Figure 1
From: Rare polyandry and common monogamy in the firefly squid, Watasenia scintillans
The mode of and change in sperm storage throughout the reproductive season in W. scintillans. (A) Population dynamics of males and mated females from January to May. A cyan box indicates the estimated mating period. Total of 1,414 males and 4,733 females were analyzed. (B) A dorsal view of the female around the neck. Arrowheads point to the spermatangia visible through the transparent mantle. (C) A single mass of spermatangium with unidirectionally oriented ejaculatory ducts (arrowheads). (D) Spermatozoa stored in the spermatangia. (E) An anatomical illustration of the female seminal receptacle along the body axis (A, anterior; P, posterior). (F) A heatmap represents the frequency of female individuals having different patterns of spermatangium number on bilateral sides of the seminal receptacle. Histograms show frequency distribution of spermatangium number for each side (upper left and upper right) and left–right symmetry (bottom). (G) No seasonal change in number of spermatangia stored in females. Total of 1,400 females were examined.
