Long-Legged Flies not only skate on the water’s surface, but frequently go airborne and land again on the water or shore. Small insects such as Long-Legged Flies must minimize the amount of body contact with the surface of the water. If the wings or body of a small insect become wet, its weight can easily double and impede or prevent takeoff.
Malcolom Burrows studied takeoff and landing in the Long-Legged Fly, Hydrophorus. He noted that the tarsi on all six legs are long and make contact with the surface along the entire length. The tarsi have hydrophobic hairs that prevent the leg from sinking and remain on the surface. To land, Hydrophorus holds its forelegs forward, middle and hind legs to the side and the wings aloft vertically. The legs distribute the impact of landing so the legs and body do not submerge. On takeoff for flight, Hydrophorus executes a jump by pushing down with its middle and hind legs. These legs create a depression in the water as they push downward but at no time go below the surface. Hydrophorus only engages its wings after it jumps. This prevents the beating wings from contacting the water’s surface.
*Malcolm Burrows. 2013. Jumping from the surface of water by the long-legged fly Hydrophorus. The Journal of Experimental Biology 216, 1973-1981.