Table 1 Developmental stages, times, and events of Ixodes scapularis embryogenesis
Developmental stage | Time in hours (h) or days (D) | Event | |
|---|---|---|---|
0 | 0–4 h | No nucleus visible |
|
1 | 5–12 h | Early nuclear division in the yolk, energids visible |
|
2 | 12 h–2D | Nuclear migration to the periphery of the egg |
|
3 | 2–3 D | Nuclear division at the periphery of the egg |
|
4 | 3–5 D | Cellularization, Blastoderm formation |
|
5 | 6–7 D | Gastrulation, Cumulus formation |
|
6 | 9–10 D | Dorsal field, cell migration to poles |
|
7 | 10–11 D | Germ band formation |
|
8 | 12 D | Perivitelline space, Inversion, Ventral furrow |
|
9 | 12–13 D | Germband segmentation and extension |
|
10 | 13–14 D | Budding appendages, the tube-like structure extends from the growth zone (post-abdomen) |
|
11 | 15–16 D | Extending appendages, germ band contraction |
|
12 | 17–18 D | Extending appendages, 4th leg retracts, Dorsal closure begins |
|
13 | 20–27 D | Ventral closure, Malpighian tubules transport waste to the rectal sac |
|
14 | 28–35 D | Embryo rotates to the final position. All external structures are in the final position. Idiosoma (fused podosoma and opisthosma) and capitulum, palps, hypostome, and chelicerae are fully developed. Last pair of legs (L4) retracted, and three leg pairs (L1-L3) fully elongated and segmented; Haller’s organ and sensory structures visible |
|
15 | 35–40 D | Dorsal closure complete, Cuticle deposition, hatching |
|
