Molecular and morphological identification of the alfalfa weevil larval parasitoids Bathyplectes anura and Bathyplectes curculionis to estimate the rate of parasitism
The alfalfa weevil (Hypera postica Gyllenhal, Coleoptera: Curculionidae) is a major pest of alfalfa crops. Chemical control measures are inefficient, but the larvae are often infested by parasitoid wasps of the genus Bathyplectes Forster (Hymenoptera: Ichneumonidae), which offer a potential biologic...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2022 |
| País: | España |
| Institución: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repositorio: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:recercat.cat:10459.1/83195 |
| Acceso en línea: | https://doi.org/10.1007/s10526-022-10141-x http://hdl.handle.net/10459.1/83195 |
| Access Level: | acceso abierto |
| Palabra clave: | Hypera postica Cytochrome C oxidase subunit I (COI) Parasitism rate Polymerase chain reaction (PCR) Biological control Bathyplectes sp Plagues--Control biològic |
| Sumario: | The alfalfa weevil (Hypera postica Gyllenhal, Coleoptera: Curculionidae) is a major pest of alfalfa crops. Chemical control measures are inefficient, but the larvae are often infested by parasitoid wasps of the genus Bathyplectes Forster (Hymenoptera: Ichneumonidae), which offer a potential biological control strategy. The development of effective biological control requires the identification of parasitoid species, but conventional methods involve the rearing of parasitoids to the puparium stage for morphological confirmation. Here we designed a PCR method in which two pairs of primers are used to detect and identify Bathyplectes curculionis Thomson and Bathyplectes anura Thomson larvae in a faster way. We compared conventional rearing to the new method as a means to determine the parasitism rates caused by each species in Spain during the 2019 and 2020 seasons. In 2019, the PCR method detected five times as many B. curculionis events and twice as many B. anura events. Similarly, in 2020, the PCR method detected seven times as many B. curculionis events and twice as many B. anura events. High mortality of H. postica larvae was recorded in 2020 due to an epizootic attack by the fungus Zoophthora phytonomi Arthur (Zygomycetes: Entomophthorales), explaining the lower overall rate of parasitism and the widespread death of the larvae. Statistical analysis confirmed that the PCR method is more sensitive than conventional rearing for the detection of target parasitoids. However, only rearing can confirm the effective parasitism or the presence of unexpected species. We therefore recommend the use of both methods in parallel when evaluating host-parasitoid systems. |
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