Journal of Insect Behavior, Vol. 16, No. 2, March 2003 ( C  2003) Starvation and the Mating Success of Wild Male Mediterranean Fruit Flies (Diptera: Tephritidae) Todd E. Shelly 1-3 and Susan S. Kennelly 2 Accepted December 4, 2002 Recent evidence suggests that the nutritional state of male Mediterranean fruit flies, Ceratitis capitata (Wied.) (medfly), is an important influence on vari- ous components of their reproductive biology, including mating success. The objective of the present study was to examine experimentally the effect of temporary starvation on the mating success of wild male C. capitata. Males were maintained on protein–sugar or sugar-only diets, and for each diet we compared the mating success of continuously fed males versus males starved for 18 or 24 h immediately before testing. In trials conducted on field-caged, host trees, males starved for 24 h obtained only about half as many matings as fed males for both diets. However, when the starvation period was 18 h, starved males reared on the protein–sugar diet mated significantly less fre- quently than fed males, whereas starved males reared on sugar mated as often as fed males. Measurements of male pheromone calling and female attraction revealed that reduced mating success likely reflected the decreased signaling activity of starved males. KEY WORDS: Ceratitis capitata; male mating success; nutrition. 1 USDA-APHIS, Waimanalo, Hawaii 96795. 2 Hawaiian Evolutionary Biology Program, University of Hawaii, Honolulu, Hawaii 96822. 3 To whom correspondence should be addressed at USDA-APHIS, P.O. Box 1040, Waimanalo, Hawaii 96795. E-mail: todd.e.shelly@aphis.usda.gov. 171 0892-7553/03/0300-0171/0 C  2003 Plenum Publishing Corporation