Especificidad y denso-dependencia inversa en parasitoides con oviposición fuera del hospedador: el caso de Mallophora ruficauda (Diptera: Asilidae) en la Pampa Argentina
We study the specificity and density dependence phenomena associated to the parasitism, in a host parasitoid system whose females do not have common host search behavior. We studied the system composed by the soil white worms (Coleoptera: Scarabaeidae) and the bee hunter robber fly Mallophora ruficauda Wiedemann 1828 (Diptera: Asilidae). The study was conducted in the nearness of eight apiaries located in the provinces of Buenos Aires and Entre Ríos, during the month of June of 1997. The robber fly possesses a 0.69 preference index in the election of his host, indicating that it is lightly selective toward Cyclocephala signaticollis (90% of parasitism). Phenomena of inverse density dependence were observed when analyzing at small scale the variable abundance of worms in the soil (ln) and percentage of parasitism (In) using lineal regression and “Jackknife” estimations. This result indicates that the parasitoid saturates their possibilities to parasite more hosts as the abundance of the latter increases in the soil. This phenomenon could be linked to the particular egg laying characteristics of the parasitoid. Eggs are not lay directly on the host, but on high vegetation taking advantage of the wind for the dispersion of its larvae. The host-parasitoid encounter could be bound to the simultaneous coincidence in the space of the distribution of the hosts and the larvae parasitoids in the soil.
| Main Authors: | , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Asociación Argentina de Ecología
2000
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| Online Access: | https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/1601 |
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