My lab is currently
investigating two broad avenues of research. The first involves elucidating
the environmental variables underlying species invasions and disease outbreaks
in the Upper Mississippi River. The second revolves around understanding
the roles that host genetics and nutrition play in the transmission of the human
parasite Schistosoma mansoni.
INVASIVE SNAILS AND PARASITES ARE ALTERING NATIVE COMMUNITIES
IN THE UPPER MISSISSIPPI RIVER
Aquatic invasive species are rapidly
altering the structure of native communities across
America, which has important
consequences for species diversity, conservation policy, and ultimately,
One of the key
hotspots for aquatic invasions has been the
system where over 50 species have been introduced over the last 30
tentaculata is an
invasive aquatic snail that has recently spread from the Great Lakes into the
Upper Mississippi River.
Range expansion has generated 2 disconcerting
patterns in the river: First, the snails appear to dominate the mollusk
community, and second, the snail transmits exotic parasites that kill waterfowl
by the thousands.
B. tentaculata and its parasites are directly
disrupting general ecosystem stability and economics in the
little is actually known about the factors
responsible for snail colonization and parasite transmission.
Using a series of field surveys, semi-natural
experiments and laboratory manipulations we are attempting to 1) elucidate the
abiotic factors correlating with invasive snails and parasites, 2) determine how
competition and infection influence
establishment, and 3) understand the role that other aquatic species play in
transmitting these exotic parasites to birds.
Preliminary data suggest that native aquatic
species may be extremely important in exotic parasite persistence and
transmission to waterfowl.
Results from this research will instrumental in the
development of management models aimed at curbing the spread of this invasive
host-parasite association. This work is conducted in collaboration with a
number of agencies including the United States Geological Survey and US Fish and
SCHISTOSOMA MANSONI, IS RESPONSIBLE FOR HUMAN SUFFERING AROUND THE GLOBE
Recent research using
microsatellite markers suggests that relative migration rates of
and its host,
Biomphalaria glabrata in
parasites to become locally adapted to their hosts, particularly if snail
populations are genetically similar and/or inbred.
migration rates appear to be low, movement among populations does occur which
could impact host-parasite interactions through the introduction of novel host
In order to investigate this scenario, we conduct
experiments aimed at assessing the effects of increased genetic variability on
the interaction between
B. glabrata and
Inbred and outcrossed
lines have been established and progeny from these lines are exposed to
different strains of
Results were somewhat unexpected, as both inbred
and outcrossed snails exhibited very high levels of parasitic infection.
However, outcrossed snails appeared to better
accommodate these infections surviving significantly longer, generating far more
eggs and producing greater numbers of viable offspring compared to inbred
cercariae tended to be released in lower numbers from
outcrossed snails relative to their inbred counterparts.
This work demonstrates that host outcrossing can
provide a fitness advantage in the face of parasitism which may have
consequences for the transmission of
in different Brazilian populations of
Click here to see a list of recent presentations or
here for a list of publications
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