1. Plant responses to herbivory are often specific to the feeding guild of the attacking herbivore. These phytochemical responses to herbivore damage can affect herbivore performance and activity. Comprehensive studies on the ecological consequences of multi‐herbivore plant interactions are key to understanding plant–herbivore community dynamics.2. This study examined how feeding damage by co‐occurring herbivores from separate feeding guilds, Myzus persicae (Sulzer), a sucking herbivore, and Leptinotarsa decemlineata (Say), a chewing herbivore, alter plant chemistry and indirectly affect herbivore performance. Performance was measured when each insect fed on plants individually, sequentially, or simultaneously in laboratory and field experiments. Phytohormone and glycoalkaloid content were measured for each feeding sequence to evaluate plant responses to herbivory by each guild. Mid‐season and end‐of‐season tuber yield were evaluated in the field study.3. Damage by L. decemlineata negatively impacted M. persicae performance in both laboratory and field settings. Damage by M. persicae did not affect L. decemlineata performance in laboratory assays. However, L. decemlineata performance was positively affected by M. persicae herbivory in the field, but this effect was temporary. Although phytohormones and plant defences varied across treatments, they provide little resolution on interaction outcomes.4. These results confirm that the presence of multiple feeding guilds on a single plant can affect these chewing and sucking herbivores differentially, but given the variability in our phytochemical analyses compared with other studies, the mechanism remains unclear. The study's findings show that aphids are negatively affected by chewing herbivores across systems, while aphids temporarily affected beetles positively.

Plant-soil feedbacks can mediate aboveground plant–herbivore interactions by impacting plant chemistry. Given that soil legacies and agricultural practices are closely tied, a better understanding of soil legacy cascades and their application in pest management are needed. We tested how cover crop legacies alter resistance to fall armyworm (Spodoptera frugiperda Smith, Lepidoptera: Noctuidae) in maize (Zea mays L., Poales: Poaceae). We compared herbivore performance and behavior of fall armyworm larvae on maize grown after four cover crop treatments: a leguminous mycorrhizal cover crop (pea: Pisum sativum L., Fabales: Fabaceae), a nonleguminous mycorrhizal cover crop (triticale: x Triticosecale Wittm. Ex A. Camus, Poales: Poaceae), a nonleguminous nonmycorrhizal cover crop (radish: Raphanus sativus L., Brassicales: Brassicaceae), and no cover crops (fallow). Soil inorganic N was highest in pea treatments and lowest in triticale treatments, while maize AMF colonization was greatest when grown after mycorrhizal cover crops compared to nonmycorrhizal or no cover crops. Cover crop legacies altered the emission of maize volatiles and fall armyworm larvae oriented toward odors emitted by maize grown after radish more frequently than triticale in olfactometer assays. Additionally, larvae performed better and consumed more leaf tissue when feeding on maize grown after radish and poorest on plants grown after triticale. When damaged by fall armyworm, maize grown after triticale expressed higher levels of lipoxygenase-3 (lox3), while plants grown after radish upregulated maize proteinase inhibitor (mpi) gene expression. Our results highlight the importance of appropriate cover crop selection and suggest that triticale could strengthen maize resistance to fall armyworm.

The timing of events in the life history of temperate insects is most typically primarily cued by one of two drivers: photoperiod or temperature accumulation over the growing season. However, an insect's phenology can also be moderated by other drivers like rainfall or the phenology of its host plants. When multiple drivers of phenology interact, there is greater potential for phenological asynchronies to arise between an organism and those with which it interacts. We examined the phenological patterns of a highly seasonal group of fireflies (Photinus spp., predominantly P. pyralis) over a 12-year period (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) across 10 plant communities to determine whether interacting drivers could explain the variability observed in the adult flight activity density (i.e. mating season) of this species. We found that temperature accumulation was the primary driver of phenology, with activity peaks usually occurring at a temperature accumulation of approximately 800 degree days (base 10°C); however, our model found this peak varied by nearly 180 degree-day units among years. This variation could be explained by a quadratic relationship with the accumulation of precipitation in the growing season; in years with either high or low precipitation extremes at our study site, flight activity was delayed. More fireflies were captured in general in herbaceous plant communities with minimal soil disturbance (alfalfa and no-till field crop rotations), but only weak interactions occurred between within-season responses to climatic variables and plant community.

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