the pine needle gall midge, Thecodiplosis japonensis Uchida et inouye, is a newly invasive pest in china that mainly harms Pinus thunbergii and P. densiflora. the occurrence and damage caused by T. japonensis in pure stands of P. thunbergii were investigated, and the needle growth and needle compound content were measured. Based on the above steps, the growth dynamics of galls and chemical defense response of P. thunbergii to attack by the gall midge were revealed. the results showed that the adults of T. japonensis in Qingdao city, china, emerged from the end of May to late July, with a peak in mid-June. needles of P. thunbergii began to differentiate in late June and stopped growing in mid-September. The length of infested needles was 60.17% less than that of healthy needles. On average, there were 9 ± 4 larvae in each gall, 22 at most and 1 at least. The number of larvae within a gall had no significant effect on the size of the gall or larvae. Compared with that in the ungalled tissues, the content of amino acids in the galled pine needle tissues increased by 40.83%, while the content of total polyphenols, tannins, carotenoids, total triterpenes, total alkaloids and other secondary substances decreased to varying degrees, which was favourable for the growth and development of the T. japonensis larvae. There are approximately one million named insects and more than 500,000 plants on Earth, accounting for more than half of the total global biodiversity 77. During the long-term process of natural selection, plants and insects are closely related in regard to nutrition, reproduction, protection, defence and diffusion. Plants provide food and habitat for insects, but insects also provide many benefits to plants, such as seed dispersal and pollination 37. There are many ways by which insects obtain nutrition from plants. Some insects, such as beetles, moths, and wasps, directly eat the leaves, stems and roots of plants, which affects the absorption of nutrients and the performance of photosynthesis by plants 26,54,74. Some suck the sap from plant tissue, such as aphids, red spiders, and whiteflies 13,19,28 , which causes the loss of green colouration, the deformity of plant tissue and plant death. In general, host plants respond positively to damage caused by pests. For instance, almost all secondary metabolites, including nitrogenous compounds (such as alkaloids and non-protein amino acids), terpenes (such as monoterpenes and diterpenoids), and phenols (such as monophenols and flavonoids), may be produced in large quantities in plant tissues due to insect attack 2,9,16,20,34,41,73. The insects that can induce plants to produce galls are called gall-forming insects and represent a large group of phytophagous insects. Galls on host plants vary morphologically among different insects 27 , these morphological differences are considered to represent the adaptability of the gall-forming insects to the environment 5,27,33. Six hypotheses have been proposed to explain this phenomenon, including the nonadaptive hypothesis,...

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The movement behavior of the pine needle gall midge (Thecodiplosis japonensis Uchida Et Inouye (Diptera: Cecidomyiidae)), an invasive species in China, was determined by using a tethered flight technique and digital videography in the laboratory. The flight distance, duration, and speed of females were compared at different ages (2–10 h) and ambient temperatures (17, 21, 26, and 30°C). Female flight distance and duration at 26°C were significantly greater than those at 17°C and 21°C. The age of T. japonensis did not significantly affect the three flight characteristics. For females at 2–10 h of age at 26°C and 70% RH, the maximum flight distance was 667.59 m; the longest flight time was 6,222.34 s; and the fastest flight speed was 0.44 m·s−1. For larvae wetted with water, the highest jump was 5.7 cm; the longest jump was 9.6 cm; and the greatest distance moved in 5 min was 27.13 cm, which showed that the active dispersal potential of larvae was very low.

Drought is among the most important natural disasters with severe effects on animals and plants. MicroRNAs are a class of noncoding RNAs that play a crucial role in plant growth, development, and response to stress factors, including drought. However, the microRNAs in drought responses in common vetch (Vicia sativa), an annual herbaceous leguminous plant commonly used for forage by including it in mixed seeding during winter and spring, have not been characterized. To explore the microRNAs’ response to drought in common vetch, we sequenced 10 small RNA (sRNA) libraries by the next-generation sequencing technology. We obtained 379 known miRNAs belonging to 38 families and 47 novel miRNAs. The two groups had varying numbers of differentially expressed miRNAs: 85 in the comparison group D5 vs C5 and 38 in the comparison group D3 vs C3. Combined analysis of mRNA and miRNA in the same samples under drought treatment identified 318 different target genes of 123 miRNAs. Functional annotation of the target genes revealed that the miRNAs regulate drought-responsive genes, such as leucine-rich repeat receptor-like kinase-encoding genes (LRR-RLKs), ABC transporter G family member 1 (ABCG1), and MAG2-interacting protein 2 (MIP2). The genes were involved in various pathways, including cell wall biosynthesis, reactive oxygen removal, and protein transport. The findings in this study provide new insights into the miRNA-mediated regulatory networks of drought stress response in common vetch.