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I am a PERT postdoc in Dan Papaj’s lab.  I am interested in how
foraging behaviors influence interspecific interactions, especially
plant-pollinator relationships.  I am currently studying bumblebee
foraging behavior, focusing on how bees deal with variation in nectar
availability across flowers, which can be generated both by variation
in nectar production rates and differences in how recently flowers
have been visited.  These processes can produce rewarding and
unrewarding clusters of flowers at a variety of different scales, from
a fine patchwork of rewarding and unrewarding inflorescences to large
zones occupied by relatively unrewarding and rewarding groups of
plants.  A bee that was able to detect the scale of patchiness in
floral rewards could forage efficiently in a wide range of habitats,
neither wasting time exploring unrewarding patches in coarse-grained
habitats nor prematurely abandoning areas with many rewarding flowers in fine-grained habitats.  However, the extent to which bees, or
indeed, any other foragers, can adjust their foraging behaviors to fit
the size of rewarding and unrewarding patches in their habitat is
largely unexplored.  I shall be presenting bees with artificial
meadows in which rewarding and unrewarding flowers are aggregated in patches of various different sizes to see how well they can tailor
their behaviors to these different circumstances.  In addition to
opening a new area of inquiry in animal foraging behavior, this
project will contribute to our understanding of the evolution of
rewardless flowers in plants.

My doctoral research explored another aspect of pollinators’ responses
to spatial variation in resource availability: the effects of flower
density on how often flowers are visited and by which pollinator
species.  I built mathematical models that made broad predictions
about what would happen if nature were simpler than it actually is and
watched flowers in the field to see what really happens.  Of course,
reality was never quite the way my models predicted it would be, but
key predictions stood up, suggesting that my models could be a useful
starting point for understanding responses of pollinator guilds to
variation in flower density.  That understanding, in turn, could aide
efforts to predict when pollination success will decline at low flower
densities, hindering the recovery of plant populations from
disturbances and increasing their risk of extinction.


Essenberg, C. J. Accepted. Explaining the effects of floral density on flower visitor species composition.  American Naturalist.

Essenberg, C. J.  2012. Scale-dependent shifts in the species composition of flower visitors with changing floral density.  Oecologia.  DOI: 10.1007/s00442-012-2391-z.

Essenberg, C. J. 2012. Explaining variation in the effect of floral density on pollinator visitation. American Naturalist 180(2): 153-166.

Sachs, J. L., C. J. Essenberg, and M. M. Turcotte. 2011. New paradigms for the evolution of beneficial infections. Trends in Ecology & Evolution 26(4): 202-209.


Contact Info
Carla Essenberg
Ecology and Evolutionary Biology
Biosciences West Rm. 512
1041 E. Lowell
University of Arizona
Tucson, AZ 85721
Lab phone: (520) 626-9012
E-mail: essenberg@email.arizona.edu

PERT web page: http://cis.arl.arizona.edu/PERT/people/Essenberg/







Last modified: 29-Jan-2013
Webmaster: Dan Papaj
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Photo of cricket by A. Pingstone. Photo of bee by D. Papaj