Tuesday, August 3, 2010 - 2:10 PM

OOS 21-3: Could rapid evolution complicate how climate change affects species interactions?

Jason Harmon, North Dakota State University

Background/Question/Methods

The myriad of factors associated with climate change have the broad potential to influence the ecology, behavior, and fitness of most species. In doing so, these factors will likely influence the ecological interactions between species. However, in exerting a strong effect on a species, climate change can also induce strong selection which could lead to rapid evolution. This rapid evolution could not only change that individual species, but also modify their interactions with other species as well. In this talk, I will address how rapid evolution in response to climate change could directly or indirectly influence the effect of species interactions and briefly illustrate this potential with a case study. 

Results/Conclusions

The pea aphid is an extremely well studied organism that is deleteriously affected by short periods of high temperatures referred to as heat shocks.  These heat shocks are predicted to become more frequent with climate change.  They also drastically reduce the population growth rate of aphids, yet in doing so heat shocks can actually benefit the aphid by reducing the normally strong, negative effect of a density-dependent generalist predator. If the frequency of heat shocks increases there is strong selection for aphids that are resistant to the effects of heat shocks. An increase in these tolerant aphids could benefit the predator and facilitate stronger predation on the entire aphid population. Since biotic interactions and rapid evolution can occur on the same timescales, it may often be necessary to consider the complexities of both ecological and evolutionary processes for predicting species response to environmental change.