Department of Biology, University of Memphis, Memphis, TN 38152, USA.
Ecohealth. 2009 Dec;6(4):565-75. doi: 10.1007/s10393-009-0272-7. Epub 2010 Feb 5.
Pathogen-induced modifications in host behavior, including alterations in foraging behavior or foraging efficiency, can compromise host fitness by reducing growth and development. Chytridiomycosis is an infectious disease of amphibians caused by the fungus Batrachochytrium dendrobatidis (Bd), and it has played an important role in the worldwide decline of amphibians. In larval anurans, Bd infections commonly result in reduced developmental rates, however, the mechanism(s) responsible are untested. We conducted laboratory experiments to test whether Bd infections reduced foraging performance of Grey Treefrog (Hyla chrysoscelis) and Fowler's Toad (Anaxyrus [= Bufo] fowleri) tadpoles. In the first experiment, we observed foraging behavior of Bd-infected and uninfected tadpoles to test for differences in foraging activity. In a second experiment, we tested for differences in the ingestion rates of tadpoles by examining the amount of food in their alimentary track after a 3-hour foraging period. We hypothesized that Bd-infected tadpoles would forage less often and less efficiently than uninfected tadpoles. As predicted, Bd-infected larvae forage less often and were less efficient at obtaining food than uninfected larvae. Our results show that Bd infections reduce foraging efficiency in Anaxyrus and Hyla tadpoles, and that Bd differentially affects foraging behavior in these species. Thus, our results provide a potential mechanism of decreased developmental rates of Bd-infected tadpoles.
病原体引起的宿主行为改变，包括觅食行为或觅食效率的改变，会通过降低生长和发育来损害宿主的适应性。蛙壶菌病是一种由真菌蛙壶菌（Batrachochytrium dendrobatidis，Bd）引起的两栖动物传染病，它在全球范围内的两栖动物减少中扮演了重要角色。在幼年蛙类中，Bd 感染通常会导致发育速度降低，但负责的机制尚未得到检验。我们进行了实验室实验，以测试 Bd 感染是否会降低灰树蛙（Hyla chrysoscelis）和 Fowler 蟾蜍（Anaxyrus [= Bufo] fowleri）蝌蚪的觅食表现。在第一个实验中，我们观察了 Bd 感染和未感染的蝌蚪的觅食行为，以测试觅食活动的差异。在第二个实验中，我们通过检查觅食期 3 小时后它们消化道中的食物量来测试蝌蚪的摄食率差异。我们假设 Bd 感染的蝌蚪会比未感染的蝌蚪觅食次数更少，效率更低。正如预测的那样，Bd 感染的幼虫比未感染的幼虫觅食次数更少，获取食物的效率也更低。我们的结果表明，Bd 感染降低了 Anaxyrus 和 Hyla 蝌蚪的觅食效率，并且 Bd 对这些物种的觅食行为有不同的影响。因此，我们的结果提供了 Bd 感染蝌蚪发育速度降低的潜在机制。
