[en] Sterile insect releases of a pupal color-based genetic sexing strain of the Mediterranean fruitfly, Ceratitis capitata (Wiedemann), were made during the summer and fall of 1991 in coffee plantations in Kauai, HI. Four treatments compared with respect to trap recapture and sterility rates induced in native populations were: (1) genetic sexing strain (≍99% males = males only), (2) genetic sexing strain (males and females), (3) genetic sexing strain (high % ♀ ♀), and (4) standard strain (males and females). Each week either 2 liters (≍120,000) of irradiated pupae for the bisexual populations or 1 liter of irradiated pupae for the unisexual populations were dye-marked and ground released in buckets. Adult flies emerged and dispersed throughout individual (≍1 ha) coffee fields. Flies were trapped weekly in standard dry traps or in liquid protein traps. Coffee berry samples were collected weekly to determine egg sterility rates, and females trapped in liquid protein were dissected for presence of sperm and sperm type. A new technique was developed to type sperm as either sterile (irradiated) or wild in mated females. An estimate of sterile fly competitiveness based on relative degrees of egg hatch suppression indicated an overall three- to five-fold increase in competitiveness of the males-only strain compared with the standard bisexual strain. Significantly, however, this difference even widened to a qualitative degree by the end of the test

[en] The autosomal recessive white puparium (wp) mutant was used to construct the first genetic sex sorting system in the oriental fruit fly, Bactrocera dorsalis (Hendel). The translocation stocks have females with the white puparium phenotype and puparia of males are the wild-type color, brown. Viability measurements of the 49-wp translocation strain indicate that fitness relative to the wild-type and white puparium strains was not lower than expected. Hatch rate and larval viability were lower for the translocation strain, but there were no significant differences between strains for eclosion rates. This translocation-based sex sorting system is the only automatic method currently available for separation of male and female oriental fruit flies in sterile insect release programs

[en] Trials for the evaluation of the effectiveness of the sterile insect technique for the suppression of greenhouse whitefly, Trialeurodes vaporariorum (Westwood), both in cage and in greenhouse conditions are described. The results show a significant reduction of the reproductive capacity of the untreated whitefly populations interacting with sterile insects. Untreated whiteflies, co-existing in a mixed population together with sterile insects, attained less than the half (44%) of their potential reproductive capacity. This trend was also evident in the cage test where the untreated whitefly population, crossed with the sterile whiteflies, increased without exceeding 2/3 of the density recorded in the control cages. These results may be based on 2 joint sterile insect technique effects: primarily a drastic reduction of the progeny of normal untreated females, when mating with sterile males, carriers of dominant lethal mutations, and secondarily a progressive reduction of the females in the population due to an increasing rate of unsuccessful matings resulting in a condition of forced arrhenotoky. No deleterious effects, on plant health and fruit quality, were observed on plants exposed to high sterile whitefly pressures

No abstract available

[en] The rates of Chromium-51 and Strontium-85 assimilation and bioelimination by the hissing cockroach, Gromphadorhina portentosa (Schaum) are described when the symbiotic mite, Gromphadorholaelaps schaeferi Till, was present or removed. Mite-infested cockroaches had significantly higher rates of ⁵¹Cr elimination relative to mite-free cockroaches, implying more rapid gut clearance times. The authors did not find a significant mite effect on ⁸⁵Sr elimination by the host, but mite effects could have been masked by the apparently unique process of nutrient assimilation and elimination by G. portentosa. Conventional models of radioactive tracer bioelimination predict a rapid initial loss of tracer due to gut clearance, followed by a slower loss due to excretion of assimilated tracer. The results indicated that assimilated ⁸⁵Sr was eliminated earlier than unassimilated ⁸⁵Sr, which was lost by defecation

[en] A technique has been developed to distinguish between irradiated (sterile) and normal (wild or laboratory) sperm found in spermathecae of mated Mediterranean fruit flies, Ceratitis capitata (Wiedemann). Darkfield microscopy (l,000 × magnification) can be used to separate readily the sperm head lengths of irradiated males (20.5-29.0 μm; mean, 25.7) from those of wild males (27.5-33.0 μm; mean, 30.1). The sperm heads of laboratory adapted, nonirradiated males are intermediate in length compared with sperm from sterile and wild individuals. Sperm heads from three different wild populations in Hawaii were all strikingly similar in length. Field-collected females can be dissected to assess the mating frequency of released males in a sterile insect technique program. The frequency of multiple matings involving both types of males can also be measured. Two Bactrocera species found in Hawaii were examined and were found to have very similar sperm-head lengths when compared with each other, yet each had ≍3 μm longer average sperm-head lengths compared with those of C. capitata. The technique may be further useful in distinguishing sperm among other interspecific or conspecific tephritid populations. The potential effects of varying laboratory rearing or irradiation conditions on sperm-head length in tephritids remain to be investigated

[en] A field experiment was conducted to assess the mating competitiveness of sterile males of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), in a natural population on Maui, HI. Systematic censuses of the study site were conducted before and after the release of marked sterile flies (both sexes), and the abundance and distribution of fruit flies and leks, incidence of male calling and number, and location of matings were recorded during the two periods. In both replicates, the abundance, distribution, and calling activity of wild males were largely unaffected by the released flies. Most of the released males joined preexisting mating aggregations of wild males and within these leks displayed similar calling activity as the wild males. Approximately 200 matings were observed following the release in each replicate. Three separate analyses indicated that in both replicates release males accounted for fewer matings with wild females than expected by chance. Given that sterile males settled and called in natural lek sites, it appears that their relatively low mating success resulted from an inability to attract wild females to their territory or perform courtship acceptable to females, or both. The results are discussed in light of current sterile insect techniques

[en] The autosomal recessive bubble wing (bw) mutant was used to construct a translocation-based genetic sex sorting system in the melon fly, Bactrocera cucurbitae (Coquillett). The translocation stock has females with the bubble wing phenotype that are unable to fly, but the males are wild-type and fly normally. The bubble wing translocation strain has lower egg hatch, larval viability, and eclosion rates than the wild-type strain. Expression of the bubble wing trait is temperature-dependent, with high expression of the trait in 92% of adults at 23°C but in only 15% of adults at 28°C. This translocation-based sex sorting system is the only method available for automatic separation of male and female melon flies in sterile insect release programs

[en] Laboratory-reared normal, sterile, and wild female Mediterranean fruit flies, Ceratitis capitata (Wiedemann), were mated with laboratory-reared normal, sterile, and wild male flies to assess the ability of males to alter olfactory-mediated behavioral responses of females to male-produced pheromone or host fruit odor. Virgin females of all 3 types showed a preferential attraction and arrestment on yellow spheres emitting male-produced pheromone in a laboratory flight tunnel. Laboratory-reared normal and wild females mated to laboratory reared normal, sterile, or wild males switched their behavior showing strong preferential attraction to, arrestment on, and egg-laying in (for laboratory-reared females) yellow spheres emitting host fruit odor (guava) over male-produced pheromone. Sterile females did not show a significant switch in behavior except when mated to sterile males. The olfactory-mediated behavioral switch was most evident in the laboratory-reared normal female × laboratory-reared normal male mating. These findings suggest that irradiation of males inducing gamete sterility does not affect the factor(s) from the male accessory gland associated with altering female olfactory behavior. The ability of sterile males to alter adequately olfactory-mediated behavior of wild females is discussed in the context of the sterile insect technique for control of Mediterranean fruit flies in the field

No abstract available