Insect frass fertilizer upregulates maize defence genes and resistance against an invasive herbivore pest.

The black soldier fly frass fertilizer (BSFFF) has gained global attention as a multipurpose input for soil fertilization and pest and disease management. However, there are limited studies that have examined its effects on insect pest resistance and the underlying mechanisms. We investigated the impact of amending soil with BSFFF on maize growth, defense gene expression and resistance to a polyphagous insect herbivore, Spodoptera frugiperda (Lepidoptera: Noctuidae) through larval feeding assay.

Biochar shifts balance between hydrophilic and lipophilic molecules in root exudates.

The current study investigated the impact of biochar on root exudate chemistry and characterized exudate molecule abundance as a function of biochar application rates. In exudates trickled over biochar, organic oxygen-rich compounds were the most common molecules stemming from biochar, comprising 67 % of the abundance of biochar-derived compounds. Eighty percent of these compounds stemming from biochar were hydrophilic.

Induced resistance to herbivory and the intelligent plant.

Plant induced responses to environmental stressors are increasingly studied in a behavioral ecology context. This is particularly true for plant induced responses to herbivory that mediate direct and indirect defenses, and tolerance. These seemingly adaptive alterations of plant defense phenotypes in the context of other environmental conditions have led to the discussion of such responses as intelligent behavior.

Associational Effects of Desmodium Intercropping on Maize Resistance and Secondary Metabolism.

Intercropping is drawing increasing attention as a strategy to increase crop yields and manage pest pressure, however the mechanisms of associational resistance in diversified cropping systems remain controversial. We conducted a controlled experiment to assess the impact of co-planting with silverleaf Desmodium (Desmodium uncinatum) on maize secondary metabolism and resistance to herbivory by the spotted stemborer (Chilo partellus). Maize plants were grown either in the same pot with a Desmodium plant or adjacent to it in a separate pot.

Volatile-mediated plant-plant communication and higher-level ecological dynamics.

Volatile organic compounds (VOCs) in general and herbivory-induced plant volatiles (HIPVs) in particular are increasingly understood as major mediators of information transfer between plant tissues. Recent findings have moved the field of plant communication closer to a detailed understanding of how plants emit and perceive VOCs and seem to converge on a model that juxtaposes perception and emission mechanisms. These new mechanistic insights help to explain how plants can integrate different types of information and how environmental noise can affect the transmission of information.

Herbivory selects for tolerance and constitutive defence across stages of community succession.

Plants defend themselves from herbivory by either reducing damage (resistance) or minimizing its negative fitness effects with compensatory growth (tolerance). Herbivore pressure can fluctuate from year to year in an early secondary successional community, which can create temporal variation in selection for defence traits. We manipulated insect herbivory and successional age of the community as agents of natural selection in replicated common gardens with the perennial herb .

Defensive functions and potential ecological conflicts of floral stickiness.

Stickiness of vegetative tissues has evolved multiple times in different plant families but is rare and understudied in flowers. While stickiness in general is thought to function primarily as a defense against herbivores, it may compromise mutualistic interactions (such as those with pollinators) in reproductive tissues. Here, we test the hypothesis that stickiness on flower petals of the High-Andean plant, Bejaria resinosa (Ericaceae), functions as a defense against florivores.

Metabolic Integration of Spectral and Chemical Cues Mediating Plant Responses to Competitors and Herbivores.

Light quality and chemicals in a plant's environment can provide crucial information about the presence and nature of antagonists, such as competitors and herbivores. Here, we evaluate the roles of three sources of information-shifts in the red:far red (R:FR) ratio of light reflected off of potentially competing neighbors, induced metabolic changes to damage by insect herbivores, and induced changes to volatile organic compounds emitted from herbivore-damaged neighboring plants-to affect metabolic responses in the tall goldenrod, . We address the hypothesis that plants integrate the information available about competitors and herbivory to optimize metabolic responses to interacting stressors by exposing plants to the different types of environmental information in isolation and combination.

Integrating plant-to-plant communication and rhizosphere microbial dynamics: ecological and evolutionary implications and a call for experimental rigor.

The perception of airborne chemical signals by plants can trigger reconfigurations of their metabolism that alter their biotic interactions. While plant-to-plant chemical communication has primarily been studied in the context of eliciting defenses to herbivores and pathogens, recent work suggests that it can also affect plants’ interactions with their rhizosphere microbiomes. In this perspective, we discuss the potential for integrating the fields of plant-to-plant communication and microbial ecology to understand the chemical ecology of plant−microbiome interactions.

Interaction diversity explains the maintenance of phytochemical diversity.

The production of complex mixtures of secondary metabolites is a ubiquitous feature of plants. Several evolutionary hypotheses seek to explain how phytochemical diversity is maintained, including the synergy hypothesis, the interaction diversity hypothesis, and the screening hypothesis. We experimentally tested a set of predictions derived from these hypotheses by manipulating the richness and structural diversity of phenolic metabolites in the diets of eight plant consumers.

