Trager M D, Boyd B M, Daniels J C, Pence J A
Department of Entomology and Nematology, University of Florida, Gainesville, FL 32611, USA.
Environ Entomol. 2009 Aug;38(4):1211-8. doi: 10.1603/022.038.0431.
Our primary objective in this study was to determine the plant level and environmental factors that affect oviposition choice and subsequent offspring survival in Megathymus yuccae (Boisduval and Leconte) on its host plant, Yucca filamentosa L. A preliminary survey suggested that the frequency of pupal eclosion tent presence increased only with host plant height. In an expanded survey conducted during the adult flight period the following spring, we found that plant height increased the probability of oviposition, whereas the density of herbaceous stems and fire damage decreased the probability of egg presence. Similarly, the number of eggs on occupied plants increased with plant height and decreased with fire damage. When we surveyed the plants from the spring 2008 sampling the following winter to determine presence of late-instar larvae or pupae, we found that the probability that at least one larva survived on previously occupied plants decreased with the density of herbaceous stems. These results collectively suggest that larger, unburned Y. filamentosa individuals and those in relatively open areas are more attractive as host plants for oviposition and that larval performance is generally, but not exclusively, consistent with female preference in this system.
我们在本研究中的主要目标是确定影响丝兰巨胸天牛（Boisduval和Leconte）在其寄主植物丝兰（Yucca filamentosa L.）上产卵选择及后续子代存活的植株水平和环境因素。一项初步调查表明，蛹羽化帐篷出现的频率仅随寄主植物高度增加。在次年春季成虫飞行期进行的一项扩展调查中，我们发现植株高度增加了产卵概率，而草本茎密度和火灾损害降低了卵存在的概率。同样，被占据植株上的卵数随植株高度增加而增加，随火灾损害而减少。当我们在次年冬季调查2008年春季采样的植株以确定老龄幼虫或蛹的存在时，我们发现先前被占据植株上至少有一只幼虫存活的概率随草本茎密度降低。这些结果共同表明，更大、未受火灾影响的丝兰个体以及相对开阔区域的个体作为产卵寄主植物更具吸引力，并且在该系统中，幼虫表现总体上（但并非唯一）与雌性偏好一致。
