Population Characteristics And Predation Of Aphidoletes Aphidimyza Reared On Rhopalosiphum Maidis At Different Temperature

As an important predative natural enemy,Aphidoletesaphidimyza（Diptera:Cecidomyiidae）plays a vital role in biological control of aphids.A.aphidimyza exists not only on the aphids-infected plants in nature but also be applied to control the aphids population in the greenhouse.Temperature is recoganised as an important non-biological factor affecting the growth and development of the organism,which plays a very significant impact on the occurrence and development of insect population.To investigate the population characteristics,predation and evaluate the control effect of A.aphidimyza under different temperatures,our present work studied the two-sex life table and its predation parameters of A.aphidimyza feeding with corn aphid（Rhopalosiphum maidis）under different temperatures（18℃,22℃,26℃,30℃）.The main results are as follows:1.Two-sex life table of A.aphidimyza under different temperatures（18℃,22℃,26℃,30℃）.The survival rate of A.aphidimyza inscreased at first and then went down as the temperature elevated.The survival rate was the lowest at 18℃,reached the highest point at26℃and decreased slightly when the temperature is 30℃comparing to 26℃.Fecundity（F）increased steadily from 22℃to 30℃.The maximum value of fecundity at 18℃was only3.40±1.39,while the highest number at 22℃was 23.39±7.27.The fecundity reached a maximum value at 30℃and the number is 56.44±10.49.The mean generation time（T）showed a downward trend as the temperature inscreased.When the temperature inscreased from 18℃to 22℃,the decline of the mean generation time is the most obvious,from 39.49±0.77d to 19.07±0.71d.The intrinsic rate of increase（r）and the finite rate of increase（λ）increased with temperature rise reaching the highest at 30℃.The net reproduction rate（R₀）exihibited an increasing trend as the temperature grow up before 26℃and had a slightly decrease at 30℃.The results show that low temperature has a great negative effect on the population of A.aphidimyza.During the low temperature,the growth and development delayed,the developmental duration increased and the number of oviposition reduced.However,A.aphidimyza showed a good adaptability to the relative high temperatures as every population parameter doesn’t change too much comparing to the suitable temperatures.In addition,the A.aphidimyza laid more eggs at higher temperature.2.The predation of A.aphidimyzaduring larval stage under different temperatures.The results indicate that the low temperature has a significant effect on the predation parameters of the larva A.aphidimyza.When the temperature is low,the larval predation rate reduced significantly.However,the larvae of A.aphidimyza showed a good adaptability to the relative high temperatures while the predation rate are really high at 30℃.The results indicated that relative low temperatures about 18℃have significant negative impacts on the development of A.aphidimyza and its predations to R.maidis.When the tempertures ranged from 26℃to 30℃,the development of A.aphidimyza are in good condition and maintain a high level on the predations to R.maidis.