Arthropod-Plant Interactions最新文献

Ant–plant associations are well known for their mutual benefits; ants defend plants from herbivores, while plants provide food and shelter. This study examines the shift from mutualism to parasitism by investigating how the interaction of the weaver ant (Oecophylla smaragdina) influences the biochemical and physiological responses of Cassia fistula L. Leaves were taken from healthy plants and from plants with mild to severe ant infestations, then tested for photosynthetic efficiency and antioxidant activity. During the initial phase of infestation, mutualism between ants and plants was observed, while severe ant infestations strongly reduced photosynthesis, with a major decline in the plant’s ability to use light energy. While mildly infested leaves showed an initial boost in protective antioxidant enzymes, these defences collapsed under severe infestation, leading to oxidative stress and cellular damage. Overall, the study reveals that while a small presence of ants may stimulate plant defences, large ant colonies harm the plant leaves by overwhelming its protective systems. The results clearly highlight that mutualism-parasitism shifts completely rely on the infestation intensity of Oecophylla smaragdina in C. fistula.

Tomato, Solanum lycopersicum, is an economically important crop in Cameroon and worldwide. Despite the potential for pollinator visits to increase fruit production, little research has been done in the region to assess plant-pollinator relationships in S. lycopersicum. The aim of the study was to evaluate the foraging activity of Xylocopa torrida and determine its impact on Solanum lycopersicum yields in Dschang, Cameroon in 2022 and 2023. The investigations focused on two treatments each year. Of 161 flower buds labelled for each year, 101 were covered, 60 intended for the single visit of X. torrida. The foraging activity and pollination efficiency of Xylocopa torrida on fruits and seeds yields were evaluated. Results showed that X. torrida collected pollen and nectar throughout the day, with a daily peak of activity between 12 h and 13 h. Fruits from the treatment with a single visit from X. torrida were heavier and contained more normal seeds compared to those from the treatment protected from insect visits. Through its pollination efficiency, X. torrida increased fruit mass by 12.71% and the formation of normal seeds by 50.01%. Given the potential of X. torrida and other Xylocopa spp. to improve tomato harvests, it is recommended to protect potential nesting sites like dead wood near farms and to carefully follow pesticide application regimes, including not applying pesticides during the flowering period.

Trichomes are specialized epidermal structures that act as physical/ chemical barriers to repel herbivores often found most abundantly in wild crop relatives compared to their cultivated genotypes. Previous studies revealed that certain wild Solanum species exhibit complete feeding antixenosis (= feeding non-preference) against ash weevil, Myllocerus subfasciatus Guerin-Meneville, an important folivore pest on brinjal (Solanum melongena). We studied the feeding behaviour of ash weevil in detail among the wild and cultivated Solanum species and their trichome morphology and secondary metabolites to identify the traits responsible for the feeding antixenosis. Detailed observations were made on the leaf trichome diversity and their biochemical characterization in the wild (S. mammosum, S. viarum, S. macrocarpon, S. sisymbriifolium, S. indicum, S. aethiopicum, S. gilo, S. torvum, S. capsicoides, S. seaforthianum and S. nigrum) as well as cultivated S. melongena that could explain the observed host plant defense (feeding-antixenosis) against M. subfasciatus. Seven types of trichomes including glandular (IV, VI, VII) and non-glandular (II, III, V, VIII) are noticed and Solanum species having glandular trichomes were less preferred by ash weevil. Most of the susceptible Solanum species mainly comprised non-glandular trichomes (type VIII) and were completely devoid of glandular trichomes. Biochemical characterization of different Solanum species trichome wash by GC–MS [Gas Chromatography–Mass Spectrometry for Volatile Organic Compounds (= VOCs)] and LC–MS/MS (Liquid Chromatography with Tandem Mass Spectrometry for phenolic acids, acyl sugars) revealed specific metabolites in glandular trichomes that might have played role in the observed antixenosis against ash weevil. Higher proportions of acyl sugars and phenolic acids that appear to be correlated with the feeding antixenosis of ash weevil were associated with glandular trichome density. Principal Component Analysis (PCA) revealed that of 45 VOCs observed, Z-11(13,13-Dimethyl) tetradecen-1-ol acetate; acetic acid, (2-benzothiazolylthio)-, ethyl ester; Z-9-Octadecenoic acid; 9-Tetradecenal, (Z) were found to contribute to the observed feeding antixenosis, whereas, n-hexadecanoic acid which is predominantly present in the non-glandular trichomes might have conferred the susceptibility of Solanum species.

