RT Journal Article
SR Electronic
T1 Coherent whole food web responses to outbreaking spruce budworm
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 615799
DO 10.1101/615799
A1 Christopher J. Greyson-Gaito
A1 Kevin S. McCann
A1 Jochen Fründ
A1 Christopher J. Lucarotti
A1 M. Alex Smith
A1 Eldon S. Eveleigh
YR 2019
UL http://biorxiv.org/content/early/2019/04/26/615799.abstract
AB The world is astoundingly variable, and individuals to whole communities must respond to variability to survive. One potent example of nature’s variability is the massive fluctuations in spruce budworm (Choristoneura fumiferana Clemens) populations that occur over 35 years. We examined how the parasitoid community altered its parasitism of budworm and other caterpillars in response to these fluctuations. Budworm and other caterpillar species were sampled from balsam fir in three plots for 13 years in Atlantic Canada. These caterpillars were reared to identify any emerging parasitoids. We found that the parasitoid community showed a simple linear, and indiscriminate, response (i.e., no preference and so densities purely dictated parasitism rates) to changes in budworm densities relative to other caterpillar species on balsam fir. Furthermore, we observed strong changes in topology and distributions of interaction strengths. These observations suggest parasitoid movement between hardwood stands and balsam fir stands is integral to the population dynamics of budworm. Furthermore, our study remarkably shows that species communities coherently alter species interactions in response to variable resources, fundamentally shifting food web pathways in a manner similar to generalist apex predators.