Krasnov Boris R, Korine Carmi, Burdelova Nadezhda V, Khokhlova Irina S, Pinshow Berry
Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990, Midreshet Ben-Gurion, Israel.
Parasitol Res. 2007 Jul;101(2):365-71. doi: 10.1007/s00436-007-0480-4. Epub 2007 Feb 13.
We hypothesized that a parasite exploits most effectively its principal host, less effectively a host that is phylogenetically close to its principal host, and least effectively a host that is phylogenetically distant from its principal host. We tested this hypothesis by quantifying the feeding efficiency of two flea species (Parapulex chephrenis and Xenopsylla ramesis) on two rodents, Acomys cahirinus, the specific host of P. chephrenis, and Meriones crassus, a preferred host of X. ramesis, and one bat, Rousettus aegyptiacus, an alien host to both flea species. In both fleas, fewer individuals succeed in feeding when offered with their nonspecific or nonpreferred rodent host to feed on compared with those allowed to feed on their preferred or specific rodent host or, surprisingly, on a bat. The proportion of P. chephrenis that fed was higher on A. cahirinus than on R. aegyptiacus. In contrast, similar proportions of X. ramesis took blood from M. crassus and R. aegyptiacus. The mass-independent size of the blood meal taken by the fleas differed significantly between species, being higher in X. ramesis than in P. chephrenis. However, each flea species took similar amounts of blood from any of the three host species. The duration of early, middle, and late digestion stages differed significantly between P. chephrenis and Xenopsylla conformis, all being shorter in the former, independent of the source of blood. Both fleas digested bat blood significantly faster than the blood of either rodent host. The time of survival after a single blood meal differed significantly between flea species, with X. ramesis surviving significantly longer than P. chephrenis, although no effect of host species on flea survival was found. In terms of the evaluation criteria that we used, we concluded that (a) the alien bat host appeared not to be inferior as a source of food to a rodent host phylogenetically close to the flea's principal host and (b) that the rarity of finding rodent fleas on bats is not related to the feeding efficiency of the fleas.
我们假设，一种寄生虫对其主要宿主的利用最为有效，对系统发育上与其主要宿主相近的宿主利用效率较低，而对系统发育上与其主要宿主距离较远的宿主利用效率最低。我们通过量化两种跳蚤（切氏副蚤和印鼠客蚤）在两种啮齿动物（切氏副蚤的特定宿主埃及刺鼠和印鼠客蚤的偏好宿主肥尾心颅跳鼠）以及一种蝙蝠（埃及果蝠，这两种跳蚤的外来宿主）上的取食效率来验证这一假设。在这两种跳蚤中，与被允许取食其偏好或特定啮齿动物宿主的跳蚤相比，当提供非特定或非偏好的啮齿动物宿主供其取食时，成功取食的个体较少；令人惊讶的是，与取食蝙蝠相比也是如此。切氏副蚤在埃及刺鼠上取食的比例高于在埃及果蝠上的比例。相比之下，印鼠客蚤从肥尾心颅跳鼠和埃及果蝠上取血的比例相似。跳蚤所取血餐的质量独立大小在不同物种间存在显著差异，印鼠客蚤的该值高于切氏副蚤。然而，每种跳蚤从三种宿主物种中的任何一种所取的血量相似。切氏副蚤和 conformis 蚤在早期、中期和晚期消化阶段的持续时间存在显著差异，前者的所有阶段都更短，且与血液来源无关。两种跳蚤消化蝙蝠血液的速度都明显快于任何一种啮齿动物宿主的血液。单次血餐后的存活时间在跳蚤物种间存在显著差异，印鼠客蚤的存活时间明显长于切氏副蚤，尽管未发现宿主物种对跳蚤存活有影响。根据我们所使用的评估标准，我们得出结论：(a) 外来蝙蝠宿主作为食物来源似乎并不逊色于系统发育上与跳蚤主要宿主相近的啮齿动物宿主；(b) 在蝙蝠身上很少发现啮齿动物跳蚤这一现象与跳蚤的取食效率无关。
