Grundel Ralph, Pavlovic Noel B, Sulzman Christina L
United States Geological Survey, Biological Resources Division, Great Lakes Science Center, Lake Michigan Ecological Research Station, 1100 N. Mineral Springs Rd., Porter, IN 46304, USA, , , , , , US.
Oecologia. 1998 Apr;114(2):243-250. doi: 10.1007/s004420050442.
Larvae of the Karner blue butterfly, Lycaeidesmelissasamuelis, feed solely on wild lupine, Lupinusperennis, from the emergence to summer senescence of the plant. Wild lupine is most abundant in open areas but Karner blue females oviposit more frequently on lupines growing in moderate shade. Can differences in lupine quality between open and shaded areas help explain this disparity in resource use? Furthermore, many lupines are senescent before the second larval brood completes development. How does lupine senescence affect larval growth? We addressed these questions by measuring growth rates of larvae fed lupines of different phenological stages and lupines growing under different shade conditions. The habitat conditions under which lupines grew and plant phenological stage did not generally affect final larval or pupal weight but did significantly affect duration of the larval period. Duration was shortest for larvae fed leaves from flowering lupines and was negatively correlated with leaf nitrogen concentration. Ovipositing in areas of moderate shade should increase␣second-brood larval exposure to flowering lupines. In addition, larval growth was significantly faster on shade-grown lupines that were in seed than on similar sun-grown lupines. These are possible advantages of the higher-than-expected oviposition rate on shade-grown lupines. Given the canopy-related trade-off between lupine␣abundance and quality, maintenance of canopy heterogeneity is an important conservation management goal. Larvae were also fed leaves growing in poor soil conditions and leaves with mildew infection. These and other feeding treatments that we anticipated would inhibit larval growth often did not. In particular, ant-tended larvae exhibited the highest weight gain per amount of lupine eaten and a relatively fast growth rate. This represents an advantage of ant tending to Karner blue larvae.
卡纳蓝蝶（Lycaeides melissasamuelis）的幼虫从植物出土到夏季衰老期间，仅以野生羽扇豆（Lupinus perennis）为食。野生羽扇豆在开阔地带最为丰富，但卡纳蓝蝶的雌蝶更频繁地产卵于生长在适度遮荫处的羽扇豆上。开阔地带和遮荫处羽扇豆质量的差异能否解释这种资源利用上的差异？此外，许多羽扇豆在第二代幼虫发育完成之前就已衰老。羽扇豆的衰老如何影响幼虫的生长？我们通过测量取食不同物候期羽扇豆以及生长在不同遮荫条件下羽扇豆的幼虫的生长速率，来解决这些问题。羽扇豆生长的栖息地条件和植物物候期一般不会影响幼虫或蛹的最终体重，但确实会显著影响幼虫期的时长。取食开花羽扇豆叶片的幼虫期最短，且与叶片氮浓度呈负相关。在适度遮荫区域产卵应会增加第二代幼虫接触开花羽扇豆的机会。此外，生长在遮荫处且结籽的羽扇豆上的幼虫生长速度明显快于生长在类似光照条件下的羽扇豆上的幼虫。这些可能是在遮荫处生长的羽扇豆上产卵率高于预期的优势。鉴于羽扇豆丰度和质量之间与树冠相关的权衡，维持树冠异质性是一项重要的保护管理目标。我们还让幼虫取食生长在贫瘠土壤条件下的叶片以及感染霉菌的叶片。我们预期这些及其他取食处理会抑制幼虫生长，但情况往往并非如此。特别是，有蚂蚁照料的幼虫每食用一定量的羽扇豆体重增加最多，且生长速度相对较快。这体现了蚂蚁照料对卡纳蓝蝶幼虫的一个优势。
