Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel.
Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel.
Med Vet Entomol. 2022 Sep;36(3):347-355. doi: 10.1111/mve.12570. Epub 2022 Mar 24.
We studied the fitness consequences of colonizing a novel host by experimental lines of fleas (Synosternus cleopatrae and Xenopsylla ramesis) maintained for 18-22 generations on the principal or novel (sympatric or allopatric) hosts via number, developmental success and size of the offspring of the fleas exploiting these hosts. We asked whether (a) fitness on non-principal hosts increases after prolonged maintenance; (b) the colonization success depends on the spatial co-occurrence of a flea and a host and (c) colonization of a novel host is accompanied by a decreased ability to exploit an original host. The ability of fleas to colonize novel hosts differed between species, with S. cleopatrae, but not X. ramesis, increasing its offspring production on novel hosts. Spatial co-occurrence did not affect colonization success. Maintenance on an alternative host was not accompanied by decreased adaptation to the original host. When fleas returned to the original host, their reproductive output was higher than that of their ancestors. We conclude that the success of colonizing a novel host is (a) context-dependent and varies between flea and host species and (b) not accompanied by the loss of ability to exploit an ancestral host but may lead to an increase in this ability.
我们通过对跳蚤（Synosternus cleopatrae 和 Xenopsylla ramesis）的实验种群进行研究，这些跳蚤在主要或新宿主（同域或异域）上已被维持了 18-22 代，以数量、后代的发育成功率和大小来研究其在新宿主上的适应度后果。我们提出了以下问题：（a）在长期维持后，非主要宿主上的适应性是否会增加；（b）种群的成功是否取决于跳蚤和宿主的空间共存；（c）对新宿主的适应是否伴随着对原始宿主的利用能力的降低。跳蚤对新宿主的适应能力在不同物种之间存在差异，S. cleopatrae 而不是 X. ramesis 增加了其在新宿主上的后代产量。空间共存并不影响种群的成功。在替代宿主上的维持并不伴随着对原始宿主的适应性降低。当跳蚤返回原始宿主时，其繁殖输出高于其祖先。我们的结论是，（a）适应新宿主的成功是依赖于环境的，在跳蚤和宿主之间存在差异；（b）并不伴随着对原始宿主的利用能力的丧失，反而可能导致这种能力的增加。
