Dermanyssidae

Abstract: We report experimental data comparing the effects of Mesostigmatid mites and Ischnoceran lice on the reproductive performance of a single group of captive rock doves (Columba livia). Several components of host reproductive success were compared for the two groups, including number of eggs laid, hatching success, nestling growth rates, fledging success, post-fledging body mass and survival. Adult body mass and survival were also compared. There was a dramatic difference in the effects of the mites and lice. The former drove host reproductive success to zero, mainly by agitating adults and causing them to incubate eggs less faithfully. Nestling growth rates and post-fledging survival were also significantly reduced by mites. Lice showed no effect on reproductive success whatsoever, even though the feather damage they cause is known to have energetic consequences (Booth, Clayton & Block, 1993). Neither parasite had a significant effect on adult birds. Although Ischnocera are found on most species of birds, our results for lice constitute the first experimental test of the impact of Ischnocera on avian reproductive success (preliminary report by Clayton & Tompkins, 1994). We discuss reasons for the different effects of mites and lice, including the relationship of horizontal (mites) and vertical (lice) transmission to the evolution of virulence.

Abstract: We experimentally investigated the effects of two haematophagous ectoparasites, larvae of the blow fly Protocalliphora parorum (Diptera: Calliphoridae) and the mite Dermanyssus hirundinis (Mesostigmata: Dermanyssidae), on the survival, health and growth of nestling house wrens Troglodytes aedon. Nestlings in broods with relatively heavy infestations (> 10 larvae, and hundreds to thousands of mites, per nestling) did not have higher mortality, reduced growth of tarsi and primary feathers, or lower pre-fledging hematocrits than nestlings occupying nests in which parasites were killed with heat

Abstract: An age-specific life table for the chicken mite Dermanyssus gallinae (DeGeer, 1778) was based on various observations carried out at 25 degrees C. The generation time was calculated to be 16.8 days; the intrinsic rate of natural increase was 0.12 per day, and the net reproductive rate was 7.2. A nonlinear function was found satisfactory to describe the developmental rate of the different immature life-stages at temperatures below 40 degrees C. The stage-specific survival of the immature life-stages was generally high between 10 and 37 degrees C, but decreased quickly outside this temperature range. Most of the eggs were laid during the first three weeks of the adult life. The proportion of surviving females rapidly decreases after moulting to the adult stage. At a temperature of 30 degrees C, the highest number of eggs (3 eggs per day) was laid.