Behaviour 2019
Effects of Environment, Genes, and Evolution on Nest Architecture  
Eva S Horna Lowell, Sean R O'Fallon, Doug A Daniels, Noa M Pinter-Wollman. University of California Los Angeles , Los Angeles, California, United States

An animal’s genes, environment, and evolutionary history each contribute to the expression of behavior. Nest architecture is an extended phenotype of ant colonies that results from a dynamic interaction between the environment and collective building behavior. Nest architecture differs among ant species and among colonies within a species, but the source of these differences remains an open question. To investigate the impact of colony identity (genetics), species (evolutionary history), and the environment on nest architecture, we compared how two species of harvester ants construct their nest in different environmental conditions. We allowed workers from four colonies to excavate nests in environments differing in temperature and humidity, then created and quantified casts of each nest. Our results reveal differences in nest structure among colonies of the same species and between species. Environmental conditions did not strongly influence nest structure in either species. Our results suggest extended phenotypes are shaped more strongly by genes and evolutionary history and are less plastic in response to the abiotic environment, like many physical and physiological phenotypes.