21 Jun 2018

Wasp genomes revealed

From Our Changing World, 9:06 pm on 21 June 2018

New Zealand has a problem. A wasp problem.

“We have some of the highest wasp densities in the world.”

But entomologist Phil Lester says that knowing what genes these wasps have could lead to exciting new ways of controlling them.

Wasps cost New Zealand millions of dollars a year in agricultural losses and ecological damage.

Wasps cost New Zealand millions of dollars a year in agricultural losses and ecological damage. Photo: CC BY 2.0 Martin Cooper

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There are two species of introduced Vespula wasps in New Zealand: the common and the German wasp. Both species arrived here accidentally around the middle of last century, and both have found the place very much to their liking.

“We have up to 40 nests per hectare in our South Island beech forests,” says Victoria University of Wellington’s Phil Lester. “And each of those has up to 5000-10,000 workers in them.”

According to the Biological Heritage National Science Challenge website, ‘a nest can produce thousands of queens and thousands of workers, and there are about a million hectares of beech forest in the South Island. Based on these figures, there could be up to … 40 billion wasp queens in the beech forest at the height of summer, and many more workers.’

“The biomass of wasps exceeds that of native birds, introduced mammals, all those things down there. It’s a massive issue,” says Phil, who is the author of the recent book The Vulgar Wasp.

By the end of summer, each wasp nest has produced thousands of queens, all with the potential to start a new wasp nest.

By the end of summer, each wasp nest has produced thousands of queens, all with the potential to start a new wasp nest. Photo: CC BY-NC-ND 2.0 Mike Hazzledine

Researcher studying wasps in the field.

Researcher studying wasps in the field. Photo: Phil Lester / VUW

The Biological Heritage National Science Challenge is trying to find solutions to the wasp problem through a research programme, led by Phil, called ‘Novel pest control technologies for wasps.’

A key part of the research is sequencing the genomes of the common and German wasps, because knowing what genes the wasps have and how they work will help in the development of new genetic tools to control them.

“One thing that is required if we are going to develop new methods of control for these species is to understand their genomes,” says Peter Dearden.

Peter is a geneticist at the University of Otago. He is also director of Genomics Aotearoa, a genetics collaboration that was formed last year between a number of New Zealand institutions.

In the last few years, technology has enabled genomes to be produced cheaply and rapidly. And Peter says that sequencing the genomes of both the common and German wasp has been a relatively easy task, as social insects (Hymenoptera) have small, compact genomes.

The common wasp genome has been almost fully assembled and contains all its DNA base pairs, in each of its 25 chromosomes, sorted into the correct order. The German wasp genome still needs more work to get to the same stage.

The job now is to annotate each genome, which involves identifying individual genes and working out what they do. This is done by comparing wasp genes to known genes in related insects, such as bees

A wasp feeding on Coprosma berries.

A wasp feeding on Coprosma berries. Photo: Lucy Johnston / VUW

Peter says the process of annotation is “always kind of dull, but it’s the bit that needs to be done to identify the really cool bits of biology that we want to get at.”

Phil says that having the completed genomes will allow researchers to do many different things. “Right from the very theoretical – what do these genes do? How do the social behaviours of wasps and bees and ants develop?

“All the way through to … if we want to control them, perhaps by something like a gene drive process, what genes would we target and how would we do that?”

A common wasp devours a hoverfly.

A common wasp devours a hoverfly. Photo: CC BY-ND 2.0 Dean Morley

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