The tomato leafminer, Phthorimaea absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), is currently the major pest threatening cultivated tomato production worldwide, causing severe yield losses. This study focused on investigating the effects of the five tomato varieties (Taykan, Torry, Verty, Seyran, and Mamston) most preferred by producers in Antalya province in Türkiye on the attraction and oviposition responses of P. absoluta females. Y-tube olfactometer bioassays were conducted to determine the attraction of tomato varieties to mated P. absoluta females. Oviposition preference bioassays were carried out in cages to establish the effect of tomato varieties on the pest’s oviposition response. Volatile organic compounds of each variety were also identified by GC-MS. Mated P. absoluta females were most attracted to the Taykan variety and least attracted to the Mamston variety in the Y-tube olfactometer. In the oviposition choice and no-choice experiments conducted in cages, mated females laid the highest average number of eggs on Taykan (92.70 ± 4.02 and 84.40 ± 3.14, respectively) and the lowest on Mamston (41.30 ± 3.95 and 39.80 ± 3.08, respectively), with a statistically significant difference observed. In GC-MS, the most abundant compounds identified in all varieties were terpenes, followed by aldehydes. Principal component analysis on volatile organic compounds from tomato varieties revealed a 71.25% variance between varieties by two components. The presence of VOCs, namely caryophyllene, humulene, 2-carene, beta-phellandrene, and o-cymene could serve as attractant to mated P. absoluta females, whereas the presence of (E)-2-hexenal, hexadecane, nerone, and mequinol could have a repellent effect. Consequently, this study showed that tomato varieties significantly influenced female tomato leafminer attraction and oviposition responses. Accordingly, the findings presented herein may prove beneficial in the development of tomato varieties resistant or tolerant to P. absoluta.

Studying interactions between plants and insects is crucial for understanding plant productivity in both natural and managed ecosystems. This background underscores the need for sustainable food production strategies addressing human health, environmental safety, and pesticide resistance. Moreover, predicting and evaluating changes in plant traits and ontogenetic plant traits is essential, as these factors influence the ecological outcomes of plant − insect interactions. This study aimed to analyze the relationship between morphological traits and insect communities—specifically herbivores, predators, and beneficial insects—across the ontogeny of lima bean (Phaseolus lunatus L.) in 25 landraces from the Yucatán Peninsula. Field data on phenotypic plant traits and insect family composition were collected for each landrace during two growth stages: vegetative (15 to 30 days after emergence) and reproductive (45 to 60 days after emergence). The variables most strongly related included color traits such as green hypocotyls and red or reddish-grey seeds, insect families, and insect guilds. Specifically, the color traits of cotyledons, hypocotyls, and seeds, along with specific leaf area, showed a notable association with the Chrysomelidae family. Our findings clarify the relationship between morphological plant traits and insect families, highlighting dynamics across two stages of lima bean ontogeny and enhancing our understanding of ecological relationships among diverse insect groups and their identities.

The melon fruit fly, Bactrocera cucurbitae (Coquillett) is an important notorious pest of many cucurbitaceous vegetables including bitter gourd (Momordica charantia). It often causes substantial yield losses in the Gangetic Alluvial Zone of West Bengal, India. We expected that the genetic variability between bitter gourd genotypes is responsible for the varying degree of resistance to fruit fly infestation through distinct morpho-chemical traits. Field screenings (preliminary and final) of twenty bitter gourd genotypes revealed significant differences in fruit infestation and maggot density per fruit and identified five resistant (US-6214, Asmita, Meghnad-2, Vivek and Chandramukhi), nine moderately resistant (Noble Katahi, Palee, Contai Bolder, Mohar, PAN-1983, Chottu, Deb-520, Malaypuri and NS-454) and six susceptible genotypes (Karishma, Abhishek, Akash, Krishna Kantedar, Prachi and Pusa Do Mausami). Resistant genotypes exhibited antixenotic traits such as long tubercles, higher tubercle density, thicker pericarp and tougher fruits, and higher concentrations of protein, total sugar, ascorbic acid, tannin, flavonols, total phenols, peroxidase and polyphenol oxidase. These traits were negatively associated with fruit infestation and maggot density, while higher fruit moisture and chlorophyll contents in the susceptible genotypes were positively correlated. Multiple regression models revealed pericarp thickness, fruit toughness, tannin and flavonols accounted for maximum variation in fruit fly infestation among all morpho-chemical factors. Principal component analysis of morpho-chemical traits using varimax rotation with Kaiser normalization extracted four principal components (PCs), explaining 92.50% of the cumulative variance in fruit fly infestation. PC1, PC2, PC3 and PC4 contributed 62.45%, 15.83%, 9.28% and 4.94% of the total variation, respectively. These findings underscore the importance of leveraging genetic diversity to develop resistant bitter gourd cultivars. Such cultivars can reduce the cost of cultivation and enhance farmers’ income while serving as a critical component of integrated pest management strategies.

