Anggang-anggang

Anggang-anggang a group of insect predators that are all included in the tribe Gerridae. Its members, around 340 species, many of which are difficult to distinguish. In the literature also mistakenly known as "water spider", although he was not a spider. The name "anggang-anggang" itself comes from the movement back and forth as she floats

This insect is easily recognizable because of his habit of always running / jumping in the water. His movements were quick, can reach 1.5 m / s. Most live in calm waters, but there are five types (from clan Halobates) are known to live on the ocean surface. Of surface water, anggang-anggang eyeing prey (usually other insects) that is near the surface.
These animals became models in biophysics research about the ability of the surface pressure in the load. There are two aspects of concern: the ability to float on the surface and its ability to move forward quickly.

Buoyancy comes from the presence of very small hairs (microsetae) arranged with a certain direction with the indentations in the nanometer size at the end of her leg and is equipped with a layer of night (wax), but more hydrophobic effect caused by the physical structure of the leg rather than lining the existing night . It is well known, there is an effective limb contact angle with water of 167.6 ° ± 4.4 °. Because small dense hairs and indentations there, the air trapped in the structure and function as a "cushion" on the surface of the water.

The ability to move rapidly also attracted the attention of scientists. To move, anggang-anggang hit the water with a couple middle legs without penetrating the surface, forming depressions in the surface. Basin is deep enough to push the insect forward. In addition, some individuals can use the wings that are sometimes possessed by these insects. In less favorable living conditions, anggang-anggang tend not winged.

Anggang-anggang (Gerridae)
Anggang-anggang Gerris remigis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Heteroptera
Infraordo: Hemiptera
Family: Gerridae
Leach, 1815

Genera
Aquarius
Eotrechus
Gerris
Halobates
Limnogonus
Limnoporus
Metrobates
Neogerris
Rheumatobates
Trepobates