Terrestrials on the Test

Written by Richard Banbury


Photo by Richard Banbury

The long hot summer has made fishing difficult on our beats but most evenings, under the trees, fish could be found quietly sipping something off the surface. With little sign of any significant up-wing or caddis fly hatches , what was it that the fish were eating? Anglers were trying the normal staples like CDC olives, spinner patterns and sedges and the fish were ignoring them.

The answer was that with the hot weather, this summer we have experienced a population explosion of Alder Beetles (Agelastica alni). This species is quite interesting as it was widely regarded as being extinct in the UK after about the mid 1940’s. It wasn’t until 2003 that some sightings were recorded in the midlands. In 2014 we had the first sightings in Hampshire. In the past 4 years, populations have exploded in the trees along the Test river. As its name suggests, Alder is the preferred foodplant and is one of the commonest trees along the river, however the species can also feed on Hazel, Popular, Willow and Hornbeam. The Beetles over-winter as adults and each female can lay up to 900 eggs in the spring. The larvae feed on the underside of the leaf creating the lattice pattern seen in these pictures. The next generation of adults hatch in August. The larvae are about 1cm in length when fully grown and readily get blown into the water on stormy days. The fish seem to love them.


Photo by Richard Banbury


Photo by Richard Banbury

To imitate, any small, peacock/black beetle pattern works very nicely. For the grubs, try tying up some slim, black, unweighted Czech style nymphs or just imitate the body shape with black thread and give it a lick of varnish or UV cure. A size 14 black diawl bach is also an option. Generally, fly size needs to be about 12-14 but worth tying a few in 16’s.

It truly is a changing world!

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