The Gilkicker Weevil Lives On!

Browndown SSSI ©Mariko Whyte

10 years after they were last surveyed, we went to Gilkicker Point to find out whether the Gilkicker weevils are still there.

The wildlife of the UK is some of the best studied in the world, thanks to a long tradition of amateur naturalists armed with pooters and sweep nets, yet despite this there are so many species that we know almost nothing about, even right on our doorstep. The Gilkicker weevil is one of these.

At first glance, the Gilkicker weevil is not much different to any other species of weevil. It’s about 4mm long, with a reddish-brown head and a cute bumbling walk. What makes it special is that, within the UK, it is only present at two sites: Browndown SSSI and Gilkicker Point (where it gets its name from!). This makes it a priority species for conservation in Hampshire, so it’s important that we know how the population is doing.

Gilkicker weevil on a piece of vegetation

Gilkicker Weevil ©Mariko Whyte

The last survey to check on the Gilkicker weevil population was done 10 years ago, so this summer I was put in charge of re-surveying the sites, to find out if the weevil was still there.

Gilkicker weevils are quite tricky to survey, because we don’t know very much about their habitat requirements. We know that they will only live on Common Bird’s-foot-trefoil, and only when the plant is growing on shingle beaches. To add to this, it seems that they only really like living on plants which are less than 15cm tall, in a hot, sunny, and ideally frost-free area: this weevil prefers to be warm! This means that, although there’s plenty of habitat for it further south in Europe, in the UK there aren’t a lot of good places. The good thing about this, from a surveying point of view, is that we can be very specific about where we sample.

Surveying for weevils requires a suction sampler. Imagine a leaf blower, but modified to suck, rather than blow, and you’ll have some idea of what I was waving around on the beach. This is used to ‘hoover’ insects up from patches of Common Bird’s-foot-trefoil. The insects (and loose bits of vegetation or soil) are caught in a mesh sample bag inside the suction sampler. This doesn’t hurt the insects at all! Everything that is sucked up has to be searched through by hand in a tray, to identify whether there are any Gilkicker weevils in there. During the surveys we found all sorts of things in the trays: 5 species of weevil, shield bugs, silver fish, and some very colourful caterpillars.

Suction sampling a patch of Common Bird's-foot-trefoil for Gilkicker Weevils

Suction sampling for Gilkicker weevils ©Mariko Whyte

The good news is that, as well as finding all of these things, we also found Gilkicker weevils at both sites. There were more weevils at Browndown SSSI than at Point Gilkicker, probably because there is more Common Bird’s-foot-trefoil around at Browndown.

There were fewer weevils than we hoped to find. It seems that this is partly because of the drought – it might be that the weevils had burrowed deep into the plants, maybe even into the roots, where they overwinter, to find fresh vegetation to feed on. This would make them hard to suction sample! Alternatively, having had such a cold winter might mean that the population declined this year. It also looks like there is a bit less Common Bird’s-foot-trefoil around on the sites compared to last time they were surveyed.

We hope that through careful management at both sites, it will be possible to increase the amount of Common Bird’s-foot-trefoil for the weevils, and, by doing this, increase the population of Gilkicker weevils. We will be carrying out more surveys in the future, and this will help us to understand more about the habitat requirements and life cycle of this fascinating weevil!