Effects of Oviposition on Remating., Response to Pheromones., and Longevity in the Female Caribbean Fruit Fly., Anastrepha suspensa (Diptera: Tephritidae)

Female Caribbean fruit flies with oviposition opportunities remate frequently, two-thirds of them after 1 wk and approximately one-third every subsequent week. Those with limited chances to oviposit remate less frequently, and about half of them mate only once during their lifetime. Ovipositing females regain receptivity to male-produced pher-omones within a week, unlike nonlaying females. Mortality rates also are higher for egg-laying females. FEMALE MATING FREQUENCY in insects is determined by the requirements of females (e.g., to replenish stored sperm or increase genetic variance in offspring) and the impositions of males (e.g., "trading" access to oviposition site for copulations [Walker 1980]). Among fruit flies there is a range of mating frequencies (Prokopy & Roitberg 1984). In the Caribbean fruit fly, Anastrepha suspensa (Loew), females visit mating aggregations under their own volition, and male sexual advances toward females on host fruit are seldom successful (Burk 1983). Therefore, remating is under female control and is considered to be infrequent (Prokopy & Roitberg 1984). However, extensive oviposition opportunities could result in depletion of stored sperm and further copulations. If so, then females might be responsive to male-produced pheromone signals at two or more times in their lives. In addition , the exhaustion of resources and increased metabolic activities associated with greater egg production could influence female senescence and mortality (see Clark and Rockstein 1964, Sokol 1985). All these implications of increased oviposi-tion are examined herein. Materials and Methods Flies were obtained from a colony maintained for over 10 yr at the Influence of Oviposition on Remating. To determine if oviposition opportunities and the de ple-tion of stored sperm resulted in a greater propensity to remate, females with and without oviposition devices were periodically given an opportunity to copulate. Virgin female flies (3 d old) were segregated in separate cages. These cages consisted of two 450-ml transparent plastic cups connected by a cotton wick that led from the water-filled bottom cup through the floor of the upper cup. The top container had a 3.8-cm screened hole for ventilation. A piece of brown sugar-torula yeast taffy on the screen provided food. Oviposition devices consisted of a rolled cloth square (6 by 6 cm) impregnated with beeswax and placed around the wick. Such waxed cloth is used on a larger scale to obtain eggs from the laboratory colony. In cages without oviposition devices, the cotton wick was pulled as nearly flush to the cage floor as possible …