Figure 6

Comparison of germline development during sexual and asexual reproductive phases. Induction of reproductive modes relies on the length of photoperiods: long days induce the asexual phase; short days induce the sexual phase (for details see Methods). From asexual to sexual reproduction (F0 to F2), embryos pregnant by the F0 females and F1 females must develop under short light period days. Expression of ApVas1 in germaria, oocytes, presumptive germ plasm, and germ cells is designated in green. (S1-S7): germline development during oviparous reproduction; (A1-A7): germline development during viviparous reproduction. S1/A1, germaria and oocytes; S2/A2, mature oocytes; S3/A3, syncytial blastoderm; S4/A4, cellularized blastoderm (blastula); S5/A5, germ band formation; S6/A6, extending germ band; S7/A7, embryos undergoing katatrepsis. Corresponding stages of development are highlighted in the bottom right corner. Presumptive germ plasm is specified in the posterior syncytial blastoderm (S3/A3); cellularization of germ cells occurs in the posterior blastula (S4/A4); germ cells are migrating during mid embryogenesis (S5-S7/A5-A7). Migrating germ cells are settled in the putative gonads of late embryos in both reproductive phases. In the sexual phase, the oviparous embryo will give rise to the fundatrix (stem mother hatched from overwintering eggs). The asexual phase begins from the birth of fundatrices bearing viviparous embryos. Data resources of germline development: oviparous development, Figures 1, 2, 3, 4, and 5 and Additional file 3: Figure S3, Additional file 5: Figure S5, Additional file 7: Figure S7, Additional file 8: Figure S8; viviparous development: [14, 42] and Additional file 2: Figure S2.