Variation in sex ratios in four Anguina (Nematoda : Anguinidae) species

Abstract

Number and ratios of adult male and females nematodes in four Anguina species, A. australis from Ehrharta longiflora, A. funesta from Lolium rigidum, A. microlaenae from Microlaena stipoides and an undescribed species from Polypogon monspeliensis, were determined and analysed. The sex ratio in A. australis and A. funesta differed statistically from the expected 1:1, with 57% and 56% females, respectively. The ratios for A. microlaenae and Angina sp. ex Polypogon conformed to the expected 1:1. Galls initiated by single sex nematodes, both male and female, were found in the four species, except that no galls containing only males were found in A. australis. Reproduction in this group appears to be amphimitic, as single sex galls contained no progeny and the data point to the possibility of a mechanism that favours female occupancy of galls.