Terrestrial deposition of aquatic insects increases plant quality for insect herbivores and herbivore density

HILARY BULTMAN; DAVID HOEKMAN; JAMIN DREYER; CLAUDIO GRATTON

doi:10.1111/een.12118

Changes in arthropod community but not plant quality benefit a specialist herbivore on plant under reduced water availability

10.1101/2020.05.25.115519 ◽

2020 ◽

Author(s):

Po-An Lin ◽

Chia-Ming Liu ◽

Jia-Ang Ou ◽

Cheng-Han Sun ◽

Wen-Po Chuang ◽

...

Keyword(s):

Water Availability ◽

Pieris Rapae ◽

Plant Quality ◽

Physiological Adaptation ◽

Insect Herbivores ◽

Specialist Herbivore ◽

Herbivore Community ◽

Two Populations ◽

Reduced Water

AbstractPlants grow under reduced water availability can have divergent effects on insect herbivores, in some instances producing benefits to them. However, the forces mediating these positive impacts remain mostly unclear. We conducted a manipulative field study using a specialist herbivore Pieris rapae, and its host plant, Rorippa indica, in two populations to identify how water availability impacts overall plant quality and multitrophic interactions. We observed that R. indica growing under low water availability led to higher survival of P. rapae larvae. The increase in survival of eggs and larvae was related to the reduced abundance of other herbivores and natural enemies. Water availability had differential impacts on members of the herbivore community through changes in plant quality. Low water availability decreased the quality of R. indica to most herbivores as indicated by reduced abundance in the field and decreased relative growth rate in feeding assays. In contrast, the performance of P. rapae larvae were not affected by differences in sympatric R. indica grown under different water availability. These results indicate that local P. rapae possess some physiological adaptation to overcome fluctuations in host quality. Our findings illustrate that reduced water availability is beneficial to a specialist herbivore, but detrimental to most other herbivores. Our work highlights the complex roles of the arthropod communities associated with plants in determining the impacts of water availability on insect herbivores.

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Invasive insect herbivores as disrupters of chemically-mediated tritrophic interactions: effects of herbivore density and parasitoid learning

Biological Invasions ◽

10.1007/s10530-017-1526-x ◽

2017 ◽

Vol 20 (1) ◽

pp. 195-206 ◽

Cited By ~ 9

Author(s):

Gaylord A. Desurmont ◽

Antoine Guiguet ◽

Ted C. J. Turlings

Keyword(s):

Tritrophic Interactions ◽

Insect Herbivores ◽

Invasive Insect ◽

Herbivore Density

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Pathways for plant-mediated negative feedback to insect herbivores: accounting for non-linear effects of larval density on plant quality and quantity

Entomologia Experimentalis et Applicata ◽

10.1111/eea.12515 ◽

2016 ◽

Vol 162 (1) ◽

pp. 93-104 ◽

Cited By ~ 5

Author(s):

David W. McNutt ◽

Kathryn Samuelson ◽

Nora Underwood

Keyword(s):

Negative Feedback ◽

Larval Density ◽

Plant Quality ◽

Insect Herbivores ◽

Non Linear ◽

Linear Effects

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Meta-Analysis Suggests Differing Indirect Effects of Viral, Bacterial, and Fungal Plant Pathogens on the Natural Enemies of Insect Herbivores

Insects ◽

10.3390/insects11110765 ◽

2020 ◽

Vol 11 (11) ◽

pp. 765

Author(s):

Ussawit Srisakrapikoop ◽

Tara J. Pirie ◽

Mark D. E. Fellowes

Keyword(s):

