Which family is the largest among true bugs and has tarsal modifications that allow walking on water?

• A. Gelastocoridae
• B. Cimicidae
• C. Miridae
• D. Gerridae

Answer: (D)

Walking on the water comes from a surface-tension walk, made possible when the leg tips press lightly on the water and the contact area is maximized without breaking the surface. Gerridae, the water-strider family, is famous for this. Their tarsi are engineered with dense fringe of hydrophobic hairs and microstructures that resist wetting, along with legs that are long and slender to spread the insect’s weight over a larger area. This combination lets the water striders distribute their weight enough so the water’s surface tension can support them, letting them skim or glide across ponds and streams.

In context, the other families listed don’t show this specialized water-walking setup. Bed bugs are terrestrial parasites, plant bugs generally feed on plants and don’t rely on surface-tension locomotion, and toad bugs have different wetland specializations. So the distinctive tarsal modifications that enable walking on water point to Gerridae.