Biological studies on Laelaps myonyssognathus G. & N. (Acarina: Laelapidae).

Abstract

Laelaps Myonyssognathus Grochovskaya & Nguyen, 1961, was studied in the laboratory at 80% and 90% RH and 30°C (±2°). The life history stages and their approximate duration follow: egg, 1–1.5 days; larva, 9–21 hr; protonymph, 2–9 days; deutonymph, 2–14 days; adult male and adult female, maximum of 75 days. The female usually gives birth to active larvae; however, eggs are occasionally laid. The female readily mates, but may also produce progeny parthenogenetically. The offspring of virgin females were all males. Molting and mating behavior are discussed briefly. The most progeny produced by a single female was 12. An increase from 80% to 90% rh significantly lowered the larval mortality rate. The larva is the active stage most susceptible to desiccation. The larva does not feed before molting. All other active stages readily feed on blood, but apparently cannot penetrate the unbroken skin of their host. Cannibalism of larvae by their mothers was observed rarely. L. myonyssognathus responds positively to human breath and artificially generated CO2, but not to human breath which has had the CO2 removed. The odor of blood also elicits a positive response. The biology of L. myonyssognathus is compared with that of related laelapines, and the significance of behavioral patterns is discussed.