Field Cricket

(Gryllus campestris)

by Rhodri Phillips

Identification: The European or black field cricket is easy to differentiate from the more common true cricket, with a dark black colouration and wider body. A patchwork of gold or bronze markings appear as the adults grow their wings, but while some European crickets are capable of flight neither of the UK’s species have this ability. Instead field crickets here in the UK spend most of their time traversing on foot before returning to their sub-terranean burrows.

Life cycle: Adult males typically create permanent burrows, with females moving around in search of the perfect mate. To attract them the males will produce a high-pitched chirping noise, signalling their position from a small platform they make near the entrance to the burrow. Interestingly, it had been observed that the species only calls on days with a temperature above 13 degrees Celsius. It is likely that this reflects the ability of the species to exist in colder climates and could be linked to their overwintering hibernation. Another adaptation that singles out the species from many other cricket species who overwinter as unhatched eggs.

Mating occurs around April and May, with females laying their eggs in the bare soil in or near the burrows. Once egg laying has occurred the Male will then never leave the area around the burrow as it defends the eggs from predation. Inversely the Female will leave in search of other Males and can lay multiple clutches of eggs in a single year. Nymphs of the species hatch in June and July before entering hibernation in August for the Winter. The new adults re-emerge in April of the following year to begin the life cycle again.

Photo taken under license by Alex Hyde

Species Importance:

Field crickets serve an important function in ecosystems they are found, helping decompose dead plant matter and natural detritus. Most plant material is formed of cellulose, a compound that is difficult to naturally breakdown. That is fi you are not specialised in doing just that, field crickets are able to digest and break down the substance speeding up the process of returning nutrients into the soil. This helps ensure soil quality and as such field crickets play an important factor in maintaining a healthy ecosystem from the ground up.

As well as regulating soil health they have also been shown to eat the seeds of many invasive species, helping protect ecosystems further. In America other species of field cricket have been used to effectively fight the spread of crabgrass in protected areas.

Conservation status: As a small flightless insect, the Field cricket has had a hard time adapting to changes in their ecosystems. The lowland heath habitat they depend on has declined by more than 80% in the UK and contributed to the near extinction of the species. That was until conservationists in partnership with the RSPB and natural England reintroduced the species in the 1980’s. Since then six populations of the species have been set up and seem to be doing well.

However outside of the UK the species is declining globally and concerning conservationists. As a species that does not travel large distances it may be difficult for it to adapt to many human caused alterations to their ecosystems. However, the work happening here helping us understand the requirements for the species. It is hoped that successful projects here in the UK can help save the species in other countries too.