Study On Population Biology And Phototaxis Of Parasitic Unionicolid Mites In Cristaria Plicata

This paper described their distribution location and correlation with their host in their parasitic mussels based on Jiangxi Province Poyang Lake the survey of the major parasitic mites' parasitic condition in Cristaria plicata mussels,and analyzed the niche of four major mites in Cristaria plicata mussels from the quantitative estimates of the value of temporal,spatial and temporal-spatial niche breadth and overlap.One year's experimental dates showed that major parasitic mites in Cristaria plicata are U.(Wolcottatax) arcutata,U.(Parasitatax) ypsilophora,U.(Vidrinatax) agilex sp.nov and U.(Anodontinatax)penicillatus.There were mites distribution in outer gills,inner gills,mantles,podium,inhalant siphona and lip of C.plicata mussels.Mites in outer gills and inner gills were distributed more and on the length of 160～220mm C.plicata were high intensity of infection.There were no specific choice of male and female mussels.U.arcutata total infection rate were the highest (58.93%),the abundance were 20.26±50.00,the highest months of infection rate was May;followed by U.penicillatus,its total infection rate was 9.52 percent and the abundance was 1.58±12.88.The highest month of infection rate was September;The infection rates of U.ypsilophora and U.agilex sp.nov were 6.94 percent and 9.33 percent,their abundance was 0.29±1.28 and 0.52±3.46.Chi-square test for inter-specific relationship indicated that they were all positive correlation but between U.arcuata and U.ypsilophora,and between U.arcuata and U.penicillatus(X~2= 23.53,V=-0.22 and X~2=4.08,V=-0.09).The results indicated that the temporal niche breadth value of U.arcutata(0.24) was the maximum,that of U.ypsilophora(0.22) was the second,and the temporal niche overlap values of U.arcutata and U.penicillatus(5.22) were maximum.The value of spatial niche breadth only U.ypsilophora(0.29) was the minimum,but the other concentrated on 0.43～0.53,and the spatiall niche overlap values most concentrated on 1.91～2.65.The temporal-spatial niche breadth value of U.arcutata (0.10) was the maximum,and the temporal-spatial niche overlap values of U. arcutata and U.penicillatus(11.60),U.arcutata and U.ypsilophora(3.38),U. ypsilophora and U.penicillatus(1.11) were large.According to the value of temporal-saptial niche breadth obvious competition were U.arcutata,U.penicillatus and U.ypsilophora,in which U.arcutata was the most obvious.In addition,the phototactic behavior of three major unionicolid mites in Cristaria plicata were studied by the use of home-made phototaxis device.The results showed that the phototaxis of U.arcutata,U.ypsilophora and U.agilex sp.nov was correlated with light intensity,light color,as well as the relevant wavelengths. With the exposure of white light under different light intensity 500Lux,600Lux, 700Lux,800Lux,900Lux,1000Lux,U.arcutata and U.agilex sp.nov were extremely significant difference(P＜0.01),U.ypsilophora has no significant difference(P＞0.05).However,at the same light intensity,in addition to the condition of 500Lux and 900Lux significant differences(P＜0.05),under the rest of light intensity between the mite there were no significant difference.With the enhancement of light intensity the phototropism of U.arcutata were becoming increasingly negative light from positive phototropism,U.agilex sp.nov were all negative phototaxis and negative phototaxis index increased gradually,negative phototaxis index of U.ypsilophora in the light intensity 800Lux increased the largest and then declined.At the exposure of the same light intensity 500Lux through seven different color filter light,the unionicolid mites all showed significant difference(P＜0.05).Under the conditions of yellow light between the mites there were no significant difference(P＞0.05),but the other most significant difference(P＜0.01) in addition to the green light significant difference (P＜0.05).U.arcutata only in the performance of the green light was positive phototropism,the rest were negative light,under the light of red,orange,yellow, indigo negative phototaxis index higher;U.agilex sp.nov all showed a negative trend of light,and negative phototaxis index higher under indigo light;U.ypsilophora only under red light was positive phototaxis,the rest were negative light,and it had the highest phototaxis index under red light.