BIOLOGICALLY BASED TECHNIQUES TO LIMIT THE DISPERSAL OF INVASIVE PESTS
Location: Insect Behavior and Biocontrol Research Unit
Title: Mating frequency of the male cactus moth Cactoblastis cactorum (Lepidoptera:Pyralidae), under laboratory conditions
Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 4, 2007
Publication Date: December 1, 2007
Citation: Mclean, S.C., Bloem, K.A., Bloem, S., Hight, S.D., Carpenter, J.E. 2007. Mating frequency of the male cactus moth Cactoblastis cactorum (Lepidoptera:Pyralidae), under laboratory conditions. Florida Entomologist. 90(04):751-752.
Interpretive Summary: The invasive cactus moth has spread along the Florida Panhandle destroying native species of prickly pear cactus. Spread of the moth into the southwestern United States and Mexico, areas that are rich in cactus diversity, will negatively impact native, agricultural, and ornamental cactus. Scientists with USDA Center for Medical, Agricultural and Veterinary Entomology in Tallahassee, FL and Crop Protection and Management Research Unit in Tifton, GA are looking into ways of controlling this insect and limiting its westward spread. To develop these control tactics, information is needed on how often the adult moths mate. Our laboratory results show that during the male cactus moth’s lifetime of 11 days, he will successfully mate with multiple females. On average, one male will mate with two females. Also, a male takes almost three days (on average) before it mates with another female. The fact that male cactus moths mate multiple times will guide the development of a Sterile Insect Technique (SIT) that may stop the moth and perhaps push back its leading edge. By mass rearing and sterilizing large numbers of male moths to be released in particular locations and at the appropriate time, matings between sterile and wild moths become likely and these result in fewer and less-fit offspring.
This study evaluated the number of times that males of the invasive cactus moth Cactoblastis cactorum (Berg) mate under laboratory conditions. Virgin females were provided to each male at 24 h intervals until male death. Females removed from the containers were dissected to ascertain their mating status. Females were dissected under a dissecting microscope to verify the presence of a spermatophore in the bursa copulatrix. The mean number of mating events recorded in the laboratory was 2.2 per male C. cactorum with a range of 1-5 events in their lifetime. Furthermore, males took an average of 2.75 d to mate again. This information is useful in the application of a sterile insect release program to stop the expansion of this invasive moth in North America. This study did not address the mating frequency of female moths, or whether males were able to mate with multiple females in a 24 h period, important questions that must be answered if a comprehensive understanding of C. cactorum mating biology is to be understood.