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ARS Home » Research » Publications at this Location » Publication #145682
Title: COMPARATIVE DISPERSAL OF HOMALODISCA COAGULATA AND HOMALODISCA LITERATA (HOMOPTERA: CICADELLIDAE)

Author
item Blackmer, Jacquelyn
item Hagler, James
item SIMMONS, G - APHIS,BAKERSFIELD, CA
item CANAS, L - U OF A, MARICOPA, AZ

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2003
Publication Date: 1/1/2004
Citation: Blackmer, J.L., Hagler, J.R., Simmons, G.S., Canas, L.A. 2004. Comparative dispersal of homalodisca coagulata and homalodisca literata (homoptera: cicadellidae). Environmental Entomology. 33: 88-99.

Interpretive Summary: Pierce's disease is a bacterium transmitted by sharpshooters, but was only an occasional problem in California before the introduction of the glassy-winged sharpshooter (GWSS). A better understanding of the factors that influence the dispersal of GWSS, as well as other native sharpshooters, could enhance our ability to institute area-wide management programs. Our objectives were to establish the validity of using a protein marker for dispersal studies, to compare the dispersal of GWSS with that of the native smoke tree sharpshooter (STSS), and to develop a better understanding of the factors that influence their dispersal. Field trials indicated that the protein marker was effective for at least 19 days and had no effect on mortality. Additionally, in our mark-release-recapture (MRR) studies, four rates (0.04, 0.2, 1 and 5 mg/ml) and two different protein markers (chicken and rabbit) were found to be equally effective for marking sharpshooters. Most sharpshooters took off during the releases and the timing of takeoff was similar for GWSS and STSS. Wind speeds greater than 3 m s-1 were associated with a decline in take-off activity for both species. Sharpshooters were usually trapped below 4.2 m in height, and based on sex-ratio comparisons, traps were equally attractive to the sexes. Regressions of recapture data with a diffusion model provided significant fits to the data with high coefficients of determination. Calculations of dispersal distances showed that 95% of GWSS and STSS were recaptured within 90 and 155 m of the release site, respectively.

Technical Abstract: Pierce's disease is a bacterium transmitted by sharpshooters, but it was only an occasional problem in California before the introduction of the glassy-winged sharpshooter (GWSS). A better understanding of the factors that influence the dispersal of GWSS and other native sharpshooters could enhance our ability to institute area-wide management programs. Our objectives were to establish the validity of using a protein marker for sharpshooter dispersal studies, to compare the dispersal of GWSS with that of the native smoke tree sharpshooter (STSS), and to develop a better understanding of the biotic and abiotic factors that influence their dispersal. Field trials indicated that the protein marker was effective for at least 19 days and had no effect on sharpshooter mortality. Additionally, in our mark-release-recapture (MRR) studies, four rates (0.04, 0.2, 1 and 5 mg/ml) and two different protein markers (chicken and rabbit) were found to be equally effective for marking sharpshooters. Approximately 95% of the marked insects took off during the releases and the timing of takeoff was similar for GWSS and STSS. Wind speeds greater than 3 m s-1 were associated with a decline in take-off activity for both species. Most sharpshooters were trapped below 4.2 m in height, and based on sex-ratio comparisons traps were equally attractive to the sexes. Regressions of recapture data with a diffusion model provided significant fits to the data with high coefficients of determination. Calculations of dispersal distances showed that 95% of the GWSS and STSS were recaptured within 90 and 155 m of the release site, respectively.