Studies on Demodex folliculorum Simon (1842). I. Life history

Abstract

1. Histological data are given about the location and frequency of the different stages of the life history of D. folliculorum in the pilo-sebaceous apparatus of man. These data are examined statistically and the relative durations of each stage and their movements in the follicle are deduced from them.2. A method of in vitro culture is described and data are given about the longevity of the various stages of the life history.3. Experiments on the behaviour of the different motile stages of the mite are described. It is concluded that the deutonymph is the distributive stage, and that distribution occurs over the skin surface.4. The life history is reconstructed by a synthesis of the evidence presented. The life-cycle lasts approximately 14½ days, the life span of each stage of it being: ovum 60 hr., larva 36 hr., protonymph 72 hr., deutonymph 60 hr., adult 120 hr. Interval between copulation and oviposition 12 hr.This work was largely carried out in the Department of Pathology of the Institute of Dermatology, London, and I wish to thank the Director of Pathology, Dr J. O. Oliver, for making available to me the facilities of his department, and for his advice and interest during the progress of the work. The photographs were prepared by Mr R. H. Lunnan of the Photographic Department of the Institute of Dermatology. I am indebted to the Dean of the Institute of Dermatology for permission to publish the photographs.I am grateful to Mr T. E. Hughes of the Department of Zoology, Birkbeck College, University of London, for his advice at all times, and to Miss Hilda Davies of the Department of Statistics, University of Sheffield, for help with statistical methods and to Mr W. Moseley, who prepared the text figures.Finally, I wish to express my thanks to Professor I. Chester Jones and Dr E. T. B. Francis of the Department of Zoology, University of Sheffield, for reading the manuscript and for their help in its preparation.

Morphometric and morphologic characteristics of Demodex bovis and Demodex ghanensis (Acarina: Trombidiformes: Demodicidae) isolated from cattle in the Sudan

“…This was attributed to the fact that fertilization took place on the skin surface, and male mites died few days after copulation, while female mites moved back in the hair follicles depositing their eggs. This finding substantiated the findings of Nemeseri and Szeky (1961) and Spickett (1961) who also reported that male Demodex mites were less in occurrence than females, and attributed this to the short life-span of male mites.…”

<i>Demodex </i>Mites – Commensals, Parasites or Mutualistic Organisms?

“…Sebaceous follicles are thought to become colonised during later childhood and early adult life by transfer from adult family members. The mites' life cycle was studied by Spickett [5] by histological and rudimentary in vitro experiments. From a synthesis of this data gener- er cutaneous microflora, may be opportunistic pathogens, that is they have the potential to change status from commensals to parasites (the mites benefit but cause harm to the host) if the host cutaneous environment facilitates their proliferation [10,11] .…”

A New Species of Pit Mite (Trombidiformes: Harpirhynchidae) from the South American Rattlesnake (Viperidae): Morphological and Molecular Analysis

“…This probably results in a short adult lifespan. This kind of life cycle is also seen in other Cheyletoidea mites, such as Demodex species, which lifespan after the adult emerges from the capsule is very short, around 120 hours [31][32][33][34].…”