Response To The Exogenous Nutrient Of The Two Parasitic Wasps Of Lithocolloetis And The Host’s Instar Distribution

The aim of this experiment was to explore exogenous nutrient influence on the longevityof the two parasitic wasps of Lithocolletis ringoniella, namely Sympiesis soriceicornis andApanteles theivorae, and their daily feeding rhythm, to master the host’s instar distributionand to further reveal the host and parasitoid’s life activity laws. The experiment wascomposed of two parts: indoor observation and outdoor observation. During the indoorobservation, the male and female parasitic wasps which took a new eclosion were led to thebeekeeping box by single head breeding, and were fed daily with the pre-prepared nutrientsolution with a concentration of100g/L,200g/L,300g/L,400g/L,500g/L（glucose, fructoseand sucrose=1:1:1mixture）at regular intervals. And then the nutrient solution with the mostappropriate concentration was selected based on this to explore the feeding time influence onthe life span of the two wasps. By setting respectively feeding freely, feeding twice and onceeveryday, every two, three, four days feed once, feeding only once on the first day, and incontrast to no feeding, observing their daily feeding rhythm on appropriate concentration. Byoutdoor observation, it means collecting leaves with Lithocolletis ringoniella in apple orchardat regular intervals in Yangling, dissect the larva indoors, and observe the sequential variationand distribution of each instar.The result indicates that the longevity of Apanteles theivorae and Sympiesis soriceicorniswere longest when the concentration of exogenous nutrient solution concentration was300g/L,however, the shortest when they fed on the contentration of100g/L. When the concentrationof the nutrient solution were the same, the longevity of S.soriceicornis was longer than A.theivorae in interspecific comparision, the female was longer than the male when comparedwithin intraspecific species.Feeding frequency showed the same law on the two kinds of parasitic wasp, as thenumber of feeding was reduced, the females and males life of kinds of parasitic wasp wereshrinking. The longevity of female and male A. theivorae was22.38d and21.80d, and thelongevity of female and male S.soriceicornis was32.68d and31.98d when they fed anytime.The female and male A. theivorae showed almost the same feeding rhythms within a day. And there were two feeding peaks, with the female peak at respectively9:00and15:00and themale at8:00and13:00. The feeding curve of A. theivorae was that the general trend of femaleand male showed the same result, there were two peaks in daily feeing, but there were nomuch difference. From June21to August31, the larvae of Lithocolletis ringoniella numberchange was divided into three stages, namely to drop quickly period (June21to July3),smooth change (July3to July19) and the waves change (July19to August31). The host’sfive instar overall sequential variation change trend was roughly similar, saddled shaped,there are two peaks and two lows in the survey timezone. Different instar distribution of thesuccession of the insect has difference, the number of the3rd instar on June21was the most,and the4th and5th instar appeared zero distribution respectively on July19and August31.From the overall level on average and the distribution difference of the different instars, thenumber of the3rd instar in the same period was significantly more than the5th, and thedistribution difference among the rest instars was not significant.It showed that the lifespan of these two wasps can be extended through supplementingdifferent concentration of nutrient solutions. The life expectancy was the longest when thenutrient concentration reached300g/L. The life span shortened when the nutrientconcentration respectively changed as the following order:300g/L>200g/L>400g/L>100g/L>500g/L. On the other side, feeding time research displayed that the lifespan of parasiticwasps were significantly extended if they were fed once over every two days. Also, thelifespan was prolonged when the feeding times increased. The feeding rhythms of the twowasps had two peaks which were different based on sex, both between species and withinspecies. The larve number change of Lithocolletis ringoniella presented certain regularity; thetemporal distribution of each instar was significantly different.