Trophic cascades initiated by fungal plant endosymbionts impair reproductive performance of parasitoids in the second generation

Härri, Simone A.; Krauß, Jochen; Müller, Christine

doi:10.1007/s00442-008-1094-y

Cited by 28 publications

(29 citation statements)

References 48 publications

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“…Aphids are good model organisms to study multi-trophic interactions (Härri et al 2008). Many aphid species are serious crop pests that cause damage by feeding on plant sap or act as vectors of virus diseases (Van Emden and Harrington 2007).…”

Section: Introductionmentioning

confidence: 99%

Enhanced aphid abundance in spring desynchronizes predator–prey and plant–microorganism interactions

et al. 2016

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Climate change leads to phenology shifts of many species. However, not all species shift in parallel, which can desynchronize interspecific interactions. Within trophic cascades, herbivores can be top–down controlled by predators or bottom–up controlled by host plant quality and host symbionts, such as plant-associated micro-organisms. Synchronization of trophic levels is required to prevent insect herbivore (pest) outbreaks. In a common garden experiment, we simulated an earlier arrival time (~2 weeks) of the aphid Rhopalosiphum padi on its host grass Lolium perenne by enhancing the aphid abundance during the colonization period. L. perenne was either uninfected or infected with the endophytic fungus Epichloë festucae var. lolii. The plant symbiotic fungus produces insect deterring alkaloids within the host grass. Throughout the season, we tested the effects of enhanced aphid abundance in spring on aphid predators (top–down) and grass–endophyte (bottom–up) responses. Higher aphid population sizes earlier in the season lead to overall higher aphid abundances, as predator occurrence was independent of aphid abundances on the pots. Nonetheless, after predator occurrence, aphids were controlled within 2 weeks on all pots. Possible bottom–up control of aphids by increased endophyte concentrations occurred time delayed after high herbivore abundances. Endophyte-derived alkaloid concentrations were not significantly affected by enhanced aphid abundance but increased throughout the season. We conclude that phenology shifts in an herbivorous species can desynchronize predator–prey and plant–microorganism interactions and might enhance the probability of pest outbreaks with climate change.Electronic supplementary materialThe online version of this article (doi:10.1007/s00442-016-3768-1) contains supplementary material, which is available to authorized users.

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Section: Introductionmentioning

confidence: 99%

Enhanced aphid abundance in spring desynchronizes predator–prey and plant–microorganism interactions

et al. 2016

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“…For instance, changes in phloem sap composition can affect organisms that feed upon these plants including sap-feeding aphids [3]. In an aphid -parasitoid -hyperparasitoid food web, the effects of host plant traits can cascade up as far as the fourth trophic level [2], even when there are no effects on the herbivores [4].…”

Section: Introductionmentioning

confidence: 99%

Aphid–parasitoid community structure on genetically modified wheat

et al. 2011

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Since the introduction of genetically modified (GM) plants, one of the main concerns has been their potential effect on non-target insects. Many studies have looked at GM plant effects on single non-target herbivore species or on simple herbivore–natural enemy food chains. Agro-ecosystems, however, are characterized by numerous insect species which are involved in complex interactions, forming food webs. In this study, we looked at transgenic disease-resistant wheat ( Triticum aestivum ) and its effect on aphid–parasitoid food webs. We hypothesized that the GM of the wheat lines directly or indirectly affect aphids and that these effects cascade up to change the structure of the associated food webs. Over 2 years, we studied different experimental wheat lines under semi-field conditions. We constructed quantitative food webs to compare their properties on GM lines with the properties on corresponding non-transgenic controls. We found significant effects of the different wheat lines on insect community structure up to the fourth trophic level. However, the observed effects were inconsistent between study years and the variation between wheat varieties was as big as between GM plants and their controls. This suggests that the impact of our powdery mildew-resistant GM wheat plants on food web structure may be negligible and potential ecological effects on non-target insects limited.

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“…These effects include, e.g., decrease in population density [10], lowered body mass [11], increased toxicity-induced mortality [12] and suppression of reproduction and growth [13]. The alkaloids produced by endophytes may also have negative effects on the natural enemies of invertebrate herbivores [14], [15]. However, experimental studies on endophytes and their effects on higher trophic levels are still scarce [2], [16], and no study has examined the cascading effects of fungal symbionts of grasses on vertebrate food chains.…”

Section: Introductionmentioning

confidence: 99%

Fungal-Mediated Multitrophic Interactions - Do Grass Endophytes in Diet Protect Voles from Predators?

Saari

Sundell

Huitu³

et al. 2010

PLoS ONE

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Plant-associated micro-organisms such as mycotoxin-producing endophytes commonly have direct negative effects on herbivores. These effects may be carried over to natural enemies of the herbivores, but this has been rarely explored. We examined how feeding on Neotyphodium endophyte infected (E+) and endophyte free (E−) meadow ryegrass (Scherodonus pratensis) affects body mass, population size and mobility of sibling voles (Microtus levis), and whether the diet mediates the vulnerability of voles to least weasel (Mustela nivalis nivalis) predation. Because least weasels are known to be olfactory hunters, we also examined whether they are able to distinguish olfactory cues of voles fed on E+ and E− diets. Neither body mass of voles nor population size differed between diets. However, contrary to our prediction, least weasels preyed more often on voles fed with E− grass than on voles fed with E+ grass. The mobility of voles fed on E+ grass was reduced compared to voles fed on E− grass, but this effect was unrelated to risk of predation. Least weasels appeared unable to distinguish between excrement odours of voles between the two treatments. Our results suggest that consumption of endophytic grass is not directly deleterious to sibling voles. What's more, consumption of endophytes appears to be advantageous to voles by reducing risk of mammalian predation. Our study is thus the first to demonstrate an effect of plant-associated microbial symbionts on herbivore-predator interactions in vertebrate communities.

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Trophic cascades initiated by fungal plant endosymbionts impair reproductive performance of parasitoids in the second generation

Cited by 28 publications

References 48 publications

Enhanced aphid abundance in spring desynchronizes predator–prey and plant–microorganism interactions

Enhanced aphid abundance in spring desynchronizes predator–prey and plant–microorganism interactions

Aphid–parasitoid community structure on genetically modified wheat

Fungal-Mediated Multitrophic Interactions - Do Grass Endophytes in Diet Protect Voles from Predators?

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