Context-dependence in an ant–aphid mutualism: direct effects of tending intensity on aphid performance

摘要: Author(s): Yoo, Ho Jung S; Holway, David A | Abstract: 1. In ant–hemipteran mutualisms, ants receive carbohydrates in the form of honeydew, while hemipterans protection from natural enemies. absence enemies, however, direct effects tending are generally less well known. We hypothesised that with increasing intensity (ant to aphid ratio), performance would increase initially, then decrease at high levels due metabolic cost producing quality honeydew.2. tested our hypothesis a greenhouse experiment by manipulating Argentine ant (Linepithema humile Mayr) colony size holding constant initial (Chaitophorus populicola Thomas) aggregations. The two parameters associated survival, survivorship maturity and longevity, declined intensity, whereas per capita birth rate time first reproduction showed no relationship attendance. intrinsic only relatively levels, suggesting nonlinearity effect intensity.3. Tending measured was similar observed free-living aggregations C. populicola. Furthermore, recruitment negatively density-dependent, indicating small tend experience highest intensity. This finding suggests aphid's may be positively mediated mutualistic interaction ant.4. ant–C. interaction, experimental manipulation revealed attendance conditional upon Experiments manipulate presence or yield an incomplete understanding if underlying nonlinearities exist.