Mémoire

Sur deux Nématodes Trichostrongyloïdes parasites d’un Muridé africain

II — Chronologie des cycles, description des stades larvaires et des immatures

On two Trichostrongyloid Nematodes parasitic in an african Murid. II — Chronology of their cycles, description of larval and immature forms

Laboratoire de Zoologie-Vers, associé au CNRS, Muséum National d’Histoire Naturelle, 61, rue Buffon, F 75231 Paris Cedex 05, France.

Accepté : 30 Octobre 1986

Résumé

Description des stades larvaires et des immatures de Neoheligmonella dossoi et de N. tranieri (Nippostrongylinae), coparasites d’Uranomijs ruddi en Afrique.

Les stades larvaires libres n’ont pu être attribués à l’une ou l’autre espèce et les mâles n’ont pu être distingués des femelles.

Chez les stades larvaires parasites, les mâles se distinguent des femelles à partir de J2 après l’infestation.

A partir de J3 après l’infestation, un nom spécifique peut être attribué aux larves.

Le développement larvaire de N. dossoi est plus lent que celui de N. tranieri.

Abstract

Larval and immature forms in Neoheligmonella dossoi and N. tranieri (Nippostrongylinae) coparasites of Uranomys ruddi from Africa are described.

The free larval stages of both species cannot be distinguished one from the other. L₁, L₂ and L₃ are identified by their size and by shape and tail length.

In the parasitic larval stages the males are distinguished from females as from the second day after infestation : the female genital primordium is displaced to the caudal extremity in a very significant way.

The L₄ can be separated from L₃ by the presence of a cephalic vesicle and a synlophe ; the immature specimens from L₄ due to the presence of a new cephalic vesicle and the synlophe of adult.

A specific name can be given to those larvae from day 3 after the infestation : plotting the length of the genital primordium in relation to total body length shows two distinct clouds representing a large and a small species. Similar clouds were obtained for day 4 to 7 post-infection. By day 6, the immature forms of the small species can be identified by the synlophe as dossoi and those of the large species as tranieri.

The larval development of N. dossoi is slower than that of N. tranieri.