How helpers help themselves: alloparental care in the African striped mouse (#516)
Alloparental care includes all behaviours
performed by a non-parent that benefit non-descendent offspring. Alloparental
care occurs in a variety of taxa and the functional benefits to both the helper
and the receiving offspring have been relatively well studied. Alloparental care
varies with the age and/or experience of the helper, showing phenotypic plasticity
of helping. However, it is unknown whether parents respond to these
developmental changes of helpers and little is known about whether alloparents
develop and enhance other behavioural phenotypes as a consequence of helping. Our
current research focuses on these issues in the African striped mouse Rhabdomys pumilio from the Succulent
Karoo of South Africa. Rhabdomys pumilio is a facultatively group-living
species, in which offspring overwinter in the group nest and provide
alloparental care to their younger siblings. Our research has provided two sets
of important findings. Firstly, daughters alter the level of alloparental care
provided as they age, which is independent of their experience of providing
care. Sub-adult daughter helpers alleviate their mother’s workload, which
impacts on the development of paternal care in their younger brothers which
they help raise. In contrast, the contribution of juvenile philopatric
daughters to alloparental care is marginal because they do not alleviate
maternal workload and do not appear to contribute to their younger siblings’
behavioural development. Secondly, female alloparents show enhanced spatial
memory, reduced anxiety in novel environments and better competitive ability
compared to non-alloparents. This suggests that, by providing alloparental
care, female alloparents can improve their own ability to locate resources
while improving their own parental skills. Our findings indicate that
alloparental care leads to dynamic responses by parents and potentially provides direct fitness benefits for alloparents.