Fig. 1

Early embryonic processes of Parasteatoda tepidariorum. Selected time-lapse images of a live wild-type embryo (Additional file 1: Movie S1) are shown along with their timelines (time [h] after egg laying [AEL]), stages of development, and illustrations of morphological characteristics. The morphology of the developing P. tepidariorum embryo undergoes symmetry transitions as shown (top). An axis of radial symmetry (embryonic-abembryonic axis) and two axes of bilateral symmetry (anterior–posterior [A-P] and dorsal–ventral [D-V] axes) are indicated by broken lines. Asterisks mark cells around the embryonic pole, cells at the closed blastopore, and cells at the posterior pole, which are in the same lineage. Scale bars,100 µm