Isolation of microbes associated with field-collected populations of the egg parasitoid,<i>Trichogramma chilonis</i>capable of enhancing biotic fitness

Srinatha, H. Seenu; Jalali, S. K.; Sriram, S.; Chakravarthy, A. K.

doi:10.1080/09583157.2015.1018134

Cited by 11 publications

(9 citation statements)

References 33 publications

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“…Metschnikowia reukaufii and M. gruessii are common and abundant inhabitants of floral nectar that have specialized on the nectar environment (Herrera et al, 2009 ; Lievens et al, 2015 ; Pozo et al, 2016 ). Additionally, both species are strongly dependent on floral visitors for transmission among flowers, including pollinators and parasitoids (e.g., Belisle et al, 2012 ; Pozo et al, 2012 ; Herrera et al, 2014 ; Srinatha et al, 2015 ). By contrast, the other three yeast species have a broader habitat range and are less dependent on insect vectors for dispersal.…”

Section: Methodsmentioning

confidence: 99%

Sweet Scents: Nectar Specialist Yeasts Enhance Nectar Attraction of a Generalist Aphid Parasitoid Without Affecting Survival

et al. 2018

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Floral nectar is commonly inhabited by microorganisms, mostly yeasts and bacteria, which can have a strong impact on nectar chemistry and scent. Yet, little is known about the effects of nectar microbes on the behavior and survival of insects belonging to the third trophic level such as parasitoids. Here, we used five nectar-inhabiting yeast species to test the hypothesis that yeast species that almost solely occur in nectar, and therefore substantially rely on floral visitors for dispersal, produce volatile compounds that enhance insect attraction without compromising insect life history parameters, such as survival. Experiments were performed using two nectar specialist yeasts (Metschnikowia gruessii and M. reukaufii) and three generalist species (Aureobasidium pullulans, Hanseniaspora uvarum, and Sporobolomyces roseus). Saccharomyces cerevisiae was included as a reference yeast. We compared olfactory responses of the generalist aphid parasitoid Aphidius ervi (Haliday) (Hymenoptera: Braconidae) when exposed to these microorganisms inoculated in synthetic nectar. Nectar-inhabiting yeasts had a significant impact on nectar chemistry and produced distinct volatile blends, some of which were attractive, while others were neutral or repellent. Among the different yeast species tested, the nectar specialists M. gruessii and M. reukaufii were the only species that produced a highly attractive nectar to parasitoid females, which simultaneously had no adverse effects on longevity and survival of adults. By contrast, parasitoids that fed on nectars fermented with the reference strain, A. pullulans, H. uvarum or S. roseus showed shortest longevity and lowest survival. Additionally, nectars fermented by A. pullulans or S. roseus were consumed significantly less, suggesting a lack of important nutrients or undesirable changes in the nectar chemical profiles. Altogether our results indicate that nectar-inhabiting yeasts play an important, but so far largely overlooked, role in plant-insect interactions by modulating the chemical composition of nectar, and may have important ecological consequences for plant pollination and biological control of herbivorous insects.

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Section: Methodsmentioning

confidence: 99%

Sweet Scents: Nectar Specialist Yeasts Enhance Nectar Attraction of a Generalist Aphid Parasitoid Without Affecting Survival

et al. 2018

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“…The microbiota generally varies with feeding habits, like sap feeders (sucking pests) to termites (wood or cellulose feeder) to insects which feed on foliage or tissue / fruit borers (Rizzi et al, 2013). Another group of insects, parasitoids, which essentially are surviving on its host and as a free-living adults feed on fruits, flowers and nectar, acquire generally yeast and sometimes bacterial microbiota (Suh et al, 2004;Nguyen et al, 2006;Srinatha et al, 2015). In insects, microbiota-insect host-plant-host interactions are formed by different factors because insects lack a 'classical' adaptive protected system (McFall-Ngai, 2007).…”

Section: Resultsmentioning

confidence: 99%

“…In an earlier study, Medina et al (2011) also observed that association of bacteria with their host confers the trait, which allows them to differentially exploit distinct host-plants. The studies shown earlier that there are documented proof that such traits are involved in different roles such as nutritional advantages (Bernays and 2002; Engel et al, 2012), defenses against natural enemies (Oliver et al, 2005) and enhancing biological traits in insect natural enemies (Srinatha et al, 2015;Hagen et al, 1970). It may be inferred that in similar parasitoids recorded from different host-insects, an association of yeast or bacteria may be caused by different host-plant species (Hansen and Moran, 2014).…”

Section: Resultsmentioning

confidence: 99%

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"Host-insect and host-plant associated diversity in microbiota isolated from most important Oriental-Australian region egg parasitoid"

