Lessons for invasion theory from social insects

Reproductive and dispersal modes of social insects mean that fundamentally different models may be required for predicting determinants of their invasions from those for sexually reproducing non-social animals or non-insects. This suggests that it is unrealistic to expect the same predictors of invasiveness will apply to all biota. Many species of social wasps, bees and ants are extraordinarily invasive. The main general advantage promoting invasiveness of social insects may be the flexibilities arising from having both individual and colony responses that enable them to withstand biotic resistance and to better match conditions in the receiving community. Social insect invasion case studies have revealed strong evidence for biotic resistance to invasions in some instances. Intercorrelated species characters and ecological variations in different disturbance regimes, regions, habitats and community histories hamper further advances in the understanding of invasion biology from comparing invasive and non-invasive species. Mole incorporation of models of conservation biology, community ecology and genetics may assist invasion biology. Experimentally designed release programmes and detailed follow-up studies of biological control agents could greatly assist the quest for better invasion models. More prolonged invasion case studies, where the underlying mechanisms of invasion are researched, and experimental manipulations are the best way that a more robust and predictive theory oof invasions can be generated. Social insects provide splendid opportunities for such research. Copyright (C) 1996 Elsevier Science Limited