Niche relations in Vicia-inhabiting Bruchus spp.

Abstract

Several authors (Hairston et al., 1960; Strong et al., 1984; Jermy, 1985) have questioned the frequent occurrence and overall importance of interspecific competition between phytophagous insects. Recent reevaluations of such relations (Damman, 1993; Denno et al., 1995), however, once again point to the role of competition in determining the structure of phytophagous insect communities, especially of those that exploit discrete resources such as seed predators. They emphasise that besides direct competition there are more subtle types, such as resource- and natural enemy-mediated interactions. While the former considers the importance of herbivore-induced changes in the resource affecting herbivore fitness, the latter refers to apparent competition of which avoidance is possible by entering enemy-free space, hence specialisation. We analyse niche relations of a predispersal seed predator (pre-DSP) guild on the basis of distribution data gained by the examination of seed predation (SP) in pods of wild-grown Vicia spp. collected in Hungary.