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Harvard Forest REU Symposium Abstract 2011

  • Title: Warming does not affect colony growth or mutualistic association with ants in the aphid Chaitophorus populicola
  • Author: Michael Marquis (Arizona State University)
  • Abstract:

    Mutualisms between ants and aphids can have a large impact on the arthropod communities around them, so it is important to understand how they might be affected by climate change. Most research on the subject to date focuses on the effects of increased greenhouse gas concentrations, rather than warming, on aphid colony growth. We examined the effects of warming on colonies of the aphid Chaitophorus populicola and the ants tending them in potted aspen (Populus tremuloides) trees over a four week period using open-top warming chambers at Harvard Forest. We monitored aphid colony growth and plant stress in the presence and absence of ants in five different warming scenarios. Three species of ants (but only one per plant) were observed tending the aphids: Camponotus pennsylvanicus, Formica subsericea, and Lasius alienus. There was no relationship between temperature and the species of the tending ant. Species of ant had no effect on production of non reproductives (apterous adults), but it did influence the number of winged reproductives (alates) produced. We found no significant relationship between temperature and aphid colony growth in either the ant tended or exclusion colonies. Similarly, temperature did not affect number of alates produced or colony lifespan in either treatment. On average, ant tended colonies survived for a greater length of time than the ant exclusion colonies and exhibited a nonsignificant trend towards producing a greater number of alates. During the course of the study, colonization of trees by another aphid, Myzus persicae, was noted and recorded. M. persicae colony size increased linearly with temperature when tended by ants. The lack of a relationship between either ant species or aphid colony growth and temperature suggests that warming does not affect C. populicola and its mutualistic association with ants, but the linear increase of M. persicae colony size with temperature indicates that this may not be true for other aphids. These findings highlight the fact that findings regarding the affects of warming should not be generalized across species or genera.

  • Research Category: Physiological Ecology, Population Dynamics, and Species Interactions