Stink bugs: what are brown marmorated stink bugs, are they the same as shield bugs - and are they harmful to humans?

The stink bug is an invasive species commonly found in people's homes during autumn and pose a threat to fruit crops

Fruit growers in the UK are bracing themselves for an invasion of insects which could threaten their harvest.

The Halyomorpha halys, commonly known as stink bugs due to the nasty smell they emit when startled or killed, are now present in the country.

Scientists have confirmed the arrival of stink bugs in more than one setting and say that now the insects are here it will be impossible to get rid of them.

Stink bugs are similar in appearance to a shield bug (pictured) but pose a bigger threat to fruit crops. (Pic: Getty Images)

But what do we know about them and the impact they will have on fruit crops in the UK - and are they harmful to humans?

Let’s take a look.

What are stink bugs?

Brown marmorated stink bugs are an invasive species that are commonly found in people's homes during late summer and autumn as the temperature outside begins to fall.

They look for shelter and warmer sites during the winter months and reemerge in early spring to become active once more, when they can be found in fields and on the side of buildings.

The bugs get their name from the unpleasant smell they emit when disturbed or crushed, which has often been described as an almond-like odour.

What do stink bugs look like?

Stink bugs are a browny-grey colour and have a marbled appearance to their shells.

They have six legs, are around two centimetres in length and have two antennae which are used to sense their environment.

They have a similar shape to shield bugs, which are slightly larger in size, but these are not thought to be agricultural pests of significance.

Where do stink bugs come from?

Stink bugs originate from south-east Asia where they are considered a pest.

They made their way over to the United States in the mid-1990s and have been there ever since as there is no natural predator to a stink bug in the country.

They are thought to have travelled accidentally on food packaging or crates and are here to stay once they have arrived, UK scientists have confirmed.

Are stink bugs dangerous?

Stink bugs aren’t known to bite or thought to pose a threat to humans - though be warned of the unpleasant odour they might emit if you attempt to kill or move them along.

The insects are a problem for fruit growers as they tend to be attracted to apples, grapes and other kinds of fruit during the warmer spring and summer months.

Stink bugs are known to leave a brown streak on the side of fruit, ruining its appearance and reducing its value, and could even destroy crops if there is an infestation.

They are considered a threat to the agricultural industry.

Why are stink bugs in the UK?

In 2020, a stink bug was discovered in the gardens of the Natural History Museum. One has since turned up at a house in Surrey, according to the Guardian.

Their spread has been tracked by scientists and will cause alarm to fruit growers, as the bug’s presence in America cost around £26m in apple losses in 2010.

Max Barclay, the senior curator in charge of Coleoptera at the Natural History Museum, said numbers of stink bugs were likely to fall after an initial surge.

“This happens because the predators and parasites and diseases that are associated with these things eventually catch up with them,” said Mr Barclay.

“The invasive species makes a nuisance of itself before gradually moving into the background and becoming part of the established fauna.”

“With climate change and global trade these stories are going to become more frequent.”