Are invasive species promoting yellowjacket invasion in Patagonia?

MASCIOCCHI, MAITÉ; VILLACIDE, JOSÉ M.; BUTELER, MICAELA; MARTÍNEZ, ANDRÉS S.

JOURNAL OF APPLIED ENTOMOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2022 p. 1 - 10

0931-2048

In  recent  decades,  yellowjacket  wasps,  including  Vespula  vulgaris,  have  successfully  been established in Patagonia. Additionally, the invasive willow Salix fragilis has also invaded areas next to watercourses, which in turn are typically colonized by the giant willow aphid (GWA, Tuberolagnus salignus),  another  invasive  species.  The  honeydew  exuded by the aphids has been reported to be used as a carbohydrate source by this social wasp. Our aim was to determine whether willows and GWA (invasive complex) on  the  stream  shores  promotes  yellowjacket  population  growth.  We  worked  under  the hypothesis that GWA provides honeydew (i.e. carbohydrates) to yellowjackets, favouring nest 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  but  also  a  higher  nest  density  of  V.  vulgaris  yellow-jackets. Even though the nests were similar in size irrespective of the distance to the stream, weight, size and nutritional status of individuals suggest that foraging/nest-ing in proximity of the invasive complex promotes larger and better nurtured wasps, including  reproductive  castes,  that  in  the  long  run  could  drive  population  growth  and spread of the species in Patagonia. In this context, our study suggests that man-agement  of  V.  vulgaris  populations  should  adopt  strategies  that  encompass  a  broad  approach, especially adopting new strategies designed to contemplate relevant multi-trophic interactions between yellowjackets and invasive willows and aphids.