Peterhouse Biology

the old Heath trap

the Tavoillot trap

As part of the Peterhouse biodiversity survey I have been setting a moth trap in the gardens at least once a month. I started using a 20 year old Heath trap but the results were very poor and I thought it time to look at a new solution. Using LEDs as the light source seemed like a good idea in principle, so I started with the LepiLED lamp connected to a phone battery pack, giving about 10 hours of illumination. These LED lamps seem to be quite effective in attracting moths but they don't get very good catches in something like the Heath trap; I caught nothing in the trap although moths were roosting around it, clearly having been attracted during the night. However, I did come across reports that the LepiLED does get good catches in combination with a louvre trap. I am now using my own trap inspired by Sebastien Verne's account of the 'Tavoillot' design.

This works on the principle that moths will tend to move up an obstruction, and so it should be possible to funnel them into a trap. The original Tavoillot is made of netting and I have modified this by replacing the netting with strips of clear plastic, maximising light coming from the trap. These strips are glued to a lightweight plastic frame and the sides are joined to one another by velcro.

overlapping plastic sheeting louvres attached to a plastic frame, leaving a 2.5 cm gap between them

This means that the disassembled trap weighs very little and takes up very little space (in this case about 30x60x15cm, to fit into a backpack). The trap weighs around 500g, considerably less than the lamp and the battery pack.

lamp attached to the lid, and battery pack

The base and top of the trap are made of sheets of perspex, again maximising illumination. A cord passes through the top sheet, suspending the light and giving the option of suspending it from a branch.

whole trap

The catches have been reasonable, with a maximum catch so far of 56 individuals of 43 moth species. Caddisflies are also strongly attracted to the trap, with up to 20 individuals of 8 species in one night, along with numerous flies, some ichneumonids, plant-hoppers and a small number of beetles.

Peterhouse garden moth trapping: