Orthoptera

^{_{Large Marsh Grasshopper Stethophyma grossum}}_{^{©Bryan Edwards}}

Orthoptera are primitive insects in that they do not have a pupal stage, hatching from the egg into small versions of the adult, then have a number of instars during the spring before becoming an adult in summer. Like most insects they prefer a warm or hot micro-climate within their habitat. Orthoptera in its strictest sense includes the grasshoppers, bush-crickets, crickets and groundhoppers. Traditionally the cockroaches (Dictyoptera) and earwigs (Dermaptera) have been recorded with the true Orthoptera and often included in identification books and county checklists.

Generally, the grasshoppers and bush-crickets are the most obvious species and found in a range of habitats although their abundance may vary from year-to-year. Groundhoppers are much less obvious and therefore under-recorded, and are best sought in bare and often damp situations both inland and on the coast. Our three native cockroaches also require a determined search, often being found beneath vegetation or under stones, although Dusky Cockroach Ectobius lapponicus can sometimes be found basking on the foliage of low shrubs.

_{^{Heath Grasshopper Chorthippus vagans ©Bryan Edwards}}

Dorset, especially Purbeck, has long been famed for its diversity of Orthoptera due to the presence of rarities such as Wartbiter Decticus verrucivorus, Large Marsh Grasshopper Stethophyma grossum and Heath Grasshopper Chorthippus vagans. The Poole Basin heaths and coast are particularly rich, due to a combination of a warm and sunny climate and relatively large areas of semi-natural vegetation, although south-facing slopes of chalk downland in the north of the county can also support a good range of species.

Habitats important for Orthoptera in Dorset:

^{_{Common Green Grasshopper Omocstus viridulus ©Bryan Edwards}}

Lowland heaths and mires
Chalk & limestone grassland
Soft clay & sand cliffs
Meadows & marshes
Acid grassland
Open woodland, rides and coppice

Other the last 25 years our Orthoptera fauna has been particularly dynamic with significant increases northwards in the range of Long-winged Conehaed Conocephalus fuscus and more recently westwards of Roesel’s Bush Cricket Metrioptera roeselii. We have also seen the arrival of new species such as the Southern Oak Bush-cricket Meconema meridionale which has become established in several places along the coast. These changes are thought to be due to a warming climate and have been mirrored elsewhere in northwest Europe.