Ground cover and floral resources in shelterbelts increase the abundance of beneficial hymenopteran families

Abstract

1 Hymenopteran parasitoids are important natural enemies of pest species in many agricultural crops, including grapes, and there is increasing interest in using habitat manipulation to enhance populations. 2 In the present study, we investigated which vegetation variables of shelterbelts are associated with increased hymenopteran family abundance by screening 60 shelterbelts adjacent to vineyards or pasture near Melbourne, Australia. 3 Associations between vegetation characteristics and parasitoid abundance, sampled five times at monthly intervals using canopy sticky traps, were investigated. 4 The presence of vineyard or pasture adjacent to the shelterbelt had no impact on hymenopteran family abundance within the shelterbelt. The availability of floral resources influenced a single family; the abundance of the Trichogrammatidae was doubled by the presence of canopy floral resources. By contrast, an increased abundance of some large Hymenoptera families was associated with a decreasing leaf litter depth and the proportion of introduced ground cover, an increased grass height and the amount of ground with vegetated cover. 5 These findings suggest that specific manipulations of shelterbelts could increase populations of beneficials to some degree, with potential effects on pests.

Diverging Effects of Landscape Factors and Inter-Row Management on the Abundance of Beneficial and Herbivorous Arthropods in Andalusian Vineyards (Spain)

“…In the case of parasitoids, the positive synergistic effect between surrounding vineyard area and vegetation cover within the sampled vineyards might also be due to the host- and habitat-specification of parasitoids [64,83] and thus to their stronger response to landscape complexity at smaller scales [28]. Our results on parasitoids underline previous findings that vegetation cover could be beneficial for natural enemies [38,84,85,86] by providing resources such as nectar, pollen, alternative hosts and shelter [40,70,87,88].…”

Cover crops in viticulture. A systematic review (1): <br>Implications on soil characteristics and biodiversity in vineyard

“…One of the best studies of natural enemy groups is Hymenoptera, for which there are different examples of parasitoids which increase when cover crops are used. The presence of Anagrus, egg parasitoids of Cicadellidae, increased with cover cropping (Begum et al, 2006;Centinari et al, 2016;English-Loeb et al, 2003;Nicholls et al, 2008Nicholls et al, , 2000Smith et al, 2015) and Erythroneura (Cicadellidae) population, in turn, decreased. The only exception found to this behaviour is an experiment performed in California, where the presence of cover crops did not affect Anagrus (Wilson et al, 2017).…”

The role ofTrichodermaspp. and silica gel in plant defence mechanisms and insect response in vineyard

“…Ichneumonidae and Braconidae) that need to be preserved by larger undisturbed areas (Thomson & Hoffmann, 2010). The abundance of small parasitoids may be more influenced by local features, such as ground cover and floral resources (Smith et al ., 2015).…”