Female genital concealment and a corresponding male clasping apparatus in Australian ripple bugs (Hemiptera: Veliidae)

Conflicts of interest over reproduction between males and females are widespread in sexually reproducing species. This is exemplified in water striders (Gerridae), where females vigorously resist costly mating attempts, and males and females often exhibit elaborate grasping and anti-grasping morphological traits. Like water striders, their sister-group, the ripple bugs (Veliidae), share similar life histories and are expected to face similar conflicts over mating. Veliids in the genus Nesidovelia exhibit elaborate sexual dimorphism, which is predicted to function in intersexual antagonistic struggles. This includes concealed genitalia in females, and elaborate pregenital abdominal modifications in males. By documenting mating behaviour in Nesidovelia peramoena and freezing pairs in copula, we show that males and females struggle prior to mating, and male abdominal modifications function to gain access to the female's concealed genitalia. This is consistent with, though not limited to, sexual conflict.