The Systematics, Ecology and Life History of Two Species of Rhaphido-phoridae (Orthoptera) at Waitomo Caves with Some Observations on Macropathus longipes (Colenso) and M. filifer Walker

Abstract

Two further species are added to the genus Macropathus and a new monotypic genus Pallidoplectron is erected. The ecology, behaviour and life history of two cave-dwelling Rhaphidophorids from Waitomo Caves are discussed, and comparison is made wherever possible with members of the family in other parts of the world. It is shown that these insects prefer a light intensity of 0.5 f.c. or less, temperatures under 60' F and humidity of 94% or more. There is no diurnal rhythm, although activity increases at dusk near the cave entrance. Emergence of the insects at night to feed on the surrounding vegetation is governed by external climatic conditions. The eyes are the primary light perceptors, with the long, highly sensitised antennae having an auxiliary function. Omnivorous in their diet, rhaphidophorids are primarily scavengers; but cannibalism is known to occur, especially during the mating season. The olfactory sense is situated in the maxillary palpi. The chief enemies of Rhaphido-phoridae are mycetophylids, opiliones and arachnids. By marking 370 Rhaphidophorids, information has been obtained on population size, general movements, longevity, sex ratio and mating behaviour. Four different types of movement have been recorded. Mating is shown to have a lunar rhythm and to reach its peak in April. The "Glands of Hancock" have not been observed in any New Zealand Rhaphidophoridae, Oviposition takes place in thick pockets of mud lining the walls inside the caves, and only one egg is laid at a time. It is estimated that the incubation period ranges from seven to eight months. The number of instars is variable both inter- and intraspecifically.