Jalali

Sriram

Venkatesan

et al. 2018

Journal of Biological Control

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Host-insect and host-plant associated differentiation of genetically divergent microbiota were recorded from economically important egg parasitoid collected from 26 locations in India, Trichogramma chilonis constituted 86.8% of the populations collected. It was recorded from 14 host-insects, 14 different crops and weed plants from 12 states. Nine species of yeast were recorded from parasitoid from 5 host-insects with Wickerhamomyces anamalus was isolated from 36.4% samples and highest numbers were recorded from parasitoid collected on sugarcane. Bacillus cereus, Pseudomonas sp. and Stenotrophomonas maltophilia from T. chilonis constitute 64.3% of bacterial diversity based on their 16S rDNA sequences. For taxonomic identification using 16s rDNA and ITS sequences, we performed taxonomic classification of total 33 ITS isolates against UNITE Fungal ITS database and assigned taxonomy hierarchy to the sequences. Also, a total of 13 isolates 16s rDNA sequences were taxonomically assigned against RDP 16s rDNA database using RDP Naive Bayesian rRNA Classifier Version 2.1. Most of the species are correctly identified in the respective species members with high confidence threshold value support.

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“…Acinetobacter has been reported in many insect groups, such as Diptera, Coleoptera, Lepidoptera, Hemiptera and Hymenoptera, including ants (Andersen et al 2013;Ceja-Navarro et al 2015;Ishak et al 2011a;Liberti et al 2015;Paulson et al 2014;Secil et al 2012;Singh et al 2012). The roles it plays in most of these groups has not been elucidated, though it was found to be important for complete development of Stomoxys calcitrans (Diptera: Muscidae) (Lysyk et al 1999), but did not influence female fitness parameters in a female wasp (Srinatha et al 2015).…”

mentioning

confidence: 99%

Population dynamics and pathogens of the invasive yellow crazy ant (Anoplolepis gracilipes) in Arnhem Land, Australia

Cooling¹

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<p>Though many populations of introduced species have been observed to collapse, the reasons behind these declines are seldom investigated. Anoplolepis gracilipes is considered among one of the top six most economically and ecologically damaging invasive ant species in the world. However, introduced populations of A. gracilipes have been observed to decline. My overall aims in this thesis were to document A. gracilipes population declines, to investigate the possibility that pathogens were playing a role in the observed population declines, and to identify putative pathogens infecting A. gracilipes as potential candidates for biocontrol agents. I documented the observed A. gracilipes population declines that were the driving force for this project. I detailed large-scale reductions in the spatial extent of four populations with before and after survey data. I also presented data on three populations that were recorded as present, but disappeared before they could be spatially delimited. I speculated on the possible reasons for these declines and explained why I do not think other explanations are likely. I then investigated the hypothesis that a pathogen or parasite is affecting A. gracilipes queens in declining Arnhem Land populations. I did this in three ways: 1) based on preliminary findings, I looked at the effect of an artificial fungal infection on A. gracilipes reproduction. I compared reproductive output between control colonies and those treated with either a fungal entomopathogen (Metarhizium anisopliae) or fungicidal antibiotics. There was no correlation between either treatment and the number of eggs, larvae, pupae or males a colony produced after 70 days. I found queen number had no effect on colony reproductive output, suggesting that queens are able to adjust their egg-laying rate in the presence of other queens. I found no evidence that M. anisopliae affected reproductive output at the tested concentrations; 2) I explored the hypothesis that a pathogen that kills or affects the reproductive output of A. gracilipes queens is the mechanism or reason behind the population declines. I measured queen number per nest, egg-laying rate, fecundity and fat content and compared them between sites in different stages of decline or expansion (population types, consisting of low, medium and high-density populations). I discovered that 23% of queens had melanized nodules, a cellular immune response in insects, in their ovaries or fat bodies. The presence of nodules was correlated with a 22% decrease in the number of oocytes per ovary; however, nodule presence was not associated with population type, suggesting that though there are clearly pathogens or parasites capable of penetrating the cuticle of A. gracilipes, they are unlikely to be responsible for the observed population declines; 3) I compared microbial communities (bacteria and viruses) between queens from different population types. I found viral sequences that match to the Dicistroviridae family of viruses in low and medium-density populations. I found no differences in bacterial community structure between population types. The presence of sequences similar to the entomopathogens Rhabdochlamydia and Serratia marcescens, as well as the reproductive parasite Cardinium in A. gracilipes, deserves further investigation. Though introduced species’ populations have been observed to decline, this is one of the first studies to quantitatively examine, document, and investigate a mechanism behind such a decline. Understanding the mechanisms by which an invader declines may have important implications for invasive ant management worldwide.</p>

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Isolation of microbes associated with field-collected populations of the egg parasitoid,Trichogramma chiloniscapable of enhancing biotic fitness

Cited by 11 publications

References 33 publications

Sweet Scents: Nectar Specialist Yeasts Enhance Nectar Attraction of a Generalist Aphid Parasitoid Without Affecting Survival

Sweet Scents: Nectar Specialist Yeasts Enhance Nectar Attraction of a Generalist Aphid Parasitoid Without Affecting Survival

"Host-insect and host-plant associated diversity in microbiota isolated from most important Oriental-Australian region egg parasitoid"

Population dynamics and pathogens of the invasive yellow crazy ant (Anoplolepis gracilipes) in Arnhem Land, Australia

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