Author
|
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/15/2004 Publication Date: 11/15/2004 Citation: Cottrell, T.E. 2004. Suitability of exotic and native lady beetle eggs (coleoptera: coccinellidae) for development of lady beetle larvae. Biological Control. 31:362-371. Interpretive Summary: Predation upon lady beetle eggs is most often occurs as in the form of egg cannibalism by larvae or adults. However, other coccinellid species account for the majority of the remaining predation events upon coccinellid eggs. Thus the recent introduction and establishment of Harmonia axyridis in the U.S. could negatively affect native species of lady beetles through egg predation. In this study it was found that larvae of native species Coleomegilla maculata and Olla v-nigrum could not feed and develop on eggs of the exotic species. In stark contrast, exotic larvae survived equally well when cannibalizing eggs or eating eggs of either native species. The data suggest that H. axyridis may prey upon the eggs of these native species, when encountered in the field, compared with the likelihood of the native species preying upon exotic H. axyridis eggs. Therefore, eggs of the native species C. maculata and O. v-nigrum will continue to be subjected to cannibalism and also to possible predation by other native species and the exotic H. axyridis. Technical Abstract: Predation upon lady beetle (Coleoptera: Coccinellidae) eggs in the field is most often instances of egg cannibalism by larvae or adults. However, other coccinellid species account for the majority of the remaining predation events upon coccinellid eggs. Thus the recent introduction and establishment of Harmonia axyridis in the U.S. could negatively affect native species of Coccinellidae via egg predation. However, little is known regarding the suitability of interspecific coccinellid eggs as a food source for larval development. In this study it was found that native 1st or 3rd instar Coleomegilla maculata and Olla v-nigrum larvae were incapable of surviving to the adult stage when provided solely exotic H. axyridis eggs. In stark contrast, H. axyridis larvae survived equally well when cannibalizing eggs or eating eggs of either native species. When C. maculata and O. v-nigrum were grouped as 'native' and compared with the exotic H. axyridis, more native eggs were attacked than exotic eggs and a higher percentage of eggs was attacked by H. axyridis larvae. Native and exotic larvae attacked a similar percentage of native eggs but native larvae attacked significantly fewer exotic eggs than did exotic larvae. The data suggest that H. axyridis may prey upon the eggs of these native species, when encountered in the field, compared with the likelihood of the native species preying upon H. axyridis eggs. Therefore, eggs of the native species C. maculata and O. v-nigrum will continue to be subjected to cannibalism and also to possible predation by other native species and the exotic H. axyridis. |
