Do invasive species encourage the invasion of social wasps in patagonia?

MASCIOCCHI, MAITÉ; MARTINEZ ANDRES S.; VILLACIDE, JOSÉ M.; BUTELER, MICAELA

San Diego

Congreso; IUSSI 2022; 2022

IUSSI

In recent decades, yellowjacket wasps,including Vespula vulgaris, havesuccessfully been established in Patagonia. Additionally, the invasive willow Salix fragilis has also invaded areasnext to watercourses, and in turn are typically colonised by the giant willowaphid (GWA Tuberolagnus salignus),another invasive species. The honeydew exuded by the aphids has been reportedto be used as a carbohydrate source by this social wasp. Our aim was todetermine whether the invasive complex formed by willows and GWA on the streamshores, promotes yellowjacket population growth. We worked under the hypothesisthat GWA provides honeydew (i.e., carbohydrates) to yellowjackets, favoringnest growth and individual fitness. Our results indicate that habitats close(< 200 m) to stream margins where S.fragilis and GWA occur, contain not only a greater abundance of workers butalso a higher nest density of V. vulgarisyellowjackets. Even though the nests were similar in size irrespective of thedistance to the stream, weight, size and nutritional status of individualssuggest that foraging/nesting in proximity of the stream/willow/GWA complexpromotes larger and better nurtured wasps, including reproductive castes, thatin the long run could drive population growth and spread of the species inPatagonia. In this context, our study suggests that management of V. vulgaris populations should adoptstrategies that encompass a broad approach, especially adopting new strategiesdesigned to contemplate relevant multitrophic interactions betweenyellowjackets and invasive willows and aphids.