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Summary This article reports the results of a faecal egg count reduction test on 4 farms in France, as an integrated part of the routine deworming strategy against horse cyathostomins and Parascaris equorum. Treatment with fenbendazole (FBZ) or ivermectin (IVM) was evaluated in yearlings on Farms 1 and 2 and treatment with pyrantel embonate (PYR) was tested on Farms 3 and 4. Calculation of the arithmetic mean faecal egg count reduction and the 95% confidence intervals (95% CI) around the mean was performed using bootstrap analysis. For equine cyathostomins, resistance to FBZ was found with an arithmetic mean reduction of 48.8% (95% CI: 1.9–69.3%). On Farms 1 and 2, horses with reduced efficacy were identified. PYR was found to be effective against cyathostomins, with an arithmetic mean reduction of 95.3% (95% CI: 84.6–99.8%), as well as IVM (100%). For P. equorum, both FBZ and PYR were effective (100% reduction). The efficacy of IVM, however, was low (45.5%; 95% CI: 0–96.3%). These results confirm that FBZ resistance in equine cyathostomins is present in France and that anthelmintic resistance to IVM is present in P. equorum. This study underlines the necessity to evaluate the efficacy of horse deworming strategies on a regular basis under field conditions.

Resume Chez le Collembole Symphypleone Allacma fusca, la periode immature preente deux phases: une phase juvenile I qui comprend uniquement la premiere intermue et une phase juvenile II qui regroupe toutes les autres intermues. Ces deux phases se distinguent par d'importantes. modifications qui concernent principalement: - la structure du tegument: a l'eclosion, il est mince et a ornementation composee exclusive-ment de grains primaires alors que des la deuxieme intermue il est epais et profoundement modifie; - le systeme tracheen, rudimentaire a l'eclosion, ramifye apres la premiere mue; - la resistance a la dessiccation: ce n'est qu'a partir de la deuxieme phase juvenile qu'Allacma fusca est capable de reguler ses defenses hydriques en montrant un diagramme de transpiration en plateau. Ces caracteristiques morphologiques, anatomiques et ecophysiologiques de la premiere intermue contraignent l'espece Allacma fusca, dont les stades ulterieurs sont tres resistants a la secheresse, a se maintenir dans le milieu forestier. En considerant l'ensemble de ces reultats, on peut admettre que les Symphypleones representent un groupe entomologique d'un grand inteiet phylogenetique qui permettra d'apporter une reponse plausible au probleme de la conquete des milieux sees, hors du systeme edaphique. La succession de deux phases juveniles distinctes fait apparaitre un clivage, vraisemblablement non homologue de la metamorphose des Insectes epimorphes, dans le cycle vital de ce groupe a developpement protomorphe. Summary Characterisation of two phases of the immature period of Allacma fusca (Collembola, Symphypleona) by their morphology and ecophysiology In the species Allacma fusca (Collembola, Symphypleona), the immature period shows two separate phases: a primary juvenile (phase juvenile I) which corresponds to the single first instar and a secondary juvenile (phase juvenile II) which groups all other stages. These two phases are differenciated by important modifications as follows: - integument structure: after hatching, the cuticule is thin and cuticular ornamentation is formed of primary or single elementary granules; during the second intermoulting, the cuticule becomes thick and its ornamentation is deeply modified by the fusion of the primary granules with their connections. - tracheal system: it is rudimentary after hatching, then becomes ramified after the first! postembryonic moulting. - resistance to dryness: it is only during the secondary juvenile phase that Allacma fusca is able to regulate its rate of water loss, showing a plateau on its typical transpiration curve. All these particular features of the first postembryonic intermoulting (morphology, anatomy and ecophysiology) force this species, in spite of the great resistance to desiccation of its following instars, to remain in the closed forest biotopes. All these results, taken together, suggest that Symphypleona are an entomological group of a great interest which will enable a plausible explanation for the way that terrestrial arthropods can live in dry places, outside the soil layers. The appearance of two juvenile phases in the life-cycle of these primitive insects could be compared with instars' succession (i. e. metamorphosis) in flying-insects, but we still do not seem to be very close to prove that it's the same process. Zusammenfassung Kennzeichnung von zwei Phasen der Jugendentwicklung von Allacma fusca (Collembola, Symphypleona) durch ihre Morphologic und Okophysiologie Der Zeitraum der ontogenetischen Entwicklungsperiode des symphypleonen Collembolen Allacma fusca umfast zwei Entwkklungsphasen: die Jugendphase I, welche ausschlieslich aus der 1. Zwischenhautungszeit besteht, und die Jugendphase II, welche alle ubrigen Zwischen-hautungszeiten umfast. Diese beiden Jugendphasen unterscheiden sich voneinander durch be-deutende Veranderungen, welche insbesondere folgende Strukturen betreffen: - die Integumentstruktur ist nach dem Schlupfen dunn und besitzt ein ausschlieslich aus einer Primarkornung zusammengesetztes Ornament, wahrend sie ab der 2. Zwischenhautungszeit verdickt und eine tiefgreifende Veranderung erfahrt - das Tracheensystem ist beim Schlupfen rudimentar und verzweigt sich nach der 1. Hautung - die Widerstandsfahigkeit gegenuber Austrocknung; Allacma fusca ist erst ab der 2. Jugendphase in der Lage, seinen Wasserhaushalt zu regulieren und zeigt dann ein sich stabilisie-rendes Ausdunstungsdiagramm. Diese besonderen morphologischen, anatomischen und okophysiologischen Merkmale der 1. Zwischenhautungszeit zwingen den Springschwanz Allacma fusca, dessen spatere Stadien gegeniiber der Austrocknung sehr widerstandsfahig sind, wahrend dieser Zeit zum Verbleib in bewaldetem Biotop. Unter Beruksichtigung der in dieser Arbeit aufgezeigten Ergebnisse ist zu erkennen, das die Symphypleona eine entomologische Gruppe von besonderem phylogenetischem Interesse dar-stellen; sie erlauben uns, fur die Besiedlungsmoglichkeit trockener Biotope auserhalb des edaphi-schen Systems eine einleuchtende Antwort zu erbringen. Die Aufeinanderfolge von zwei unter-schiedlichen Jugendphasen last innerhalb des Lebenszyklus dieser Gruppe mit protomorpher' Entwicklungsweise eine Aufspaltung erkennen, die wahrscheinlich nicht als homolog mit der Metamorphose der epimorphen Insekten angesehen werden kann.

