One of the great things about entomology is that it’s a low cost pursuit. A few household items or discount store purchases can help you get started in the field. In the first installment of this series I talked about a trunk trap made from a soft drink bottle. This time it’s one of our most inexpensive but useful pieces of field equipment; one that is always hanging around my neck or stuffed in my pocket or clenched in my teeth when I’m in the field. A length of surgical tubing, some stiffer plastic tubing, a piece of mesh fabric – I’m referring, of course, to the aspirator (or pooter, as it’s more euphoniously known by our Old World colleagues).
The concept is simple – breath power sucks insects through a tube where they are trapped in a small vial or against a mesh screen. The specimens can then be transferred to a killing jar or a vial of preserving fluid.
There are two great advantages to an aspirator: it allows a collector to target a particular insect, often in situations where swinging a net just isn’t practical (think: cactus; crack between rocks; or somebody else’s head); and it provides an easy way to get the insects you want out of a sweep net.
Of course, there are also situations in which a standard aspirator is definitely not practical. Lots of flies and other insects can be found on dead animals, or the dung of live animals, or rotting vegetation or fungi. Sucking things directly from these substrates is what we in the field call a “Fairly Bad Idea”. Not to worry – imaginative entomologists have found a way around this minor obstacle of bad smells and bad bacteria – “blow aspirators” or “venturi aspirators” use a slightly different mechanism to create a vacuum in the intake tube when the operator (that’s you) blows air out through the venturi mechanism. An even more effective method involves an aspirator tube and collecting chamber connected directly to a portable hand-held vacuum cleaner. That way, the field entomologist can collect to their heart’s content, from any substrate, and save their breath for telling everybody within earshot about the greatness of insects.