| The population ecology of Onchidium struma was studied by ecology method. The development of the reproductive systems was studied by the examination of histological methods and Electron Microscope. On the basis of morphological study, the sorts of nutriment during the different development were studied by the biochemical methods.1. Study on the population ecology of Onchidium strumaThe population number, inhabitaion, commensal, behaviour characteristics, ecological factor and the effect of growth and survive on Onchidium struma were studied on the basis of sample collected from Beibao harbor of Chongming from September 2005 to September 2006. The results showed that Onchidium struma is a kind of hermaphrodite allogamy mollusk, its life history can be divided into three phases:embryo(cleavage stage, blastula stage, coenteron stage, trochophore state inside ovum, veliger stage inside ovum), pelagic(Mouth-open stage, big veliger larva) and reptation (cling stage, reptation larva, adult). Onchidium struma feed on the benthic diatom, organic detritus, sediment, humus and minitype living things carried by tide. The biomass of Onchidium struma is late spring and early autumn > early spring, late autumn > summer>winter. All kinds of ecological factor can influence the reproductive capacity, growth and survive of Onchidium struma, such as salt, temperature, dissolved oxygen, pollutant, disease, preied on , the number and species of animals and plants, climate and catching. The results of the number and species of the community show that it is a kind of community with low species diversity and species abundance. And the species is distributed asymmetrically, and the degree of dominance is obvious.2. Study on the development of the reproductive systems of Onchidium strumaOnchidium struma is a kind of protandrous hermaphrodite marine pulmonate, reproductive system is composed of ovotestis, albumen gland, vitellarium, glandula conchae and copulatory organ. The reproductive cycle of Onchidium struma can be divided into four stages: proliferating stage, growing stage, maturing stage and degeneration stage (resting stage). By the morphological characters of oocytes and developmental rules, the course of oogenesis can be dividied into the phase of oogonium, oocyte and mature oocyte and degenerative ovum. The phase of oocyte can be dividied into previtellogenic oocytes. And the development of ovarian is divided into 3 phages: under-development phase, developing phase and phase of ovulation. By the course of meiosis of the spermatozoon, the course of spermatogenesis can be divided into spermatogonium, spermatocyte, pre-sperm and mature sperm. Pre-sperm is a special kind of stage adapting to its special method of reproduction. The sperm tail is composed of axial filament twisted with the lateral fin, and the axial filament is typical 9+2 structure of microtubule.3. Study on the change of sorts of nutriment during the different development of Onchidium strumaThe changes of nutrient ingredient and digestive enzyme in different development of Onchidium struma were analyzed by biochemistry method. The results show that the content of biochemical composition changed with the development of Onchidium struma. Onchidium struma has a high content of protein but low content of fat. The contents of protein in hepatopancreas are lower than those in muscle during the whole reproductive cycle. But the contents of fat in hepatopancreas are higher than those in muscle. The contents of protein and fat in both tissue change significantly(P<0. 05) before and behind the maturing stage. But the ash content in both tissue was not significant (P>0.05).Sixteen kinds of amino acids (AA) except Tau and Cystine of Onchidium struma were analyzed in different development stages, which contain7 essential amino acid, 3 semi-essential amino acid and 6 nonessential amino acid existed in each tissue. Among these amino acids, the content of Glu was the highest, the average content was 3.09, and the Val was the lowest, the average content was 0.10. The content of all the amino acids is Asp, Leu, Lys, Pro, Met, Arg, Ala, Gly, He, Phe, Tyr, Ser, His except Thr. The content of Pro changes obviously, and the coefficient of variability fluctuates from 0.35 to 0.74. And the coefficient of variability of Ala is the lowest, fluctuates from 0.13 to 0.14. The content of total AA has a trend of "high-low-high" with the development of the ovotestis. Twenty-eight kinds of fatty acids were analyzed in different development stages, which contain 10 SFA, 8 MUFA and 10 PUFA. The composition of total lipid is different in different development stages. The contents of SFA in ovotestis drop obviously from 55.96% in proliferating stage to 40.15% in growing stage, then rise gradually and reach to peak value in maturing stage.The MUFA has the similar trend with SFA. The SFA and MUFA in vitelline gland has similar trend. Both has the highest value 53.75% and 36.55% in maturing stage, and in other stages is low comparatively, but the PUFA has the contrary trend. The content of PUFA in hepatopancreas is lower than the other tissues, and the content has no significant different(P>0.05), the content of MUFA drop significantly from peak value 34.88% in proliferating stage to 15.39% in maturing stage, but the PUFA has different trend, rise from the lowest value 26.71% in proliferating stage to the highest 45.3% in maturing stage.The activities of digestive enzymes are different in different tissue and change with the development of ovotestis. The activity of trypsin in hepatopancreas changes significantly (P<0. 05) . The activity of trypsin in ovotestis was not significant (P>0.05). The activity of trypsin in vitelline gland is significantly lower than others (P<0.05), and the activity of trypsin in degeneration stage reach to peak value 0. 114 ±0. 008 U/mgprot, it is significantly higher than other stages(P<0.05). The activity of amylase in hepatopancreas in proliferating stage is significantly higher than other stages(P<0.05). The activity of amylase in ovotestis is similar with hepatopancreas, also significantly higher than other stages(P<0.05). The activity of amylase in vitelline gland is lower than the two other tissues, and begins to rise, and reaches to the peak value 0.112±0.008 U/mgprot. The activity of lipase in hepatopancreas has a trend to reduce, and was not significant (P>0.05) as a whole. The activity of lipase in ovotestis reaches to the peak value 20.920±6.280 U/mgprot in maturing stage, and significant higher(P<0.05) than degeneration stage. And The activity of lipase in vitelline gland was not significant (P>0.05), but significant lower than the two other tissues(P<0.05).
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