ORTHOPTERA > CAELIFERA > Acrididae (Grasshoppers) > Oedipodinae

The Large Marsh Grasshopper is a nationally rare and highly sought-after species that is currently pretty much restricted to a relatively small number of locations within the New Forest and on Dorset heathland. Sadly, all of the known populations elsewhere in the country have declined dramatically over the past fifty or so years, largely due to the widespread drainage of wetlands and resultant damage to the associated habitat where this impressive insect once lived. There have been attempts to reintroduce it, notably to a site in Norfolk, but its last strongholds are the valley mires and wet heaths of southern Hampshire and Dorset.

Stethophyma grossum is Britain's largest breeding grasshopper with an overall body length of 21-36mm; the females being larger than the males. They are fully winged and fly well, often travelling some metres when disturbed. The typical colour form is yellowish-green to olive-brown with red on the lower half of the hind femora. There's also an uncommon plum-red variant of the female known as the 'purple form' that was thought to only occur occasionally in large colonies, but having had the privilege of photographing a few different individuals with this colouration in an area where clearly the population was small, I know that other factors must come into play.

They are very specific regarding habitat requirements preferring acid bogs with areas of sedges and tussocky grass, especially Purple Moor-grass. These areas are typically wetter than those used by other orthopteran species apart from the Bog-bush cricket, although at the site where the following individuals were photographed there were Long-winged Coneheads and some Meadow Grasshoppers. However, it had been extremely dry, so it will be interesting to see if the dynamics of the location change in future years.

Like most other grasshoppers, nymphs emerge in late spring, with the adults appearing from late July and surviving through the summer and autumn, possibly into November if conditions are suitable.

The 'song' of the Large Marsh Grasshopper is said to be distinctive and unlike that of any of the other species, consisting of a series of brief clicking noises made by kicking the wings with the hind legs. There can be up to three clicks per second, repeating for anywhere between 5-10 seconds.