Locomotion and predatory strategy in backswimmers (Hemipter a: Notonectidae)

Adaptation of Buenoa, Notonecta and Martarega to different aquatic habitats is discussed. Martarega swim against a current while waiting for prey stranded on the water surface to be carried within reach. Because their prey are immobile, Martarega have not developed capabilities for rapid acceleration in the pursuit of prey and have reduced the size of their preyrestraining appendages while increasing their ability to maintain their position in a current. Notonecta and Buenoa live in static water and sit and wait for prospective prey. Since most of their potential prey are free-swimming and have a capability for escape, Buenoa and Notonecta have evolved large fore- and midlegs capable of prey restraint, as well as an ability to quickly lunge from a still position, and rapidly accelerate to overtake and capture their prey. The adjustment of locomotive capabilities to fit different predatory strategies has, in terms of the metathoracic leg, been accomplished by changing the mechanical advantage experienced in swimming.