Interactions among species in a tri-trophic system: the influence of ants on the distribution of the Sinai Baton Blue butterfly

Abstract

Metapopulation dynamics is now so widely used to describe the distribution and abundance of species living in fragmented landscapes that other ecological factors (e.g. habitat quality) can be overlooked. To determine the precise habitat requirements of an endangered and narrowly endemic lycaenid butterfly, I studied its distribution within a patch of habitat, examining the effects of hostplant choice on larval survival. Ovipositing females were selective in the hostplants chosen: they selected a brief stage of flower-bud development, and preferred plants with many inflorescences. The distribution of surviving larvae was positively correlated to the presence of an attendant ant, suggesting that this ant caused their distribution. However, closer examination of the interactions occurring among species within the tri-trophic system revealed that another species of ant exerted a much stronger influence on larval survival and therefore the distribution of newly eclosed adults.