| Bradysia odoriphaga Yang et Zhang and Bradysia difformis Frey are the main root maggot pests such as chives?leek and garlic in Gansu Province.In order to determine the influence of high temperature on the survival characteristics and population dynamics of two species.Choosing chives for food,and using light incubator to study the effect under thermostats on the growth,development and fecundity.And to further determinethe activities of protective enzymes(SOD,POD,CAT),soluble protein and carbohydrate(soluble sugar,glycogen and trehalose)dynamic changes in the 4th instar larvae were measured by short-term high temperature.Provide a theoretical basis for the comprehensive prevention and treatment of B.odoriphaga and B.difformis.1.The effect of biological characteristics of Bradysia odoriphaga Yang et Zhang and Bradysia difformis Frey by high temperatureThe growth and development and reproductive characteristics of the Bradysia odoriphaga Yang et Zhang and Bradysia difformis Frey were different under the 4 temperature gradients of 25?,28?,31? and 34?,,and their optimal growth and development ranged from 25? to 28?,growth slows at 31?,while 34? high temperature is to inhibit the hatch of their eggs.The developmental stagefrom egg to pupa ofB.odoriphaga and B.difformis were the longest at 31?,respectively 22.58 d and 22.00 d,28 ? was the shortest 21.00 d and 17.38d;With the increase of temperature,the life span of female and males was the first increase and then decrease,and the B.odoriphagalongevity of female was shorter than that of male,but the opposite of B.difformis law;The fecundity highest at 25?,which was B.odoriphaga 114.44,and B.difformis 87.11;The survival rates of all the life span were the highest at 25?;The net reproductive rate,intrinsic rate of increase and finite rate of increase of two specieswere higher at 25~28?.Therefore,the optimum temperature range of growth and development is 25?~28?,while the high temperature of 31? can inhibit its growth,and the egg can not hatch normally at 34?,which directly affects the development of its generation.2.The effect ofgrowth and development of Bradysia odoriphaga Yang et Zhang and Bradysia difformis Frey by brief exposure to high temperatureThe 24 h oviparous eggs,the 4th instar larvae of 1 day old and the 1 day old pupa under the suitable temperature(25±1?).After being treated at 34,37 and 40? for 1h,2h,4h and 6h,then kept it at proper temperature and kept on raising for studying the effects of short-term high temperature on the growth and development of B.odoriphaga and B.difformis.The results showed that the egg hatching rate,4th instar larvae pupation rate and the pupa emergence rate under the same processing time decreased with the increase of temperature;And decreased with the prolongation of processing time at the same temperature.B.odoriphaga and B.difformis was all died under the conditions of 40?,the 4th instar larvae 1h,eggs and pupae 2h.The developmental times of eggs,4th instar larvae and pupae increased with the increase of processing time at the same temperature,while it was shortened first and then lengthened at shorter treatment time.It can be seen that the brief exposure to high temperature had significant effects on the egg developmental duration and hatchability,4th instar larvae developmental duration and pupation rate,pupa developmental period and feathering rate of B.odoriphaga and B.difformis.The higher the temperature,the longer the processing time,the greater the impact.And the tolerance of eggs and pupae of both species to high temperature was higher than that of the 4th instar larvae.3.The effect of protective enzymes and Soluble protein of Bradysia odoriphaga Yang et Zhang and Bradysia difformis Frey bybrief exposure to high temperatureThe SOD enzymatic activity of two species was increased significantly with the increase of treatment time at 34?,whereas the SOD enzymatic activity increased at the higher temperature of 37? and then decreased with the increase of treatment time,the lowest was 37?6h treatment group,at this time,the SOD enzymatic activity of B.odoriphaga was 8.07ug/mg·min andB.difformiswas 5.73ug/mg·min,but still higher than that of the control group 7.89ug/mg·min and 6.54ug/mg·min.The POD enzymatic activityof B.odoriphagawas increased at the same exposure temperature with the increase of treatment time,but when the temperature reached 37?,with the increase of treatment time PODenzymatic activity was not high at 34?;However,at 34?,thePOD enzymatic activity of B.difformiswas increased,with the increase of treatment time.but when the temperature was raised to 37?,by compared with control,it'sPOD enzymatic activity wasincreased first and then decreasedwith the increase of treatment time,the lowestwas 4.54ug/mg·min at 37?6h,which was lower than the control.The CATenzymatic activity in two species was increased with the increase of treatment time at 34?,but decreased with the increase of treatment time when the temperature was raised to 37 ?;It shows that the CATenzymatic activitypromotionhas a certain limit underthe short-term hightemperature,too high temperature treatmentr to long time will lead to decreased.Under the same exposure temperature,the soluble protein content in two species was increased with the increase of treatment time except B.odoriphagaat 37?6h,and higher than that at 34?content,higher than the appropriate temperature control at 25?.4.The effect of carbohydrateof Bradysia odoriphaga Yang et Zhang and Bradysia difformis Frey bybrief exposure to high temperatureBrief exposure to high temperature stress on the two species main carbohydrate content has a certaininfluence.Thesoluble sugar andglycogen of the two species of Bradysiashowed an upward trend at 34? after short-term high temperature treatment,and decreased with the increaseing time at 37?.The lowest was 37?6h treatment group,at this timethe soluble sugar content ofB.Odoriphagawas7.9ug/mg,lower than the control's 8.8ug/mg,the glycogen content was 1.32ug/mg,lower than the control's1.40ug/mg;B.difformishas a similar pattern.However,the trehalose co-ntent in the two species was the highest at the same temperature,the trend of first increased and then decreased with the increase of processing time,this indicat that although trehalose content in mosquitoes was increased by short-term high tempera-ture treatment,But also reduced after toohightemperatures for long time. |
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