| Pentatomidae is a large group of Hemiptera insects,most of which are herbivorous.Eurydema gebleri and Dolycoris baccarum are the two most common agricultural pests of Pentatomidae,which are widely distributed in China.Previous studies mainly focused on the description of morphological characteristics,but not on the life history and biological characteristics of the two pests.Therefore,the biological characteristics of two important Pentatomidae pests were studied by field observation and indoor feeding,and the morphological characteristics,life history and living habits of different development stages were described.At the same time,the ultrastructure of the mouthparts of these two insects was observed by scanning electron microscope.The morphological structure of the mouthparts and the function and behavior adaptability of the sensilla were analyzed.Based on this study,reasonable pest control measures were put forward.In addition,the maximum entropy prediction model Max Ent was used to predict the potential habitats of these two pests in China.It provides the necessary theoretical basis for further research on Hemiptera taxonomy and pest control.The main results are as follows.1.It was found that there were 2-3 generations of Eurydema gebleri in Taigu area of Shanxi Province.The duration of different stages was about 7 days for eggs,3-5 days for first instar nymphs,4-7 days for second instars,5-9 days for third instars,4-8 days for fourth instars,6-10 days for fifth instars,and 22-39 days for nymphs.The first generation of nymphs flourished in late May and emerged successively from late May to early July.The second generation of Eurydema gebleri hatched from mid June to early August,and emerged successively from mid July to early september.From June to July to the end of autumn,the third generation of Eurydema gebleri hatched from early August to mid September,and emerged from mid September to late October.The second and third generation adults overwinter in the first and middle of November.2.In Taigu area of Shanxi Province,two or three generations of Dolycoris baccarum can occur,and the majority of them are two generations.The duration of different stages was about 7 days for eggs,2-3days for first instar nymphs,5-7 days for second instars,6-9 days for third instars,8-10 days for fourth instars,12-15 days for fifth instars and 33-44 days for whole nymphs.In the last ten days of March,the temperature rose and began to move.In mid April,the adults mated and laid eggs in the wheat field.The larvae hatched at the end of April and the beginning of May.The peak period was in June.The eggs of the second generation were hatched from late June to early July,and began to emerge in late August.The third generation was hatched from late August to mid September and emerged in mid late October.After harvest of autumn crops in the first and middle of October,some of the adults moved to cabbage and radish fields,and then moved to wheat fields to overwinter in the first and middle of November.In this study,two species of parasitic flies were found in the feeding of Dolycoris baccarum.They were Gymnosoma sp.and Cylindromyia sp.3.The results of scanning electron microscopy（SEM）showed that the Eurydema gebleri and Dolycoris baccarum structure of the mouthparts of the two species were similar to those of other Heteroptera insects.The upper lip was specialized into a triangular bone piece,and the lower lip was divided into four segments.There are two kinds of sensilla in the stomatal organ of Eurydema gebleri,which are trichoid sensilla and conical sensilla.There are three kinds of sensilla in the mouth organ of Dolycoris baccarum,which are one kind of hairy sensilla and two kinds of conical sensilla.4.The results showed that the suitable range of Dolycoris baccarum in China was much wider than that of Eurydema gebleri.The suitable range of Eurydema gebleri was widely distributed in the north of China,and Dolycoris baccarum was more suitable to live in the south of China.Annual mean temperature is the main climate factor affecting the distribution of Eurydema gebleri,and the relative contribution value is 41.7%.The contribution values of annual precipitation and precipitation seasonality were 30.3% and17.8%,respectively.However,the contribution of precipitation seasonality and mean diurnal range were very low,which were 5.3% and 5% respectively.The mean diurnal range was the main climate factor affecting the distribution of the Dolycoris baccarum,with the relative contribution value of 60.4%.The contribution values of mean temperature of wettest quarter and isothermality were approximately the same,accounting for 18.2% and 15.4% respectively.However,precipitation seasonality has the lowest contribution value 6%. |
