Sexual selection and secondary sexual characters of wetas and king crickets.

Abstract

Although some secondary sexual structures of wetas and king crickets have been illustrated in the literature, there are no published descriptions of their behavioural function or detailed analyses of structure. This chapter presents a review and new descriptions of the morphological variety of such structures with a worldwide treatment, new data on details of allometric growth in New Zealand tree wetas (Hemideina), structural analyses of mandibles and behavioural applications of male mandibular weapons related to sexual selection. Four kinds of male sexual characters are found in the Anostostomatidae: (i) development of tusks or knobs projecting anteriorad from the mandibles; (ii) enlarged and sometimes asymmetrically distorted crania; (iii) elongated and/or bowed mandibles, often reinforced; and (iv) spines or lobes projecting from the gena or frons.