Endemic New Zealand aphids (Hemiptera: Aphididae) parasitised by native Aphidiinae (Hymenoptera: Braconidae), not biological control parasitoids

Abstract

Almost all known Aphidiinae (Hymenoptera: Braconidae) parasitoid species in New Zealand have been introduced as biological control agents (BCAs) for introduced aphids or have self‐introduced. The New Zealand endemic aphid (Hemiptera: Aphididae) fauna consists of a small number of species that are parasitised, on occasion, by Aphidiinae that remain unidentified. A persistent concern has been that introduced BCAs are among the parasitoids attacking the rare endemic aphids. After 14 years of collection, 66 cytochrome oxidase I (COI) gene sequences were obtained from emerged parasitoids, mummies or by specific PCR from parasitised New Zealand aphids. Parasitoid samples were from 13 aphid species (eight endemic, plus five introduced species feeding on native plants) at 20 locations. The Aphidiinae COI sequences comprised two new clades of native New Zealand parasitoids. One species‐rich clade appeared to represent a radiation after dispersal to New Zealand, whereas the second clade consisted only of parasitoids from a single endemic host. The patterns of aphid/parasitoid associations were strongly suggestive of host specificity towards the endemic aphids, while a subgroup of the newly discovered native Aphidiinae was found parasitising four introduced aphid species, despite the short time period these aphids are assumed to have been in New Zealand. We found no evidence for attack of endemic aphids by introduced BCAs or other introduced aphidiines. On the rare occasions that parasitism was detected in the most common endemic Aphidinae aphid, Aphis cottieri Carver, 1999, it was by a native Aphidiinae lineage, not by Aphidius ervi Haliday, 1834.

Sizing the Knowledge Gap in Taxonomy: The Last Dozen Years of Aphidiinae Research

“…In the last few years, different researchers started using DNA barcodes for the molecular identification of Aphidiinae [79,98,136]. The identification of Aphidiinae based solely on molecular data (barcodes) is not reliable, because species and genera boundaries, based on barcoding sequences, vary significantly.…”