I am interested broadly in maternal investment in offspring, how levels of investment may alter over time and in response to other variables, and how maternal investment may trade off with investment from other individuals – in the case of the meerkat, from subordinate helpers.

My PhD (so far!) is divided into two areas of research: offspring sex ratio variation, and allolactation.

1.   Adaptive offspring sex ratio variation is seen throughout the animal kingdom, and has led to the development of a number of influential theories – for example, the Trivers-Willard hypothesis, which suggests that individuals may adjust the sex ratio of their offspring according to their environmental conditions and fitness.

The meerkat fits the basic assumptions of this model, indicating that there is the potential for facultative sex ratio adjustment in this species. The meerkat’s complex life history and social structure introduces a host of factors that will affect the relative costs and benefits of producing male and female offspring at any point in the female’s life history trajectory, making the study of sex allocation in this species complicated – but fascinating!

Variation in litter sex ratio also varies the level of androgen exposure offspring experience in utero. How will this affect their growth and development? I am particularly interested in how such variation in early experience could influence key tendencies in the meerkat behavioural phenotype – towards cooperation, or aggression.

2.   Allolactation is the nursing by a female of pups that are not her own. This is seen in a variety of species throughout the animal kingdom – and in the meerkat. What factors determine whether a female will invest costly resources in this extreme example of cooperation? I aim to investigate what influences the decision to allolactate, and how much females invest. I also will look at how investment in allolactation affects a female’s investment in other cooperative behaviours, and what costs and benefits are associated with this behaviour.

Answering these questions will involve detailed analysis of the long-term database, hormonal analysis, and behavioural observation and experiments at the Kalahari Meerkat Project.