Rhizophagus parallelocollis Gyllenhal, 1827
POLYPHAGA Emery, 1886
CUCUJOIDEA Latreille, 1802
RHIZOPHAGINAE Redtenbacher, 1845
A widespread Western Palaearctic species recorded throughout much of Europe north to central provinces of Fennoscandia; it is locally common in western areas from the Pyrenees to Western Germany, but otherwise very local and generally scarce. It is also established in eastern North America, having been introduced from Europe sometime before 1895. In the UK it occurs locally in south-eastern, Central and Northern England, Wales, and Southern Scotland and it is also recorded from Ireland. Adults sometimes occur under damp bark or among fungi, and they often visit sap, but they are primarily subterranean, emerging from the ground to disperse or to find suitable sites for oviposition and larval development. They have been found in numbers both within and among the soil around coffins, and in the spring they often emerge and swarm around burial sites, hence the common name, but they also occur more generally; on mouldy substrates in cellars, in deep compost heaps, mammal burrows and among old bones. Adults occur year-round; they overwinter in soil or compost etc, and are active from April until August, peaking in abundance during May and June. Little is known of the biology but reproduction occurs in the spring before the adults disperse, and larvae are either mould feeders, or they may predate other mould-feeding insect larvae. Teneral adults are common in the spring, suggesting that larvae may continue to develop through the winter or that pupation occurs in late summer or autumn and that many of these overwinter. Adults may be found under damp bark on decaying broadleaf trees or at sap, they may also be sampled in subterranean or flight-interception traps, and they are sometimes common among flood refuse.
Rhizophagus parallelocollis 1
Rhizophagus parallelocollis 2
3.0-4.3 mm. Elongate and parallel-sided, body entirely reddish-brown or with the head and/or pronotal disc darkened, appendages brown. Head smoothly and weakly convex between small convex eyes and long, almost parallel temples, clypeus produced anteriorly beyond the antennal insertions and truncate apically. Antennae 11-segmented with a round 2-segmented club, third segment as long as 4-6 combined, and segments 4-9 transverse. Pronotum elongate, broadest across slightly projecting anterior angles and narrowing to rounded posterior angles, surface reticulate and strongly but not densely punctured, lateral and basal margins bordered and very finely crenulate, at least around the posterior angles. Elytra weakly curved from projecting shoulders to an almost continuous apical margin, striae parallel and regularly punctured, remaining distinct but becoming confused subapically, lateral striae much weaker, interstices slightly wider than the striae, impunctate and distinctly reticulate. Legs short and robust; femora unarmed, front and middle tibiae produced into an external tooth apically, hind tibiae with short terminal spurs. Female tarsi 5-segmented, male tarsi 5-5-4. Claws smooth and not toothed at the base.