"Aim: to capture surface active invertebrates"

alive or dead?

Dead

I would use stripes of material covered with glue. It works in case of tree climbing insects so it should work here as well. Moericki traps could also be option

Moericki trap are yellow or white cups or bowls. They do attract flying insects since they imitate flowers. Traps should be filled with some preservatives and some washing liquid.

Another option could be placing e.g. 3 cm high cup (Barber trap) and surround it with gravel, , sand or canvas so animals could climb to traps. It should be covered by wooden, plastic , stone roofs - insects would hide there so would be trapped too.

good luck

Thank you all for the brainstorm over my question!

Pitfall traps I've been using for a long time, filled with glycole and a drop of detergent in them. Trapping on shallow or nonexistent soils on dry rocky meadows seem to remain an open question. The habitat is granite rock with moss-carpet and spots of organic matter accumulated in the cracks. Here I summarize my conclusions:

- The sticky trap is something I must seriously consider, I only must find a product without any pheromones added.

- I can also perform short-term pitfall trapping with shallow cups placed in the moss-mats. 2-3 days can be enough, so the liquid won't evaporate.

- Building a mound from pebbles or soil around the trap is a good idea, but it's more difficult than it seems. I tried it last year, and there were problems with it: It created a micro-habitat itself, biasing spatial distribution of some animals which - as a result -were be over-represented in the trap. Also, it was difficult to maintain the level at the trap's brim as gravity, raindrops etc. destructed the pebble/soil structure.

- Colour pan traps indeed attract pollinators, but this time I'm interested in epigaeic inverts (e.g. ground beetles, millipedes, etc.).

Thank you All once again! Ferenc

Silicone? You've just given the million-dollar idea! :) Thank you!

Sir, Please see attachment regarding pitfall