Passaloecus angustus GUSSAKOVSKIJ 1952
Passaloecus species are small to very small, elongate, black wasps which nest particularly in beetle borings in posts and other cavities, and prey on aphids. The biology of this species is described by Merisuo (1973), and keys to the European species groups of the genus Passaloecus are in Merisuo (1974).
Entirely restricted to south-eastern England, with most modern records from east Norfolk, the Thames corridor and Dungeness.
Abroad, this species is widely distributed throughout central and northern Europe, but found only rarely. Also occurs in western Russia, eastwards to Uzbekistan (Lomholdt 1975-76).
Listed in Shirt (1987) as Vulnerable (RDB2), and in Falk (1991) as Rare (pRDB3).
Found around reed beds in brackish and fresh water.
June to August.
The prey is unknown but may be aphids, in common with other species of its genus.
The species has been reared by G H L Dicker from Lipara lucens (Diptera, Chloropidae) galls in common reed and also from the cut, hollow stems of the reed itself (Dicker 1978). Abroad, honeysuckle stems are also used as nesting sites (Lomholdt 1975-76). Nest construction has not been observed, but as in all other Passaloecus, the cell partitions and nest closure are probably made from a mixture of resin and small pebbles.
Not known to visit flowers; adults of the wasp are seldom encountered in the field.
Abroad, Trichrysis cyanea is recorded as a parasitoid (Lomholdt 1975-76).
2002