Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2008
Publication Date: 7/6/2008
Citation: Bloem, S., Bloem, K., Hight, S.D., Carpenter, J.E., Dorn, S., Sarvary, M., Zimmermann, H., Floyd, J. 2008. Understanding the factors that influence the geographical expansion of cactoblastis cactorum in non-native habitats. XXIII Internatinal Congress of Entomology, Durban, South Africa. Interpretive Summary: Not required.
Technical Abstract: Cactoblastis cactorum is renowned for its role as a highly successful biological control agent for weedy Opuntia cactus, but more recently it is notorious as an invasive pest in North America. Interestingly, historical accounts of the geographical expansion of C. cactorum when deployed as a biological control agent suggest that dispersal ability is rather limited compared to the more robust dispersal documented for C. cactorum as a pest in the southeastern States of the USA and some offshore islands near Yucatan, Mexico. Laboratory bioassays using a flight mill were used to examine the influence of age, gender, mating status, body size and seasonal generation on diel flight pattern and flight performance of adults. Direct evidence of dispersal was studied using release/recapture techniques. Both laboratory bioassays from ETH Zurich and field release/recapture trials in the USA and Mexico detected heterogeneity in the population with respect to dispersal behavior and ability, and measured differences associated with various parameters. The factors that influence the geographical expansion of C. cactorum in non-native habitats are numerous and provide opportunity for complex interactions. Laboratory bioassays and field trials have provided some insights into this complicated area of study and have demonstrated the value of C. cactorum as a model system for future studies. This information is then used to design better control and management methods towards the insects’ eradication and delimitation that would prevent its further invasion to sensitive cactus areas in the USA and Mexico.