Mohammad Ashraf

REARING, REPRODUCTIVE BEHAVIOUR AND GAMMA STERILIZATION OF FRUIT FLY, DACUS ZONATUS (DIPTERA: TEPHRITIDAE)

Investigations were made on rearing, reproductive behaviour and gamma sterilization of one‐day old male adults of Dacus zonatus. The larvae were successfully reared on an artificial diet based on wheat shorts. Adult emergence ranged from 89–99% with a sex ratio of about 1:1. Mating occurred at dusk and its duration ranged from 8–13 hours. Males mated a second time with the same female but preferred mating if the already mated female was replaced with a sexually mature virgin female. The optimum dosage for inducing sterility amongst one‐day old male adults was 12 kR.

REPRODUCTIVE BIOLOGY AND RADIATION STERILIZATION OF THE SUGARCANE TOP BORER, TRYPORYZA NIVELLA

Reproductive biology and gamma sterilization of the sugarcane top borer, Tryporyza nivella F., were investigated under laboratory conditions. Mating took place on the night of emergence of the moths. Females were found to mate only once. One male mated for a maximum of four times when confined with five females. The mating frequency was maximum between 23.00 and 00.30 hr; the mating duration ranged from 60–165 min with an average of 127.5 min. On average 113 eggs were laid by a mated female and 40 by a virgin female during the total life‐span. The males and females had an average life‐span of 2.6 days and 2.4 days, respectively.

Species‐, age‐, and sex‐specific susceptibility of Mediterranean fruit flies 1 , oriental fruit flies 1 , and melon flies 1 to carbon dioxide 2

Abstract The 3 tephritids in Hawaii of economic importance, namely the Mediterranean fruit fly (medfly), Ceratltls capltata (Wiedemann), the oriental fruit fly, Dacus dorsalis Hendel, and the melon fly, D. cucurbitae Coquillett, showed marked differences in species‐, age‐, and sex‐specific susceptibilities to CO2 anesthetization. Mortalities for medflies exposed to CO2 increased more with time than did mortalities for the other 2 species. Older medflies and oriental fruit flies were more susceptible to CO2 exposure than were younger flies. Female medflies and oriental fruit flies were generally affected more by CO2 exposure than were males. Melon files were the least affected of the tested species by anesthetization with CO2.

Sterilization of melon flies: Mating competitiveness after treatment with tepa or gamma irradiation and ratios of treated to untreated flies producing population suppression 1

Abstract Male melon flies, Dacus cucurbitae Coquillett, treated with a single dose of the chemosterilant tepa (tris(l‐aziridinyl) phosphine oxide), or with gamma irradiation, either single or fractionated doses, did not differ significantly in sexual competitiveness as determined by percentage hatch of eggs. Mating competitiveness of males treated by either method ranged from 53 to 66% of that of untreated males. In another study, melon flies (males and females) sterilized with 0.0125% tepa, the threshold dose for both sexes, completely suppressed a population when the ratio was 16:16:1:1 (sterile males‐sterile females‐untreated males‐untreated females) as determined by no egg hatch.

Enhanced longevity and species-specific resistance to malathion of adult Mediterranean fruit flies, melon flies, and oriental fruit flies fed on diets with hydrolyzed protein

Abstract Mortalities of laboratory‐reared adult Mediterranean fruit flies, melon flies, and oriental fruit flies fed hydrolyzed protein were less than those fed whole protein or no protein. Dosage mortalities of these species treated with malathion showed differential toxicities for each species similar to the diet‐specific longevity relationships. Species‐specific sex differences in laboratory mortalities of adult flies were noted: male Mediterranean fruit flies lived longer than females; female melon flies and female oriental fruit flies lived longer than males.

