1. The six families of craneflies are as follows.
| English Family Name | Family | Species |
| Long-palped Craneflies | Tipulidae | 88 |
| Damsel Craneflies | Cylindrotomidae | 4 |
| Hairy-eyed Craneflies | Pediciidae | 20 |
| Simple-veined Gulper and Spurless Craneflies | Limoniidae | 220 |
| Winter Gnats | Trichoceridae | 10 |
| Fold-winged Craneflies | Ptychopteridae | 7 |
| | | 329 |
The above figures are slightly increased from the official checklist to allow for other known British species; most of the extras are in the test keys produced by the Dipterists Forum.
2. Most of the predatory craneflies are among the Hairy-eyed and Gulper Craneflies. These larvae are very active and ferocious.
3. The Long-palped Craneflies include the ctenophorines (Combe-horned Craneflies), which are impressive mimics which pretend to be large dangerous social or ichneumon wasps. Some other types have pattered wings, such as the Large cranefly(Tipula maxima) which vies with the Hornet Robberfly (Asilus crabroniformis) as the largest British fly.
4. Many craneflies in other families also have colour-patterned wings, and some of these are very attractively marked.
5. The Fold-winged Craneflies have rat-tailed larvae, very similar to those of some hoverflies, a very interesting case of convergent evolution. This adaptation consists of an adjustable length periscope-like tail which can be extended to the water surface to reach air whilst the body of the larva remains secluded in submerged mud.
6. There are many other extraordinary adaptations, such as the green caterpillar-like larva of Cylindrotoma distinctissima which is the only European fly larva to feed externally on leaves. The larvae of a Spurless Cranefly, Erioptera squalida, have breathing tubes with a sharp point which can plug into the air spaces in submerged water plants (similar to the hoverfly Melanogaster).
7. And why do craneflies have long legs? There may be no single answer, but here are some interpretations.
a) They fly at night. By holding their legs splayed out horizontally, the legs longer than the wings, they can detect hazards (like cat's whiskers) and thus avoid damage to the wings.
b) If they bump into a spider's web, there is a good chance that initially only a tiny area of a very thin leg will make contact. With such a small surface area stuck in the 'glue' of the web, they can often break free before getting fully stuck or grabbed by the spider.
c) The legs easily break-off, in the same way that a lizard sheds it's tail if grabbed by a predator. An adult insect cannot grow new legs, but escape gives the cranefly a chance to complete it's function of mating and laying eggs.
d) Some resting craneflies are able to bob up and own, like press-ups on all six legs at once. This action is so fast that the outline of the body is only seen as a blur, making it difficult for a predator such as a bird to grab the cranefly as food. Any attack that misses gives the cranefly a chance to fly-off whilst the predator is still confused.
e) Many female craneflies poke or sink their abdomen into the ground vertically, so that the eggs are laid well out of sight. Long legs are very useful to form a six-legged tripod.
1. Craneflies occur in practically all habitats, from high on mountains to the marine inter-tidal zone, and from dry soils to submerged in water. The richest faunas are mainly in moist and wet situations.
2. Biodiversity Action Plan (BAP) Priority Habitats with Red Data Book (RDB) Insufficiently known (K) or Nationally Scarce (N) species are as follows:-
| BAP Habitat | RDBK | N | Comment |
| Ancient hedgerows | 0 | 2 | |
| Aquifer fed fluctuating water | 0 | 2 | |
| Blanket Bog | 4 | 0 | 1 RDB/Scotland |
| Chalk rivers | 2 | 0 | |
| Coastal etc.grazing marsh | 3 | 2 | |
| Coastal saltmarsh | 2 | 0 | |
| Coastal sand dunes | 2 | 1 | |
| Eutrophic lakes | 0 | 0 | |
| Fens | 5 | 4 | new data |
| Limestone pavement | 0 | 1 | |
| Littoral/sublittoral Chalk | 0 | 1 | |
| Lowland beech & yew woodland | 2 | 2 | |
| Lowland calcareous grass | 1 | 2 | |
| Lowland heath | 5 | 8 | |
| Lowland raised bog | 2 | 2 new data | |
| Lowland wood-pasture/park | 8 | 1 | |
| Maritime cliffs & slope | 5 | 1? | |
| Mesotrophic lakes | 0 | 0 rich fauna | |
| Purple moor grass etc. | 0 | 0 rich fauna | |
| Raised bog | 2 | 3 | |
| Reedbeds | 4 | 1 | |
| Saline lagoons | 1 | 0 | |
| Upland calcareous grassland | 0 | 1 | |
| Upland mixed ash woodland | 0 | 0 | good fauna |
| Upland oak woods | 0 | 0 | good fauna |
| Wet woodland | 4 | 9 | + 3 Priority species. |
| Priority | RDB | N | Total |
| Craneflies In Defra report 3 | 36 | 26 | 65 |
| New habitat data | 4 | 2 | 6 |
| Totals 3 | 40 | 28 | 71 |
The above figures take into account the following extra information:-
Maritime cliffs & slopes (correction to Defra report)
Symplecta chosensis, RDBK (re-identification of English and Welsh S. scotica, the latter now endemic, only known from the old type specimens from Dingwall, Scotland)
Raised bog:- new data (from Cumbria and Whixhall Moss, Salop)
RDB1 Phylidorea heterogyna, Idiocera linnei (both by pools)
Notable Idioptera pulchella, Phalacrocera replicata, Triogma trisulcata
Fens (new listing)
RDB
Dicranomyia danica RDB3 (brackish fen)
Erioptera bivittata RDB2 (brackish fen)
Erioptera meijeri RDB2 (by pools & ditches)
Pilaria species A RBDK
Tipula marginella RDB3 Notable
Dicranomyia melleicauda (brackish fen)
D. ventralis
Erioptera nielseni
Phylidorea abdominalis
Other
Ptychoptera scutellata (springs) HABITAT/FAUNA ANALYSIS
1. Craneflies have 148 RDB and Notable species in the National Review by Falk (1991), with at least 8 extra species now recognised = 156 species.
