Diversity, abundance, and distribution of insect visitors to macadamia flowers

Fifty-five species of insects visited macadamia flowers in orchards in eastern Australia. Only two species, the social bees Apis mellifera L. and Trigona carbonaria Smith, were common. Abundance of T. carbonaria, but not A. mellifera, was significantly positively correlated with extent of surrounding eucalypt vegetation. A. mellifera and T. carbonaria showed no preference for heavily versus lightly flowering trees. Both bee species, but especially T. carbonaria, preferred outer racemes to shaded racemes, possibly reducing the effectiveness of these species as pollinators. Both bee species were present for the major period of macadamia flowering. T. carbonaria foraged for a mean of 7 h a day compared with 10 h for A. mellifera. Both species showed moderate annual variation in abundance at some sites. Four bird species were also observed feeding on macadamia flowers, they may play a role in pollination