The life cycle of Anguina agrostis: Embryogenesis

Abstract

Bpird A. F. and Sptynes B. A. 1981. The life cycle of Anguina agrostis: embryogenesis. International Journal for Parasitology 11: 23–33. Egg development, from laying to hatching, of two widely separated populations of Anguina agrostis, has been followed over a range of temperatures. Development rates for these two populations have been shown to be identical with a thermal optimum between 18 and 20°C. The minimum time recorded for embryogenesis through to hatching was 9–10 days. Embryogenesis was inhibited by temperatures of 27°C and above and hatching by temperatures greater than 23°C. No significant differences were detected in the dimensions of eggs from either population. These eggs have an average length of 95 μm and an average width of 38 μm. Electron microscope studies of sections through eggs undergoing synchronous development show that the first and apparently only moult of the larva in the egg commences about 7 days after the start of embryogenesis under optimal conditions. The sequence of morphological events that occur throughout embryogenesis are described and recorded for whole specimens observed at low resolution and the moulting sequence is described from high resolution electron micrographs of the cuticles of synchronously developing embryos and larvae.