Effect of Elevation and Host Availability on Distribution of Sterile and Wild Mediterranean Fruit Flies (Diptera: Tephritidae)
Effects of elevation and host fruit availability on the distribution of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), were evaluated with cylindrical traps baited with a female-biased food-based synthetic lure. Tests were conducted in the Santa Mara valley, Guatemala during a sterile male release program. Traps were placed in or near host trees (primarily coffee and citrus) and in non-host trees when no hosts were available. Trap locations were grouped according to elevation every 170 m. Elevation group midpoints were 1103, 1273, 1443, and 1613 m above sea level. The spatial distributions of sterile males, wild males, and females were clumped throughout the 13 wk of sampling. More wild female flies were captured in coffee in the 1273 m elevation and on non-host trees in the 1103 m elevation. The number of wild males was directly related to the number of wild females captured, and the sex ratio (female: male) was highest at the 1443 and 1613 m elevation ranges. There was no relationship between the number of sterile males and number of wild females in the traps at any elevation. At all elevation ranges, an inverse relationship was observed between the numbers of wild females and males with the mean numbers of sterile males per trap. Wild C. capitata populations appeared to decrease when 40 sterile males were captured per trap with wild females per week. The results indicated that, during the sampling period evaluated, coffee appeared to be the main host plant for the wild population, C. capitata were more abundant at the 1273 m elevation range than at other elevations. Additional or alternative host species may harbor the female population at other times.