Structural Characteristics Of Ant Populations And Variation In Morphological Traits In Agricultural Areas Of Eastern China

With the rapid economic development and deepening of urbanization in recent years,the ecological environment in the eastern agricultural area,as a concentrated distribution area of China’s agricultural ecosystem,is continuously deteriorating,the agricultural ecosystem has also been damaged.The risk of pest outbreaks and the possibility of invasion of alien organisms have increased sharply,soil animal diversity has been lost,and ant species resources have also been seriously damaged.To investigate the relationship between ground-dwelling ant community structure and morphological characteristics and bioclimatic factors in different habitats in the eastern agricultural areas of China,five sampling sites were selected as seasonal sampling unit grid points in the eastern agricultural region of China,namely,Mazhang agricultural region in Guangdong,Lishui agricultural region in Jiangsu,Xushui agricultural region in Hubei,Shenbei agricultural region in Liaoning,and Nong’an agricultural region in Jilin,and 43 additional sampling sites were selected as sampling sites for ant morphological characteristics.Three repeated sampling areas were set up in each sampling cell,and three different habitats of farmland,plantation forest and grassland were randomly selected in each sampling area.The area of each different sampling habitat is not less than 100 m^2,and five ground-dwelling ant collection squares with an area size of 1 m² are set up according to different spatial locations in each living area,and the spacing between each sampling sample is more than 10 m.Ground-dwelling ant were collected by the trematometer method,and the collected ants were stored with absolute ethanol,and brought back to the laboratory for ant species identification and morphological characteristics measurement.The results of the study showed that:（1）A total of 7372 ants were collected in five agricultural areas of eastern China,belonging to 97 species in 31 genera in 4 subfamilies.Among them,there are 44 species in 13 genera of Myrmicinae,with a total of 5133 ants;There are 43 species in 10 genera of Formicinae,with a total of 1962 ants;There are 6 species in 5 genera of Ponerinae,with a total of 35 ants;There are4 species in 2 genera of Dolichoderinae,with a total of 242 ants.A total of 2330 ants were collected from 45 species of 25 genera in farmland habitats.A total of 2694 ants were collected from 48 species of 26 genera in grassland habitat.A total of 2348 ants were collected from 51species of 25 genera in the artificial forest.（2）From the perspective of ant species richness,Lishui Agricultural Area of Jiangsu（33species）>Mazhang Agricultural Area of Guangdong（25 species）>Xushui Agricultural Area of Hebei Province（14 species）>Shenbei Agricultural Area of Liaoning Province（13 species）=Jilin Nong’an Nong Area（13 species）.From the perspective of ant number,Liaoning Shenbeinong District（2619 individuals）≈Lishui Agricultural District of Jiangsu Province（2451 individuals）>Jilin Nongnong District（1275 individuals）>Mazhang Agricultural District of Guangdong（686individuals）>Xushui Nong District of Hebei Province（341 individuals）.（3）From the perspective of the number of ant species in different habitats,the number of ant species in grassland habitat（19 species）in Mazhang agricultural area,Guangdong was slightly higher than that in farmland habitat（15 species）and significantly higher than that in plantation habitat（11 species）.The number of ant species in the plantation habitat（29 species）in the Lishui agricultural area of Jiangsu Province was significantly higher than that in the farmland habitat（19 species）and the plantation habitat（19 species）,while there was little difference in ant species in the other three agricultural areas.From the perspective of the number of ants in different habitats,the number of ants in grassland habitat（338 individuals）in Mazhang agricultural area of Guangdong was slightly higher than that of farmland habitat（225 individuals）,significantly higher than that of plantation habitat（123 individuals）,the number of ants in grassland habitat（600 individuals）in Agricultural and Agricultural Area of Jilin was higher than that of plantation habitat（426 individuals）and significantly higher than that of farmland habitat（249 individuals）,and there was no significant difference in the number of ants in the three habitats in the other three agricultural areas.（4）From the perspective of dominant species,the dominant species in the Mazhang Agricultural Area were Solenopsis invicta,Polyrhachis dives,and Anoplolepis gracilipes;The dominant species in Lishui agricultural area are Tetramorium caespitum and Formica japonica;The dominant species in Xushui Agricultural Area are Messor aciculatus and Tetramorium caespitum;The dominant species in Shenbei agricultural area is Tetramorium caespitum;The dominant species in the Nong’an area are Tetramorium caespitum and Lasius alienus.（5）The number of ant species and individual density of the three habitats in the five sampling points had obvious seasonal trends.The diversity index,evenness index and dominance index of the three habitat ants in the five sampling points also had obvious seasonal change trends.Among them,the change trend of diversity index and uniformity index is roughly the same as the change trend of species number,while the change trend of dominance index and species number is roughly the opposite.（6）From the perspective of community similarity coefficients between the three habitats,the community similarity between the three habitats in the north and south was slightly different,among which the Mazhang agricultural area and Lishui agricultural area both had the highest community similarity coefficients of farmland and grassland habitats,while Xushui agricultural area,Shenbei agricultural area and Nong’an agricultural area all had the highest community similarity coefficients between farmland habitats and plantation forest habitats.From the community similarity coefficient of ground-dwelling ant between different months,the two months with the highest similarity coefficient basically appeared in the four months from May to August.（7）The one-dimensional morphological feature clustering of Tetramorium caespitum was not significantly correlated with the geographical distribution of collection points.The clustering of bioclimatic factors showed obvious correlation with geographical distribution.The correlation between morphological characteristic values and biological factors showed that the principal component MC1（individual length factor）was significantly negatively correlated with MPC3（maximum rainfall factor）of bioclimatic factors（p<0.05）,while the correlation analysis of nine linear morphological characteristic values of grass paving ants with latitude and longitude showed that only HFL of hindfoot leg segment length was positively correlated with latitude（p<0.05）.In conclusion,the species richness of ants in the eastern agricultural areas of China showed a gradual trend of decreasing from south to north,and the number of individuals did not show a pattern from south to north as a whole.The species richness and individual number of ants in the three habitats showed no regularity.The species richness,individual density,diversity index,evenness index and dominance index of ants in the three habitats showed obvious seasonal trends.The hind leg segment length（HFL）of grass paving ants was significantly positively correlated with latitude,and there was no gradient law in the distribution of body size in the latitudinal space of agricultural areas in eastern China.