PDF(Pubmed)
Abstract：
The American burying beetle, Nicrophorus americanus Olivier, is a federally protected insect that once occupied most of eastern North America. Adult beetles feature distinct, recognizable markings on the pronotum and elytra, and color changes with age have been observed. Among the challenges faced by research scientists and conservation practitioners is the ability to determine beetle age in the field between and including teneral (young) and senescent (old) adult stages. Using 20 (10 male and 10 female) captive-bred beetles, we characterized the change in greyscale and red, green, and blue (RGB) color channels over the lifespan of each beetle for field-aging applications. Individual beetles were photographed at set intervals from eclosion to death, and color data were extracted using open-source ImageJ Version 1.54f software. A series of linear mixed-effects models determined that red color showed the steepest decrease among all color channels in the pronotum and elytral markings, with a more significant decrease in the pronotum. The change in greyscale between the pronotum and elytral markings was visibly different, with more rapid darkening in the pronotum. The resulting pronotum color chart was tested under field conditions in Oklahoma, aging 299 adult N. americanus, and six age categories (day range) were discernable by eye: teneral (0-15), late teneral (15-31), early mature (31-45), mature (45-59), early senescent (59-76), and senescent (76-90). The ability to more precisely estimate age will improve population structure estimates, laboratory breeding programs, and potential reintroduction efforts.
摘要：
美国埋葬甲虫，美洲显微镜Olivier，是一种联邦保护的昆虫，曾经占据了北美东部的大部分地区。成年甲虫的特征明显，在前胸和垂直线上可识别的标记，并观察到颜色随年龄的变化。研究科学家和保护从业人员面临的挑战之一是在包括teneral（年轻）和衰老（老年）成年阶段之间确定甲虫年龄的能力。使用20只(10只雄性和10只雌性)圈养甲虫，我们描述了灰度和红色的变化，绿色,和蓝色（RGB）颜色通道在每个甲虫的寿命，用于现场老化应用。从羽化到死亡，以固定的间隔拍摄个体甲虫，使用开源ImageJ版本1.54f软件提取颜色数据。一系列线性混合效应模型确定，在前胸和囊纹的所有颜色通道中，红色显示出最急剧下降。前胸的减少更明显。前胸和外衣标记之间的灰度变化明显不同，前胸底部变黑更快。在俄克拉荷马州的野外条件下测试了所得的前胸膜颜色图，299岁的成年美国人，和六个年龄类别（日范围）可以通过眼睛辨别：teneral（0-15），晚音（15-31），早熟（31-45），成熟（45-59），早期衰老（59-76），和衰老（76-90）。更精确估计年龄的能力将改善人口结构估计，实验室育种计划，以及潜在的重新引入努力。