Human-Mediated Land Use Change Drives Intraspecific Plant Trait Variation.

In the Anthropocene, more than three quarters of ice-free land has experienced some form of human-driven habitat modification, with agriculture dominating 40% of the Earth's surface. This land use change alters the quality, availability, and configuration of habitat resources, affecting the community composition of plants and insects, as well as their interactions with each other. Landscapes dominated by agriculture are known to support a lower abundance and diversity of pollinators and frequently larger populations of key herbivore pests.

Predictability of Biotic Stress Structures Plant Defence Evolution.

To achieve ecological and reproductive success, plants need to mitigate a multitude of stressors. The stressors encountered by plants are highly dynamic but typically vary predictably due to seasonality or correlations among stressors. As plants face physiological and ecological constraints in responses to stress, it can be beneficial for plants to evolve the ability to incorporate predictable patterns of stress in their life histories.

Soil Microbiomes From Fallow Fields Have Species-Specific Effects on Crop Growth and Pest Resistance.

Communities of microorganisms in the soil can affect plants' growth and interactions with aboveground herbivores. Thus, there is growing interest in utilizing soil microbiomes to improve plant performance in agriculture (, for pest control), but little is known about the phenotypic responses of various crop species to different microbiomes. In this study, we inoculated four crop species from different botanical families, maize (, Poaceae), cucumber (, Cucurbitaceae), tomato (, Solanaceae), and lettuce (, Asteraceae), with diverse soil microbiomes originating from actively-managed agricultural fields or fallow fields under varying stages of succession (1, 3, and 16-years post-agriculture) sourced from a large-scale field experiment.

The ecological consequences of herbivore-induced plant responses on plant-pollinator interactions.

Plant induced responses to herbivory have long been found to function as plant direct and indirect defenses and to be major drivers of herbivore community and population dynamics. While induced defenses are generally understood as cost-saving strategies that allow plants to allocate valuable resources into defense expression, it recently became clear that, in particular, induced metabolic changes can come with significant ecological costs. In particular, interactions with mutualist pollinators can be significantly compromised by herbivore-induced changes in floral morphology and metabolism.

Pollen defenses negatively impact foraging and fitness in a generalist bee (Bombus impatiens: Apidae).

Plants may benefit from limiting the community of generalist floral visitors if the species that remain are more effective pollinators and less effective pollenivores. Plants can reduce access to pollen through altered floral cues or morphological structures, but can also reduce consumption through direct pollen defenses. We observed that Eucera (Peponapis) pruinosa, a specialist bee on Cucurbita plants, collected pure loads of pollen while generalist honey bees and bumble bees collected negligible amounts of cucurbit pollen, even though all groups of bees visited these flowers.

Soil organic matter attenuates the efficacy of flavonoid-based plant-microbe communication.

Plant-microbe interactions are mediated by signaling compounds that control vital plant functions, such as nodulation, defense, and allelopathy. While interruption of signaling is typically attributed to biological processes, potential abiotic controls remain less studied. Here, we show that higher organic carbon (OC) contents in soils repress flavonoid signals by up to 70%.

Insect Herbivory Selects for Volatile-Mediated Plant-Plant Communication.

Plant volatile organic compounds (VOCs) are major vehicles of information transfer between organisms and mediate many ecological interactions [1-3]. Altering VOC emission in response to herbivore damage has been hypothesized to be adaptive, as it can deter subsequent herbivores [4], attract natural enemies of herbivores [5], or transmit information about attacks between distant parts of the same plant [6-9]. Neighboring plants may also respond to these VOC cues by priming their own defenses against oncoming herbivory, thereby reducing future damage [10-12].

High levels of abiotic noise in volatile organic compounds released by a desert perennial: implications for the evolution and ecology of airborne chemical communication.

Plants release airborne volatile organic compounds (VOCs) in response to abiotic and biotic stimuli, including herbivory. These chemicals are used by insect parasitoids as sources of information that aid in finding hosts. It is unclear how biotic and abiotic factors interact to affect blend composition and the ability of insects to interpret signals.

Eco-evolutionary processes affecting plant-herbivore interactions during early community succession.

The quality and outcome of organismal interactions are not only a function of genotypic composition of the interacting species, but also the surrounding environment. Both the strength and direction of natural selection on interacting populations vary with the community context, which itself is changed by these interactions. Here, we test for the role of interacting evolutionary and ecological processes in plant-herbivore interactions during early community succession in the tall goldenrod, Solidago altissima.

Phenolic root exudate and tissue compounds vary widely among temperate forest tree species and have contrasting effects on soil microbial respiration.

Root-soil interactions fundamentally affect the terrestrial carbon (C) cycle and thereby ecosystem feedbacks to climate change. This study addressed the question of whether the secondary metabolism of different temperate forest tree species can affect soil microbial respiration. We hypothesized that phenolics can both increase and decrease respiration depending on their function as food source, mobilizer of other soil resources, signaling compound, or toxin.