Fang Chi-Chun, Rajakumar Arjuna, Kenny Andrew, Mueller Ulrich G, Abouheif Ehab, Stein David
Department of Integrative Biology, The University of Texas at Austin, Texas, USA.
Department of Biology, McGill University, Quebec, Canada.
J Exp Zool B Mol Dev Evol. 2025 Jul;344(5):284-302. doi: 10.1002/jez.b.23296. Epub 2025 May 12.
Ants exhibit complex social organization, morphologically and functionally distinct castes, and the exploitation of diverse ecological niches. How these features have influenced embryonic development relative to other insects remains unclear. Insect embryogenesis has been classified into three modes: In long germ-band development, exemplified by the fruit fly Drosophila melanogaster, segments along the entire anterior-posterior axis of the embryonic primordium are established almost simultaneously, before gastrulation, with the initial embryonic primordium surrounding almost the entire volume of the egg. In short and intermediate germ-band modes, the embryonic primordium occupies a smaller proportion of the egg surface, with anterior segments initially specified, and remaining segments being added sequentially from a posterior growth zone. Here, we examine embryogenesis in three myrmicine ants, the fungus-gardening ants Atta texana and Mycocepurus smithii, and the red imported fire ant Solenopsis invicta. We find that these ant embryos combine features of short germ-band development with a newly characterized progressive pattern of segmentation that has been associated with some long germ-band-developing insects. Despite similarities in the size of ant and Drosophila eggs, embryogenesis in the three ant species is 10- to 20-fold longer than in Drosophila and is also significantly longer than in two other hymenopteran species that have been studied, the honeybee Apis mellifera and the jewel wasp Nasonia vitripennis. Moreover, the embryos produced by A. texana foundress queens develop to first instar larvae 25% faster than embryos produced by mature queens. We discuss these results in the context of the eusocial lifestyle of ants.
蚂蚁展现出复杂的社会组织、形态和功能各异的品级，以及对多样生态位的利用。相对于其他昆虫而言，这些特征如何影响胚胎发育仍不清楚。昆虫胚胎发生已被分为三种模式：在长胚带发育中，以果蝇黑腹果蝇为例，在原肠胚形成之前，胚胎原基沿整个前后轴的体节几乎同时建立，最初的胚胎原基几乎包围了整个卵的体积。在短胚带和中胚带模式中，胚胎原基占据卵表面的比例较小，前部体节最初确定，其余体节从后部生长区依次添加。在此，我们研究了三种蚁科蚂蚁的胚胎发生，即培育真菌的德克萨斯切叶蚁和史密斯氏菌蚁，以及入侵红火蚁。我们发现这些蚂蚁胚胎结合了短胚带发育的特征以及一种新描述的渐进性分节模式，这种模式与一些长胚带发育的昆虫有关。尽管蚂蚁和果蝇的卵大小相似，但这三种蚂蚁物种的胚胎发生时间比果蝇长10到20倍，也明显长于另外两种已研究的膜翅目物种，即蜜蜂意大利蜜蜂和丽蝇蛹集金小蜂。此外，德克萨斯切叶蚁蚁后产生的胚胎发育到一龄幼虫的速度比成熟蚁后产生的胚胎快25%。我们在蚂蚁的群居生活方式背景下讨论了这些结果。
