Small World Discoveries
by Tony Enticknap - tickspics
Taking a close look at insects and other small species that can be found in and around East Dorset and the New Forest ...
ORTHOPTERA | Grasshoppers & Crickets
Orthoptera, a name derived from the ancient Greek words orthos and ptera effectively meaning 'straight-winged', is a large insect order of well over 20,000 species that mostly occur in tropical and subtropical areas of the world.
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Perhaps it's not surprising, therefore, to learn that this group of insects are poorly represented in Britain with only 40 or so recorded species, of which quite a number have been introduced by one means or another. In fact, there are only 26 that are regarded as being truly native and, some of those, such as the Scaly-cricket and Mole-cricket, are rarely seen, so that when you start looking at the distribution records more closely, you'll find that there are actually not that many that are likely to be encountered even if you live in the south of the country where most occur. And, if you happen to live in the north, you may only have three or four types of grasshopper and, subject to the region, perhaps little if no chance of seeing a bush-cricket.
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The orthopteran order is broken down into two major divisions or suborders; Caelifera (grasshoppers and allies) and Enisfera (bush-crickets and crickets). The primary distinguishing feature is that the former group have short, segmented antennae, whereas the latter have long, thread-like antennae. The body shape and form of the various species also differs with the grasshoppers generally being smaller and slimmer than bush-crickets and, when at rest, typically fold their rear legs down alongside the abdomen, which the bush-crickets can't do as their legs are longer and slimmer, resulting in the 'knee' joint being held at an angle above the body.
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After hatching, the young nymphs go through several moults (instars) as they transform into adults. Most look like miniature versions as they develop, except that they are generally lighter in colour and do not possess wings. Although some may be recognisable at an early stage, others, notably grasshoppers, will lack defining details making it difficult to determine the species. Wings start showing towards the end of the development process and it's during these final stages when it may be unclear whether a particular individual is a nymph or, in fact, a short-winged adult. This is when it's necessary to have a good look at the wing structure to check if there are both longitudinal and cross-veins forming a net-like appearance, which would indicate that it's an adult or, in the case of nymphs, whether the stubby or short wings are simple, without cross-veins, and with a pattern that roughly resembles a fan. Another easy visual feature is to note whether the wings are separated rather than overlapping, which normally shows that it's not an adult.
When I first started thinking about this section in June 2022, it quickly became apparent that I had very little knowledge of these species and very few photographs. I've made an effort to rectify that situation, but there are still a couple of species that I'm trying to find, hence the 'place-holders'.
CAELIFERA
Acrididae (Grasshoppers)
Of the 11 native species found in Britain, only four have widespread distribution; Field Grasshopper [Chorthippus brunneus], Meadow Grasshopper [Pseudochorthippus parallelus], Common Green Grasshopper [Omocestus viridulus] and Mottled Grasshopper [Myrmeleotettix maculatus]. They are all regarded as common, as is the Lesser Marsh Grasshopper [Chorthippus albomarginatus] except that this species is only found in central and southern areas of the country. Locally to where I live in East Dorset, a further four species can be encountered; Stripe-winged Grasshopper [Stenobothrus lineatus], the nationally scarce Woodland Grasshopper [Omocestus rufipes] and, with a bit more hunting, the rare Heath Grasshopper [Chorthippus vagans] and the equally rare and highly sought-after Large Marsh Grasshopper [Stethophyma grossum].
The two I won't find locally are the Rufous Grasshopper [Gomphocerippus rufus] that has never been recorded in my general area, and the Lesser Mottled Grasshopper [Stenobothrus stigmaticus] which is confined to a particular site on the Isle of Man.
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Generally, nymphs start appearing in Spring, maturing during June and July, and remaining active through to Autumn. The males 'sing' to attract females with each species having a distinctive call that experts will use as a means of identification before even starting to look for individuals. Their general appearance can be very variable so, apart from the song, the most important feature in either sex is the pattern and structure of the pronotum. It has a pair of ridges that run lengthwise along the lateral edges either side of the central ridge on the dorsal midline. The outer ridges are known as side keels. In some species, notably the Lesser Marsh Grasshopper, they are virtually straight and parallel with each other, whereas in other species they are inflexed to varying degrees.
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Whilst with most of our grasshoppers, the female is usually larger than the male and has shorter antennae, the best way of separating the sexes in the absence of any species-specific features, is to have a look at the end segments of the abdomen. The females have a more parallel end that gently tapers and terminates with the tips of the upper and lower ovipositor valves. They also have two small appendages, called the cerci. Their abdomen looks more enclosed at the end than the male's, except for after egg-laying when it's usually swollen and extended, making identification easier. In contrast, the male's abdomen distinctly curves up giving it a more blunt-ended appearance. The upturned end is the subgenital plate, in front of which are the cerci that are noticeably larger than those of the female.
