The Multiple Mating Behavior Of Two Bemisia Tabaci Parasitoids With Different Reproductive Modes And Its Effects On The Production Of Female Progeny

The whitefly, Bemisia tabaci(Gennadius)(Hemiptera, Aleyrodidae),(Middle EastAsia Minor 1, MEAM1), geneally known as biotype “B” is a pest of many agricultural crops such as vegetables, ornamental plants and become one of the utmost and vital invasive pests in China. B. tabaci is a complex species and one of the most important pests of cotton crop. The most widespread MEAM1, was recognized in the 2000 and has been quickly effected and began to create economic losses. There are two important whiteflies parasitiods known as Encarsia sophia(Girault and Dodd)(Hymenoptera: Aphelinidae) a heteronomous hyperparasitoid and Eretmocerus hayati(Zolnerowich and Rose)(Hymenoptera: Aphelinidae) a solitary parasitoid, showed significantly suppress B. tabaci and they are considered as excelent bio-control agents. However, the reproductive behavior of both parasitoids species regarding to sex allocation need to be explored.With the aim of examining efficient way of mass rearing and utilizing these parasitoids laboratory experiments were conduncted to understand the courtship behavior, multiple mating as well as its effects on the production of female progeny. The main objective of this thesis was to investigate En.sophia and Er.hayati for the control of B. tabaci by whether they accept multiple mating, the mate choice as well as their sex allocation with different reproductive modes. The main results and conclusions are as follows:1. The acceptance of multiple mating for specified interval of hours The occurrence of multiple mating of En.sophia and Er.hayati of females with a replication of 20 were observed under laboratory condition(26°C ± 2°C, 65 ± 5 % RH), to evaluate the acceptance of multiple mating after a period of time interval of these two parasitoids. The results showed that 47% female of En.sophia and 67% of Er.hayati female accepted second mating after two hours interval which indicated that the female both species accept multiple mating in a short time interval after first mating.2. The courtship and mating behavior during multiple mating The courtship and mating behavior of both En.sophia and Er.hayati were observed to determine the series of behavior during copulation. Courtship consists of a series of beaviour including pre-mounting, mounting, copulation and post copulation. The results showed that the male of both species performed a greater variety of behavior while females responded with relatively limited behavior during both the first and second matings. Mean time duration of copulation in En.sophia and Er.hayati during first mating was 61.9±2.5s and 65.9±2.5s, respectively and for second mating was 70.1±2.1s and 70.1±1.6s, respectively.3. The mate choice in both sexes with different mating experience The mating choice of both virgin and once-mated males and females on opposite sex with or without mating experience were observed. Results showed that un-mated males of En.sophia of both species displayed more contact with virgin female but eventually mated with females having mating experinece same preference was observed in females. Moreover, in Er.hayati un-mated and mated males were equaly preference to contact and mating with virgin and mated females and same preference was observed in females. Both species mated male and female were more likely active to perform courtship and to achieve mating as compared to virgin ones.4. The effect of female age and day period on mate choice of unmated male The effect of female age(1, 5 and 8 day-old) and day period(morning 8:00–9:00, afternoon 14:00–15:00 and evening 18:00–19:00) on male mate choice between virgin or once-mated females were observed. No significant effect of female age on the male choice was found while the mean times spent in courtship, copulation and post copulation behavior with different age of females were significantly different. For the period of day it did not significant affect on frequencies of courtship and copulation in both parasitoids species.5. Multiple mating and its effect on the production of female progeny and longevity of female Multiple mating and its effect on the production of female progeny and longevity of female of En.sophia and Er.hayati were investigated under controlled conditions. The results showed that, the number of matings(once and twice-mating) had a positive significant effect on the number of female progeny, while a negative effect on longevity of both parasitiods species. In En.sophia twice mated female produced more female progeny(94.3±1.0) than once-mated female(85.3±1.2). Similarly, in longevity also have significantly effect in twice-mated had shorter longivety(13.4±0.2 days) than once-mated female(14.4±0.3 days). As same as in Er.hayati, once-mated female produce(67.7) ±0.5 and twice-mated female produced(73.1) ±0.8 female lifetime progeny, while once-mated female has longer longevity(19.4±0.2 days) as compared with twice-mated female(16.6±0.4 days).Conclusion This study suggested that both En.sophia and Er.hayati male and female could accept multiple mating soon(2-h interval) after first successful mating. Current study also determines the significance, that female using qualities from the nuptial gift(sperm) and utilizes it on production of additional eggs in parasitoids wasps. However, in biological control only females are effective; therefore the number of female progeny is more imperative than the overall progeny.