“…Almost any part of the male can be modified in this way, from the sucker-like ''bursa'' of male nematodes to the cephalothorax, the chelicerae and anterior legs of spiders, the antennae and telson in crustaceans, and the head, mandibles, antennae, pronotum, cerci, and wings of insects. As pointed out by Robson and Richards (1936), the mechanical function of many (though not all) of these structures is to grasp the female during copulation, the same function that is performed by a large fraction of the male genital structures that are species-specific in form (summaries in Eberhard 1985Eberhard , 2004aScudder 1971). The line between ''true'' genital claspers and non-genital claspers is, in the end, arbitrary (Chapman 1969;Darwin 1871;Eberhard 1985; see also Ghiselin 2009;Leonard and Cordoba-Aguilar 2009).…”