2. Five habitats stand out very strongly.
- Fens
- Lowland heath (especially wetland mosaics, but some saproxylics)
- Lowland Wood-pasture and parkland (especially the former for saproxylic fauna)
- Maritime cliff and slope (in particular soft cliffs with ground water seepages and springs)
- Wet woodland
3. Other habitats with at least 2 Red Data Book craneflies are:-
- Blanket bog
- Chalk rivers
- Coastal and flood plain coastal marsh
- Coastal sand dunes
- Coastal saltmarsh
- Lowland beech and yew woodland
- Reedbeds
4. It should be noted that 85 Red Data Book and Notable craneflies have not been allocated to Priority Habitats (over 50% of the total). No doubt some could be squeezed into the Priority Habitats but the majority do not easily fit or have very different habitats.
Important habitats not on the priority list are:-
- Rivers and streams. At least 24 species come into this category. Unfortunately Special Areas of Conservation (SAC) rivers have been selected on flora rather than taking account of the invertebrate fauna of bed and banks. One of the key rivers for Diptera is the River Monnow on the Hereford/Gwent border, which lacks formal status recognition. A considerable variety of stream and bed types is entailed, perhaps many of which are incidentally within scheduled sites. The matter needs proper review.
- A large number of omitted species occur in a range of ground water seepages and springs that do not easily fit within the Priority Habitats. For instance some may occur within the few listed woodland types, but others do not. The data will needed fuller analysis to clarify the coverage of the criteria species.
- Other woodland craneflies do not fit either. For instance Tipula luridirostris larvae live in moss on tree branches in western oak woods where rainfall is relative high, but in lowland oak woods rather than the priority Upland oakwoods. The rare saproxylic Rhipidia for some reason are mainly recorded at trees in habitats other than the listed ones.
5. The Cranefly Recording Scheme has immense amounts of data. When the resources to process this data are available, analysis relative to sites and habitats will become much more practical.
HABITAT MANAGEMENT
Across such a varied range of ecological situations it is only practical here to summarise some main themes.
1. Many species live in wet or moist situations.
Hence maintenance of natural hydrology is essential. Even minor drainage or alteration of ground or surface water levels can cause a profound impoverishment of the fauna.
2. The adults generally need some shelter; places to hide from predators during the day or to shelter from inclement weather.
Thus on open moorland the presence of clumps of rushes or longish heather has a distinct advantage over closely grazed turf. Or in woodland, the presence of herbs or scrubs has an advantage over a very barren woodland floor.
3. However, very dense vegetation may be a barrier to females intent on laying their eggs into the soil.
Various craneflies need bare soil, or wet mud and peat, to be exposed as small patches within a mosaic of vegetation, or accessible among rather sparse vegetation. This is especially evident at water margins or in wet fen or marsh. Such conditions may be self-perpetuating in natural situations on landslips or river banks, but in fens, marshes and along grazing level ditches, it is often poaching by cattle that is a key factor. In some circumstances, it is public trampling along a path that maintains the ecological situation.
4. Saproxylic habitat is vital to some craneflies. In the case of craneflies, they live in rotting wood in rot-holes in live trees, or in fallen tree trunks and logs, and some in the saproxylic fungi. Some species seem to be restricted to large timber.
Such a fauna is dependent on continuity of habitat. Whilst some craneflies remain widespread (the ones that can get by on quite small logs and rot-holes), others have special requirements and are restricted to those ancient woods where continuity of large ancient trees has remained possible through the centauries. Tidying-up fallen timber and removal of less pristine timber trees has been the main problem so greater effort to accommodate the ecological needs of this fauna is required
5. River ‘improvement’ by canalising has ruined many river catchments. The trawling out of the river bed and sediment margins has created a sharp-sided trough. Streams and ditches have suffered the same fate. Cherishing naturalness of bed and banks along rivers and streams is vital, and restoration of over-engineered water courses is highly desirable.
Though some species live on the river bed, most occur at the margins. Exposed riverine sediment and other types of gentle banks are generally the place of highest cranefly biodiversity. Restoration schemes need to be tailored accordingly: the expedient of engineering a berm at ‘normal’ water level can assist greatly.
REFERENCES
Stubbs, A. 2003. Managing Priority Habitats for invertebrates. Volume 17: Tipulidae and allies - craneflies. Buglife - The Invertebrate Conservation Trust, Peterborough.
