Arthropod-Plant Interactions最新文献

Inducible defense is an important anti-insect strategy in plants. This study investigated whether larval feeding by Hyphantria cunea at low-density and high-density levels can initiate inducible defense responses in the low-fitness host plant Tilia amurensis on the 7th- and 21th-day post-feeding. The results revealed significant alterations in the nutrient composition (e.g., amino acids, soluble sugars, and total proteins) within T. amurensis, with notable decreases observed on the 7th-day post-feeding, followed by increases on the 21st day, respectively. Specifically, the low-density feeding group prompted significant increases in tannin, total phenols, and total flavonoids on the 7th day, whereas the high-density feeding group induced significant decreases in these compounds. Conversely, total alkaloid levels exhibited an inverse pattern, with lignin contents notably decreasing. By the 21st-day post-feeding, all secondary metabolites demonstrated significant increases. Expression analysis of flavonoid biosynthetic genes mirrors the changes observed in the total flavonoid content. Furthermore, larval feeding activates the α-linoleic acid metabolism pathway consistently across all time points. Subsequent generations of H. cunea larvae in low-density feeding and high-density feeding groups demonstrated decreased growth, along with downregulation of growth regulatory genes and key genes involved in energy metabolism, digestion, and detoxification. Notably, the expression of digestive gene LIP10 and detoxification genes GST18 and CARE14 exhibits adaptive regulation in response to T. amurensis’ inducible defense. Overall, larval feeding by H. cunea elicits a robust and enduring inducible defense response in T. amurensis, ultimately decreasing the fitness of the subsequent generations of H. cunea larvae on T. amabilis.

Graphical abstract

Ants, a prominent insect group, play important roles in various terrestrial ecosystems, by engaging in diverse biotic interactions, such as those involving plants bearing extrafloral nectaries (EFNs). This study investigates the seasonal dynamics of this interaction throughout the dry and rainy seasons in a southern Sonoran Desert site. Results indicate that despite a relatively low coverage of EFN-bearing plants (4.97% ± 4.60), interactions between ants, and these plants are frequent, involving 31% of the perennial plant community (35 species) and 54% of the ant community (35 species). The cactus family exhibited the highest species richness (7 of 11 species) with EFNs in the study area. The location of EFNs varied among plant species and were associated with both vegetative and reproductive organs. Employing selective trapping for ants that forage on plants bearing EFNs, a higher ant species richness was recorded during the rainy season (19 vs 12 spp.). The network’s topology is associated with plant phenology, and slight seasonal differences in network structure parameters were observed. Seasonal variation in the interaction align with the phenology of EFN-bearing plants. Factors such as water availability could influence competition and, consequently, the inter-season variation in the number and dependencies of ant–plant interactions. Only two species were consistently recorded in both seasons within the core of generalists: the cactus Cylindropuntia fulgida and the ant Forelius pruinosus. Given the substantial involvement of ants with EFN-bearing plants, this association emerges as a fundamental component within the community of this desert site.

Annual loss of rice caused by insect pests accounts for about 30% of total production, and the use of traditional pesticides has brought about environmental pollution, food safety, and other problems. The use of secondary metabolites of rice to control pests has become a research hotspot, but little is known about the mechanism of rice self-resistance. Rice is a typical silicon accumulating crop. Previous study showed that silicon can significantly enhance the resistance of rice to Chilo suppressalis, but anti-insect active substances in silicon-treated rice were unknown. In current study, metabolomics analysis has been performed on two groups of rice (T1, treated with silicon and insect; T3, treated with only insect). A total of 151 significantly different metabolites were obtained, compared with T3 group, 23 metabolites in T1 were significantly up-regulated and 128 metabolites were significantly down-regulated. Different metabolites were mainly enriched to tryptophan metabolism, lipoic acid metabolism, linoleic acid metabolism, isoflavone biosynthesis, and indole alkaloid biosynthesis. The different metabolites (p < 0.1) enriched to lipoic acid metabolism and fatty acid biosynthesis were all significantly up-regulated. Ten significantly up-regulated different metabolites were selected from T1. These were 3-hydroxy-palmitic acid methyl ester (1), octanoic acid (2), 3-hydroxyoctadecanoic acid (3), 12-hydroxyoctadecanoic acid (4), 2-linoleoylglycerol (5), methyleugenol (6), alpha-asarone (7), 2,4,5-trimethoxybenzaldehyde (8), acitretin (9), and menatetrenone (10), and their anti-insect activity was evaluated. Compounds 1–5 and 7–10 could significantly inhibit the growth of Chilo suppressalis. Compounds 2 and 3 inhibited growth of the insect by 35.5 and 64.5%, respectively. Compound 2 belongs to lipoic acid metabolism and fatty acid biosynthesis. We speculate that silicon positively regulated the metabolic pathway of lipoic acid and fatty acid to enhance the resistance of rice to insects.

