HEFETZ A, ROBINSON G E., HUANG Z -Y., BORST D W., CNAANI J
G.S. Wise Faculty of Life Sciences, Department of Zoology, Tel Aviv University, 69978 Tel Aviv, Israel
J Insect Physiol. 1997 Apr;43(4):373-381. doi: 10.1016/s0022-1910(96)00106-0.
To study the possible role of juvenile hormone in caste determination in Bombus terrestris, we measured development and rates of juvenile hormone biosynthesis in vitro in larvae destined to develop into either workers or queens. Larvae of both castes developed through four instars and had the same growth rates. However, the duration of the instars was longer for queen larvae, and their head width at the third and fourth instars was significantly larger. After validating the well-known radiochemical assay of JH for bumble bee larvae, we show that worker larvae corpora allata exhibited a constant and low rate of JH biosynthesis, never more than 5 pmol JH/h/pair. Queen larvae, in contrast, had two peaks of JH biosynthesis: a small one during the first instar, which has previously been correlated with caste determination; and a large peak, previously undetected, above 40 pmol JH/h/pair, during the second and third instars. We suggest that caste determination in this species is mediated by JH and that the duration of larval instars is a key factor. The possibility that the queen influences caste determination via an effect on instar duration is also discussed. Copyright 1997 Elsevier Science Ltd. All rights reserved
为研究保幼激素在熊蜂（Bombus terrestris）级型分化中的潜在作用，我们测定了注定发育为工蜂或蜂王的幼虫的发育情况及体外保幼激素生物合成速率。两种级型的幼虫均历经四龄，生长速率相同。然而，蜂王幼虫的龄期持续时间更长，且其在三龄和四龄时的头宽显著更大。在验证了针对熊蜂幼虫的著名保幼激素放射化学测定法后，我们发现工蜂幼虫的咽侧体保幼激素生物合成速率恒定且较低，从未超过5皮摩尔保幼激素/小时/对。相比之下，蜂王幼虫有两个保幼激素生物合成高峰：一个在一龄时较小，此前已与级型分化相关；另一个大高峰在二龄和三龄时出现，此前未被检测到，超过40皮摩尔保幼激素/小时/对。我们认为该物种的级型分化由保幼激素介导，幼虫龄期的持续时间是关键因素。还讨论了蜂王通过影响龄期持续时间来影响级型分化的可能性。版权所有1997爱思唯尔科学有限公司。保留所有权利
