Bibio pomonae ( Fabricius, 1775 )

Skartveit, John, 2010, The larvae of European Bibioninae (Diptera, Bibionidae), Journal of Natural History 36 (4), pp. 449-485 : 458-460

Bibio pomonae ( Fabricius, 1775) (®gures 12±18)

Larva described by Morris (1921), who was not quite sure about its identity, con®rmed by Brindle (1962).

Reddish brown, dull. Total length full-grown 20±25 mm. Processes rather long.

Head. Reddish. Head capsule width of sixth instar 0.99±1.23 mm (n = 55), of seventh instar 1.35±1.67 mm (n =167). Labrum (®gure 12) with one pair of short setae on the transverse carina. Mandible (®gure 13) with ®ve teeth. Maxilla (®gure 14) comb with six teeth, seta on outer front margin rather long. Inner surface with long and pointed spines, 10±14 round`holes’. Row of ®ve spines on membraneous area of maxillary palp. Prementum (®gure 14) with 10 sensillae. Stemmata present in most individuals but usually few and weakly pigmented. Antenna diameter ca 60 m m with one large and three to four smaller sensillae.

Body. Processes rather long. Dorsal processes arranged in three pairs, progressively shorter inwards. Posterior processes ca 3/5 as long as last segment. Postspiracular processes approximately 3.5 times as long as spiracle diameter, situated slightly more than one spiracle diameter posterior to spiracle. Cuticular scales: prothorax (®gure 15) in front of ®rst segment row rather rounded, 20±35 m m wide, each scale with 4±12 pointed spines which are slightly longer than the scale. In lateral view the spines appear rather strongly curved. Numerous smaller, unarmed scales between the larger, spine-bearing scales except in the very anterior end. The larger scales on the second and more posterior segments are rather irregular in outline. Metathorax (®gure 16) larger scales 30±50 m m wide mostly with one to four, but some with up to 12 spines. Fourth abdominal segment (®gure 17) larger scales 25± 45 m m wide mostly with one, but some with up to three spines. Ninth abdominal segment (®gure 18) scales diameter 25±45 m m, mostly with one short spine. Ventral surface scales of the ninth abdominal segment with rather large, single spines laterally, with tiny, slender spines mesally. Spiracles: projecting approximately onehalf spiracle diameter from body surface.

Distribution. All of Europe, but only in the highlands in the southern part. East Asia: Kamtchatka, Amur Area, probably generally distributed. Closely related species in East Asia ( Bibio consanguineus Loew ) and North America ( Bibio holtii McAtee , B. bryanti Johnson ).

Ecology. Eurytopical species. Deciduous forest, heathlands, mountain meadows, willow shrubbery. Full-grown larvae in June to September (probably also the rest of the year because of long life cycle). Life cycle length in mountain areas at least 2 years, possibly longer.

Material. Larvae : Norway, HOI: Ulvik, near Finse, Barber pitfall traps, 6 May to 16 September 1985, P. Ottesen leg. 222 larvae .