Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2005
Publication Date: 8/22/2005
Citation: Wheeler, G.S., Ordung, K.M. 2005. Secondary metabolite variation affects the oviposition preference but has little effect on the performance of boreioglycaspis melaleucae: a biological control agent of melaleuca quinquenervia. Biological Control. 35:115-123. Interpretive Summary: The species Melaleuca quinquenervia is an invasive weed that threatens the Florida Everglades. Nutrients and defensive chemicals in the leaves of Melaleuca can limit the effect of biological control agents. Two distinct types of Melaleuca occur in Florida that differ in the types of defensive chemicals present. A biological control agent the psyllid Boreioglycaspis melaleucae feeds on leaf juices of Melaleuca. We studied the survival, growth and development of nymphs fed trees fertilized at three levels of each chemical type. We found that survival increased and development time decreased when the nymphs were fed leaves from the higher fertilizer level. The chemical type of Melaleuca did not influence the nymph performance. However, the chemical type of melaleuca influenced oviposition preference, where more than twice the number of eggs was laid on the viridiflorol type. These results indicate that difference in susceptibility between the psyllid B. melaleucae and the weevil Oxyops vitiosa may be explained by differences in feeding behavior whereby the psyllid feeds selectively inside leaves and avoids defensive compounds stored in oil glands.
Technical Abstract: Variation in plant quality frequently impacts the biology of insect herbivores. This variability can affect the outcome of biological control projects especially during the initial releases of a new species as colonies are being mass produced and incipient populations are released. The invasive species Melaleuca quinquenervia is a weed of Florida that decreases the biodiversity of natural areas. At least two chemical variants of M. quinquenervia occur in Florida that differ in their terpenoid composition of their leaves and each is dominated by either viridiflorol or E-nerolidol. Biological control efforts against this weed resulted in the release of two insect species and one of the chemotypes decreases the biotic potential of the first released agent, a weevil Oxyops vitiosa. The second agent, a psyllid Boreioglycaspis melaleucae was introduced in 2002 and the effect of these chemical variants at three fertilizer levels on psyllid biology are described here. The results indicate that chemotype differences only influenced oviposition preference, where more than twice the number of eggs was laid on the viridiflorol chemotype. Regardless of chemotype, nymphal survival increased and development time decreased when fed leaves from the higher fertilizer level. The difference in susceptibility between the psyllid B. melaleucae and the weevil O. vitiosa may be explained by differences in feeding behavior whereby the psyllid feeds selectively inside leaves and avoids defensive compounds stored in oil glands.