Predatory Arthropods associated with potential locally-adapted native insectary plants for Australian vineyards

Abstract

Context and purpose of the study – Three locally-adapted native plants were evaluated to determine their capacity to provide insectary benefits to predatory arthropods in association with vineyards, and thereby to enhance biological control of insect pests. Native plants are preferred as supplementary flora, as they are naturally adapted to Australia’s climatic conditions.

Materials and methods – Stands of mature Bursaria spinosa, Leptospermum continentaleand Rytidosperma ssp. located adjacent to or in the mid-rows of Adelaide Hills, Barossa Valley and Eden Valley vineyards were sampled for arthropods in 2013/14. Vitis viniferawas also sampled.

Results – Twenty seven thousand and ninety-one individual invertebrate specimens were collected, comprising 20 orders and 287 morphospecies. Eight thousand, eight hundred and eighty predators, 6,790 herbivores and 11,421 other specimens were collected. Predatory arthropods dominated the diversity of morphospecies present on each plant. Out of a total of 98 predatory morphospecies, 67 were found on B. spinosa, 63 on L. continentale, 56 on V. vinifera and 38 in association with Rytidosperma ssp. The difference between predatory and herbivore morphospecies was highest on Rytidosperma ssp. (2:1 predators: herbivores), followed by L. continentale, V. vinifera and B. spinosa. The richness of predator morphospecies across all plant types was nearly double the number found in association with grapevines. It may be possible to increase the functional diversity of predatory arthropods by more than 3x when either B. spinosa or L. continentale is present versus grapevines only, and increase the net number of predator morphospecies by around 27% when Rytidosperma ssp. are planted in combination with the grapevines. The selected plants provide a suitable habitat to support diverse and functional populations of predatory arthropods. The opportunity to plant selected native insectary species could help wine grape growers save time and resources by producing fruit with lower pest incidence, while enhancing biodiversity of their vineyards.