(A) The difference in density of the tree canopy covering a forest creates micro-habitats with varying levels of light, which can be a factor for niche partitioning leading to the birth of new fly species from the Drosophila family (B) Diagram showing the five fly species studied belonging to the obscura subgroup, which have an inverse relationship between the size of their eyes and antennae. D. pseudoobscura (left) has the smallest eyes and biggest antennae, and D. subobscura (right) has the biggest eyes and smallest antennae (not drawn to scale). (C) Diagrams illustrating the different mating rituals for each of the five species. D. pseudoobscura flies have the smallest eyes, are the least attracted to light, and have the least vision-dependent courtship (the male courts from the back of the female). D. subobscura, on the other hand, have the biggest eyes, are the most attracted to light, and have the most visually dependent courtship (fully frontal). The other species in the subgroup display a gradient of the morphology, light attraction, and mating behaviour. (D) Phylogenetic tree of these species and the main geographical locations where they can currently be found.
Image credit: Joe Brock.