Du He, Chouvenc Thomas, Su Nan-Yao
Department of Entomology and Nematology, Ft. Lauderdale Research and Education Center, University of Florida, Institute of Food and Agricultural Sciences, 3205 College Ave., Ft. Lauderdale, FL 33314 (
Environ Entomol. 2017 Apr 1;46(2):311-318. doi: 10.1093/ee/nvw162.
Age polyethism in a social insect colony occurs when individuals of different ages perform different tasks. In termites (Isoptera), it has mostly been reported in higher termites, but elements of age polyethism were recently found in juvenile colonies of a lower termite, Coptotermes formosanus Shiraki (Rhinotermitidae). The objective of this study was to compare age polyethism in immature colonies (10-mo-old) of C. formosanus to the age polyethism observed in juvenile colonies (4-yr-old), to investigate if age polyethism emerges as soon as old workers are present, or if it emerges later on, as the colony grows and ages. Age polyethism may be displayed with different patterns in immature colonies of C. formosanus when compared with juvenile colonies, owing to a difference of environmental condition within the nest, i.e., demographics and colony size. Ten-month-old colonies were observed in planar arenas and termite activities were recorded using camcorders. Larval and worker instars were determined by measuring their head width and the occurrence of behaviors was compared with behavioral data previously obtained from 4-yr-old colonies. Workers were the major workforce in both the 10-mo-old and 4-yr-old colonies. Age polyethism was minimal in 10-mo-old colonies, but was more extensive and complex in 4-yr-old colonies. Therefore, age polyethism emerges in C. formosanus as the colony matures, and may recapitulate the transition from a one-piece colony type to an extended nest colony type, with changing conditions inside the nest as the colony grows.
当社会昆虫群体中不同年龄的个体执行不同任务时，就会出现年龄多态行为。在白蚁（等翅目）中，年龄多态行为大多在高等白蚁中被报道，但最近在一种低等白蚁——台湾乳白蚁（鼻白蚁科）的幼蚁群体中发现了年龄多态行为的一些元素。本研究的目的是比较台湾乳白蚁未成熟群体（10个月大）中的年龄多态行为与在幼蚁群体（4岁）中观察到的年龄多态行为，以调查年龄多态行为是在老工蚁出现后就立即出现，还是在群体生长和老化过程中稍后出现。由于巢穴内环境条件的差异，即种群统计学和群体大小的差异，与幼蚁群体相比，台湾乳白蚁未成熟群体中的年龄多态行为可能会以不同的模式表现出来。在平面场地中观察10个月大的群体，并用摄像机记录白蚁的活动。通过测量幼虫和工蚁的头宽来确定龄期，并将行为的发生情况与之前从4岁群体中获得的行为数据进行比较。在10个月大的群体和4岁的群体中，工蚁都是主要的劳动力。10个月大的群体中年龄多态行为最少，但在4岁的群体中更广泛、更复杂。因此，台湾乳白蚁的年龄多态行为随着群体的成熟而出现，并且可能随着群体的生长，随着巢穴内条件的变化，概括了从单一体型群体到扩展巢穴体型群体的转变。
