Effect of a Fungal Endophyte on the Growth and Survival of Two Euplectrus parasitoids

Bultman, Thomas L.; Borowicz, Kristin L.; Schneble, Robert M.; Coudron, Thomas A.; Bush, Lowell P.

doi:10.2307/3545812

Cited by 68 publications

(76 citation statements)

References 36 publications

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“…Under such conditions, a reduced lifespan will most likely result in a shorter reproductive time and thus reduced fitness. Similar fitness penalties of endophytes are known for predators and primary parasitoids (Bultman et al 1997;de Sassi et al 2006;Härri 2007). Ours is the first study showing experimentally that even the top trophic level in this aphid-parasitoid food web can suffer from ubiquitous endophytic fungi in agricultural grasses.…”

Section: Discussionmentioning

confidence: 55%

Fungal endosymbionts of plants reduce lifespan of an aphid secondary parasitoid and influence host selection

2008

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Complex biotic interactions shape ecological communities of plants, herbivores and their natural enemies. In studies of multi-trophic interactions, the presence of small, invisible micro-organisms associated with plants and those of a fourth above-ground trophic level have often been neglected. Incorporating these neglected factors improves our understanding of the processes within a multi-trophic network. Here, we ask whether the presence of a fungal endosymbiont, which alters plant quality by producing herbivoretoxic substances, trickles up the food chain and affects the performance and host-selection behaviour of aphid secondary parasitoids. We simultaneously offered hosts from endophyte-free and endophyteinfected environments to secondary parasitoids. Older and more experienced parasitoid females discriminated against hosts from the endophyte-infected environment. Developing in lower quality hosts from the endophyte-infected environment reduced the lifespan of secondary parasitoids. This indicates that aphid secondary parasitoids can perceive the disadvantage for their developing offspring in parasitoids from the endophyte environment and can learn to discriminate against them. In the field, this discrimination ability may shift the success of primary parasitoids to endophyte-infected plants, which co-occur with endophyte-free plants. Ultimately, the control of aphids depends on complex interactions between primary and secondary parasitoids and their relative sensitivity to endophytic fungi.

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Section: Discussionmentioning

confidence: 55%

Fungal endosymbionts of plants reduce lifespan of an aphid secondary parasitoid and influence host selection

2008

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“…In some cases, however, the development of the parasite larvae was retarded in hosts that had been fed on artificial diets containing diterpenes, alkaloids usually produced by A. lolii. In the same manner, Bultman et al (1997) verified in the F. arundinacea-A. coenophialum interaction, that there was interference of alkaloids produced by the fungus not only on the fall armyworm S. frugiperda, but also on two parasites that control this pest, Euplectrus comstockii and E. plathypenae.…”

Section: Endophyticmentioning

confidence: 57%

Endophytic microorganisms: a review on insect control and recent advances on tropical plants

Azevedo¹,

Maccheroni²,

Pereira³

et al. 2000

Electron. J. Biotechnol.

566

320

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In the past two decades, a great deal of information on the role of endophytic microorganisms in nature has been collected. The capability of colonizing internal host tissues has made endophytes valuable for agriculture as a tool to improve crop performance. In this review, we addressed the major topics concerning the control of insects-pests by endophytic microorganisms. Several examples of insect control are described, notably those involving the interactions between fungi and grazing grasses from temperate countries. The mechanisms by which endophytic fungi control insect attacks are listed and include toxin production as well as the influence of these compounds on plant and livestock and how their production may be affected by genetic and environmental conditions. The importance of endophytic entomopathogenic fungi for insect control is also addressed. As the literature has shown, there is a lack of information on endophytes from tropical hosts, which are more severely affected by pests and diseases. The natural and biological control of pests and diseases affecting cultivated plants has gained much attention in the past decades as a way of reducing the use of chemical products in agriculture. Biological control has been frequently used in Brazil, supported by the development of basic and applied research on this field not only in our country but also in South America as it can be found in several reviews (Lecuona, 1996;Alves, 1998;Melo and Azevedo, 1998). In fact, by having vast agriculturable areas and most of its territory in the tropical region, Brazil and all Latin America, show their agriculture severely affected by agricultural pests. The use of agrochemicals, although decreasing the attack of insects and phytopathogenic microorganisms, still represents a high risk to field workers and consumers. In addition, their use is, in certain cases, economically unviable. The control of pests and diseases by means of biological processes i. e., use of entomopathogenic microorganisms or those that inhibit/antagonise other microorganisms pathogenic to plants, is an alternative that may contribute to reduce or eliminate the use of chemical products in agriculture.

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“…However, experimental studies on endophytes and their effects on higher trophic levels are still rare (Faeth and Bultman 2002;Müller and Krauss 2005). Existing studies have generally found negative effects on herbivores and no or negative effects on the associated natural enemies (Barker and Addison 1996;Bultman et al 1997;Goldson et al 2000;Bultman et al 2003;de Sassi et al 2006). However, no study so far has investigated the effects of endophytes on the reproductive ability of parasitoids developing within herbivores feeding on endophyte-infected plants.…”

Section: Introductionmentioning

confidence: 99%

“…However, no study so far has investigated the effects of endophytes on the reproductive ability of parasitoids developing within herbivores feeding on endophyte-infected plants. Other studies on endophytes and parasitoids have mainly concentrated on the parasitism rate (= attack rate) of endophytenaïve individuals and on developmental time and survival to adulthood of their offspring (Barker and Addison 1996;Bultman et al 1997;Bultman et al 2003). Here, we additionally examine fecundity traits (i.e.…”

Section: Introductionmentioning

confidence: 99%

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

2008

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Trophic cascades initiated by fungal plant endosymbionts impair reproductive performance of parasitoids in the second generation Variation in plant quality can transmit up the food chain and may aVect herbivores and their antagonists in the same direction. Fungal endosymbionts of grasses change the resource quality by producing toxins. We used an aphid-parasitoid model system to explore how endophyte eVects cascade up the food chain and inXuence individual parasitoid performance. We show that the presence of an endophyte in the grass Lolium perenne has a much stronger negative impact on the performance of the parasitoid Aphidius ervi than on its aphid host Metopolophium festucae. Although the presence of endophytes did not inXuence the parasitism rate of endophyte-naïve parasitoids or their oVspring's survival to adulthood, most parasitoids developing within aphids from endophyte-infected plants did not reproduce at all. This indicates a delayed but very strong eVect of endophytes on parasitoid performance, which should ultimately aVect plant performance negatively by releasing endophyte-tolerant herbivores from top-down limitations.

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Effect of a Fungal Endophyte on the Growth and Survival of Two Euplectrus parasitoids

Cited by 68 publications

References 36 publications

Fungal endosymbionts of plants reduce lifespan of an aphid secondary parasitoid and influence host selection

Fungal endosymbionts of plants reduce lifespan of an aphid secondary parasitoid and influence host selection

Endophytic microorganisms: a review on insect control and recent advances on tropical plants

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

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