The effect of post‐teneral diets on the mating performance, pheromone production and longevity of sterileAnastrepha ludensandAnastrepha obliquafruit flies (Diptera: Tephritidae) was investigated. Enriched pre‐release diets improved male mating performance. Wild and sterile males fed on mango and orange fruits achieved the greatest copulatory success, followed by those fed on a 3 : 1 sugar : yeast (SY) diet. Males fed only on a sugar diet achieved the lowest number of matings. The mean numbers of copulas achieved by wild males were significantly higher than those by sterile males fed on a sugar‐only diet, while there were no significant differences between wild males and sterile males fed on yeast diets. There was a trend of reduced mean number of copulas as the proportion of yeast was reduced in the diet, but differences were not significant. Pre‐release diets had a significant effect on pheromone production. Males fed on a 3 : 1 SY diet produced the greatest amount of the three main pheromone components inA. ludensmales and two major components inA. obliquamales, followed by males fed on fruits or pasteurized fruit juice. Males fed on a sugar only diet produced the lowest amounts. The longevity response to post‐teneral diets was complex. The most yeast‐rich diet and the poorest diet (sugar only) resulted in the lowest life expectancies. Flies fed on 24 : 1 SY diets showed the highest life expectancies for both males and females of the two species. Considering the tradeoffs between mating performance and longevity, the 24 : 1 SY diet would be recommended for programmes integrating the sterile insect technique, but the effects of these diets on field survival and dispersal still need to be investigated.

A new genetic sexing strain of the Mexican fruit fly, Anastrepha ludens (Loew), was evaluated in tests of sexual behavior to determine its possible application

A genetic sexing strain of Anastrepha ludens (Loew), Tapachula-7, was developed by the Mexican Program Against Fruit Flies to produce and release only males in programs where the sterile insect technique (SIT) is applied. Currently, breeding are found at a massive scale, and it is necessary to determine the optimum irradiation dose that releases sterile males with minimum damage to their sexual competitiveness. Under laboratory and field conditions, we evaluated the effects of gamma irradiation at doses of 0, 20, 40, 60 and 80 Gy on the sexual competitiveness of males, the induction of sterility in wild females and offspring survivorship. The results of the study indicate that irradiation doses have a significant effect on the sexual behavior of males. A reduction of mating capacity was inversely proportional to the irradiation dose of males. It is estimated that a dose of 60 Gy can induce more than 99% sterility in wild females. In all treatments, the degree of offspring fertility was correlated with the irradiation dose of the parents. In conclusion, the results of the study indicate that a dose of 60 Gy can be applied in sterile insect technique release programs. The application of this dose in the new genetic sexing strain of A. ludens is discussed.

The effect of four temperatures (18, 20, 25 and 30°C) on pupa development and sexual maturity of Anastrepha obliqua adults was investigated under laboratory conditions. The results showed that the duration of the pupal stage decreased with an increase in temperature (29, 25, 13 and 12 days, respectively), and maintaining the pupae at 18°C and 20°C results in a low percentage of pupation, pupa weight loss and lesser flying ability. However, it significantly favored sexual behavior, a higher proportion of sexual calls and matings. While enhanced pupa development was observed at a temperature of 30°C, adults had low sexual efficiency, as well as a lower proportion of calls and matings. Gas chromatography-mass spectrometry (GC-MS) analysis of male volatiles showed that the amount of (Z,E)-α-farnesene did not vary among males from pupae reared at different temperatures; however, less (E,E)-α-farnesene was emitted by males obtain from pupa reared at 30°C. Male flies kept at 30°C during their larval stage had more (Z)-3-nonenol and, also, an unknown compound was detected. The fecundity of the females was higher at low temperatures. Regarding fertility, no significant differences were found between temperatures. The optimal temperature on pupa development was 25°C when males displayed ideal attributes for rearing purposes.