Testing background matching and disruptive colouration in a sexually dichromatic grasshopper: a computer detection experiment

Cryptic colouration is an adaptative mechanism against predators. Colour patterns can become cryptic through background matching and disruptive colouration, which breaks up the outlines of animal because pattern does not coincide with shape outline animal's body. Background could be advantageous in chromatically homogeneous microhabitats, whereas favoured visually heterogeneous microhabitats. Grasshoppers genus Sphenarium (Orthoptera: Pyrogomorphidae) inhabit very environments exhibit both strategies. Adults show substantial continuous variation longitudinal transverse bands on thorax abdomen. However, males often considerably more number than females, tend to have uniform colouring (flatter patterns). In this study, we analysed properties colour females zapotecum Sanabria-Urbán, H. Song & Cueva del Castillo tested effectiveness using humans as ‘predators’ a computer detection experiment. We found that are dichromatic seem follow different strategies their colouration: higher level matching. addition, areas, predators spent most time searching for striped male morphs lower properties, well female high matching, potentially increasing prey survival. As associated males, our results help explain evolution sexual dichromatism other species grasshoppers Sphenarium.