The role of evolution in mating behavior of lekking species  (Page 8/11)

The hotshot hypothesis

While the preference model suggests that females are biased towards aggregated males in general, the hotshot model proposes that females show a preference for particular individual males (Young 2009). The theory claims that leks form as aggregations of inferior males around the preferred “hotshots” in attempts to increase their successes in attracting females by intercepting the females attracted to the hotshot. This theory leads to the logical prediction that preferred males should display in central territories with inferior males aggregated about them (Young 2009).

Opposition

Cichlids

A study performed in Africa by Kyle Young followed the behavior of a species of bower -building cichlid fish, Nyassachromis cf. microcephalus (Young 2009). Male bowers are volcano-shaped nests that males defend and territorialize in their courtship of passing females. This species is native to Lake Malawi, Africa, and demonstrates many characteristics that suit it for studying lek behavior. The male cichlids build bowers that are easily quantified in size and their reproductive behaviors are easily assigned cost and benefit figures. Additionally, researchers can easily study female choice, as males of this species do not actively pursue females but rather court them as they pass the males’ bowers. Variation in courtship rates is therefore a result of female, rather than male, choice because the males play no role in the coordination of a partnership. Finally, the series of mating behaviors in this species relies first on indirect female choice, in swimming past a male’s bower, then on direct female choice, as the female assesses the pursuing male and his bower and determines whether to proceed with the mating process (Young 2009).

Researchers followed three different leks for one week during peak mating season, documenting every instance of a male beginning courtship with a female, acting out of aggression toward a male of the same species, acting aggressively toward a male of a different species, building his bower, and engaging in foraging behavior. The researchers then created a correlation matrix relating the position and size of the bower, male behaviors, and female interest.

The results of the study, however, did not show support for the hotshot hypothesis. Researchers determined a negative correlation between conspecific attack rate and bower location, which suggests that there is, in fact, an added cost that the hotshots must bear to hold the central lek territory, but this did not affect their encounter rate with females (Young 2009). In other words, lek position, bower size, and attack rate had no correlation to courtship initiation by females. Additionally, none of these factors correlated significantly with the reproductive success of the cichlid males either. In further evidence against the hotshot theory, once courted, females did not show any direct preferential selection for males holding territories in the center of the lek.