Lekking and the small-scale distribution of the sexes in the Caribbean fruit fly,Anastrepha suspensa (Loew)

Abstract

Male and female Anastrepha suspensa(Loew) had a clumped distribution in the foliage of their guava host plants. Males were no closer to other males than they were to females or than females were to other females. Flies were often found in roughly the same locations over time. However, contemporaries (flies present at the same time) were closer to each other than subsequent flies were to their predecessors. Males were more likely to be found near spots previously occupied by males than they were to spots used previously by females. Some trees had more flies than others, but there was no regional (northwest, etc.) preference within trees. Females were no more likely to be found in the vicinity of clumped (lekking) males than they were by isolated males. About a third of the females taken from inside leks had sperm in their spermathecae, and it is not clear if their motive for being in these areas was sexual. In pairs of males (within 15 cm of each other), the larger fly tends to be in a position farther up the branch, suggesting that larger males may control preferred territories. It seems possible that males attempting to intercept females accumulate in favorable microhabitats where females are likely to be concentrated and that leks have evolved from such clumping.