Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2007
Publication Date: 1/30/2008
Citation: Mclean, S.C., Bloem, K.A., Bloem, S., Hight, S.D., Carpenter, J.E. 2008. Mating frequency of the male cactus moth, Cactoblastis cactorum (Lepidoptera: Pyralidae), under laboratory conditions. Florida Entomologist. 90(4):751-752. Interpretive Summary: A moth native to northern Argentina was found in North America for the first time in 1989. This moth is damaging only to prickly pear cactus. The insect's spread from the Florida Keys along the coast of southeastern United States to Alabama and South Carolina has raised concerns about this moth's unavoidable and unwanted impact on native, agricultural, and ornamental cactus in its new homeland. Scientists with USDA Center for Medical, Agricultural and Veterinary Entomology in Gainesville and Tallahassee, FL and Crop Protection and Management Research Unit in Tifton, GA are looking into ways of controlling this insect in urban, agricultural, and natural settings. Experiments were conducted with eggs and larvae of this moth in growth chambers to identify the influence of temperature on the survival of the eggs and larvae, and on the rate that the insect develops. Also, the rate of development of this insect was evaluated in outdoor cages during the summer and winter. This information will be combined with ongoing experiments to determine which areas in North America the cactus moth can survive, and to know which stages of the insect will be present at different times of the year.
Technical Abstract: This study evaluated the effects of three constant temperatures (20°, 25° and 30°C) on the rate of development and life history of the invasive cactus moth Cactoblastis cactorum (Berg). Results from these laboratory experiments were used to predict C. cactorum rate of development in the field during fall and summer generations. In this study, temperature had a significant effect on percentage of C. cactorum egg hatch at all temperatures, with the highest percentage hatch at 30°C. The shortest time to egg hatch (20 days) and shortest overall developmental time (61 days from egg to adult) was observed at 30°C, suggesting that 30°C is the optimal temperature tested for C. cactorum development. In general, results obtained in the field study coincided with trends observed in the laboratory study. Exposure to higher average summer temperature (26.6°C) resulted in a shorter time to and a higher percentage of egg hatch than at the lower average winter temperature (15.0°C). Developmental rate for time to first egg hatch and time to first adult emergence under field conditions at a given mean but fluctuating temperature also were similar to those obtained at the same constant temperature in the laboratory.