Ecology and Taxonomy of Fossorial, Granivorous Gryllacridids (Orthoptera: Gryllacrididae) from Arid Central Australia

Abstract

Bothriogryllacris Rentz, gen. nov., comprising at least three macropterous species from arid central Australia, constructs vertical cylindrical burrows in the ground. B. turris Rentz, sp. nov., projects its burrows slightly above the surface of the ground and provides them with a cap composed of soil particles. The burrows and cap are strengthened internally by silken strands presumed to be oral secretions. B. brevicauda Rentz, sp. nov., constructs burrows which open level with the surface of the ground, and uses a pebble to cover its entrance, sewing it tightly in place with silk. A wingless, unrelated gryllacridid (ANIC number Gen. Nov. 13, sp. 2) from south-west Queensland was also observed to build a cap for its burrow. B. turris has one generation per year; individuals hatch in late summer or autumn and die late in the following summer. The species are granivorous, subsisting almost entirely on seeds of ephemeral grasses. We speculate that sealed caps may: (I) reduce moisture loss from the burrow, which is important given that the diet is low in free water; (2) aid in avoidance of parasites or predators.