Projects


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POPULATION DIFFERENCES IN ANIMAL PERSONALITIES

Over the last ten years behavioral ecologists have been increasingly aware that the behavioral responses of individuals are often correlated. For example, in Merriam's kangaroo rats we have demonstrated that anti-predator responses, aggression toward conspecifics, and foraging behaviors are correlated in complex ways (Dochtermann and Jenkins 2007, Dochtermann et al. 2012). Interestingly these "animal personalities" often differ across populations, leading to questions about what ecological factors might promote the occurence of personalities. While much of the research on this topic has focused on the effects of predators on the expression of personalities, we have demonstrated that personality differences can also be found between populations that differ in the competitive pressure they experience (Dochtermann et al. 2012).

At NDSU we will continue to examine how differing ecological factors can lead to differences among populations in personality structure. Pursuing this topic will incorporate two general research projects: i) field research comparing behavioral responses of small mammal populations (likely thirteen-lined ground squirrels) & ii) laboratory research comparing determining quantitative genetic differences among populations of field crickets.

Within both of these over-arching projects we will pursue a variety of different questions. Proposed questions include: How does behavioral variation correspond to variation in fitness? What is the potential for personalities under-pinned by genetic correlations to constrain evolutionary responses? To what degree do population differences in personalities correspond to differences in underlying genetic architecture?


POPULATION DYNAMICS, INDIVIDUAL VARIATION, AND THE MESSINESS OF NATURAL POPULATIONS

Another key area of research will continue to be the study of population dynamics. In particular we will continue to attempt to understand differences both within and between populations of the same species. The degree to which population sizes vary from one generation to the next and the degree to which populations are goverened by density-dependence varies more within species than between species (Dochtermann and Peacock 2010, 2012). This degree of within species variation makes it difficult to tease apart general properties of population regulation. Further, both population size variability and density-dependence can be tied to the likelihood that populations go extinct. These connections make understanding within species variation in population parameters of interest from both a basic science question and due to our continued changes to the climate on a global scale.

While individual variation in life-history traits appears to be a primary driver of population size fluctuations (Dochtermann & Gienger 2012), the generality of this result is unclear. At NDSU we'll seek to examine differences amongst small mammal populations and communities throughout remenant tallgrass prairie habitat. This will be used to not only test for relationships between habitat variation and community function but also connections between within population individual variation and between population differences in population dynamics.


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