Ecology of the field cricket (Gryllidae: Orthoptera) in farmland: the importance of livestock grazing

The field cricket Gryllus campestris used to be very common throughout Europe, but in recent decades its population has declined. We study ecology and behavior of crickets near the Odolanów, Poland, between 2009 2011, with emphasis on the effects of grazing of cattle and horses on insects population. We compared the number of burrows per square meter on both grazed and non-grazed areas and examined the size of the arena in front of the burrow. We hypothesized that juvenile crickets would have smaller arenas in front of the burrows compared to adults. We also hypothesized that crickets would prefer burrows with entrances facing southwards. We found that: (1) the number of burrows in area grazed by cattle and horses was higher compared to non-grazed areas; (2) there was the interindividual variation in arena size in front of the burrows, with adult insects having bigger arenas in comparison to the arenas of the young; (3) there was diversity in geographical direction of the burrow entrance with the south being the preferred one. We propose that grazing may have a positive impact on biodiversity of meadows biocenosis and is important for the protection of the field cricket populations.