Northmoor Trust

The biology of the speckled bush cricket Leptophyes punctatissima.

Background
We have been studying Leptophyes punctatissima for many years, mostly the acoustic biology. The animal communicates using ultrasound at 40 kHz and so is inaudible to humans. Communication between males and females in one of the fastest interchanges in the insect world, being complete in as little as 25 thousandths of a second. Such short ultrasonic signals are likely to be scattered substantially by vegetation in the environment and we have been looking at the types of habitat occupied by these animals. In doing so we discovered that the animals have food preferences – the young stages at the Warren in Folkestone feed on sage, which is not present at the site in Germany. Leptophyes is flightless, so the UK population is derived from those individuals who followed the retreat of the ice northwards at the start of the present inter-glacial period and arrived before the English Channel formed. A preliminary survey at Wittenham showed that the animals there were not feeding on sage (sage does not appear to be present), so we are going to use animals collected in Germany for food preference trials.

Future plans
We intend to monitor the population at several sites in the Warren, Wittenham and Germany over several years. We will record the food plants that the animals are feeding on, estimate the numbers present and their spacing, record temperature and humidity data and also try and discover where the females lay their eggs (still completely unknown).

In parallel with the habitat survey, we are continuing to investigate the sound communication system of these animals, including measuring effective communication distances in different plant mixtures within the habitats.

Life cycle
Young hatch from mid-May onwards and mature through 6 larval stages to adult, with about one week for each state and one week for the adult to become sexually mature. Males appear to have a shorter adult life than females. Females can still be around in early November but we do not believe that any survive the winter.

Study areas at Wittenham

The habitat occupied by Leptophyes at Wittenham is on the edges of paths where there is good sunlight with both brambles and nettles. We have identified three sites along the footpath marked on the map below, where Leptophyes occurs.

As we do not know where the female lays her eggs, we can’t say what management regime would work best for the populations. Cutting back nettles and bramble in late autumn, which will allow new growth the following year, probably does not harm the population and may benefit the next generation as there will be new growth for the newly hatched young to feed on.