Molecular Entomology, 2025, Vol.16, No.1, 39-49 http://emtoscipublisher.com/index.php/me 40 not only has basic ecological significance, but also directly serves the sustainable management of agricultural pests and provides a scientific basis for ensuring food security. Given the important position and complex impact of herbivorous insects in agriculture, this study will analyze their evolutionary adaptation mechanisms and species dynamics, introduce the basic characteristics and ecological roles of herbivorous insects in agricultural ecosystems, focus on the evolutionary adaptation mechanisms of herbivorous insects, discuss the species dynamics and population ecology of herbivorous insects in agricultural ecosystems, and summarize the ecological influencing factors of the adaptive evolution and species dynamics of herbivorous insects. This study sorts out the research progress on the evolutionary adaptation and species dynamics of herbivorous insects in recent years, deepens the understanding of the laws of ecological adaptation of pests, and provides scientific support for the formulation of green agricultural pest management strategies. 2 Characteristics and Ecological Role of Herbivorous Insects in Agricultural Ecosystems 2.1 Biological and ecological characteristics of herbivorous insects Herbivorous insects refer to insect groups that use tissues or products of living plants (including crops) as food sources. There are many species, covering almost all major insect orders (Onstad et al., 2009; Jankielsohn, 2018). In agricultural ecosystems, common herbivorous insects include: moth larvae of Lepidoptera (such as armyworms and cotton bollworms), beetles of Coleoptera (such as corn weevils and sweet potato weevils), Homoptera of Hemiptera (such as planthoppers, aphids, and whiteflies), locusts of Orthoptera, etc. These insects have their own characteristics in morphology and life history. For example, locusts have powerful hind legs that can jump and migrate, planthoppers and whiteflies have piercing and sucking mouthparts to suck plant sap, and moth larvae have chewing mouthparts that specialize in eating leaves or fruits, etc. (Dofuor et al., 2024). Different groups of herbivorous insects have significantly different host ranges: some are monophagous or oligophagous, feeding on only one or a few closely related plants (such as the rice stem borer, which is mainly a rice pest); others are polyphagous (broad-spectrum) pests that can feed on multiple families of plants (such as cotton bollworms, which can harm dozens of crops such as cotton, corn, and tomatoes). Generally speaking, polyphagous insects are more likely to survive and spread in agricultural landscapes due to their wide food sources, but at the same time they need to evolve complex detoxification and adaptation mechanisms to cope with the defense chemicals of different plants (Crossley et al., 2021). In contrast, monophagous insects often develop highly specialized adaptive traits in their long-term co-evolution with specific hosts, such as feeding behaviors or enzyme systems corresponding to specific herbivorous parts (Horgan, 2024). 2.2 The role of herbivorous insects in agricultural ecosystems In agricultural ecosystems, the most direct role of herbivorous insects is as pests, affecting crop yield and quality (Fiallo-Olivé et al., 2020). Most herbivorous insects feed on leaves, stems, fruits, seeds or juices of crops, causing crop yield reduction or quality decline. According to statistics, in the absence of prevention and control, the yield loss of major food crops in the world due to insect feeding can reach more than 30% (Savary et al., 2019). Even in modern agriculture, pests still cause huge economic losses and food losses every year. In addition, some herbivorous insects can also act as vectors of pathogens, exacerbating the damage to crops (Fiallo-Olivé et al., 2020). On the other hand, herbivorous insects are also a key link in the agricultural ecological network (Wyckhuys et al., 2024). They are at the middle level of the food web. On the one hand, they feed on plants and transfer the energy and materials of primary production to higher trophic levels. On the other hand, they provide food sources for predators and parasites (such as parasitic wasps, predatory insects, birds, etc.) at higher trophic levels (Figure 1) (Li et al., 2023; Dofuor et al., 2024). Therefore, the existence of herbivorous insects maintains multiple relationships such as predator-prey and host-parasitoid in farmland ecosystems (Adhikari et al., 2024). If the population of herbivorous insects decreases excessively (for example, extreme use of broad-spectrum pesticides causes the decline of pests and beneficial insects together), some natural enemies may decline due to lack of food, thereby destroying the ecological balance (Wyckhuys et al., 2024).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==