Spodoptera litura, commonly known as the tobacco cutworm or cotton leafworm, is a significant agricultural pest belonging to the family Noctuidae. Being polyphagous, it can feed on a wide variety of host plants and the larvae are particularly voracious feeders, causing substantial damage to crops. However, Zea mays (African tall variety) harbour a robust defense system and releases defensive proteins and allelochemicals that retard growth and development of S. litura. To identify and isolate the proteins responsive to maize allelochemicals, a comparative proteomic analysis of the mid-gut of maize-fed S. litura larvae was conducted. This analysis revealed the upregulation of 203 and downregulation of 376 differentially abundant proteins (DAPs). The DAPs were categorized into various functional groups, such as carbohydrate and lipid metabolism, defense, growth and development, transport, signaling, molecular processes, and digestion. The downregulation of proteins associated with digestion, detoxification, immunity and growth or development, suggests a non-adaptive mechanism against maize allelochemicals. This information can be crucial for understanding the impact of maize metabolites on insect gut and potentially exploiting it for pest management.

Larvae of the sawfly genus Dolerus are herbivorous, feeding on different species of graminoids. The larvae are notable for their asymmetrical labrum, an atypical trait among Hymenoptera, yet the associated feeding mechanism remains unclear. The wheat-preferring Dolerus tritici Chu provides key insights into this behavior. In this study, we investigated the feeding behavior and mouthpart ultrastructure of D. tritici larvae through field observations and scanning electron microscopy. For the first time, we identified the ultrastructural basis underlying their feeding mechanism. The key evidence came from distinct wear patterns, which indicated that three pairs of slanted cutting points were involved in leaf incision, while the maxillary and labial palps are responsible for positioning the leaf during this process. Ultramorphological evidence, including a notch in the left side of the labrum, mesally protruding incisors and molars on the left mandible, and mechanoreceptors on the penultimate maxillary palps, suggests a coordinated specialization of the larval feeding apparatus for feeding on plants with parallel-veined leaves. We propose that this tilted-head strategy represents an adaptation to feeding on straight, parallel-veined leaves.

Due to the global decline of pollinators, global food security is at risk. Crops essentially dependent on pollinators such as pumpkin (Cucurbita moschata Duchesne, Cucurbitaceae) are the most affected. Although the importance of pollinators for crop productivity is known, there are many gaps in knowledge regarding the influence of pollination on crop quality, especially on the chemical composition of fruits and seeds. Here, we evaluated the relationship between floral display, frequency of visits and crop production, using three pumpkin plantations in the semi-arid region of NE Brazil as a model. In all sites we recorded floral display, floral visitors, and compared fruit set, fruit quality and seed number between natural (NP) and cross (CP) pollination experiments. Bees were the main pollinators, and Apis mellifera and Trigona spinipes were the most frequent. Floral display was positively correlated with the total number of visits, which had a positive relation with fruit weight, specifically because of T. spinipes visits. Visitation by A. mellifera had a negative relationship with pericarp length. Fruit set was about 9% higher in NP than in CP, whose fruits had lower antioxidant activity than the former. Floral display was positively related to the frequency of visits of pumpkin produced in the semi-arid region of northeastern Brazil. Bees were the main pollinators, especially T. spinipes and A. mellifera, which positively influenced fruit weight. Thus, pollinators favored fruit set, weight, and quality, in addition to promoting antioxidant potential.

Water scarcity is expected to intensify, posing major challenges for crop production. Insect pests such as Chrysodeixis includens further reduce yields, especially in large monocultures. Water stress and plant resistance operate as bottom-up forces affecting herbivores and their natural enemies, whereas parasitoids impose top-down control. This study evaluated the effects of two common bean genotypes (a landrace variety and a commercial cultivar) on the growth and survival of C. includens under well-watered and water-stressed conditions. We also assessed whether the performance of the egg parasitoid Trichogramma pretiosum was influenced when developing in eggs from moths previously reared on the different genotypes and water regimes. Levels of hydrogen peroxide, malondialdehyde, and antioxidant enzymes were quantified. Water stress did not affect any biological parameter of the pest, although preliminary assays indicated reduced larval weight. The Manteigado genotype lowered larval survival by 27% and showed greater tolerance to C. includens defoliation compared with BRS Esplendor; however, neither genotype exhibited tolerance to water stress. None of the biological parameters of T. pretiosum were affected by bean genotype or water availability. Potential defense mechanisms were detected in Manteigado plants, including a 13–21% increase in superoxide dismutase activity, which detoxifies superoxide radicals, and a 21% reduction in total protein content, which may limit herbivore development. Manteigado therefore displays promising resistance traits for managing C. includens and may serve as a donor in breeding programs. Moreover, both genotypes appear compatible with T. pretiosum use even under water deficit, supporting sustainable pest management in bean crops.