Melittobia Courtship Behaviour: a Comparative Study of the Evolution of a Display

Publisher Website
Google Scholar
Abstract
Twenty-five batches of Melittobia (Hym., Chalcidoidea-Eulophidae) were available for a comparative study of courtship displays. Batches were crossbred to assemble them into "species"; batches were considered conspecific ifinterfertile. The species status of the majority was clear-cut. The outcome of some crosses led to ambiguities; the implications were discussed. Courtship displays were described and the nature of specific differences examined. Species were arranged in clusters and relative positions were discussed. We found a "relict" species (M. clavicornis) which we suppose to reflect a collection of ancestral conditions, both in its morphology and behaviour. We took its display behaviour as the starting point for further comparisons. Series of transformations were constructed. The extraordinary position of M. clavi- cornis made it possible to indicate the direction of transformations. The transition from a display with a continuous repetition of similar movements coupled with a periodic discharge of receptivity-inducing stimuli, to one with new elements being added underway and coupled with a single discharge at display's end is considered a major evolutionary change within the genus Melittobia. We presented a hypothesis for the origin of this development. Further important evolutionary changes refer to the timing of male willingness to copulate and to the duration of display sequences. We showed that sequence duration is largely determined by the male, which makes him independent of variable recep- tivity thresholds of females. In this way a male may space out successive copulations at a to him most profitable rate: the sex ratio is extremely female-biased; one male could serve a large number of females. The spacing procedures may be necessary to avoid sperm depletion. Male pugnacity was discussed with respect to this point. We presented some speculation on the possible, ambivalent, origin of Melittobia displays.

This publication has 0 references indexed in Scilit: