Corresponding author: Johann Waringer (
Academic editor: R. Holzenthal
Waringer J, Graf W (2014) The larva of
From Europe, ten species of genus
Synoptic key for the currently known European
Species/character | Mandible with 2 cutting edges (Fig. |
Mandible sickle-shaped, 1 cutting edge (Fig. |
Head with distinct dark patches (Fig. |
Hind tibiae with 2 long setal fringes (Fig. |
Number of long setae on protrochantin (Figs |
Basal seta of 2nd and 3rd tarsal claw rudimentary? (Figs |
References |
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no | yes | yes | no | 1 | no | |
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no | yes | no |
no | 1 | yes |
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no | yes | yes | no | several | yes | |
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no | yes | no | yes | several | no | |
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no | yes | yes | no | 1 | yes | |
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yes | no | yes | no | 1 | no |
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no | yes | yes | yes | 1 | no | |
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no | yes | no | no | several | yes | present paper |
Larvae in brackish water; very pale head pattern may be present in some larvae (
In
The larvae were sampled on 18 December 2012 by Wolfram Graf in the Thaya river at Hohenau, a short distance upstream of its confluence with the March river in Lower Austria. The catchment of the Thaya is situated within the granite and gneiss complex of the Bohemian highlands. Due to its low slope, the river meanders strongly and has created some scenic, deeply carved valleys descending up to 150 m steeply downwards from the figau of the surrounding highlands. The watershed area of the Thaya is 13.319 km² with an average discharge of 43.9 m³ s–1 and a Strahler stream order of seven. Some river stretches of the Thaya situated within the Czech Republic have been transformed in reservoirs used for irrigation, drinking water supply and hydroelectric power plants (
Species association was enabled by the fact that all other five
The 5th instar larvae of
Mandible sickle-shaped, with only one cutting edge; head capsule without distinct dark patches; hind tibiae without double row of long setal fringes; number of long setae on protrochantinus is > 1; basal setae on 2nd and 3rd tarsal claw rudimentary.
Body length of 5th instar larvae ranging from 2.7 to 4.5 mm, head width from 0.66 to 0.70 mm (n = 15).
Head capsule surface very smooth, roundish and hypognathous with pale yellow coloration. Light muscle attachment spots on frontoclypeus and parietalia very indistinct (Figs
Pronotum covering posterior section of head, light yellowish-brown, semitransparent, without distinct markings and muscle attachment spots (Fig.
Mesonotum completely covered by two sclerites, yellowish and paler than pronotum, with distinct markings and muscle attachment spots (Figs
Metanotum without sclerotization except by pleural sclerites and with dense dorsal setal cover; pleural sclerites arrangement as on mesonotum (Fig.
Legs yellowish, with very numerous setae, especially on coxae, trochanters and femora (Figs
First abdominal segment with one dorsal (Fig.
Gills single-filamented; dorsal gills present at most from 2nd segment (presegmental position) to 3rd segment (presegmental position); ventral gills only at 3rd segment (presegmental); lateral gills absent.
Larval case 3.0–3.7 mm long (n = 15), curved, tapered (width at anterior opening 1.2–1.5 mm and at posterior opening 0.6–0.7 mm), consisting of mix of mineral particles of unequal grain size (Fig.
Within genus
Our collection time of the larvae is in accordance with the reported spring to summer emergence and flight periods of the species; the emergence period is short and mostly limited to two months or less (
As pointed out by
The long, single-bladed predatory jaws of
This study was financially supported by the BioFresh EU project–Biodiversity of Freshwater Ecosystems: Status, Trends, Pressures and Conservation Priorities (contract No. 226874), the European Territorial Co-Operation Austria – Czech Republic 2007–2013 and the Austrian Federal Ministry for Agriculture, Forestry, Water Management and Environment.