Tactic responses of the parasitic mite, Psoroptes ovis, to light and temperature

Abstract

The astigmatid mite, Psoroptes ovis (Hering) (Acari: Psoroptidae), is an obligate, non-burrowing ectoparasite of vertebrates, of particular economic importance in domestic sheep flocks where it causes clinical psoroptic mange. To help understand the behaviour which facilitates transmission via the environment, the responses of P. ovis derived from rabbits (syn. Psoroptes cuniculi) to temperature and light were examined in the laboratory. On a vertical surface of uniform temperature, the presence and direction of illumination had a significant effect on the distance and direction moved by the mites. In darkness or with illumination from both above and below, the mites moved relatively little, but this movement was upwards. In contrast, with illumination from above only, mites moved downwards. When the direction of the illumination was reversed so that it came from below only, the mites moved upwards. On a vertical surface with a temperature gradient, in darkness or with illumination from both above and below, the mites moved up or down towards the area of highest temperature, depending on whether this was above or below, respectively. However, the movement of the mites in response to the temperature gradient was strongly displaced up or down by the presence of unidirectional illumination from above or below, respectively. The results indicate that the movement of these mites is strongly directed towards areas of high temperature but away from higher light intensity. These behaviours might be expected to maintain the position of the mites on a host animal and help them locate the skin surface of a new host when displaced into the environment.

Responses of Ornithonyssus sylviarum (Acari: Macronyssidae) and Menacanthus stramineus (Phthiraptera: Menoponidae) to Gradients of Temperature, Light, and Humidity, With Comments on Microhabitat Selection on Chickens

“…Some parasitic mites have been known to respond to light (Camin 1953, Kilpinen 2005, Pegler and Wall 2004, and even though the NFM does not have obvious eyes, it will move away from light. NFM fed readily on a chick in the partially lit or darkened half of a feeding chamber (Sikes and Chamberlain 1954).…”

“…NFM fed readily on a chick in the partially lit or darkened half of a feeding chamber (Sikes and Chamberlain 1954). The astigmatid mite, Psoroptes ovis (Hering), likewise showed a marked tendency to avoid light even though no light-detecting organs have been identiÞed (Pegler and Wall 2004). When exposed to light, D. gallinae responded to CO 2 by ceasing movement, but movement continued when CO 2 was presented in the absence of light, indicating both the ability to detect light and a possible adaptation to avoid being eaten by the host (Kilpinen 2005).…”

Penetration of light into carpet, and responses of the European house-dust mite (Dermatophagoides pteronyssinus) to varying light intensity and diurnal cycle

“…Sometimes this is host-or food-seeking behaviour, as in the case of the negative phototaxis exhibited by scab mites such as Psorptes ovis (Pegler and Wall 2004) and tetranychid grass mites such as Oligonychus pratensis (Li and Margolies 1991). Alternatively, light cues may assist mites to seek out more favourable microenvironments (temperature, RH, etc.)…”