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Large Marsh Grasshopper (NR)
Stethophyma grossum
Lesser Marsh Grasshopper
Chorthippus albomarginatus
Meadow Grasshopper
Pseudochorthippus parallelus
Common Green Grasshopper
Omocestus viridulus
Field Grasshopper
Chorthippus brunneus
Heath Grasshopper (NR)
Chorthippus vegans
Stripe-winged Grasshopper
Stenobothrus lineatus
Woodland Grasshopper (NS)
Omocestus rufipes
Mottled Grasshopper
Myrmeleotettix maculatus
Tetrigidae (Groundhoppers)
Although superficially similar in appearance to grasshoppers, these species differ in that they have an extended pronotum that covers the entire length of the abdomen. They do not stridulate like grasshoppers and tend to favour damp, often cool and shady environments that most grasshoppers can't tolerate. There are three British species, the Common Groundhopper [Tetrix undulata], the Slender Groundhopper [Tetrix subulata], and the nationally scarce and highly localised Cepero's Groundhopper [Tetrix ceperoi].
Slender Groundhopper
Tetrix subulata
Placeholder for a target species I've yet to see or photograph.
Common Groundhopper
Tetrix undulata
ENISFERA
Tettigoniidae (Bush-crickets)
Excluding two rare immigrants and the endangered Wartbiter [Decticus verrucivorus], there are ten species in this family that may be found in Britain of which only five are likely to be seen in central areas of the country and only a couple in parts of the north. From a personal point of view, I'm lucky that, in theory, I could see all ten in my local patch of East Dorset and the adjoining New Forest.
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The most frequently seen species in my area are the Speckled Bush-cricket [Leptophyes punctatissima], Dark Bush-cricket [Pholidoptera griseoaptera] and Roesel's Bush-cricket [Roeseliana roeselii]. The arboreal and primarily nocturnal Oak Bush-cricket [Meconema thalassinum] is listed as common, but by nature of its habits is difficult to see and photograph. There's also an introduced close relative of this species, named the Southern Oak Bush-cricket [Meconema meridionale], which is slowly spreading west and north. The Long-winged Conehead [Conocephalus fuscus] used to be a lot harder to see than it is today and is now more likely to be encountered than its close relative the Short-winged Conehead [Conocephalus dorsalis]. That leaves the Great Green Bush-cricket [Tettigonia viridissima] that I've yet to see, and two scarce and very localised species, the Bog Bush-cricket [Metrioptera brachyptera] and the coastal Grey Bush-cricket [Platycleis albopunctata].
Bush-cricket nymphs hatch and mature a little bit later than grasshoppers, with the adults of most species not likely to be seen before late July or early August. They will, however, persist longer, remaining active through September and well into October subject to the weather. Bush-crickets are much less variable than grasshoppers as will be noted from the associated 'species accounts', which makes identification a bit easier. And, the sexes are also easy to distinguish as the females have prominent ovipositors.
The males 'sing' to attract a female in much the same was as grasshoppers except that the 'songs' are higher pitched and often inaudible to most human ears.
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Placeholder for a target species I've yet to see or photograph.
Great Green Bush-cricket
Tettigonia virridissima
Dark Bush-cricket
Pholidoptera griseoaptera
Roesel's Bush-cricket
Roeseliana roeselii
Long-winged Conehead
Conocephalus fuscus
Oak Bush-cricket
Meconema thalassinum
Speckled Bush-cricket
Leptophyes punctatissima
Grey Bush-cricket (NS)
Platycleis albopunctata
Bog Bush-cricket (NS)
Metrioptera brachyptera
Placeholder for a target species I've yet to see or photograph.
Short-winged Conehead
Conocephalus dorsalis
Other native species
Gryllidae is large family worldwide, but is only represented in Britain by five species, one of which is very rare, the others all introduced and mostly rare. These crickets spend much of their time running about on the ground and burrowing rather than frequenting bushes and, consequently, the hind femora aren't designed for jumping. I wasn't going to mention this family as I'm extremely unlikely to encounter our only native species, the Field-cricket [Gryllus campestris] but, having taken a photo of one in Austria, I thought I'd feature it here, albeit simply as an enlargeable thumbnail rather than having a 'species account'. To my knowledge, the species has never been recorded in Dorset.
Field-cricket (NR)
Gryllus campestris
Wood-cricket (NS)
Nemobius sylvestris
Placeholder for a target species I've yet to see or photograph.
Scaly-cricket (NR)
Pseudomogoplistes vicentae
Formerly in the Gryllidae family with the Field-cricket, but now separated, the nationally scarce Wood-cricket [Nemobius sylvestris] - family Trigonidiidae, has its last stronghold in the New Forest, so definitely worth a mention. Similarly with two other very rare species that have a known population locally. The first is the Scaly-cricket [Pseudomogoplistes vicentae] - family Mogoplistidae, which can be found under stones on the strandline along both the sea and Fleet sides of Chesil Beach in Dorset. The other is the now critically endangered Mole-cricket [Gryllotalpa gryllotalpa] - family Gryllotalpidae that, as far as I'm aware, is only found at one protected site in the New Forest. Although I'm not going to be able to feature the Mole-cricket, I am going to make an effort to find the other two given that they both occur in my general area and, in fact, I'm pleased that I've been able to update this section with a few photos of Wood-crickets. Unfortunately, all of those I've seen to date have been immature nymphs rather than adults, but at least I now have a linked page for the species.
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Original list created June 22 | updated Dec.23 (v.2)