03648nas a2200325   4500008004100000020001400041245008200055210006900137260001800206300001400224490001600238520255600254653001202810653001702822653001002839653002902849653001602878653001802894653000902912653005502921653005502976653001003031653002303041653004203064653001203106653005503118653001003173100001603183856012303199       1992                        eng d  a0031-182000aEctoparasite impacts on Gerbillus andersoni allenbyi under natural conditions0 aEctoparasite impacts on Gerbillus andersoni allenbyi under natur  aENGLANDc1992  a479 - 4880 v104 ( Pt 3)3 aTo assess ectoparasite impact on individuals and populations of Gerbillus andersoni allenbyi under natural conditions, I addressed the following questions. Do ectoparasites affect their host fitness and, if so, how? Do ectoparasites affect host population level? Does this parasite-host interaction support the traditional concept of parasite evolution towards avirulence? For this purpose, host infestation, infection, survival, haematological indices, and physical condition were recorded. A field experiment which included manipulating host infestation while recording host survival was conducted to determine the causal relations between these variables. G. a. allenbyi was infested by 2 fleas (Synosternus cleopatrae and Stenoponia tripectinata), 5 mesostigmatid mites (Androlaelaps centrocarpus, A. hirsti, A. insculptus, A. marshalli and Hirstionyssus carticulatus), 1 tick (Rhipicephalus sanguineus), and 1 louse (polyplax gerbilli). Ectoparasite burden significantly reduced host survival and red blood cell indices (red cell concentration, haemoglobin concentration and haematocrit). Ectoparasite burden did not significantly affect white blood cell concentration. Gerbils were not infected by haemoparasites or gut helminths which potentially could cause anaemia. The causal relationship between S. cleopatrae burden and host survival was established by manipulation of host infestation. Both ectoparasite removal and initial level of infestation significantly affected host survival. Ectoparasites that caused anaemia were not associated with host physical condition (PC), measured as weight/length3. None of the red blood cell indices was correlated with host PC. These results suggest both that host PC was not affected by ectoparasite burden and that exsanguination leading to anaemia was the main effect of the ectoparasites. Ectoparasite pressure on the host population (based on the ectoparasite effects as estimated by statistical models, combined with dispersion of the infestation within the host population) changed seasonally and was greatest when host density was the highest. A large segment of the gerbil population was affected by ectoparasites during the entire year. An explanation for the evolution of parasite virulence, contrasting parasites that evolve towards increased virulence with parasites that evolve towards avirulence is presented. This classification is primarily based on whether parasite impact is equated with a higher efficiency of host exploitation, or whether it is a 'side effect' of parasite biology.10aanimals10aectoparasite10afleas10aGerbillinae/parasitology10ahealth care10ahost parasite10alice10aLice Infestations/blood/physiopathology/veterinary10aMite Infestations/blood/physiopathology/veterinary10amites10apopulation density10aRodent Diseases/blood/physiopathology10aSeasons10aTick Infestations/blood/physiopathology/veterinary10aticks1 aLehmann, T.  uhttps://phthiraptera.myspecies.info/content/ectoparasite-impacts-gerbillus-andersoni-allenbyi-under-natural-conditions02190nas a2200301   4500008004100000245010000041210006900141260000900210300001400219490000800233520138100241653001001622653000901632653001001641653001201651653001701663653000901680653000901689653001001698653001501708653001701723653000901740653001301749653001101762100002201773700002101795856007201816       1995                        eng d00aComparative effects of mites and lice on the reproductive success of rock doves (Columba livia)0 aComparative effects of mites and lice on the reproductive succes  c1995  a195 - 2060 v1103 a<p>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 and 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 and 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,</p>
10acliff10acost10adoves10aecology10aectoparasite10ahost10alice10amites10aparasitism10areproduction10arock10aswallows10avector1 aClayton, Dale, H.1 aTompkins, D., M.  uhttp://www.phthiraptera.info/sites/phthiraptera.info/files/0742.pdf