{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,31]],"date-time":"2025-10-31T07:15:16Z","timestamp":1761894916494},"reference-count":33,"publisher":"Cambridge University Press (CUP)","issue":"3","license":[{"start":{"date-parts":[[2009,4,6]],"date-time":"2009-04-06T00:00:00Z","timestamp":1238976000000},"content-version":"unspecified","delay-in-days":6153,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Parasitology"],"published-print":{"date-parts":[[1992,6]]},"abstract":"<jats:p>To assess ectoparasite impact on individuals and populations of <jats:italic>Gerbillus andersoni allenbyi<\/jats:italic> 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\u2013host 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. <jats:italic>G. a. allenbyi<\/jats:italic> was infested by 2 fleas (<jats:italic>Synosternus cleopatrae<\/jats:italic> and <jats:italic>Stenoponia tripectinata<\/jats:italic>), 5 mesostigmatid mites (<jats:italic>Androlaelaps centrocarpus, A. hirsti, A. insculptus, A. marshalli<\/jats:italic> and <jats:italic>Hirstionyssus carticulatus<\/jats:italic>), 1 tick (<jats:italic>Rhipicephalus sanguineus<\/jats:italic>), and 1 louse (<jats:italic>Polyplax gerbilli<\/jats:italic>). 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 <jats:italic>S. cleopatrae<\/jats:italic> 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\/length<jats:sup>3<\/jats:sup>. 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 \u2018side effect\u2019 of parasite biology.<\/jats:p>","DOI":"10.1017\/s0031182000063745","type":"journal-article","created":{"date-parts":[[2009,6,5]],"date-time":"2009-06-05T14:24:55Z","timestamp":1244211895000},"page":"479-488","source":"Crossref","is-referenced-by-count":31,"title":["Ectoparasite impacts on <i>Gerbillus andersoni allenbyi<\/i> under natural conditions"],"prefix":"10.1017","volume":"104","author":[{"given":"T.","family":"Lehmann","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"56","published-online":{"date-parts":[[2009,4,6]]},"reference":[{"key":"S0031182000063745_ref030","first-page":"295","volume-title":"Coevolution of Parasitic Arthropods and Mammals","author":"Traub","year":"1985"},{"key":"S0031182000063745_ref012","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7998.1976.tb04702.x"},{"key":"S0031182000063745_ref006","first-page":"1","article-title":"Mites associated with rodents in Israel","volume":"8","author":"Costa","year":"1961","journal-title":"Bulletin of the British Museum (Natural History) Zoology"},{"key":"S0031182000063745_ref003","doi-asserted-by":"publisher","DOI":"10.1139\/z80-230"},{"key":"S0031182000063745_ref005","first-page":"129","article-title":"Some effects of the sucking louse, Haematopinus eurysternus, on the cattle on unsupplemented range","volume":"146","author":"Collins","year":"1965","journal-title":"Journal of the American Veterinary Medical Association"},{"key":"S0031182000063745_ref010","first-page":"219","article-title":"Effect of the sheep body louse (Damalinia ovis) on host weight gain and fleece value","volume":"2","author":"Kettle","year":"1974","journal-title":"Journal of Experimental Agriculture"},{"key":"S0031182000063745_ref031","unstructured":"Waisel Y. , Pollak G. & Cohen Y. (1982). The Ecology of Vegetation of Israel. (In Hebrew). 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The Hebrew University of Jerusalem, Israel."},{"key":"S0031182000063745_ref011","first-page":"3","volume-title":"Coevolution of Parasitic Arthropods and Mammals","author":"Kim","year":"1985"},{"key":"S0031182000063745_ref014","doi-asserted-by":"publisher","DOI":"10.2307\/3276790"},{"key":"S0031182000063745_ref023","doi-asserted-by":"publisher","DOI":"10.1038\/201103a0"},{"key":"S0031182000063745_ref026","doi-asserted-by":"publisher","DOI":"10.2307\/1446041"},{"key":"S0031182000063745_ref015","volume-title":"The Ecology of Ectoparasitic Insects","author":"Marshall","year":"1981"},{"key":"S0031182000063745_ref016","doi-asserted-by":"publisher","DOI":"10.1098\/rspb.1983.0075"},{"key":"S0031182000063745_ref017","first-page":"186","volume-title":"Coevolution","author":"May","year":"1983"},{"key":"S0031182000063745_ref019","volume-title":"Ecology of Insect Vector Populations","author":"Muirhead-Thomson","year":"1968"},{"key":"S0031182000063745_ref020","doi-asserted-by":"publisher","DOI":"10.1093\/jmedent\/13.4-5.389"},{"key":"S0031182000063745_ref021","doi-asserted-by":"publisher","DOI":"10.1016\/0014-4894(70)90096-2"},{"key":"S0031182000063745_ref022","first-page":"455","volume-title":"Advances in Herpetology and Evolutionary Biology","author":"Rand","year":"1983"},{"key":"S0031182000063745_ref024","doi-asserted-by":"publisher","DOI":"10.1017\/S0031182000052367"},{"key":"S0031182000063745_ref025","doi-asserted-by":"publisher","DOI":"10.1126\/science.7112113"},{"key":"S0031182000063745_ref028","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.en.21.010176.001103"},{"key":"S0031182000063745_ref032","first-page":"32","article-title":"Some ectoparasites found on polecats in Britain","volume":"12","author":"Walton","year":"1970","journal-title":"Nature in Wales"},{"key":"S0031182000063745_ref033","doi-asserted-by":"publisher","DOI":"10.2307\/3543598"}],"container-title":["Parasitology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.cambridge.org\/core\/services\/aop-cambridge-core\/content\/view\/S0031182000063745","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,5,16]],"date-time":"2019-05-16T21:36:29Z","timestamp":1558042589000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cambridge.org\/core\/product\/identifier\/S0031182000063745\/type\/journal_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1992,6]]},"references-count":33,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1992,6]]}},"alternative-id":["S0031182000063745"],"URL":"https:\/\/doi.org\/10.1017\/s0031182000063745","relation":{},"ISSN":["0031-1820","1469-8161"],"issn-type":[{"value":"0031-1820","type":"print"},{"value":"1469-8161","type":"electronic"}],"subject":[],"published":{"date-parts":[[1992,6]]}}}