A PRELIMINARY-ANALYSIS OF WEEVIL ASSEMBLAGES IN THE SUB-ANTARCTIC - LOCAL AND REGIONAL PATTERNS

Weevil assemblages were examined on the Prince Edward Islands and compared to those of the other South Indian Ocean Province archipelagos. Patterns found on both Marion and Prince Edward Islands are strikingly similar, despite the different glacial histories (i.e. extent of disturbance) of these islands, and indicate that interspecific competition is an important process underlying assemblage structure in the historically old epilithic biotope, whereas interspecific competition is unimportant in the young vegetated biotope, into which weevils are currently radiating. These findings support previous hypotheses concerning the importance and likelihood of interspecific competition in old, moderately-harsh, predator-free environments. Comparison of all the archipelagos in the province revealed major differences in assemblage structure between the archipelagos which do not support the competition hypothesis, but which are best explained by the varying geological and climatological histories (i.e. extent of disturbance) of the islands. These apparently contradictory findings are reconciled by taking scaling effects into consideration, and highlight the interaction between local and regional processes during the evolution of these assemblages.