Tri-trophic interactions--------------------------- --return
herbivore: Euura lasiolepis (Hymenoptera:Tenthredinidae)
parasitoid: Lathrostizus euurae(Hymenoptera:Ichneumonidae)
host plant: Salix lasiolepis (Salicaceae)
image copyrighted by J. Itami
Relationship Between Oviposition Preference and Larval Performance in
a Shoot-Galling Sawfly
Regulation by a Stem-Galling Sawfly on the Arroyo Willow.
Craig, T. P., P. W. Price and J. K. Itami. 1992 Facultative sex ratio shifts in response to host plant quality in an herbivorous insect. Oecologia 92:153-161.
Craig, T. P., and S. Mopper. 1992. Sex ratio variation in sawflies. Pages 61-92 in, M.R. Wagner and K.F. Raffa, editors. Sawfly adaptations to woody plants. Academic Press, New York
Craig, T.P., J.K. Itami and P.W. Price. 1990. Intraspecific competition and facilitation by a shoot-galling sawfly. Journal of Animal Ecology 59: 147-159
Craig, T. P., P. W. Price, K. M. Clancy, G. L. Waring and C. F. Sacchi. 1988. Forces preventing coevolution in the three-trophic-level system: willow, a gall-forming herbivore, and parasitoid. Pages 57-80, in K. C. Spencer, editor. Chemical Mediation of Coevolution, Academic Press, New York
Price, P. W., N. Cobb, T. P. Craig, G. W. Fernandes, J. K. Itami, S. Mopper and R. W. Preszler. 1990. Insect herbivore population dynamics on trees and shrubs: new approaches relevant to latent and eruptive species and life table development. Pages 1-38 in E. A. Bernays, editor. Focus on Insect-Plant Interactions. Volume 2, CRC Press, Boca Raton
Price, P. W., G. L. Waring, R. Julkunen-Titto, J. Tahvanainen, H. A. Mooney and T. P. Craig. 1989. The carbon/nutrient balance hypothesis in within species phytochemical variation of Salix lasiolepis. Journal of Chemical Ecology 15:1117-1131
Sacchi, C. F., P. W. Price, T. P. Craig and J. K. Itami. 1988. Impact of shoot galler attack on sexual reproduction in the arroyo willow. Ecology 69:2021-2030.
Price, P. W. and T. P. Craig. 1984. Life history, phenology, and survivorship of a stem-galling sawfly, Euura lasiolepis (Hymenoptera: Tenthredinidae), on the arroyo willow, Salix lasiolepis, in Northern Arizona. Annals of the Entomological Society of America 77:712-719.
Clancy, K. M., P. W. Price and T. P. Craig. 1986. Life history and natural enemies of an undescribed sawfly near Pontania pacifica (Hymenoptera: Tenthredinidae) that forms leaf galls on the arroyo willow, Salix lasiolepis. Annals of the Entomological Society of America 79:884-892
We studied the three-trophic interaction between a willow, sawfly, and parasitoids, examing both "bottom-up" effects originating from the willow and the "top-down" impact of the parasitoid on the interaction.
image copyrighted by J. Itami
The search time required to successfully attack a larva is long as can be seen by the many "firework" like ovipositor traces left by previous attemps to locate the larva in the large galls. Once a larve is located the prasitoid offspring is only successful if the egg is placed in the upper middle region of the sawfly larva where it can lie undetected by the sawfly larva's immune system.
Window of Vulnerability of a Shoot-Galling Sawfly to Attack by a Parasitoid,
Timothy P. Craig, Joanne K. Itami, and Peter W. Price