Worcestershire Record No. 2 April 1997 p.8

TERRESTRIAL (LAND) CADDIS

G H Green

Worcestershire's Land Caddis Enoicyla pusilla are quite well-known from the writings of the late Norman Hickin. During a February 1997 foray with Brett Westwood into the countryside north of Kidderminster I collected a few bags of woodland leaf litter to search for invertebrates. Within one of these David Green found a Land Caddis about 5 mms long. This prompted me to write this note and to appeal to recorders to look for the species in Worcestershire's woods so that we can determine its actual distribution. In Wyre Forest area it is also worth looking in Shropshire and Staffordshire!

To find Land Caddis larvae it is best to examine woodland leaf litter and moss on site. Probably best to look between March and June when the larval cases are maximum size about 7-10 mms long and 1-2 mm diam. Shake the litter over a white sheet and examine carefully. After examination return the litter and the caddis to the woodland floor.

The larvae and pupae of most Caddis flies, Trichoptera, are, of course, aquatic. Many species make cases to enclose larvae and pupae. Others spin webs in water to catch debris or tiny invertebrates.

According to Hickin between 1868 and 1879 McLachlan and Fletcher first found Land Caddis near the city of Worcester. From that date until 22nd April 1957 it had not been recorded in Worcestershire until Norman Hickin found them in the Wyre Forest (Hickin 1967). Fletcher (1901) in The Victoria County History of Worcestershire states that Terrestrial Caddis has probably not been found in Britain outside Worcestershire and as a site gives "by a rill, Little Eastbury" In recent times the species has been found occasionally in other woods in and around Wyre Forest, and near Worcester in Nunnery Wood and Monkwood. One hears indistinctly on the grapevine that it has been found in a few other woods but there are no records in the BRC.

Where is Little Eastbury? Using the "Place-names of Worcestershire" and an OS map I found such a place near Hallow. But is this the correct location and where is the rill?

In a recent review (Wallace 1991) the species is designated RDB3 (Red Data Book 3) which means "locally common". For this species this means that it is only found in parts of Worcestershire and no-where else in Britain. Apparently it is known mainly from "greater Wyre Forest" - the forest and surrounding woods.

The species has a patchy continental distribution and knowledge of its biology comes from Europe.

The species is unique in British Trichoptera is having terrestrial larvae and pupae, and a wingless adult female, and worldwide the genus is unique is having these features.

According to Hickin, who reported European studies, the adults emerge during September to November. The females cannot fly and live for about five days. The males live a couple of weeks. The eggs are laid shortly after mating and hatch in about three weeks. The tiny larvae immediately start to construct a curved protective case which is about 1.5 mm long at the end of the first day and by the following June is about 10 mms long and little over 1 mm diameter. The case is made of tiny fragments of dead leaf and sand grains. The larvae feed on softer tissues of dead leaves, especially oak, mosses and algae, as they move around within woodland ground litter. When full-grown they burrow down, close the case with silk, and pupate for about a month.

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