Studies On The Composition, Origin And Function Of The Secretion Which Discharged By Female Adults Apriona Germari (Hope) During The Stage Of Egg Laying

Apriona germari (Hope) is an important stem borer in china. It was listed in the forestry dangerous pests in 2002. Secretion discharged by female adults during egg-laying is smeared on the nidus. Discharging secretion is a very important process of female adults'oviposition behavior. The important function of the secretion is to protect eggs and to maintain stable embryo-developing environment. The secretion may also be some chemicals that related to information exchange between borers and hosts, borers and natural enemies, or among the different individuals. Experimental research on the composition, origin and function of the secretion will be beneficial to deeply understand the oviposition habits of female adults. On the other hand the study will provide theoretical basis for effective control of Apriona germari. The article included the following contents: (1)the comparative anatomy on the reproductive organs of female adults Apriona germari and observations on oviposition habits of female adults,(2)the study on the components of the secretion that discharged by female adults during egg-laying,(3)the research on organs that the secretion come from,(4)the influence of the secretion on the diurnal variation of water content,pH and microbial quantity of the nidus microenvironment in embryonic development period,(5)the preliminary study on the aerobe in the secretion.The main results were as follows:1. Oviposition behavior of Apriona germari included 4 successive phases, such as searching oviposition site, gnawing a nidus, ovipositing and blockading the nidus. The mean length of ovipositor is (4.28±1.91) mm. There are a lot of sense hairs on valvulae. The mean size of nidus is as follows: (13.78±1.75) mm long, (6.94±0.99) mm wide. There were a pronounced linear correlation between nidus'width and the diameter of host branch as well as the nidus'width and the thickness of xylem. Moreover, the linear correlation of the depth of nidus and the thickness of xylem was also very conspicuous. The difference of length and width between the nidus with or without egg was not conspicuous. But the nidus without egg was not deep enough for female adult to lay egg.2. Fresh secretion is a clear and viscous jelly which could dissolve in water. It was not easy to be denatured that the secretion dissolved in PBS (pH 6.8 and pH 7.0). Also the secretion could become solid in the air and there was a white viscous substance separated out while the secretion extracted by acetone, methanol or ethanol. The mean weight of the secretion was (0.006 2±0.003 4)g. Difference of weight between two successive secretions was not conspicuous. Percentage weight of component in the secretion was: water 80.10 %, protein 2.29 %, soluble sugar 0.49%,free amino acid 0.05 %. PAGE electrophoresis analysis showed that there was only one clear protein band in the secretion protein. And the SDS-PAGE electrophoresis analysis revealed that the secretion protein were composed by 123.0 KDa,97.7 KDa,72.6KDa,63.4 KDa,55.4 KDa,43.0 KDa bands.3. Difference of fresh weight between secretion and bursa copulatrix was not significant. But there was significant difference of fresh weight between secretion and other reproductive organs. Percentage weight of protein, soluble sugar and free amino acid in the secretion were not significantly different compared with the content of spermathecal gland. Comparative analysis of the protein composition between the secretion and the content of spermathecal gland by PAGE indicated that the protein of the secretion come from spermathecal gland. Comparative study of the protein composition between the secretion and tissue or content of every reproductive organ was also done. The analytic result indicated that spermathecal gland was the store organ of the secretion. But spermathecal gland may also be the synthetic organ of some partial protein of the secretion.4. At the prophase of embryonic development, the secretion was the sustainer which can keep water content of the nidus waving in certain extent. Diurnal variation of the pH values of the barks where a nidus in it was not influenced by the secretion. But the variation of microbial quantity of the nidus was effected by the secretion. Before 4th day after egg-laying, microbial quantity growing was inhibited.5. There were a few aerobic microbes in the secretion. Aerobic microbe in fresh egg surface might mainly come from bark surface or intestinal microbe. Quantitative and population of aerobic microbe might be influenced by female adults'feeding, gnawing nidus and oviposition behavior. Aerobic microbe in the intestinal contents of larvae was acquired by larvae's gnawing of chorine and medial nidus. Female adults'oviposition behavior might transfer some harmful or beneficial aerobic microbe to larvae.