Hardiness, longevity, mortalities, and differences according to sex of adult oriental fruit flies, Mediterranean fruit flies and melon flies subjected to a cold environment and deprivation of food and water

Abstract The 3 Tephritids in Hawaii of economic importance, namely oriental fruit flies, Dacus dorsalis Hendel, Mediterranean fruit flies (medfliea), Ceratltis capitata (Wiedemann) and melon flies, D. cuourbitae Coquillett do not survive more than 2–3 days as adults kept at ambient temperatures (75°‐85°F) when deprived of sugar. When adults are deprived of sugar in a cold environment (40oF) for up to 10 days (tests terminated) there are survivors at different age levels, depending upon periods of exposure. Young flies generally withstand food deprivation in the cold environment longer than older flies. This discovery has important implications regarding introduction and spread of new infestations. Theoretically, a gravid female might survive a trip in a cold storage area in the hold of a cargo vessel with fruit and start a new infestation when the fruit is removed and the adult female returned to ambient temperature at the ships destination.

Species‐specific enhancement of oviposition of female oriental fruit flies 1 , melon flies 1 , and mediterranean fruit flies 1 when mated with normal males or with males sexually sterilized by tepa or gamma irradiation 2

Abstract Laboratory‐reared virgin females of 3 species of Tephritidae oviposited significantly fewer eggs than similar previously mated females. Melon flies, Dacus cucurbitae Coquillett, were most affected (3.0X more eggs for mated females), and Mediterranean fruit flies, Ceratitis capitata (Wiedemann), were least affected; oriental fruit flies, D. dorsalis Hendel, were in between. Numbers of eggs laid by females mated with males treated either with tepa in drinking water or with gamma irradiation were not significantly different from those laid by females mated with untreated males. Thus, mating per se was important in enhancing oviposition regardless of the fertility of the males.

Sexual sterilization of oriental fruit flies 1 and Mediterranean fruit flies 1 by thiotepa: Dosage‐response, mating competitiveness, and resistance to deprivation of food and water 2

Abstract When oriental fruit flies, Dacus dorsalis Hendel, of mixed sex were supplied with sugar treated with 0.026% thiotepa for 3 days after eclosion no eggs hatched. Only 0.2% hatched when the dose was 0.0065% thiotepa. A dose of 0.10% was toxic to the insects. Mediterranean fruit flies, Ceratitis capitata (Wiedemann), were not completely sterilized at any dose tested although eggs hatched when flies of mixed sex were supplied with 0.051% thiotepa, and only 0.4, 0.7, 0.7, and 0.8% hatched when the dose was 0.051, 0.026, 0.013 or 0.0065%, respectively. A dose of 0.82% was toxic. Mortality of both species was lower among treated flies that were fed normally after treatment, especially among those treated at or near the threshold dosages, than among untreated flies. Also, when both species were deprived of food and water, treated flies survived longer than untreated flies. Treated oriental fruit fly males were 84% as competitive in mating with females as their untreated counterparts; treated male Mediterr...

Comparative mating ability of gamma sterilized and normal fruit flies, Dacus zonatus.

Mating competitiveness of Dacus zonatus (Saunders), when irradiated as mature pupae at 9 kR or as 1-day-old adults at 12 kR and caged with normal flies, was determined under laboratory conditions. The normal males were about thrice more competitive than the males irradiated in pupal stage. The irradiation of males as 1-day-old adults showed an improvement over pupal irradiation, but still they were half as competitive as the normal males. The normal males, males irradiated as pupae and adults transferred sperm almost equally in the spermathecae of females on first mating.

Histopathological effects of gamma radiation on testes of the spotted bollworm of cotton, Earias insulana (Lepidoptera: Arctiidae)

Histological structure of pupal testes of the spotted ballworm of cotton, Earias insulana Boisd, and effects of gamma radiation on spermatogenesis are described. Increase in dosage and time between irradiation and fixation increased the degenerative changes in various cells. The spermatogonia were most sensitive to radiation followed by spermatocytes and spermatids. The sperm bundles were broken at higher levels of irradiation, but sperm damage was not microscopically visible. (auth)