Correlation Between Wing Type And Development Of Flight Muscles And Gonads In Acrididae

[Objective]The common insect wing types include long wing,short wing and wingless.Wing types are important characteristics for studying insect evolution.The current studies on insect wing type mainly focu on aphids,planthoppers,and stick insects.However,wing types of locusts are rarely studied.There are many kinds of wing types with different lengths,ranging from the long-winged type that facilitate flying to the wingless type where the front and rear wings completely disappear in Acridoidea.The diversity of wing types is a trade-off strategy for adaptability to the living environment.Wingless or short-winged species can use the energy initially for developing flight muscles for reproduction.Thus,they can produce more eggs earlier and have a selective advantage in harsh environment.It has not been systematically studied whether the wing-type diversity of locusts is related to the development of flight muscles,gonad of femals and males,etc.In this paper,based on the collection of a large number of natural locust populations,the statistical methods were used to verify the hypothesis that the flight and reproductive trade-off of locusts and revealed the adaptive changes of locusts' wing type,flight muscle and gonad traits.[Methods]1.Data of wing length,body length,flight muscle weight,testis/ovarian weight and other traits of wild Acridoidea species was collected.2.Kruskal-Wallis and Mann-Whitney U non-parametric analysis of variance were used to test the difference on wing length,flight muscles and gonads of 58 male and 56 female locusts in different life forms.3.Spearman rank correlation analysis method was used to analyze the correlation of wing length,flight muscle weight and gonad index(GSI)between male and female adults.4.T-test was used to compare the difference on relative flight muscle weight and gonadal index of five species of male and female winged dimorphic insects.5.Based on the mitochondrial genomic sequence data,phylogenetic tree of Acridoidea species was constructed.By using phylogenetic comparison method,comparison on relative wing length,relative flight muscle weight and the gonad index of 39 species of Acridoidea species' characteristic values for phylogenetic signal analysis were conducted in R 3.6.1.[Results]1.A total of 64 species of locusts were collected in ten provinces and regions,and 54 species were both female and male available.There were 39 species of long-winged males,16 species of short-winged,and 3 species of wingless;relative flight muscle weight of long-winged locusts was significantly larger than that of short-winged locusts,and the wingless locusts had no flight muscle.There were 36 species of long-winged females,18 species of short-winged,and 2 species of wingless;the gonad indexes of wingless grasshoppers and short-winged grasshoppers were significantly higher than that of long-winged grasshoppers.The gonad index of short-winged locust(Filchnerella tenggerensis)reached 0.2945.2.There was no significant difference on relative wing length,relative flight muscle weight and gonadal index of male locusts in different life forms(P>0.05);there was no significant difference on relative wing length and relative flight muscle weight of female locusts(P>0.05).But the gonad index of ground-dwelling female locusts was significantly higher than that of grass-dwelling female locusts(P<0.05).3.The relative wing length of female and male showed a strong positive correlation with the relative weight of flight muscle(?r=0.7269,? r=0.8344);the relative flight muscle weight between female and male showed a negative correlation with gonad index(?r=-0.5024,?r=-0.2649).4.The difference on relative flight muscle weight between male and female adults of the same species was significant(P<0.05).The relative flight muscle weight of short-winged male locusts was significantly greater than that of female locusts with scaly wings(P<0.05),the gonad index of female locusts with scaly wing was significantly higher than that of male species with short wings.5.Phylogenetic signal analysis showed that male and female insects had significant phylogenetic dependence on relative wing length,relative flight muscle weight and gonad index.Of all the traits above,relative wing length showed the strongest phylogenetic signal(K>1).The gonad index phylogenetic signal of females is relatively weak like that of males(K<1).[Conclusion]Insects of Acridoidea species have a trade-off countermeasure between flight and reproduction.Wingless or short-winged species lack flying muscles.The energy for initial flying muscle development is used more for reproduction and the gonad development,which shows a selective advantage.The length of male and female wings,the size of flying muscles and gonads have a significant phylogenetic dependence,and the length of wings shows a high degree of consistency in the phylogenetic relationship.