Research Interests
The evolution
and maintenance of "cooperative" interactions
present problems of great interest and importance both
theoretically and practically, such as the evolution
of sociality and group living, the evolution of
avirulence of parasites, and the role of symbiosis /
mutualism in the origin of cell organelles. My research
examines a number of questions related to the problem
of how fundamentally "selfish" behaviors of organisms
results in interactions that are mutually beneficial,
such as: How does mutualism originate? What processes
regulate the costs and benefits of mutualism? How do
density- and frequency-dependent processes limit the
extent to
which individuals of one species derive benefit from another? What
limits individuals from taking advantage of mutualistic services
or resources?
I am addressing these questions
in the obligate pollination / seed predation mutualism
between yuccas (Yucca, Agavaceae) and
yucca moths (Tegeticula, Incurvariidae). Yucca moths are the only
pollinators of yuccas, but the seeds of yuccas are the only food
for yucca moth larvae. The yucca moth mutualism involves a rich
set of interactions, including both obligate and facultative "cheating",
and it can be experimentally manipulated.
We are currently examining the following
problems in this system: Do yuccas follow a set of consistent
rules for abscising fruit
containing too many yucca moth larvae? Do yucca moths spread their
eggs among yucca flowers in a way that maximizes the chance of
eggs being in fruit that are not abscised? What processes prevent "cheaters" from
becoming too numerous in this system? What are the effects of an
aphid / ant mutualism on the yucca / yucca moth mutualism? How
does cheating by yuccas arise and how is it maintained?
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