Stable fly, Stomoxys calcitrans, mouthpart removal influences stress and anticipatory responses in mice

Abstract Biting fly attack induces a variety of stress and anxiety related changes in the physiology and behaviour of the target animals. Significant reductions in pain, or more appropriately, nociceptive sensitivity (latency of a foot-lifting response to an aversive thermal stimulus), are evident in laboratory mice after a 1 h exposure to stable flies, Stomoxys calcitrans. The role of the various components of biting fly attack in the development of this stress-induced reduction in pain sensitivity (analgesia) is, however, unclear. This study demonstrates that fly-naive mice do not exhibit a stress-induced analgesia when exposed to stable flies whose biting mouthparts have been removed. In contrast, mice that have been previously exposed to intact stable flies exhibit significant analgesia when exposed to flies that are incapable of biting. However, the level of analgesia induced is lower than that elicited by exposure to intact stable flies. Exposure to non-biting house flies, Musca domestica , has no effect on nociceptive sensitivity. It appears that the actual bite of the stable fly is necessary for the induction of analgesia and probably other stress and anxiety associated responses in fly naive mice. However, mice rapidly learn to recognize biting flies and exhibit significant, possibly anticipatory analgesic responses to the mere presence of biting flies.     

Ecology of the biting midge Leptoconops albiventris in French Polynesia. I. Biting cycle and influence of climatic factors

Abstract. The diurnal biting cycle of Leptoconops albiventris de Meijere (Diptera: Ceratopogonidae) is described from beaches of Nuku-Hiva, French Polynesia. Biting activity increased during the morning, diminished during the afternoon and was sufficiently intense to constitute a nuisance throughout the whole day. Correspondence Analysis indicated that climatic factors influenced biting activity. Activity was initiated by and positively associated with sunshine, whereas high temperatures, increased wind speed and rainfall were factors limiting activity. Decreased density of females during the dry season and their low capacity for dispersal were considered potentially advantageous with respect to control.