So you’ve got a problem with wasps. They’re raiding beehives, assailing bees, depriving native birds of honeydew, spoiling harvests and just generally wreaking the sort of havoc invasive species do. That’s the case with two types of European wasps – Vespula germanica and Vespula vugaris – that have earned a reputation as major environmental and economic pests in New Zealand.

Invasive Wasp Newzealand 23 04 2014
Tiny mite hitchhikers huddled on a European wasp (Vespula germanica). Image: Landcare Research

Now, one research team thinks the invaders could be tackled with a new biocontrol weapon: an army of mites with a hankering for wasp wings. The team from Landcare Research recently secured funding to test their 'mite theory' out ... and with as many as 30 wasp nests per hectare in some parts of New Zealand, their findings could be a much-needed game changer.

The idea was sparked when wasp researcher Bob Brown discovered tiny mites squatting, microscopic mouthparts happily hooked in, on the wings of European wasps. The hitchhikers had colonised areas that were difficult for the wasps to groom, making the unwanted guests hard to dislodge. Mite-infested wasps showed signs of wing deformation, and, what's more, wasp colonies overtaken by the tiny arthropods eventually collapsed.    

“These findings encouraged us to reinvestigate a biocontrol programme for wasps in New Zealand, and pursue this potentially promising mite-agent,” says Landcare Research scientist Ronny Groenteman.

Landcare Research's team sees mite biocontrol as a great option: cheap, self-sustaining and effective over large areas and in inaccessible terrains. But before the mite army can be deployed, the researchers have a long list of things to investigate, including figuring out why the mites have not already conquered more wasp colonies on their own steam. Critically, they'll also need to make sure wing-mangling mites stick to the invasive wasps ... and don't turn their attention to native bees. 

“Biocontrol agents aren’t a ‘quick fix’ but instead work quietly over a number of years in conjunction with other existing control methods. While biocontrol agents introduced to New Zealand 30 years ago failed to control wasps, this mite could be playing a different game, and it is already here and established. We are convinced that investigating its potential is the prudent thing to do,” Groenteman says.

Top header image: nutmeg66, Flickr