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Aboveground herbivores and belowground microbes have been interacting via terrestrial plants since their origins, but whether and how feeding guild affects root bacterial-fungal community structure, diversity, and co-occurrence patterns remains poorly understood. Here we examined the effect of chewing and sucking herbivory on bacterial and fungal communities in the root endosphere and rhizosphere, and further explored whether such effect was mediated by herbivoryinduced changes in plant performance. Our results show that chewing herbivory decreased fungal alpha diversity, while sucking herbivory increased the diversity. Chewing increased microbial competition and network complexity, whereas sucking showed the opposite effect. Moreover, chewing herbivory increased root-associated microbial community stability while sucking herbivory decreased it. Path analysis indicated that chewing and sucking herbivory affected root microbial diversity and co-occurrence network complexity and stability mainly through their influences on plant defense and associated plant growth impacts. Together, chewing and sucking herbivory showed distinct effect on root microbiota, and specific plant performance responses to the corresponding feeding guild may mediate these processes. These results have important implications for understanding the impact of aboveground herbivore diversity on belowground microbial community diversity, co-occurrence and ecosystem function. [ABSTRACT FROM AUTHOR]

Background: The efficacy of Bt crystal proteins has been compromised due to their extensive utilization in the field. The second-generation Bt vegetative insecticidal proteins could be the best-suited alternative to combat resistance build-up due to their broad range affinity with midgut receptors of insects. Material and results: The codon-optimized synthetic vegetative insecticidal proteins (Vip3Aa) gene under the control of CaMV35S promoter was transformed into a locally developed transgenic cotton variety (CKC-01) expressing cry1Ac and cry2A genes. Transformation efficiency of 1.63% was recorded. The highest Vip3Aa expression (51.98-fold) was found in MS3 transgenic cotton plant. Maximum Vip3Aa protein concentration (4.23 µg/mL) was calculated in transgenic cotton plant MS3 through ELISA. The transgenic cotton plant (MS3) showed one copy number on both chromatids in the homozygous form at chromosome 8 at the telophase stage. Almost 99% mortality of H. armigera was recorded in transgenic cotton plants expressing double crystal proteins pyramided with Vip3Aa gene as contrasted to transgenic cotton plant expressing only double crystal protein with 70% mortality. Conclusions: The results obtained during this study suggest that the combination of Bt cry1Ac, cry2A, and Vip3Aa toxins is the best possible alternative approach to combat chewing insects. [ABSTRACT FROM AUTHOR]

Insect–plant interactions occur in several ways and have considerable environmental and ecological importance. Many feeding strategies have evolved among herbivorous insects, with host–herbivore systems likely being influenced by trophobionts with ants. We investigated how these interactions vary across elevation gradients by evaluating the structure of the herbivorous insect community and ants associated with Baccharis dracunculifolia at three distinct elevations (800, 1100, and 1400 m a.s.l.) on a mountain in southeastern Brazil. Moreover, we evaluated the diversity and specialisation of interactions between herbivores and host plants along the elevational gradient. We sampled herbivores and ants on 60 plants at each elevation (totalling 180 plant individuals). Herbivore species composition differed among elevations, as did interaction diversity and specialisation. Richness and abundance of chewing insects increased with elevation, while β‐diversity among patches of the host plant was higher at the lowest elevation, probably due to the patchy occurrence of B. dracunculifolia. Richness and abundance of sap‐sucking insects were higher at the intermediate elevation, possibly due to local environmental conditions. We observed a positive relationship between ant and herbivore trophobiont richness on B. dracunculifolia. We found that interactions were more specialised and less diverse at higher elevations compared to the lowest elevation. Changes in vegetation and environmental variables shaped species distributions and their ecological interactions along the elevation gradient. Our study demonstrates that increased elevation changes the structure and patterns of interactions of the herbivore insect guilds associated with the host plant B. dracunculifolia. Ant effects depend on the context, the environment, and the species of ants involved, and are essential for the presence of insect trophobionts. [ABSTRACT FROM AUTHOR]

Herbivorous insects that have evolved to feed on senescing tissues of plants, or the phloem flowing from those tissues, comprise a distinct sub-guild of the major trophic guilds, the senescence-feeders. Some senescence-feeders have evolved the capacity to accelerate the rate at which the tissues they feed on senesce, thus enhancing the quantity and quality of their food. Other species prolong their access to good food by feeding alternatively on both senescing and flushing tissues. Senescing plant tissues release a poorer quality food more slowly than the rapid inflow to new growth. As a result, senescence-feeders grow more slowly than equivalent flush-feeders. Any environmental stress of a plant that hastens its rate of senescence results in faster growth and higher survival of senescence-feeders. Senescence-feeders therefore succeed best on damaged or stressed plants and frequently reach outbreak levels on drought-stressed trees. If the distinctive ecology of senescence-feeders and the way in which they differ from flush-feeders in their response to the condition of their host plants are to be recognized and understood, it is important to identify species that belong to this separate trophic sub-guild. Such understanding is also necessary if attempts to control or manage their attacks on crops and forests are to succeed. [ABSTRACT FROM AUTHOR]

Recently, strong top-down (consumer) control of cordgrass (Spartina alterniflora) has been demonstrated. Here, we manipulated the densities of cordgrass consumers, acridid grasshoppers (Melanoplus bivittatus and Melanoplus femurrubrum), to examine their impact on cordgrass in the Plum Island Estuary (PIE), MA, USA. After 1 month, there was no detectable effect of grasshopper density on S. alterniflora biomass and grasshoppers at the highest densities (34 individuals per square meter) consumed only ~14% of the standing stock biomass. However, significant impacts of grasshopper density on grazing damage were seen. For example, plant damage and scarring length increased by 160% and 6,156%, respectively, at the highest grasshopper densities relative to exclusion (zero grasshoppers) densities. Plant height was significantly reduced with increasing grasshopper densities, although this may be a function of leaf tip removal instead of reduced plant growth. No other strong consumers of cordgrass (e.g., Littoraria irrorata, Prokelisia marginata) were observed in PIE and we suggest that consumer regulation of cordgrass is weak in this system. [ABSTRACT FROM AUTHOR]

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Insect pests are major problems for all crops, worldwide. In this review we will focus on legumes, which are attacked by a range of insect pests including pod/seed feeders, defoliators and sap feeders. We review the history of breeding for resistance to insect pests in legumes, which has had mixed success, and discuss further opportunities in this area. We also review the extraordinary array of direct and indirect mechanisms contributing to insect defence in legumes, the understanding and exploitation of which offer opportunities for both legume and non-legume crops. There is also good potential to improve insect resistance in legume crops through a detailed understanding of the signaling pathways that regulate induced responses to insect feeding, and recent progress in this area, primarily obtained from non-legume systems, is reviewed. The importance legumes play in farming systems, their wide range of novel chemistry and the emergence of model systems suitable for genomic approaches present opportunities for research in this area strongly linked to breeding programs to help develop legume crops with enhanced insect resistance. [ABSTRACT FROM AUTHOR]