The endogenous protein complex myrosinase and glucosinolates form a defense system in cruciferous plants against insect pests. Transgenic ablation of myrosin cells produced MINELESS seeds of Brassica napus used to investigate plant–aphid interactions. In the present study, we conducted a non-choice experiment to test the performance and fecundity of the aphids Brevicoryne brassicae (specialist) and Lipaphis erysimi (generalist) on MINELESS transgenic seedlings and the wild-type cultivar Westar. Feeding preference showed that B. brassicae preferred wild-type seedlings and L. erysimi preferred MINELESS. Progeny of generalist and specialist aphids establish and affect wild-type and MINELESS seedlings differently. Glucosinolate hydrolysis products were higher under the influence of B. brassicae in both wild-type and MINELESS seedlings. In addition, allyl isothiocyanate decreased under the influence of L. erysimi, except 3,4 -epithiobutane nitrile. Infestation by L. erysimi induced the reduction of glucosinolates, whereas B. brassicae had an opposite effect. In conclusion, the present study showed that myrosin cells affected the preference of aphid species for Brassica napus plants.

Insect pests pose a global threat to ecosystem stability and food security, necessitating a move away from chemical pesticides and towards more environmentally friendly options. As a potential biocontrol tool, entomopathogenic fungi provides focused pest management with minimal negative impacts on humans and the environment. The processes underlying the action of entomopathogenic fungi, clarifying aspects affecting efficacy, contemporary formulations of mycoinsecticides and mycoacaricides that were available to combat various pests, emphasizing their crucial role in pest control initiatives and for a more sustainable and safe future were explored below. The formulations encompassing several entomopathogenic fungi, offer a wide range of environmentally beneficial alternatives for managing insect pests, signalling a paradigm change in plant protection methods towards remedies inspired by nature. In addition, a thorough assessment of the state of mycoinsecticide formulations, providing information on recent advancements and potential lines of inquiry were also presented. This review article lays the way for a harmonious cohabitation of agriculture and the environment by outlining an agenda for leveraging the potential of entomopathogenic fungi in sustainable insect pest management techniques.

Bark and ambrosia beetles use trees as hosts, and the preferred host condition—whether healthy, weakened, or dead—varies among beetle species. Though attraction to volatiles from trees under favorable conditions have been well studied in beetles, only a few studies have examined the repulsion of volatiles from trees under unfavorable conditions. We focused on this aspect by using the oak ambrosia beetle, Platypus quercivorus, as a model. This beetle attacks healthy oaks, causing Japanese oak wilt. Previous studies have suggested that leaf volatiles are important cues to detect the hosts of this beetle. Therefore, we used a Y-tube olfactometer to evaluate the beetle response to volatiles from fresh and dried leaves of their hosts and non-hosts. Volatile components were analyzed by gas chromatography-mass spectrometry (GC–MS). In the Y-tube, P. quercivorus preferred fresh leaf volatiles to clean air and did not generally prefer dried leaf volatiles. This preference was observed regardless of whether the source was a host or non-host. The degree of attraction to fresh leaf volatiles increased when the counterpart of the Y-tube was changed from clean air to dried leaf volatiles, suggesting a repelling effect of the dried leaf volatiles. The GC–MS results showed a clear difference in the chemical components of the volatiles from fresh and dried leaves. Common chemicals among the dried leaf volatiles of hosts and non-hosts, such as trans-2-hexenal, have been suggested as candidate repellents for P. quercivorus. The results suggest the possible use of dead branches to avoid beetle infestation.

