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Harvard Forest REU Symposium Abstract 2015

  • Title: Selective Forces that Shape Physiological Traits
  • Author: Jordan K Zitnay (Unity College)
  • Abstract:

    Ants occupy a wide variety of environments but their abundance and distribution can be limited by numerous biotic and abiotic factors. In particular, for the common woodland ant (Aphaenogaster picea), the northern edge of its range does not extend past 45N in Maine despite suitable nesting habitat. Limitations in physiological tolerance for temperature extremes may limit their range expansion. To determine whether climatic variables shape thermal tolerance, we associated measures of hot and cold temperature tolerances for 18 colonies that were collected along the species’ northern range under common garden conditions with climatic factors. High temperature tolerance was measured as the loss of motor function during slow ramping temperature treatment (CTmax) and cold temperature tolerance was measured as recovery time after exposure to cold shock (CTmin). There was no relationship between CTmax and mean annual temperatures for A. picea colonies collected at their northern range boundary. However, there was a negative relationship between cold tolerance of ants and mean annual temperature. Temperature acts as a force of selection for cold but not heat tolerance on the populations of a common woodland ant at the northern end of their range.

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