Caterpillar-parasitoid food webs and biological control in two extensive crops

Publication date: Available online 31 December 2019Source: Biological ControlAuthor(s): Susana Avalos, Ezequiel González, Arnaldo Mangeaud, Graciela ValladaresAbstractFood webs offer a useful approach to the study of complex communities interacting across trophic levels, potentially linking community structure and ecosystem services such as biological control. Herbivore-parasitoid food webs are relevant for agricultural production, in terms of pests and their control. Here, we compare caterpillar-parasitoid food webs in a perennial (alfalfa) and an annual (soybean) crop in Central Argentina, by analyzing their diversity, food web structure and parasitism rates using four years of data. Caterpillar – parasitoid communities in extensive agricultural systems have barely been addressed in a food web context. We found the same eleven defoliating Lepidoptera species in both crops, with similar annual richness values. However, alfalfa sustained larger caterpillar populations and richer parasitoid assemblages than soybean, even when only summer data (when both crops coexisted) were considered. Parasitism rates were also higher on alfalfa (only for yearlong data), suggesting bottom-up effects on the third trophic level, and may reflect the resource continuity offered by this crop. A discriminant analysis separated alfalfa from soybean food webs, mainly on the basis of vulnerability (an indicator of the mean number of parasitoid species per host), which was in turn unrelated to para...
Source: Biological Control - Category: Biology Source Type: research