Optimal Reproductive Conditions and Parasitical Mechanism of Scleroderma Guani Xiao et Wu Using Tenebrio Molitor L. as Host
|School||China Agricultural University|
|Course||Agricultural Entomology and Pest Control|
|Keywords||Scleroderma guani Xiao et Wu Tenebrio molitor L. optimal reproductive conditions antennal sensillum kariomone|
A bethylid, Scleroderma guani Xiao et Wu, is the parasite wasp of many borers, which have many natural hosts, more than 50 species in 22 families under 3 orders. The optimal reproductive conditions of the bethylid by using Tenebrio molitor L. as host were researched. By analyzing the main nutrition of two types of hosts, observing the shape and configuration of senlilla on the antenna of bethylid, and researching the inducement effect of kairomone, the parasitical mechanism of Scleroderma guani Xiao et Wu was discussed.The main results are as follows:1. The relationship between temperature and developmental rate is in direct ratio. The developmental period is shorter with the temperature higher in the measuring temperature range. The temperature threshold and thermal requirement for development from eggs to adults are 13.60 and 320.07 day-degree respectively. Temperature has significant effect on parasite rate, successful parasite rate, egg number, filial generation’s number and sex ratio of bethylid. Moderate temperature (26 ) is optimal for byethylid development and reproduction. The most favorable temperature for mass rearing of bethylid was at the temperature range of 24~28 in biological control.2. The ratio of bethylid and host has obvious effect on egg number and filial generation’s number. And the 2:1 is the best. But the ratio of bethylid and host has little effect on parasite rate, successful parasite rate and sex ratio of bethylid. The best rear ratio is 2:1, and also can rear with 4:2 for enhance the efficiency.3. The method that the medium host dealed with mixed liquid (1:10, chloroform: alcohol) 2~6 hours can attribute the parasite rate, successful parasite rate, egg number and filial generation’s number of bethylid significantly, rising the reproductive efficiency rearing with medium host.4. By analyzing water, sugar, fat, protein and amino acid of two types of hosts, little difference between the medium host (Tenebrio molitor L.) and the natural host [Semanotits bifasciatus (Motschulsky)] was found. Tenebrio molitor L. is one of best medium hosts.5. Thirteen types of sensilla on the antenna of bethylid were found by scanning electron microscopy. There are differences in type, number and distribution between sexes. Trichoid sensillum I, II, chaetica senlissum, basiconic sensillum, squamiformic sensillum, styloconic sensillum, campaniform sensillum and ampullaceous sensillum occurred in both sexes, but each of them was different in the number and location between male and female. Placodeum sensillum, long-basiconic sensillium, culindric sensillum I , II and auricillic sensillum were only found on female’s antenna.6. Preliminary research on the behavioral response of bethylid to longicorn’s blood lymph, dejection, extractive of secretion was conducted. Kairomone has significant effect in the process of bethylid searching host. And kairomone exists in dejection mostly, which main component possibly is alkane or its derivants.