Consumption of grass endophytes alters the ultraviolet spectrum of vole urine

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• 作者：Otso Huitu ; Marjo Helander ; P?ivi Lehtonen and Kari Saikkonen
• 关键词：Fluorescence ; Lolium pratense ; Microtus agrestis ; Predation ; Reflectance
• 刊名：Oecologia
• 出版年：2008
• 出版时间：May, 2008
• 年：2008
• 卷：156
• 期：2
• 页码：333-340
• 全文大小：294.9 KB

文摘

Fungal endophytes of grasses are known to benefit their hosts directly by increasing resistance to herbivores through mycotoxins. We propose and test assumptions of a novel hypothesis according to which fungal endophytes of grasses may benefit their hosts also indirectly by increasing the conspicuousness of a mammalian herbivore, the field vole (Microtus agrestis), to its avian predators by enhancing the ultraviolet visibility of vole urine. We found that field voles feeding on endophyte-infected meadow ryegrass (Lolium pratense) lost body mass, while voles feeding on non-infected meadow ryegrass gained mass. More interestingly, the maximum peak intensity of ultraviolet fluorescence in the urine of voles feeding on endophyte-infected grass shifted from over 380 nm to circa 370 nm, which is the suggested maximum sensitivity of the ultraviolet pigments in the eyes of vole-eating raptors. Therefore, grazing on endophyte-infected grass alters the ultraviolet spectrum of vole urine, thus potentially enhancing its visibility to avian predators.