Water strider
Water striders are fascinating six-legged insects belonging to the family Gerridae, characterized by their slender bodies and long legs, which enable them to walk on the surface of calm bodies of water such as ponds. With approximately 750 species, they are commonly known by various names, including water skeeters, pond skaters, and water gliders. These insects predominantly inhabit freshwater environments, although some genera can be found in marine settings. Water striders have unique adaptations, such as hydrofuge hairpiles that cover their bodies, allowing them to distribute their weight evenly on water's surface and avoid sinking. They feed on small insects and mosquito larvae, using their rostrum to pierce and suck out fluids from their prey.
Reproduction takes place in spring and summer, with females laying up to 20 eggs on vegetation. The young hatch within a month and resemble wingless adults, growing through a molting process. Water striders face threats from birds and pollution, which can harm their food sources and lead to drowning. They hibernate during winter in shoreline vegetation and become active again in April, where they mate and continue their life cycle. With their remarkable adaptations and ecological roles, water striders contribute to the balance of their aquatic environments.
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Water strider
Water striders are six-legged insects with long, slender bodies and heads which live on the surface of ponds and other calm bodies of water with vegetation. These insects walk slowly across the water and feed on small insects and mosquito larvae.
Kingdom: Animalia
Phylum: Anthropoda
Class: Insecta
Order: Hemiptera
Family: Gerridae
Genus: Various (see below)
Species: Various (see below)
The family Gerridae contains about 56 genera and 750 species of insects called water striders. They are also known as water skeeters, water scooters, water bugs, pond skaters, water skippers, water gliders, water skimmers, and puddle flies. These are related to nearly 1,700 species of bugs worldwide that live on the surface of the water. Other families of water bugs are water measurers (family Hydrometridae), smaller water striders (family Veliidae), water treaders (family Mesoveliidae), and velvet water bugs (family Hebridae).
Water striders are most common in the tropics and live on the surface of ponds and other calm bodies of water with aquatic, or water, vegetation. Most species of gerrid inhabit freshwater. However, the genera Asclepios, Halobates, Stenobates, and a few others inhabit marine waters.
The dark-colored, stretched, slender bodies and heads of the water striders typically measure between 1/10 to 1/2 an inch (2 to 12 millimeters) long, though some genera are slightly longer at 1/2 to 1 inch (12 to 25 millimeters) long. Females tend to be longer and generally bigger than the male species, with the exception of the largest species, Gigantometra gigas, which measure as long as 1 1/2 inch (36 millimeters). They have six very long, thin legs with which they walk slowly across the water's surface.
It is easy to confuse water striders in this family with water measurers in the family Hydrometridae. Water measurers, though, have longer, more slender bodies as well as very long legs. Unlike the gerrids, most water measurers do not have wings.
The uppermost layer of water is like a thin layer of skin or an elastic film which can support very light objects. Many tiny hairs, called hydrofuge hairpiles, cover the undersides of the water striders, and their legs have pads with more hairs and claws at the tips. All the body and leg hairs repel water. With their legs extended, the striders' weight is evenly spread across the water so they do not sink. All these features help the long legs move across the uppermost surface of the water. During bad weather they hold onto vegetation.
As members of the order of insects called bugs, water striders have beak-like mouthparts, called rostrums. When they are not in use, the rostrums fold underneath the heads of the water striders. The sharp, pointed rostrums enable the water striders to pierce the bodies of prey and suck the fluids. Their prey includes the larvae and adults of many insect species. The water striders can sense vibrations and ripples in the water caused by prey on the surface. Prey may either live on the surface, fall onto the surface and become trapped, or rise from the water below. It is possible that water striders may sometimes eat their own young when there is a lack of food or they confuse the vibrations of their young with those of prey.
Birds and pollution are the greatest dangers to water striders. Pollution kills the insects' prey and causes the insects to sink into the water and drown.
Reproduction is likely similar to that of other water bugs. During the spring and summer, males beat their legs on the water to attract females. Fights may occur between males for mates. A female water strider attaches up to 20 eggs to vegetation along the shore. One month after being laid, the young hatch, usually between May and July. The young look like wingless adults and grow by molting, or shedding their skins. Late in the summer, when they are about four months old, this new generation of water striders mate and then die. The young from this batch of eggs hatch in August and September and then fly away to settle in other bodies of water. Winter means they must hibernate amid the shoreline vegetation, but in April they become active and mate. This generation of water striders lives almost twice as long as the one before them and die when they are about eight months old.
Some genera of water striders include:
Aquarius
Gerris
Halobates
Limnogonus
Limnoporus
Metrobates
Neogerris
Rheumatobates
Trepobates
Some species of water strider with common names include:
Common water strider Aquarius remigis
Pacific pelagic water strider Halobates sericeus
Hawaiian pelagic water strider Halobates hawaiiensis
Bibliography
Cassis, G. “Family Gerridae.” Australian Biological Resources Study, Australian Government, Oct. 2010, biodiversity.org.au/afd/taxa/GERRIDAE. Accessed 22 May 2024.
“Water Strider Revisited (Family Gerridae) – Field Station.” University of Wisconsin-Milwaukee, 10 Oct. 2012, uwm.edu/field-station/bug-of-the-week/water-strider-revisited/. Accessed 22 May 2024.
“Water Striders.” National Wildlife Federation, www.nwf.org/Educational-Resources/Wildlife-Guide/Invertebrates/Water-Striders. Accessed 22 May 2024.