Anomalies of centriolar derivatives were identified in ejaculates and testicular and tracheal biopsies of a sterile stallion, using light, scanning, and transmission electron microscopy. LM revealed that over half the sperm population had only a vestigial or no tail, while the rest had tails of variable length and shape. The vestigial tail was represented by its anlage, which was implanted on the nucleus and differentiated up to capitulum and collum stage. The stunted tail had an axoneme and its derivatives, but was short in all tail segments. Regardless of the tail length or shape, virtually all axonemes were devoid of the central tubular complex ("9 + 0" defect). Abnormal tail segmentation was associated with missing or defective flagellar sheaths and a profusion of extraneous dense fibers, which contributed to the knobby, bulbous, or lobuliform tail configurations. The gradient of flagellar anomalies seems associated with the inability of the distal centriole to implant on the plasmalemma, to produce the axoneme, or maintain its growth, and to induce the normal differentiation of periaxonemal structures. In contrast to sperm, the tracheal epithelium displayed moderate changes, which are manifest in circumscribed rarefaction of cilia, increased incidence of compound cilia, and disturbed orientation of cilia regarding the plane of central tubular complex. The tracheal cilia were free of "9 + 0" defect.

Songhaica nigeriana gen. et sp.n. is described from tropical rain forest in Nieria. Sminthurus stylifer Murphy from wooded Savanna and cultivated soils in Gambia also belongs in this new genus.