Monday, 9 September 2013

A great green chorus

As the car slowed on our approach to the level crossing gates I could hear a sound I recognised. ‘Conehead?’ queried my fellow passenger; ‘great green bush-cricket?’ came my response. ‘Yes, that’s it, shall we take a look?’ At this time of the day the crossing gates would be down for a while and the traffic on this minor road was always minimal. Alongside the road was an expanse of rank grassland, bracken and nettles, an ideal spot for the largest of our British orthoptera (grasshoppers and crickets). Within a couple of minutes I had located an adult male, perched (as they often do) towards the top of a bracken stem. It was a stunning beast.

The great green bush-cricket lives up to its name. At 40-50 mm in length, this is a striking insect. Despite this, the species is often overlooked within its southern range, a range that lies to the south of a line drawn from the Wash to South Wales. In part this is down to its preferred habitat of rank grassland that is moving in succession towards scrub – it’s not a habitat most people inspect too closely. However, the great green bush-cricket’s nocturnal habits probably also have a role to play. The males usually begin to sing from mid-afternoon on sunny days but the main activity happens at night. The females are inactive during daylight hours, spending the time basking. If found, and disturbed, they will climb up the stem on which they have been resting, a behaviour that is uncharacteristic of bush-crickets more generally, which tend to dive into cover at your approach.

These engaging insects are omnivorous, feeding on plant material, aphids, flies, caterpillars and other grasshoppers and crickets. Their habits have been well studied in captivity where, according to the famous French entomologist Henri Fabre, they resemble the English, doting on ‘underdone rump steak seasoned with jam’!  Observations of captive individuals have revealed that the eggs are laid in the soil during summer, passing two or more winters before hatching in a subsequent spring (usually late April or early May). The adults emerge in July, following a number of larval instars, and remain active into October, so now is a good time to look for them.

No comments:

Post a Comment