Towards a life history explanation of the origin and maintenance of eusociality: A role specific energy budget for the primitively eusocial paper wasp Polistes fuscatus.
Abstract: Natural selection predicts that each individual should strive to
maximize its genetic contribution to the next generation. However, in eusocial organisms,
many individuals give up some or all of their reproduction to help another individual. In
highly eusocial organisms, like the honeybee, workers are partially or completely sterile
and could not found their own colony. However, in ... read moreprimitively eusocial organisms like
Polistes, workers are capable of reproducing and founding
their own colonies. In addition, mated females often accept worker-like roles on new
colonies rather than founding their own colonies. This opens the question of why an
individual that could reproduce would choose, instead, to help another individual. To
address this question I looked at the energetic costs of being a worker or a dominant,
solitary, or subordinate foundress, as well as the metabolic differences among these
individuals. I measured the cost of different behaviors, including interactions between
individuals, flight, grooming and nest care. I found that foraging related behaviors
(performed by solitary and subordinate foundress and workers) were quite expensive, while
interactions (performed primarily by dominants) were relatively low cost. I also looked at
the thermoregulation necessary for some of these behaviors, and found that flying
Polistes thermoregulate, another energetically costly
behavior. When I compared the cost of maintaining ovarian development among these different
roles, I found that workers and subordinate foundresses spent more energy to maintain the
same level of ovarian development, suggesting that they would need to expend more energy to
create a colony, and, therefore, be less able than the average solitary foundress to
maintain a successful colony. Finally, I created an energy budget for each role. I found
that workers used more energy than any other role, but, after that, solitaries with workers
used approximately the same amount of energy on tasks as subordinates. Solitaries prior to
worker emergence would be expected to use even more energy. This suggests that an
individual with low resources and a high energetic cost of egg maintenance might be have a
low success as a solitary foundress, and, therefore, be better off taking a subordinate
role and helping a sister.
Thesis (Ph.D.)--Tufts University, 2011.
Submitted to the Dept. of Biology.
Advisor: Philip Starks.
Committee: Sara Lewis, William Woods, Michael Reed, and Ken Prestwich.
Keywords: Biology, , and Ecology.read less