Ant-Plant-Homopteran Interactions R . BUCKLEY I . Summary . . . . . . . . . . . . . . . . . . . . . I1 . Introduction . . . . . . . . . . . . . . . . . . . . . . . . . A . Ant-Plant . . . . . . . . . . . . . . . . . . . . B . Homopteran-Plant . . . . . . . . . . . . . . . . . IV . The Indirect Components . . . . . . . . . . . . . . . . A . Plants Affecting Ants via Homoptera . . . . . . . . . . . B . Plants Affecting Homoptera via Ants . . . . . . . . . . . C . Ants Affecting Plants via Homoptera . . . . . . . . . . . D . Ants Affecting Homoptera via Plants . . . . . . . . . . . E . Homoptera Affecting Ants via Plants . . . . . . . . . . . F . Homoptera Affecting Plants via Ants . . . . . . . . . . . V . Discussion and Conclusions . . . . . . . . . . . . . . . A . Effect on Host Plant Populations, and Long-Term Persistence of APHI B . Abiotic Factors, and Embedding in Higher-Order Interactions . . . C . Directions for Research . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . 111 . The Twofold Components - Direct or Pairwise Interactions C . Ant-Homopteran . . . . . . . . . . . . . . . . . Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 53 . . . 54 . . . 56 . . . 56 . . . 51 . . . 60 . . . 66 . . . 66 . . . 66 . . . 67 . . . 68 . . . 68 . . . 68 . . . 70 . . . 70 . . . 72 . . . 73 . . . 73 . . . 74 I . SUMMARY Ants. plants and Homoptera interact in.a wide variety of ways . Each participant in these interactions can affect the other two either directly. or indirectly by affecting the third participant . The outcome of a particular interaction may also be affected by other species interacting with one or more of the participants. and by abiotic factors such as fire. soil and climate . The quantitative significance. and the degree of specificity. obligacy . and specialisation for each participant vary widely between interactions . Whilst there are many interactions between ants and plants which do not ADVANCES IN ECOLOGICAL RESEARCH Vol 16 ISBN 11-12-0139 16-2 Copyrighi 0 1987 Academic Press Inc (London) Limited A// righis of reprodirriron in on) form reseri rd 53