Habitats & Collecting Methods
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Water in Plants
Micropools formed by epiphytes and flowers
Introduction.

In the tropics, Several groups of hydrophilids apparently specialize in living in the micropools of rainwater that collects in certain kinds of plants. In Bromeliads, these pools can be quite large and also filled with other detritus that falls into them. Up-right inflorescences including some species of Heliconia and Gingers also can be frequented by this hydrophilids. These beetles are not just passing through, but actually can breed in these situations, as evidenced by larvae found in these habitats as well. It is not yet clear how specific hydrophilids are with their "host" plant...will species that breed in gingers also breed in heliconias? The habitat is not that frequently collected, and when it is, usually just "bromeliad" or "heliconia" is put on the label, and the host information is lost. I have begun to keep more detailed records on species associations. Perhaps in the next fifty years there will be enough information to draw some conclusions...

All photos on this page are of the actual plants and flowers in which I encountered hydrophilids.

Collecting techniques.

Inflorescences. In Costa Rica, I have had the best luck in Heliconias (a variety of species), and recently found some gingers to also be inhabitated by hydrophilids. With few exceptions, they are in the genus Pelosoma. I use a machete, sturdy fix-blade buck knife, and a few handy zip-lock plastic bags. Generally, I cut off each bloom and peal back one leaf/bract at a time. I usually put smaller blooms in the plastic bags (usually gingers) and deal with them at night. Very old and dried out booms tend to be the least productive, while recently opened (but not TOO recent) tend to be the best. This may be that tiny black beetles are harder to see in the mush that's often inside the moderately old flowers. The percentage of blooms that contain beetles varies. In January in Costa Rica, I recovered about 35 adult specimens from more than 100 heliconia stalks. I've had better success in recent trips, but suspect that is an artifact of knowing which flowers are more likely to contain these beetles.

Above and left: Heliconia species in Costa Rica

Below: A ginger in Costa Rica.

Bromeliads & other Epiphytes. Bromeliads can be frustrating to collect in. There are certainly beetles in them, but many bromeliads often results in only a few beetles. A good knife helps. Usually putting them over a plastic sheet and going peeling back the leaves one by one is the best method. Watch out for ants, scorpions, snakes, and other surprises that are often living inside also. Often, enough have fallen upright or are low enough to reach with a machete. I have also theatened a chain-saw blade to rope handles and saw down or scrape off bromeliads up to 10 meters high in the low canopy branches (e.g. photo at right). The most commonly encountered genera seem to be Dactylosternum an Phaenonotum.
Above: Collecting in a bromeliad in northern Venezuela Above: Cutting down bromeliads from branches in Costa Rica
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