Submitted to: Ecology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/15/2000
Publication Date: 6/20/2001
Citation: Barbosa, P., Segarra, A.E., Gross, P., Carlson, R.W., Ahlstrom, K., Grissell, E.E., Ferguson, D.C., Hodges, R.W., Woodley, N.E., Schauff, M.E. Differential parasitism of macrolepidopteran herbivores on two deciduous tree species.. Ecology. 82:698-704. 2001. Interpretive Summary: Biologically based pest control helps to reduce the use of chemical pesticides and decreases costs to farmers while increasing food safety. Beneficial parasitic wasps are heavily used in biological control and a thorough understanding of their biology is essential to utilizing them effectively. This paper reports on rates of parasitism of a number of large caterpillars which feed on deciduous trees in eastern North America. Parasitism rates were higher on caterpillars on box elder than on black willow. The same was true for total parasitism rates. This information will be useful to ecologists, biocontrol workers, and pest managers working on biologically based control of crop pests.
Technical Abstract: We examined patterns of larval parasitism among species in the macrolepidopteran assemblages on two riparian tree species, box elder and black willow. Larvae were collected throughout the growing season, for four years, and reared for parasitoid emergence. Total levels of parasitism of all larvae were assessed and parasitism of larvae on each of the two tree species were compared. Total levels of parasitism of species within each of seven families were also compared. Finally, a comparison was made of levels of larval parasitism on each tree species for species that feed on both hosts. Total parasitism of larvae on box elder was significantly higher than that of larvae on black willow. Comparison across families showed that among species in five of seven families parasitism was significantly higher when larvae were on box elder than when on black willow. For species whose larvae feed on both tree species, total parasitism was significantly higher when larvae were box elder than when on black willow. In family comparisons larvae of species in four of seven families suffered significantly higher levels of parasitism when they resided on box elder than when on black willow. Potential mechanisms causing these differences are discussed.