Development of Skrjabinocerca prima (Nematoda: Acuarioidea) in Hyalella azteca (Amphipoda) and Recurvirostra americana (Aves: Charadriiformes), with comments on its precocity

Abstract

Skrjabinocerca prima Shikhobalova, 1930 developed to the infective third stage in 40 days in Hyalella azteca (Saussure) maintained at 21 °C. Infective larvae occur free in the haemocoel and may impede the amphipod's motility because they lie semirigid and parallel to the longitudinal axis in the posterior abdominal segments. The genital primordium in infective-stage males was 200–520 μm long (averaging 19% of body length) and in females 860–1175 μm (averaging 42% of body length). This is unusually large, even compared with other acuarioids in which precocial development of the third-stage genital primordium is known. Additional evidence is provided for the hypothesis that precocity in nematodes is related to rapid maturity in the final host; in experimentally infected American Avocets (Recurvirostra americana Gmelin), moulting third-stage S. prima were found 2 days postinfection and moulting fourth stage at 4 days. Female nematodes contained embryonated eggs at 7 days; eggs in females became larvated between 10 and 18 days postinfection. In birds, the heads of larval and adult nematodes were attached to the mucosa of the buccal cavity or the upper third of the oesophagus, and adults provoked chronic inflammation in the form of yellow plaques. Worms are able to detach and reattach. Third-stage S. prima given to Marbled Godwits (Limosa fedoa (L.)) and Western Willets (Catoptrophorus semipalmatus inornatus (Brewster)) developed to maturity; the parasite has not been reported from the former species in the wild.