Dual mimicry in the dimorphic eusocial wasp Mischocyttarus mastigophorus Richards (Hymenoptera: Vespidae)

The eusocial vespid wasp Mischocyttarus mastigophorus exhibits two colour morphs, with males and females of each morph co-occurring at Monteverde, Costa Rica. Each morph closely resembles a different sympatric species of swarm-founding wasp in the genus Agelaia. We propose that the Agelaia species are models for a dual mimicry system. The Agelaia species (A. yepocapa, mimicked by the M. mastigophorus pale morph, and A. xanthopus, mimicked by the M. mastigophorus dark morph) are locally abundant wasps with large, aggressively defended colonies. The mimic and models are restricted to high-elevation habitat in the Monteverde area, and the elevational ranges of both Agelaia species partially overlap the elevational range of M. mastigophorus. Relative frequencies of the M. mastigophorus colour morphs vary with elevation, with the pale morph predominating at lower elevations. Elevational differences in the relative abundances of the Agelaia species suggest that the models act as a selective force maintaining the M. mastigophorus colour polymorphism at Monteverde. Mischocyttarus mastigophorus overlaps only A. xanthopus in the northern part of its range (S. Mexico), and overlaps only A. yepocapa in the southern part of its range (Ecuador). We hypothesize that the M. mastigophorus colour morphs evolved in allopatry and later came into contact in Central America. Appropriate high-elevation habitat for cloud forest species is distributed as discrete patches in Central America and Northern South America. The island-like nature of suitable habitat may favour the isolation and rapid evolutionary diversification of vespid species that are restricted to high elevations in the Neotropics. (C) 1999 The Linnean Society of London.