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“That’s not the one,” I exclaimed as I glowered at the evil looking insect in the glass jar. “The one we are after is twice as big as that!”

Alas, it was the one, I just didn’t want the legend to end. For five years now this giant ichneumon wasp species had haunted me and a handful of the volunteers. Every summer we spotted one. Awestruck by their size, they have led us on a merry dance around the reserve as we tried to get a better view. Cameras would swing into action in their wake, but mysteriously all of the photos came out blurred. None of us could ever get close enough to confirm its identification. Until now.

Amblyjoppa proteus

Amblyjoppa proteus, by Hannah Breach

I tentatively held the jar aloft, almost expecting it to shatter into dust as the ichneumon made good its escape. I marvelled at it through the glass, watching its long black antennae marked with a single white band on each twitching away, constantly searching for an escape. A cream spot on its thorax was the only other decorative feature amongst the black of its head, thorax, abdomen and legs. It must have been 30mm in length, not including its long antennae. It was by far the biggest ichneumon species I had ever seen (not that I can identify many). Volunteers Kevin and Hannah had glimpsed it by chance whilst out on the fen surveying swallowtail caterpillars. After a quick rummage in a rucksack a specimen pot was expertly wielded, safely trapping the ichneumon. 

An email exchange of photos and descriptions with the national ichneumon expert, Dr Mark Shaw, confirmed Kevin and Hannah’s identification; Amblyjoppa proteus had made its way into the Wheatfen species record books, a first for the reserve, and what a name! 

Elephant hawk moth caterpillar

Elephant hawk moth caterpillar by Ann Kerridge

Like all ichneumon wasps, Amblyjoppa proteus is a parasitoid. Out on the fen, before its sudden capture, it had been searching for its host species; elephant hawk moth caterpillars. These impressive looking caterpillars of the equally impressive looking moth grow up to a whopping 80mm long. Said to look like an elephant’s trunk, the caterpillar’s general colouration is that of a greenish-brown, with a pointy horn near its rear. Two enormous pairs of dark eye spots act as a defence against various predators, swelling when threatened to give the impression of a snake-like false head. This defence mechanism may deter some bird species, but it does not stop the ichneumon. 

The caterpillar’s preferred fodder is willowherb, where it chomps away harmlessly only to be ambushed, impaled and injected with eggs via the ovipositor of a mated female Amblyjoppa. The caterpillar flinches, rearing up to confront its tormentor. It is too little too late. The caterpillar will complete this stage of its lifecycle, feeding and growing before going off to pupate, often near or in the ground. But it will not be the large, stunning pink moth that should appear the following year. Amblyjoppa proteus will rise again. 

On unscrewing the jar’s lid, Amblyjoppa was liberated back into the wild. We stared in awe as she took flight, heading off out into the fen to continue her lifecycle. Legends will come and go at Wheatfen, the reserve attracts them. I only wonder what the next one will be…

Will Fitch

Author Will Fitch

I have been the Warden at Wheatfen for a number of years now, helping to look after and manage the reserve with the help of our trusty volunteers. You can often find me either out and about at the reserve, or in the Warden's hut in the car park.

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