Editing Gerridae (section)

==Description==
[[File:Vesimittareita.ogv|thumb|right|Video of water striders]] 
The family Gerridae is physically characterized by having [[hydrofuge]] hairpiles, retractable preapical claws, and elongated legs and body.<ref name="Ward">{{cite book |author=Ward, J.V. |year=1992 |title=Aquatic Insect Ecology: 1. Biology and habitat |location=New York |publisher=Wiley & Sons |pages=74, 96, 172, 180}}</ref>

Hydrofuge hairpiles are small, [[hydrophobic]] microhairs. These are tiny hairs with more than one thousand microhairs per mm.<ref name="Ward"/> The entire body is covered by these hairpiles, providing the water strider resistance to splashes or drops of water. These hairs repel the water, preventing drops from weighing down the body.

===Size===
They are generally small, long-legged insects and the body length of most species is between {{convert|2|and(-)|12|mm|in|abbr=on|2}}. A few are between {{convert|12|and(-)|25|mm|in|abbr=on}}.<ref name=Andersen1997>{{cite journal| author=Andersen, N.M. | year=1997 | title=A phylogenetic analysis of the evolution of sexual dimorphism and mating systems in water striders (Hemiptera: Gerridae) | journal=Biological Journal of the Linnean Society | volume=61 | issue=3 | pages=345–368 | doi=10.1006/bijl.1996.0130 | doi-access=free }}</ref> Among widespread genera, the North Hemisphere ''[[Aquarius (bug)|Aquarius]]'' includes the largest species, generally exceeding {{convert|12|mm|in|abbr=on}}, at least among females, and the largest species averaging about {{convert|24|mm|in|abbr=on}}.<ref name=Andersen1997/><ref>{{cite journal| author1=Damsgaard, J. | author2=Zettel, H. | year=2003 | title=Genetic diversity, species phylogeny and historical biogeography of the Aquarius paludum group (Heteroptera: Gerridae) | journal=Insect Systematics & Evolution | volume=34 | issue=3 | pages=313–328 | doi=10.1163/187631203788964791 }}</ref> Females typically average larger than males of their own species,<ref name=Andersen1997/> but it appears to be reversed in the largest species, the relatively poorly known ''[[Gigantometra gigas]]'' of streams in northern Vietnam and adjacent southern China. It typically reaches a body length of about {{convert|36|mm|in|abbr=on|2}} in wingless males and {{convert|32|mm|in|abbr=on|2}} in winged females (winged males, however, only average marginally larger than females). In this species each middle and hind leg can surpass {{convert|10|cm|in|abbr=on|0}}.<ref>{{cite journal| author1=Tseng, M. | author2=Rowe, L. | s2cid=56016772 | year=1999 | title=Sexual dimorphism and allometry in the giant water strider Gigantometra gigas | journal=Canadian Journal of Zoology | volume=34 | issue=6 | pages=923–929 | doi=10.1139/z99-071 }}</ref>

===Antennae===
[[File:Gerris by webrunner.JPG|thumb|Waterstrider in the genus ''[[Gerris]]'']] 
Water striders have two antennae with four segments on each. Antennal segments are numbered from closest to the head to farthest. The antennae have short, stiff bristles in segment III.<ref name="Merrit">{{cite book|author1=Merrit, R.  |author2=Cummins, K. |year=1996 |title=An Introduction to the Aquatic Insects of North America |publisher=Kendall/Hunt Pub. Co. |pages=275–282}}</ref> Relative lengths of the antennae segments can help identify unique species within the family Gerridae, but in general, segment I is longer and stockier than the remaining three.<ref name="Slater">{{cite book| author=Slater, J |year=1995 |title=True Bugs of the World (Hemiptera: Heteroptera) |publisher=Comstock Pub. Associates |pages=1–15}}</ref> The four segments combined are usually no longer than the length of the water strider head.

===Thorax===
The [[Thorax (insect anatomy)|thorax]] of water striders is generally long, narrow, and small in size. It generally ranges from 1.6&nbsp;mm to 3.6&nbsp;mm long across the species, with some bodies more cylindrical or rounder than others.<ref name="Slater"/> The [[pronotum]], or outer layer of the thorax, of the water strider can be either shiny or dull depending on the species, and covered with microhairs to help repel water.<ref name="Merrit"/> The abdomen of a water strider can have several segments and contains both the metasternum and omphalium.<ref name="Merrit"/>

===Appendages===
Gerridae have front, middle, and back legs. The front legs are shortest and have preapical claws adapted to puncture prey. Preapical claws are claws that are not at the end of the leg, but rather halfway through, like [[mantises]]. The middle legs are longer than the first pair and shorter than the last pair and are adapted for propulsion through the water. The hind pair is the longest and is used for spreading weight over a large surface area, as well as steering the bug across the surface of the water. The front legs are attached just posterior to the eyes, while the middle legs are attached closer to the back legs which attach midthorax but extend beyond the terminal end of the body.<ref name="Merrit"/>

===Wings===
Some water striders have wings present on the dorsal side of their thorax, while other species of Gerridae do not, particularly ''Halobates''. Water striders experience wing length [[Polymorphism (biology)|polymorphism]] that has affected their flight ability and evolved in a phylogenetic manner where populations are either long-winged, wing-dimorphic, or short-winged.<ref name="Andersen">{{cite journal| author=Andersen, N. |year=1993 |title=The Evolution of Wing Polymorphism in Water Striders (Gerridae): A Phylogenetic Approach |journal=[[Oikos (journal)|Oikos]] |volume=67 |issue=3 |pages=2412–2428 |jstor=3545355|doi=10.2307/3545355 }}</ref> Wing dimorphism consists of summer gerrid populations evolving different length wings than winter populations within the same species. Habitats with rougher waters are likely to hold gerrids with shorter wings, while habitats with calm waters are likely to hold long-winged gerrids. This is due to potential for damage of the wings and ability for dispersal.<ref name="Schuh"/>