The Effects of Aphid Traits on Parasitoid Host Use and Specialist Advantage

Specialization is a central concept in ecology and one of the fundamental properties of parasitoids. Highly specialized parasitoids tend to be more efficient in host-use compared to generalized parasitoids, presumably owing to the trade-off between host range and hostuse efficiency. However, it remains unknown how parasitoid host specificity and host-use depends on host traits related to susceptibility to parasitoid attack. To address this question, we used data from a 13-year survey of interactions among 142 aphid and 75 parasitoid species in nine European countries. We found that only aphid traits related to local resource characteristics seem to influence the trade-off between host-range and efficiency: more specialized parasitoids had an apparent advantage (higher abundance on shared hosts) on aphids with sparse colonies, ant-attendance and without concealment, and this was more evident when host relatedness was included in calculation of parasitoid specificity. More traits influenced average assemblage specialization, which was highest in aphids that are monophagous, monoecious, large, highly mobile (easily drop from a plant), without myrmecophily, habitat specialists, inhabit non-agricultural habitats and have sparse colonies. Differences in aphid wax production did not influence parasitoid host specificity and host-use. Our study is the first step in identifying host traits important for aphid parasitoid host specificity and host-use and improves our understanding of bottom-up effects of aphid traits on aphid-parasitoid food web structure

Unraveling a 146 Years Old Taxonomic Puzzle: Validation of Malabar Snakehead, Species-Status and Its Relevance for Channid Systematics and Evolution

The current distribution of C. diplogramma and C. micropeltes is best explained by vicariance. The significant variation in the key taxonomic characters and the results of the molecular marker analysis points towards an allopatric speciation event or vicariant divergence from a common ancestor, which molecular data suggests to have occurred as early as 21.76 million years ago. The resurrection of C. diplogramma from the synonymy of C. micropeltes has hence been confirmed 146 years after its initial description and 134 years after it was synonymised, establishing it is an endemic species of peninsular India and prioritizing its conservation value

A synopsis of Goniothalamus species (Annonaceae) in Thailand, with descriptions of three new species

A comprehensive taxonomic revision of Goniothalamus species (Annonaceae) occurring in Thailand is presented for the first time. Twenty-five species are recognized, including three that are described as new to science (Goniothalamus aurantiacus from South-Western Thailand, Goniothalamus maewongensis from Northern Thailand, and Goniothalamus rongklanus from Northern and North-Eastern Thailand). Several taxonomic and nomenclatural misunderstandings are corrected. The name G. griffithii is shown to be widely misapplied for populations in Northern Thailand, for which the name G. calvicarpus should be applied; 'true' G. griffithii is restricted to South-Western Thailand and Myanmar. In addition, the widely used name G. marcanii is shown to be a synonym of G. tamirensis, and the name G. latestigma, previously regarded as a synonym of G. undulatus, is reinstated. Goniothalamus cheliensis is furthermore newly recorded from Thailand. Most species are restricted to Peninsular Thailand and represent a Malesian floristic component. © 2008 The Linnean Society of London.link_to_subscribed_fulltex

Exploring the factors involved in the absence of parasitism of Chaetosiphon fragaefolii by generalist parasitoids in strawberry

Chaetosiphon fragaefolii Cockerell (Hemiptera: Aphididae) is a worldwide strawberry pest with scarce records of parasitoids for its control. The parasitization rate of two generalist parasitoids, Aphidius colemani Viereck and Aphidius matricariae Haliday, their behavior and aphid defensive behaviors were evaluated with Aphis gossypii Glover (Hemiptera: Aphididae) as a comparative host. Defensive endosymbionts were also surveyed. C. fragaefolii was never parasitized in simple-choice tests, whereas in preference tests both parasitoids chose A. gossypii over C. fragaefolii. No contacts of A. matricariae with C. fragaefolii were observed while A. colemani made more antennal contacts and “stings” on A. gossypii than on C. fragaefolii with the latter exhibiting less defensive behaviors against the parasitoid. The bacterium Acinetobacter sp. was detected in all samples of C. fragaefolii, but with an unknown function. Further research on the possible defensive role of the glandular hairs covering the body of this aphid, the role of chemical signals and the existence of defensive internal mechanisms against parasitoids could provide plausible explanations for the absence of parasitism found.Instituto de Microbiología y Zoología AgrícolaFil: Francesena, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Estudios Parasitologicos y de Vectores. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitologicos y de Vectores; Argentina.Fil: Arneodo Larochette, Joel Demian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola e Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rocca, Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Estudios Parasitologicos y de Vectores. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitologicos y de Vectores; Argentina.Fil: Greco, Nancy Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Estudios Parasitologicos y de Vectores. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitologicos y de Vectores; Argentina. Provincia de Buenos Aires. Comisión de Investigaciones Científicas; Argentin