Abstract: The rich resources of natural enemies in Xinjiang have great potential for exploitation and utilization. In this paper, the diversity and seasonal dynamic changes of ladybug communities in six typical habitats in fields of wheat, corn, alfalfa and cotton, farmland shelterbelt, and orchard in northern Xinjiang were investigated by sweeping method from May to September 2019. A total of 5501 specimens were collected, which were identified to belong to 23 species, 12 genera, 6 families, 3 subfamilies. Adonia variegata (28.52%), Propylea quaturodecimpunctata (20.21%), and Stethorus punctillum (16.51%) were the dominant populations. The number of individuals and groups of ladybug communities differed between habitats, alfalfa fields harbored the highest population size (262 ladybugs/sample plot/time) and the most abundant species (20 species), while cotton fields had the lowest figures (48 ladybugs/sample plot/time and 4 species). Community diversity analysis showed that shannon-Wiener diversity index, Margalef richness index and Pielou evenness index ranked from high to low were the first half of August, the second half of July, the second half of May, the second half of August, the first half of July, the second half of June, the first half of September, and the first half of June. Among all the habitats, shelter forest showed the highest diversity index (0.62), richness index (2.06) and evenness index (0.72) in the whole growing season, followed by alfalfa fields (0.55, 2.35, 0.49), and cotton fields were of the lowest diversity index (0.21), richness index (0.46) and evenness index (0.57), but harbored the highest dominance index (0.70). The similarity analysis showed that the ladybug communities were basically medium similar between different habitats (0.5 ≤ q ≤ 0.75). Among the 28 different month groups, the highest similarity coefficient (0.94) was found between the second half of August and the first half of September, among which there were 15 common species including Stethorus punctillum, Hippodamia Variegata, and the other groups were basically medium similar or very similar. In northern Xinjiang, the number of individuals and groups of ladybug communities are relatively rich, and the distribution is relatively uniform in different months, and their natural control service is relatively strong. Especially, shelter forest and alfalfa fields should be strengthened to protect and utilize the local natural predator resources, so as to provide scientific basis for promoting the sustainable development of green agriculture.

Key words: Xinjiang, natural enemy ladybugs, diversity analysis, biological control, seasonal dynamic