Foraging behaviour of the exotic waspVespula germanica(Hymenoptera: Vespidae) on a native caterpillar defoliator

Abstract

Vespula germanica is a social wasp and an opportunistic predator. While foraging, these wasps learn and integrate different kinds of cues. They have successfully invaded many parts of the world, including native Nothofagus and Lophozonia forests located in the Andean-Patagonian region, where they forage on native arthropods. Perzelia arda, a lepidopteron defoliator of Lophozonia obliqua, uses the foliage to hide in and feed on. The purpose of this work is to study whether V. germanica use olfactory cues when foraging on P. arda. To do this, we used a Y-tube olfactometer and established three treatments to compare pairs of all combinations of stimuli (larvae, leaves with larval traces, and leaves without larval traces) and controls. Data were analysed via two developed models that showed decisions made by V. germanica and allowed to establish a scale of preferences between the stimuli. The analysis demonstrates that V. germanica wasps choose P. arda as larval prey and are capable of discriminating between the offered stimuli (deviance information criterion (DIC) null model = 873.97; DIC simple model = 84.5, n = 152). According to the preference scale, V. germanica preferred leaves with traces of larvae, suggesting its ability to associate these traces with the presence of the prey. This may be because, under natural conditions, larvae are never exposed outside their shelters of leaves and therefore V. germanica uses indirect signals. The presence of V. germanica foraging on P. arda highlights the flexible foraging behaviour of this wasp which may also act as a positive biological control, reducing lepidopteran populations.

Ecosystem services provided by aculeate wasps

“…Predatory wasps are common in a range of agricultural environments, suggesting that such crops provide rewarding forage patches (Bommarco et al ., 2011; Rodriguez et al ., 2012; Souza et al ., 2013; Jacques et al ., 2015, 2018; Tomazella et al ., 2018). Moreover, observational studies report social predatory wasps as one of the main natural predators of lepidopteran pests in agricultural settings (Rabb & Lawson, 1957; Picanço et al ., 2006, 2010; Bommarco et al ., 2011; Picanço, 2012; Pereira et al ., 2018; Lourido et al ., 2019) and that they can successfully locate such prey using olfactory cues (Pietrantuono, Moreyra & Lozada, 2018; Southon et al ., 2019). A third reason why social wasps are promising biocontrol agents is due to the sheer numbers of hunters provided by each colony; a single V. vulgaris colony has up to 10000 workers and produces thousands of larvae; Vespula has been suggested as a viable candidate for development as a manageable pest controller (Donovan, 2003).…”

Hydrocarbons mediate seed dispersal: a new mechanism of vespicochory

“…1; Chen et al, 2017). These predators are sensitive to hydrocarbons (Ruther et al, 2002;Cini et al, 2009;Bruschini et al, 2011) and use olfactory cues when foraging for insect prey (Wang et al, 2014;Pietrantuono et al, 2017). Indeed, New Phytologist these seed dispersers attack diaspores of S. tuberosa in the same way as V. velutina (Movie S1).…”

Evidence of associative blocking during foraging in the social wasp Vespula germanica

“…While foraging, social wasps usually find resources guided by odor and visual cues (e.g., Moreyra et al ., 2006; D'Adamo & Lozada, 2011; Buteler et al ., 2015; El‐Sayed et al ., 2018; Pietrantuono et al ., 2018). The social wasp Vespula germanica (Fabricius, 1793) (Hymenoptera: Vespidae) frequently returns to an abundant resource (Takagi et al ., 1980; Raveret Richter & Jeanne, 1985; Cheng, 2000, Jarau & Hrncir, 2009; Lozada & D'Adamo, 2014).…”