Brinkerhoff R Jory, Markeson Amelia B, Knouft Jason H, Gage Kenneth L, Montenieri John A
Department of Ecology and Evolutionary Biology, University of Colorado, Boulder CO 80309, USA.
J Vector Ecol. 2006 Dec;31(2):355-63. doi: 10.3376/1081-1710(2006)31[355:apotoc]2.0.co;2.
Behavioral, genetic, and immune variation within a host population may lead to aggregation of parasites whereby a small proportion of hosts harbor a majority of parasites. In situations where two or more parasite species infect the same host population there is the potential for interaction among parasites that could potentially influence patterns of aggregation through either competition or facilitation. We studied the occurrence and abundance patterns of two congeneric flea species on black-tailed prairie dog (Cynomys ludovicianus) hosts to test for interactions among parasite species. We live-trapped prairie dogs on ten sites in Boulder County, CO and collected their fleas. We found a non-random, positive association between the two flea species, Oropsylla hirsuta and O. tuberculata cynomuris; hosts with high loads of one flea species had high loads of the second species. This result suggests that there is no interspecific competition among fleas on prairie dog hosts. Host weight had a weak negative relationship to flea load and host sex did not influence flea load, though there were slight differences in flea prevalence and abundance between male and female C. ludovicianus. While genetic and behavioral variation among hosts may predispose certain individuals to infection, our results indicate apparent facilitation among flea species that may result from immune suppression or other flea-mediated factors.
宿主种群内部的行为、遗传和免疫变异可能导致寄生虫聚集，即一小部分宿主携带了大部分寄生虫。在两种或更多种寄生虫感染同一宿主种群的情况下，寄生虫之间存在相互作用的可能性，这种相互作用可能通过竞争或促进作用来影响聚集模式。我们研究了黑尾土拨鼠（Cynomys ludovicianus）宿主上两种同属跳蚤的出现情况和丰度模式，以测试寄生虫物种之间的相互作用。我们在科罗拉多州博尔德县的10个地点对土拨鼠进行活体诱捕，并收集它们身上的跳蚤。我们发现两种跳蚤，即多毛山蚤（Oropsylla hirsuta）和土拨鼠山蚤（O. tuberculata cynomuris）之间存在非随机的正相关关系；携带一种跳蚤数量多的宿主，携带另一种跳蚤的数量也多。这一结果表明，土拨鼠宿主上的跳蚤之间不存在种间竞争。宿主体重与跳蚤数量呈弱负相关，宿主性别不影响跳蚤数量，尽管雄性和雌性黑尾土拨鼠在跳蚤感染率和丰度上存在细微差异。虽然宿主之间的遗传和行为变异可能使某些个体易受感染，但我们的结果表明，跳蚤物种之间存在明显的促进作用，这可能是由免疫抑制或其他跳蚤介导的因素导致的。
