Zusammenfassung
A new type of ant male dimorphism, consisting of wingless (ergatoid) and short-winged (brachypterous) males, was found in a species of the "Cardiocondyla kagutsuchi"-complex from Malaysia. The ergatoid males show the typical morphological and behavioral characteristics of those of many other Cardiocondyla species. The brachypterous males are morphologically intermediate between ergatoid males and ...
Zusammenfassung
A new type of ant male dimorphism, consisting of wingless (ergatoid) and short-winged (brachypterous) males, was found in a species of the "Cardiocondyla kagutsuchi"-complex from Malaysia. The ergatoid males show the typical morphological and behavioral characteristics of those of many other Cardiocondyla species. The brachypterous males are morphologically intermediate between ergatoid males and typical winged males of other taxa in this genus. On one hand, they share a number of morphological and behavioral features with ergatoid males that might be adaptations to the loss of flight and intranidal mating: aggressive behavior towards rival males, a prolonged spermatogenesis, which is unique in winged males, paler body coloration, smaller compound eyes, shorter antennal funiculi, more rounded heads - perhaps due to the increased development of mandibular muscles, and an angular pronotum, probably for neck protection. Their short wings appear to protect the petiolar joints during fighting. On the other hand, the brachypterous males have not become as specialized as the ergatoids and to some extent keep the nature of the winged males of other species, i.e., they escape from the nest with a higher probability and with less injuries and do not show a reduction of the ocelli. In the sexual production season, the ergatoid males emerged first in small numbers and then both male morphs emerged in large numbers. The sex ratio was extremely female-biased in the earlier stage of sexual production, probably due to local mate competition.