An invader supported by a parasite: Mistletoe berries as a host for food and reproduction of Spotted Wing Drosophila in early spring

Abstract

The Spotted Wing Drosophila (SWD), Drosophila suzukii Matsumura, an invasive pest species in Europe and the Americas, is able to feed and reproduce on numerous fruit crops and a wide range of wild host plants. SWD is thought to overwinter outside of agricultural fields in forests and hedges. To identify overwintering sites and early spring oviposition hosts, traps were installed in forests. In spring 2015, traps in the canopy of pine trees parasitized by mistletoe, Viscum album subsp. laxum, captured significantly more SWD than traps in pine trees without mistletoe. We found SWD females with ripe eggs coinciding with ripening and ripe mistletoe berries. We investigated whether mistletoe may serve as a host for SWD. Under laboratory conditions, SWD developed from egg to adult in mistletoe berries. More adults emerged from wounded berries. Females were observed to feed on berries and survived up to eight days without other food. A few adults emerged from wild mistletoe berries. To understand the attraction of SWD to parasitized trees, we analyzed the volatile organic compounds (VOCs) collected from the headspace of mistletoe berries by GC-MS and identified the main components. Thirty-two VOCs were found.Wounded and unwounded berries differed significantly in the quantity of 11 VOCs emitted. The odor spectrum showed many similarities to other typical berry odors. The combination of field surveys and laboratory assays identified a new reproduction host for SWD in spring. This host plant may help SWD to withstand the bottleneck period for survival in winter and spring. Key message• Mistletoe berries support SWD nutrition and reproduction. • SWD abundance in the canopy of pine trees parasitized by V. album was higher than in the canopy of P. sylvestris without V. album or at lower heights in the vegetation. • The odor spectrum showed many similarities to other typical berry odors. • Adult SWD emerged from field-collected mistletoe berries indicating that mistletoe is one of the first reproductive hosts for SWD in Central Europe.

Spotted wing drosophila (Drosophila suzukii) utilization and dispersal from the wild host Asian bush honeysuckle (Lonicera spp.)

“…Drosophila suzukii was found commonly in five wild hosts that are present in the habitats surrounding blueberry fields in central and west‐central Michigan across two growing seasons (Table ). This pest is highly polyphagous and is known to utilize a variety of wild hosts, many of which were not found in the present study (Lee et al ., ; Poyet et al ., ; Briem et al ., ; Kenis et al ., ; Thistlewood et al ., ). We expect that the wild hosts sampled are only a fraction of the hosts available to D. suzukii in our landscape and these data do not represent the complete host range of wild fruits.…”

“…Honeysuckle and other wild hosts that bear fruit before berry crops ripen (e.g. mistletoe, Briem et al ., ) may serve as important drivers in the local abundance of D. suzukii and should be evaluated for their role in the ecology of this new pest on farmland.…”

Cost–benefit analysis of controlling the spotted wing drosophila (Drosophila suzukii (Matsumura)) spread and infestation of soft fruits in Trentino, Northern Italy

“…The worldwide distribution of the SWD and of its economic importance has been recently reviewed by Asplen et al . The major factors affecting the population dynamics of D. suzukii include temperature and humidity, the availability of essential food resources, and the presence of effective biological control agents …”

The effect of border sprays and between‐row soil tillage on Drosophila suzukii in organic blackberry production

“…Border sprays can be useful against pests that migrate from surrounding environments (Chouinard et al 1992;Trimble and Solymar 1997;Blaauw et al 2015);. Although we did not evaluate fly presence in surrounding areas or migration in this study, D. suzukii has been shown to utilize wild hosts in wooded areas surrounding blueberries, blackberries and raspberries (Lee et al 2015b;Liburd et al 2015;Briem et al 2016) and as a result, can increase pressure on adjacent crops (Klick et al 2016). Klick et al (2016) found that D. suzukii captures were higher in raspberry fields that were adjacent to wild 'Himalaya' blackberry (Rubus armeniacus Focke) than fields that were not in close proximity.…”