The Effect Of Food And Temperature On Development And Reproduction Of Agasicles Hygrophila

Alternanthera philoxeroides,a global invasive alien,causing great losses to the ecosystem and economy in invaded area.And the Agasicles hygrophila is an effective natural enemy that can prevent and control it.But the survival rate of A.hygrophila in winter is low in the northern subtropics.Therefore,it is very necessary to study the technology of raising A.hygrophila.In order to explore the artificial diet and feeding conditions of A.hygrophila.The author determined the nutritional components of aquatic and terrestrial A.philoxeroides.Then,the effect of different ecotypes of A.philoxeroides and temperature on the growth,development and reproduction of A.hygrophila was studied by two-sex life table.Finally,ten kinds of semi-artificial diets were prepared with the dry powder of A.philoxeroides as raw materials.And evaluate the effect of them on development of larval and reproduction of adult.1.The effects of two ecotypes of Alternanthera philoxeroides on development and reproduction of Agasicles hygrophila.Nutrition ingredients of the host plant was assayed,including soluble sugar,soluble protein,crude fat,amino acid and water content.The results are following:the nutritional ingredients of aquatic A.philoxeroides are significantly different from those of terrestrial A.philoxeroides.The protein,crude fat,soluble sugar and amino acid content of the terrestrial A.philoxeroides are higher than those of the aquatic A.philoxeroides.But the water content is lower.The data of two-sex life table are showing:The larvae of A.hygrophila have the lowest survival rate(90%)when feed terrestrial A.philoxeroides.But it is no significant difference from aquatic A.philoxeroides.And adults have the shortest development period of pre-spawning,male adult lifespan and female adult lifespan 4.53d,64.88d and 49.14d respectively.It is no significant difference from the aquatic plant.The values for the intrinsic rate of(r),finite rate of increase(λ),and net reproductive rate(R0)for the Adults of A.hygrophila when reared on the terrestrial plant were 0.1669 d-1,1.1817 d-1,and 240.65 offspring,respectively.Among them,the intrinsic rate(r)and the finite rate of increase(λ)were significantly lower than the aquatic plant.The average period(T)of the generation of the A.hygrophila with the terrestrial A.philoxeroides as the host plant is at least 32.28 days,which is no significantly different from the aquatic plant.it can be seen from the population dynamic parameters that the reproductive capacity of A.hygrophila when the aquatic A.philoxeroides as the host plant is stronger than that of the terrestrial A.philoxeroides.2.The effect of temperature on development and reproduction of Agasicles hygrophila.The chapter reflect the development and reproduction of A.hygrophila under the different temperature conditions by establishing two-sex life table.The results show:the growth and reproduction ability is better on 25℃,and the period of the growth and development shortened with the increase of temperature on 20℃-30℃.The egg production is the highest on 25℃.the larval stage,pupa stage,APOP,Female longevity and Male longevity are significant differences on 20℃ and 25℃.From the dynamic parameters of the population,we can see that 25℃ is the most suitable temperature for the growth and development of the lotus grass.3.The effect of different formulae of semi-artificial diets on development and reproduction of Agasicles hygrophila.Designing the semi-artificial diets formula,respectively according to the main nutrition ingredient content of A.philoxeroides,the A.philoxeroides leaf meal content in the semi-artificial diets,several known semi-artificial diets formula of insects.The dieted formula No.4 was better than others for adults:The life span of adult fed with No.4 diet was 9.20±0.95 days,but eggs couldn’t be laid.And the feeding of larvae is not ideal.a successful semi-artificial diet has not been developed.