BIOLOGICAL HISTORY

1. Introduction

The longhorn grasshoppers belonging to the family Tettigoniidae, suborder Ensifera, and order Orthoptera are highly diverse insects with complex evolutionary histories [1, 2]. The family has more than 6,400 species characterized by their long filiform antennae (which may exceed the body length), strong hind limbs, powerful chewing mouthparts, four tarsal segments, male tegminal stridulatory organs, and front tibial tympanum [3, 4]. The genus Ruspolia is a group of large, elongate, cone-headed tettigoniids with yellow jaw base [5–8]. These insects usually occur in the grassland and open bushveld; they are active at night, mainly feed on flowers and seeds of cereals especially the millet and maize which they crack using their powerful jaws; males usually produce a very loud continuous hissing call for up to 5 minutes; nymphs hatch in 1-2 months; and they reach adult maturity in 2-3 months [9–12]. Many Ruspolia spp. have no apparent diagnostic features, and thus their taxonomy largely requires molecular evidence. However, the relationships among this genus have seldom been inferred based on molecular data [13, 14].