Dear Readers, the field cricket is a sturdy insect, and at almost an inch long one of our larger invertebrate inhabitants. Alas, their physical robustness did not save them from coming close to extinction – in the 1980s there were less than 100 individuals at just one site in West Sussex.
Field crickets have only one brood per year and are flightless, so they clearly can’t travel very far. In the spring, the male digs a burrow (a task which takes less than ten minutes), makes himself a little platform and then ‘sings’ his heart out, beating up any other males that wander within range. The females travel about listening to the various ‘songs’, and when they hear one that they like, mating takes place. The female then lays her eggs close to or in the male’s burrow. The nymphs hatch in the summer and shed their skins until they are large enough to survive winter hibernation, finally emerging for their final moult in April of the following year, whereupon they join the chorus. Have a listen to some field crickets in the recording below (made by Gareth K in the UK, these are some of the insects from the species recovery programme)
So, why were field crickets so endangered? Our old friend intensive agriculture was part of the reason, along with the breaking up and reduction of habitat. But one established way of helping a species to survive is to enlarge the area where they currently live, making the edge of the habitat more suitable, and also to translocate the insects to another suitable habitat. And this is exactly what happened. Field crickets were reintroduced to the RSPB reserves at Farnham Heath and Pulborough Brooks, and corridors were established between parts of the existing sites so that the crickets could travel to ‘meet’ one another more easily. As you can see from the photo above, crickets need areas of bare ground to construct their burrows, and so areas of bramble were cleared from some parts of the reserves.
The results were very heartening. In 2010, 12 field cricket nymphs were moved to Farnham Heath. By 2013, just three years later, 43 males were heard calling at the reserve. And by spring 2019, 337 males were heard calling, a truly remarkable result, with other populations becoming established at Pulborough Brooks.
As with last week, this success story was the result of collaboration between a number of wildlife and conservation charities, but it was also picked up by the media, and the ever-popular UK wildlife TV programme Springwatch did a feature on the field cricket, an insect that I’m sure most people had never heard of or met. The collaboration continues, with local landowners meeting to discuss ways to extend the range of the field crickets even further. Although this is still a delicate recovery (after all, 337 crickets is not really very many), it is a sign of what can be done when people work together. And here is a short film of a field cricket doing what it does best – stridulating. Long may it continue.