Insect flower visitors of planted native species within the arable landscape on the Canterbury Plains, New Zealand

Abstract

Almost all of the original native vegetation of Canterbury Plains has been replaced with an arable landscape of managed exotic vegetation. A previous study planted small areas of native trees on arable farms in 2013 to enhance the abundance and diversity of beneficial insect crop pollinators. The aim of the current study was to assess insect flower visitation at three sites in the fifth year after planting. Weekly standardised surveys of native flower visitors were conducted between September 2017 and February 2018. A total of 2349 insects from 37 taxa were observed within three native plantings. Native bees (Lasioglossum sordidum 20%) and the honey bee, Apis mellifera (19%), were the most common followed by the large hoverfly, Melangyna novaezelandiae (16%). The calliphorid flies, brown blowfly Calliphora stygia (8%) and blue blowfly Calliphora vicina (6%), were also well represented. The most abundant insects visited four or more of the eight study plant species. Most (52%) of the flower visitors where natives. Many of these insects are known crop pollinators and it is likely that they assist with crop pollination.

Pollination by hoverflies in the Anthropocene

“…Simosyrphus grandicornis, an Australasian species, has been anthropogenically introduced to Hawaii and French Polynesia where no previous hoverfly species were known to occur [15]. Eristalis tenax is thought to have been introduced to New Zealand from Britain or California some time before 1888 and is now very abundant in the country [93] and known to visit the flowers of various native plants [94]. The effects of these non-native species on the native flora and fauna are not currently known and this will be an important area of research to determine the effects of using some species as managed pollinators.…”

The potential management of the drone fly (<i>Eristalis tenax</i>) as a crop pollinator in New Zealand

“…It is a cosmopolitan hover fly species occurring across Europe (Francuski et al 2013a), China (Zhang et al 2011;Guo et al 2017), Japan (Buckton 1895), the Indian subcontinent and throughout the New World (Mehrabi & Ssymank 2008;Patnaik et al 2012). It is found visiting the flowers of various New Zealand native plants (Schmidlin et al 2018) and can pollinate various crops including pak choi (Brassica rapa subsp. chinensis (L.) Hanelt) and onion (Allium cepa L.) in New Zealand (Rader et al 2009;Howlett et al 2017a), kiwifruit (Actinida deliciosa (A.Chev.)…”