Habitats & Collecting Methods
Home>>>Habitat & Collecting>>>Hygropetric Habitats

Hygropetric Habitats
Waterfalls, seeps, wet rocks, etc.
Hygropetric habitats (essentially water on a vertical surface) harbor an incredibly unique and endemic hydrophilid community in both the New and Old World tropics. These habitats have received surprisingly little attention and most of the species living in these habitats have never been collected, let alone scientifically described. Two entire new families of beetles have been found in these habitats in just the last few years. One reason for this is the difficulty and frustration that can often result in collecting in these habitats, which may require staring at rock faces for hours while constantly being splashed with (cold) water. Fortunately, new techniques used in recent years have made collecting in these habitats significantly more efficient, namely "fogging", a derivation of the same concept used in canopy fogging.
Members of the five genera in the Oocyclus-group of Laccobiini are almost all exclusively hygropetric. Members of Laccobius, Notionotus, Enochrus, and Anaceana are also known to have at least some Hygropetric species in the tropics. Several new Neotropical genera from these habitats still await description.
What makes a good hygropetric habitat?
These habitats can be extremely frustrating to collect in. Two rock faces may look identical but one will have lots of individuals, while the other will have none. A nice mossy boulder may be tough going while the cement wall next to it might be crawling with beetles. However, there are some rules of thumb that can maximizing success:

1. Look for rock faces that are always wet. A rock face that just gets wet because it rained that day will not have an established water beetle community. The area within the "spray zone" of a waterfall, though, is likely to be wet all the time, regardless of other factors.

2. Don't look in "rushing" water. These beetles are not equipped with grappling hooks. They are capable of hiding cracks and in moss, but don't usually occur in the swift current where they would get swept away if they emerge from a crevice; they hang out on the margins that get the splash and seep from the main flow, or in areas where only a gentle film of water is coming down.

3. They like to hide. Most of these beetles, especially Oocyclus and relatives, don't sit exposed on the rock face, but hide under small blobs of mud, behind a moss or small liverwort, or in cracks and crevices. Smooth surfaces can have them too, but polished surfaces are unlikely to be very good.

Above: Collecting Oocyclus around Merida, Venezuela
Below: Mauricio Garcia and Andrew Short discussing a new species of Oocyclus on a rock face in the Serrania de Perija, Venezuela with Lorena Garcia
Fogging. These beetles frequently hide themselves such that, unless they move, they are essentially invisible. They may also hide in cracks or holes in rocks, making them not only invisible but inaccessible. To get around this, several researchers have been using an insecticidal fogging technique, similar in principle to that used in tropical canopy fogging. A small amount of fog applied to the moss or rock causes the beetles to move around and leave their hiding places, facilitating their collection. Numerous new species have been found using this method in otherwise intractable habitats.
Left. An Oocyclus on a rock face in Costa Rica. Below left: A wet rock face with Oocyclus and Anacaena. Below: Collecting Oocyclus along a road/dam near Jaji, Venezuela.
Above left: Seep/waterfall habitat near Chorroni, Venezuela.

Above: Seep habitat of a new species of hydroboiine hydrophilid on Kauai, Hawaii.

Left: Anacaena on a wet rock face in Tapanti National Park, Costa Rica.

Back to Hydrophiloidea home
Contact webmaster