Fry Catherine L
Department of Biology, University of Maryland, College Park, MD 20742, USA.
Evol Dev. 2006 Mar-Apr;8(2):191-201. doi: 10.1111/j.1525-142X.2006.00089.x.
Trade-offs between developing body parts may contribute to variation in allometric scaling relationships in a variety of taxa. Experimental evidence indicates that both circulating levels of juvenile hormone (JH) and sensitivities of developing body parts to JH can influence morphology in polyphenic insects. However, the extent to which JH may regulate both the development of traits that scale continuously with body size and trade-offs between these traits is largely unknown. Here, I present evidence that the JH analog methoprene applied to final instar larvae of a stalk-eyed fly (Cyrtodiopsis dalmanni) can induce males to produce larger eye-stalks relative to their body size. Examination of testis growth, sperm transfer, and egg maturation indicates that JH induces a trade-off between eye-span and gonad development in adult males, but not females. Age at sexual maturity was unaffected by larval JH applications to either sex. Collectively, these results are consistent with JH-mediated allocation of resources to eye-span at the expense of testes, and indicate potential costs for the production of an exaggerated trait.
身体各部位发育之间的权衡可能导致各种分类群中异速生长比例关系的变化。实验证据表明，保幼激素（JH）的循环水平和发育中的身体部位对JH的敏感性都会影响多型昆虫的形态。然而，JH在多大程度上可以调节与体型连续缩放的性状的发育以及这些性状之间的权衡，在很大程度上尚不清楚。在这里，我提供证据表明，应用于眼柄蝇（Cyrtodiopsis dalmanni）末龄幼虫的JH类似物烯虫酯可以诱导雄性相对于其体型产生更大的眼柄。对睾丸生长、精子转移和卵子成熟的检查表明，JH在成年雄性而非雌性中诱导了眼间距和性腺发育之间的权衡。性成熟年龄不受幼虫JH应用于任何性别的影响。总体而言，这些结果与JH介导的以牺牲睾丸为代价将资源分配给眼间距一致，并表明产生夸张性状的潜在成本。