Natural Enemies ◽

Indirect Effects ◽

Plant Pathogens ◽

Meta Analysis ◽

Trophic Levels ◽

Plant Diseases ◽

Plant Quality ◽

Insect Herbivore ◽

Insect Herbivores ◽

Fungal Plant Pathogens

Indirect effects are ubiquitous in nature, and have received much attention in terrestrial plant–insect herbivore–enemy systems. In such tritrophic systems, changes in plant quality can have consequential effects on the behavior and abundance of insect predators and parasitoids. Plant quality as perceived by insect herbivores may vary for a range of reasons, including because of infection by plant pathogens. However, plant diseases vary in their origin (viral, bacterial or fungal) and as a result may have differing effects on plant physiology. To investigate if the main groups of plant pathogens differ in their indirect effects on higher trophic levels, we performed a meta-analysis using 216 measured responses from 29 primary studies. There was no overall effect of plant pathogens on natural enemy traits as differences between pathogen types masked their effects. Infection by fungal plant pathogens showed indirect negative effects on the performance and preference of natural enemies via both chewing and piercing-sucking insect herbivore feeding guilds. Infection by bacterial plant pathogens had a positive effect on the natural enemies (parasitoids) of chewing herbivores. Infection by viral plant pathogens showed no clear effect, although parasitoid preference may be positively affected by their presence. It is important to note that given the limited volume of studies to date on such systems, this work should be considered exploratory. Plant pathogens are very common in nature, and tritrophic systems provide an elegant means to examine the consequences of indirect interactions in ecology. We suggest that further studies examining how plant pathogens affect higher trophic levels would be of considerable value.

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Aphid Feeding Induces Phytohormonal Cross-Talk without Affecting Silicon Defense against Subsequent Chewing Herbivores

Plants ◽

10.3390/plants9081009 ◽

2020 ◽

Vol 9 (8) ◽

pp. 1009

Author(s):

Scott N. Johnson ◽

Rhiannon C. Rowe ◽

Casey R. Hall

Keyword(s):

Salicylic Acid ◽

Jasmonic Acid ◽

Cross Talk ◽

Brachypodium Distachyon ◽

Rhopalosiphum Padi ◽

Plant Quality ◽

Insect Herbivores ◽

Plant Facilitation ◽

Aphid Feeding ◽

Model Grass

Prior feeding by insect herbivores frequently affects plant quality for herbivores that subsequently feed on the plant. Facilitation occurs when one herbivore improves plant quality for other herbivores, including when the former compromises plant defenses. Silicon (Si) is an important defense in grasses that increases following activation of the jasmonic acid (JA) pathway. Given that aphids often stimulate the salicylic acid (SA) pathway, we hypothesized that this could reduce Si defense because of the well documented antagonistic cross-talk between SA and JA. We tested this in the model grass Brachypodium distachyon with and without Si (+Si and −Si, respectively); half of the plants were exposed to aphids (Rhopalosiphum padi) and half remained aphid-free. Aphid-free and aphid-exposed plants were then fed to chewing herbivores (Helicoverpa armigera). Aphids triggered higher SA concentrations which suppressed JA concentrations but this did not affect foliar Si. Chewing herbivores triggered higher JA concentrations and induced Si uptake, regardless of previous feeding by aphids. Chewer growth rates were not impacted by prior aphid herbivory but were reduced by 75% when feeding on +Si plants. We concluded that aphids caused phytohormonal cross-talk but this was overridden by chewing herbivory that also induced Si uptake.

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Fish predation on Eurasian watermilfoil (Myriophyllum spicatum) herbivores and indirect effects on macrophytes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f06-010 ◽

2006 ◽

Vol 63 (5) ◽

pp. 1049-1057 ◽

Cited By ~ 16

Author(s):

Darren M Ward ◽

Raymond M Newman

Keyword(s):

Aquatic Plant ◽

Field Experiments ◽

Field Survey ◽

Myriophyllum Spicatum ◽

Fish Predation ◽

Insect Herbivores ◽

Eurasian Watermilfoil ◽

Euhrychiopsis Lecontei ◽

Herbivore Density ◽

Invasive Aquatic Plant

We assessed the effect of fish predation on native and naturalized insect herbivores of the invasive aquatic plant Eurasian watermilfoil (Myriophyllum spicatum) using manipulative field experiments within lakes and a field survey across lakes. For the field experiments, we manipulated sunfish (Lepomis spp.) density in cages in the littoral plant beds of two contrasting lakes: one with many sunfish, few watermilfoil herbivores, and abundant Eurasian watermilfoil; and one with few sunfish, many herbivores, and little Eurasian watermilfoil. Watermilfoil herbivores, including the milfoil weevil (Euhrychiopsis lecontei) and aquatic caterpillars, were suppressed by fish in both experiments. Herbivore density was also negatively related to sunfish abundance in the multiple-lake survey. We conclude that abundant sunfish can strongly suppress watermilfoil herbivores. Furthermore, in one of our experiments there was a marginally significant effect of fish exclosure on watermilfoil, suggesting that fish suppression of watermilfoil herbivores can have a positive, indirect effect on plant growth. Fish predation on macrophyte herbivores may be an important trophic interaction in freshwater lakes.

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