Multitrophic interaction between the ryegrassLolium perenne,its endophyteNeotyphodium lolii,the weevil pestListronotus bonariensis,and its parasitoidMicroctonus hyperodae

Goldson, S. L.; Proffitt, J. R.; Fletcher, L. R.; Baird, David

doi:10.1080/00288233.2000.9513423

Cited by 31 publications

(24 citation statements)

References 24 publications

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“…Endophyte infection may also have implications for other trophic levels: for instance, by altering responses of parasitoids to hosts that are affected by endophyte infection of grasses (Goldson et al. ; Bultman et al. , ; Härri et al.…”

Section: Discussionmentioning

confidence: 99%

Volatiles in perennial ryegrass infected with strains of endophytic fungus: impact on African black beetle host selection

Qawasmeh

Raman

Wheatley

2014

J Applied Entomology

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Perennial ryegrass (Lolium perenne) is often infected with the fungal‐endophyte Neotyphodium lolii. In addition to the ‘wild‐type’ strain (EWT), several ‘selected’ strains of N. lolii are now being marketed as AR1 (EAR1) and AR37 (EAR37). Each of these strains impact positively on L. perenne's resistance against many insects, including the African black beetles (Heteronychus arator). The impact of volatile oils produced specifically by each strain in the endophyte–grass association in enhancing the grass's resistance to insects is still largely unknown. Keeping these in view, we determined the volatile oil profiles produced by L. perenne infected with either EWT or EAR1 or EAR37 and determined the impacts of these volatiles on the host‐selection behaviour of H. arator adults. In the absence of endophyte infection (E–), L. perenne produced 18 different volatile oils. In L. perenne EWT, quantities of 2‐ethyl‐1‐hexanol acetate (Rt = 14.5 min), (Z)‐2‐octen‐1‐ol (Rt = 22.2 min), and butylated hydroxyl toluene (Rt = 23.2 min) were 24, 16 and 26%, respectively, greater than L. perenne E–. The strains EAR1 and EAR37 affected differently the quantities of the volatile compounds but not their identity. In the four‐choice bioassay, males and females of H. arator were equally attracted to each strain. In Y‐tube olfactometer, compared against E–, H. arator adults were less attracted to L. perenne EWT and EAR1. The attractiveness of EAR37 was similar in effect to E– to H. arator. The results indicate that each strain of N. lolii alters the profile of volatile oils in L. perenne differently and that alteration can influence H. arator adult‐host selection.

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Section: Discussionmentioning

confidence: 99%

Volatiles in perennial ryegrass infected with strains of endophytic fungus: impact on African black beetle host selection

Qawasmeh

Raman

Wheatley

2014

J Applied Entomology

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“…The selectivity of sequestration and transfer of perietin to eggs suggest a defensive function; however, a defensive hypothesis has not been tested (Hesbacher et al 1995a). Endophytic fungi, which can provide their hostplants with chemical defence (Cheplick & Clay 1988), are another potential source of defensive compounds for herbivores (Goldson et al 2000;Rudgers & Clay 2005). Interestingly, fungal endophytes and the mycotoxins they produce are often patchily distributed among uninfected plants (Faeth 2002), creating opportunities for the semiindependent regulation of PSM and mycotoxin intake, even among specialist herbivores.…”

Section: I E T a R Y M I X I N G O N S H O R T T I M E S C A L E Smentioning

confidence: 99%

Defensive mixology: combining acquired chemicals towards defence

Mason

Singer

2014

Functional Ecology

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Summary The myriad chemicals produced by plants may act in combination to enhance chemical defence against herbivores. Many animals have evolved the ability to harness plant secondary metabolites (PSMs) and other chemical resources for their own defence, but few studies have addressed the compelling notion that non‐human animals combine exogenous chemicals from different sources to defend themselves against predators, parasites and pathogens. We consider the use of ‘defensive cocktails’ from an evolutionary ecology perspective, introducing the term, ‘acquired combinatorial chemical defence’ (ACCD). We define ACCD as the adaptive use of multiple chemicals of discrete origin resulting in defence against natural enemies. First, we discuss the defining characteristics of ACCD: the ability to harness interspecific chemical variation, to independently regulate it, and to obtain defensive benefits via synergy that exceed those associated with single sources. Then, we describe three non‐mutually exclusive modes by which acquired chemicals may operate against natural enemies: different chemical resources may provide defence during different stages of development, may be effective against different enemies or may work additively or synergistically against a given enemy at a given developmental stage. Next, we describe possible avenues by which chemical combinations may be acquired by herbivores and other taxa, including the mixing of exogenous chemicals from different items in the diet and mixing chemicals of dietary origin with those from non‐food resources. We discuss possible costs of ACCD, including detoxification costs and interactions with the immune system, and discuss methods of testing for ACCD and its costs. Finally, we discuss the evolutionary prediction that herbivores may converge on the use of complementary combinations of chemical resources from the environment or chemical defence syndromes. Opportunities to combine chemical resources abound, suggesting that animal and human medication may be more closely aligned than previously recognized.

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“…Likewise, invertebrates feeding on endophyte-infected grasses may also sequester and use endophytic alkaloids in their defence against their predators and parasites (Faeth, 2002, Faeth and Bultman, 2002and Cheplick and Faeth, 2009). Endophytic alkaloids may negatively affect growth, development and survival of parasites (e.g., Barker and Addison, 1996, Goldson et al, 2000, Omacini et al, 2001and Bultman et al, 2003) and predators (e.g., de Sassi et al, Härri et al, 2008) of herbivorous insects. Although the effects of endophytes on higher trophic levels are still poorly understood , recent evidence suggests that endophytic alkaloids in grasses may affect natural enemies of herbivores more than the herbivores themselves, thus creating 'enemy-free space' (Jeffries & Lawton 1985) on infected plants.…”

Section: Natural Enemies Often Nullify or Reverse Chemical Defencesmentioning

confidence: 99%

Fungal grass endophytes and arthropod communities: lessons from plant defence theory and multitrophic interactions

Faeth

Saari

2012

Fungal Ecology

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Abstract:Alkaloids produced by systemic fungal endophytes of grasses are thought to act as defensive agents against herbivores. Endophytic alkaloids may reduce arthropod herbivore abundances and diversity in agronomic grasses. Yet, accumulating evidence, particularly from native grasses, shows that herbivore preference, abundances and species richness are sometimes greater on endophyte-infected plants, even those with high alkaloids, contrary to the notion of defensive mutualism. We argue that these conflicting results are entirely consistent with well-developed concepts of plant defence theory and tri-trophic interactions. Plant secondary chemicals and endophytic alkaloids often fail to protect plants because: (1) specialist herbivores evolve to detoxify and use defensive chemicals for growth and survival; and (2) natural enemies of herbivores may be more negatively affected by alkaloids than are herbivores. Endophytes and their alkaloids may have profound, but often highly variable, effects on communities, which are also consistent with existing theories of plant defence and community genetics.Arthropods | Communities | Endophyte | Herbivores | Neotyphodium | Parasites |

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Multitrophic interaction between the ryegrassLolium perenne,its endophyteNeotyphodium lolii,the weevil pestListronotus bonariensis,and its parasitoidMicroctonus hyperodae

Cited by 31 publications

References 24 publications

Volatiles in perennial ryegrass infected with strains of endophytic fungus: impact on African black beetle host selection

Volatiles in perennial ryegrass infected with strains of endophytic fungus: impact on African black beetle host selection

Defensive mixology: combining acquired chemicals towards defence

Fungal grass endophytes and arthropod communities: lessons from plant defence theory and multitrophic interactions

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