This study investigated whether silicon applied as a drench to cowpea (Vigna unguiculata L.) could complement mutation-derived resistance to cowpea aphid (Aphis craccivora Koch). Lutembwe is a cowpea variety widely grown in Zambia but is susceptible to aphids. Genotypes LT 3-8-4-1, LT 4-2-4-1 and LT 11-3-3-12 are cowpea mutants derived from Lutembwe using gamma irradiation and have been identified as having partial resistance to cowpea aphid. Silicon accumulation capacity of cowpea genotypes and aphid performance parameters including colony growth, mean relative growth rate and feeding behaviour were assessed. Where silicon was applied to plants significantly higher silicon concentrations were recorded in LT 3-8-4-1, LT 4-2-4-1, LT 11-3-3-12 and Lutembwe genotypes compared to untreated plants. Silicon application on Lutembwe resulted in slower aphid colony growth and lower mean relative growth rates compared to untreated plants. Electrical penetration graph recordings of aphid feeding on silicon-treated Lutembwe plants showed that silicon-derived aphid resistance is mediated by phloem-based resistance factors. Silicon application to LT 3-8-4-1, LT 4-2-4-1 and LT 11-3-3-12, however, did not enhance aphid resistance. This may be due to the partial resistance of mutation-derived genotypes masking any benefits from silicon application to these plants. These results indicate that silicon application or use of mutation-derived genotypes may be effective tools with which to manage aphids on cowpea, but there appears to be little benefit of combining these approaches. This has important implications for developing an integrated pest management framework for cowpea aphid.

Hyphantria cunea is a significant invasive pest characterized by its polyphagous nature and robust reproductive capabilities. In the present study, the interaction between Morus alba seedlings and H. cunea larvae was revealed by combining the induced chemical defense of M. alba with the adaptive strategies of H. cunea larvae. Larval feeding damage swiftly triggers both local and systemic chemical defenses in M. alba, involving nutrients (amino acids, proteins, soluble sugars), secondary metabolites (total phenol, total flavone, tannin, lignin), and flavonoid synthesis pathways. Mild damage induced defense responses in M. alba that persisted until day 21, inhibiting the growth of a subsequent batch of H. cunea larvae after 7 days of continuous feeding. Conversely, at moderate damage levels, these induced defenses diminished by day 21, temporarily failing to affect the larval growth. In response to these defenses, H. cunea larvae significantly up-regulated the expression of most detoxification enzyme genes, which remained active throughout. Initially, some trypsin and lipase genes in the larvae were significantly up-regulated, but with prolonged feeding, gene expression shifted towards the α-amylase family. Feeding by H. cunea larvae can stimulate the induced chemical defense of M. alba. The H. cunea larvae can adapt to the M. alba chemical defense by modulating their digestive and metabolic detoxification mechanisms.

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Herbivory plays a central role in the structure of plant communities. However, there is a scarcity of research that simultaneously examines the impact of herbivory on both vegetative and reproductive traits. Using two species of Malpighiaceae as ecological models, Byrsonima intermedia and Peixotoa tomentosa, we hypothesized that plants that are free from herbivory exhibit greater growth and higher performance in vegetative (number of leaves) and reproductive (number of buds, flowers, and fruits) traits compared to plants subjected to natural herbivory. We conducted an experimental field study regarding the presence or absence of insect herbivores on plants and assessed plant traits for a 5-month interval in a Brazilian savanna area, the Cerrado. Our results revealed that B. intermedia individuals free from herbivory produced 4.3 times more young leaves compared to those subjected to herbivory. Regarding reproductive traits, we observed that the percentage of buds that successfully flowered was significantly higher in P. tomentosa individuals without herbivory than in those experiencing herbivory. Therefore, we suggest that the leaf herbivory may affect the plant’s vegetative and reproductive structures differently according to their ontogeny. The production of young leaves and the maturation of flower buds into flowers is lower when leaf herbivory occurs. However, to confirm this pattern, long-term studies should be carried out and consider the chemical compounds of the plants and the nutritional composition of the soil.