Neotropical songbird chick predation by an invasive wasp, the German yellowjacket (Vespula germanica)

GOROSITO, C.A.; CUETO, V.R.

Austral Ecology

John Wiley and Sons Inc

Año: 2024 vol. 49

Social wasps (Family: Vespidae) are opportunistic and generalist feeders, whichcan occasionally feed on live vertebrates. The German yellowjacket (Vespulagermanica) is native to Eurasia and Northern Africa, and has invaded manycountries around the world, producing several environmental, economic and social impacts. Here we report the first video-recorded evidence that this waspspecies preys on chicks. Over six breeding seasons, we studied the parentalcare behaviour of the Chilean Elaenia (Elaenia chilensis), a long-distance migratory bird that breeds in the Andean-Patagonian Forest. We filmed 59 nestswhen chicks were 2–3 and 10–11days old, and recorded in a nest containingtwo 10-day-old nestlings the predation of one of them by German yellowjackets.The other chick was found alive on the ground, indicating that it escaped fromthe wasps. Parents did not defend offspring against wasp attacks. The rarity ofthis observation may suggest either that this insect is not yet a significant nestpredator or that it is difficult to obtain a record of predation by wasps, becausebirds may remove dead nestlings from the nests (i.e. nest sanitation). AlthoughChilean Elaenia is not threatened, 41% of bird species in the Andean-PatagonianForest are endemic, and this new nest predator may potentially become a threatto the conservation of any of those species, which deserves further research.Hence, to evaluate the German yellowjacket impact on bird populations, it is imperative to conduct videotaped nest monitoring in order to remove the maskingeffect of nest sanitation on predator identity, which will allow to determine howmuch this wasp contributes to nest failure in the invaded zone of the Neotropicalregion