The Host Specificity And Spatial Pattern Of Amata Sp.

Cayratia japonica (Thunb.) Gagn., a perennial despicable weed in Jiangsu Province, causes great damage to green hedge, lawn and ornamental by climbing onto them, it also causes some damage to shelters or some cultivated facilities. Cayratia japonica(Thunb.) Gagn. has great insecticide resistance, the control effect of common chemical herbicide is bad. Cayratia japonica (Thunb.) Gagn. is the main host plant of Amata sp.. Amata sp. has strong resistance, the control of common chemical herbicides generally is less effective. According to preliminary observation, when the occurrence of Amata sp.is larght in the Cayratia japonica fild, the following year the number of Amata sp. was significantly lower, so, Amata sp. is the main biological factors of natural constraints of Cayratia japonica (Thunb.) Gagn. The objective of the present study was to investigate the ecological characteristics of Amata sp., host specificity and risk assessment, spatial pattern and population dynamics of Amata sp. in the land of Cayratia japonica (Thunb.) Gagn., The growth and reproduction, the food consumption of Amata sp..These knowledge may be of crucial importance to provide a theoretical basis for explaining the control effect of Amata sp. Ctenuchidae.to Cayratia japonica (Thunb.) Gagn..1. The host specificity of Amata sp. determined that:Among C.japonica., Visit viniferous, Parthenocissus tricuspidata, Ampelopsis japonica and Gynostemma pentaphyllum5closely related species of plants, the biggest selectivity of Amata sp. was C.japonica.. The selective rate from first to the fifth larvae were15.55%,22.00%、31.11%、30.00%and35.56%, the selectivity of several other plants weak (0-6.67%) The larvae of Amata sp. were mainly feeding C.japonica., not feeding on other plants, or only feeding a small amount, even in the host stress, were only feeding on a small amount of other plants, Amata sp., on only C.japonica. can complete the development phase. Adults in several plants on the oviposition preference tests showed that Amata sp. only lay their eggs on C. japonica.(number is46.36grain per one), while on other plants do not lay eggs. The results show that C. japonica. is the only host plant of Amata sp..2. The research of food consumption on Amata sp. shows that:Amata sp. can feed the flower buds and leaves of C. japonica., young larvae are not feeding the stems and fruits of C. japonica.. Food consumption increases with the growth of insect larvae, third instar larvae in food consumption surge. Under the conditions of different population density of Amata sp., on C. japonica.’s food consumption of different organs are different. Under different population density, the food consumption of Amata sp. larvae was significantly different, population density had no significant effect on1instar larvae, while other instar larvae feed the most in9/sish, and24h food consumption from2ed to5th larvae were60.20mg、90.00mg、142.50mg and210.12mg. Largh instar larvae(4、5instar) had no significant different at1/dish and9/dish. Under different temperature conditions the food consumption of Amata sp. were different. Higher temperature is conducive to its feeding.3. Under different population density and temperature conditions, the growth and reproduction of Amata sp. studies have shown that:a different population density of Amata sp. had a certain extent on the growth and reproduction:under different conditions of rearing density, the larvae developmental differences were seen in the young stage, and after3rd instar larvae, the larvae rearing density on development rate is not obvious influence. With the growth of age showed accelerated growth rate trend, the4th instar larvae developmental duration, compared with an age of about50%shorter, Amata sp. have a certain gregarious nature, proper stocking density can increase the growth rate of Amata sp. The developmental period and of eggs、larvae and pupa were raletively shortest while the survival rate were the highest in the condition of5/sish. Different temperature conditions on Amata sp. growth and reproduction to a certain extent:in the25-34℃temperature range, the temperature of a developmental duration of larvae significantly affected, but to larvae of other age, the developmental period was not significant. Different temperature on the survival rate of Amata sp. larvae have significant impact, the general trend of temperature and survival were negatively correlated, the temperature increased, the lower survival rate, each instar had the most survival rate in25℃, that was98.35%、86.63%、100%、100%、100%;34℃has the most obvious effect on the survival rate of different ages.4. Amata sp. on the spatial pattern and sampling studies have shown that:Amata sp. adults are aggregated distribution, aggregation is due to the role of some environmental factors cause, rather than due to insect activity; Amata sp. larvae are aggregated distribution, aggregation is due to Amata sp. aggregation behavior or caused by Amata sp. and the environment differences. The observation period for the spread of trends analysis of Amata sp. showed that the adults were in the uniform distribution while the larvae were in the aggregation process in a certain period of time. This phenomenon is consistent with the performance of C. japonica. field. Amata sp. on theoretical sampling research shows that with density of the adults and larvae increased, the survey sample size diminished, but at the same density, sampling number with the reduction in tolerance increased. In practice, according to the survey time and manpower to choose the appropriate tolerance, and to determine the density of the survey plots, and then look-up table to determine the detailed investigation required number of samples.