Tag: Indonesia

This blog was first published on #theBOUblog. Check it out at https://www.bou.org.uk/blog-oconnell-olive-backed-sunbird-sexual-dimorphism/

Going right back to the time of Darwin, competition has always been seen as a driver of evolution. When we think of natural selection we often think of hyaenas and lions fighting it out on the plains of Africa, or a pack of wolves hassling a bear over a carcass. Resource competition like this is a daily part of survival for most animals, with a delicate balance of power between competitors which can change in different environments. However competition for resources takes place not only between species (interspecific competition), but within them (intraspecific competition), and often this is where competition is at its most fierce. Sexually dimorphic species present a special case when studying competition in different environments. They are species where the males and females are physically different, often in body size, but also in colouration and other characteristics. Males and females in sexually dimorphic species often occupy different but interlinked ecological niches. If intraspecific competition becomes more intense within a population of a sexually dimorphic species then one sex may suffer more than the other due to being smaller. In our recent paper in Emu – Austral Ornithology we report on one such case with a niche contraction in female Olive-backed Sunbirds (Cinnyris jugularis), but not males, in a highly competitive environment on small islands. This work was carried out on the remote and understudied islands of South-east Sulawesi, Indonesia (Figure 1), where a joint team of scientists from Trinity College Dublin (TCD) and Halu Oleo University (UHO) have been carrying out research into bird evolution since 1999.