Antennal sensilla on cave species of Australian Paratemnopteryx cockroaches (Blattaria : Blattellidae)

Abstract

The external morphology and distribution of antennal sensilla of cave-dwelling Australian cockroaches, Paratemnopteryx stonei (Races B and C), P. howarthi and P. sp. nov. (Blattaria : Blattellidae), are described using scanning electron microscopy. Eight major types of sensilla were found. Long and medium-length sensilla chaetica are deeply grooved mechano and contact chemo-receptors with a terminal pore; the long type forms 5–11% and the medium-length 7–22% of all sensilla. Sensilla trichodea type 1 are very slender, non-porous, and form 43–60% of all sensilla. Sensilla trichodea type 2 are stouter, shorter and have wall pores; they form 5–14% of the sensilla. Sensilla basiconica type B are very short, non-porous, inflexible-socket receptors that are known to be hygro- and thermo-receptors; they comprise less than 0.6% of the sensilla. Sensilla basiconica type Gl are short, grooved and have a terminal pore; they form 5–11% of all sensilla. Type G2 are longer with indications of a terminal pore and form 7–10% of the sensilla. Sensilla basiconica type P are short with wall pores, and they form 3–9% of the sensilla. Total sensillar numbers ranged from 5700–8900 for P. stonei, depending on the race and sex, 6950–9950 for P. sp. nov. and 11,700-15,100 for the smaller and possibly more epigean-related P. howarthi. Females had 700–3150 fewer sensilla than males. Comparisons are made between Paratemnopteryx and common epigean cockroaches in relation to sensillar types and numbers.