Wasted efforts impair random search efficiency and reduce choosiness in mate-pairing termites

Abstract

Random search theories predict that animals employ movement patterns that optimize encounter rates with target resources. However, animals are not always able to achieve the best search strategy. Energy depletion, for example, limits searchers movement activities, forcing them to adjust their behaviors before and after encounters. Here, we quantified the cost of mate search in a termite, Reticulitermes speratus, and revealed that the searching cost reduces the selectivity of mating partners. After a dispersal flight, termites search for a mating partner with limited reserved energy. We found that their movement activity and diffusiveness progressively declined over extended mate search. Our data-based simulations qualitatively confirmed that the reduced movement diffusiveness decreased the searching efficiency. Also, prolonged search periods reduced colony foundation success and the number of offspring. Thus, mate search imposes doubled costs on termites. Finally, we found that termites with an extended mate search reduced the selectivity of mating partners, where males immediately paired with any encountering females. Thus, termites dramatically changed their mate search behavior depending on their physiological conditions. Our finding highlights that accounting for the searchers internal states is essential to fill the gap between random search theories and empirical behavioral observations.