Anhydrobiosis and reproduction in Anguina australis

Abstract

Survival and reproductive strategies of the leaf gall nematode, Anguina australis Steiner 1940, in annual veldt grass, Ehrharta longiflora Smith, in Western Australia were studied. The adults were found to survive anhydrobiotically over the dry summer within galls. When rehydrated and removed from the gall, about 70% of adults survived an initial cycle of desiccation and rehydration. About 30% survived a further two cycles. Galls contained up to seven adults with a ratio ranging from one to three females per male, increasing with the number of nematodes in the gall. With moist incubation of galls, reproductive activity was greatest at 20°C, limited at 10, 15 or 28°C, and did not occur at 5°C. At 20°C, reproductive activity commenced after 3 weeks and continued for 7 weeks (the period of observation). This reproductive behaviour differs from that of most other anguinid nematodes but is well suited for parasitism of a rapidly maturing host in a seasonally arid Mediterranean climate.