

3) To what extent do social cues from others within a population (those where EPP Is high, or absent) affect the occurrence of EPP as a meta-trait? (influenced by others within the population)

Given the long-standing conundrum of female extra-pair behaviour, this project has the potential forward this field significantly. Methodologically, using social network analysis to test hypotheses in evolutionary biology is not straightforward, because data points are relational and thus not independent. This studentship will explore recent suggestions of randomization for social network analysis in behavioural ecology and develop respective tools for quantitative genetic analyses.