. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 7. Origin of the egg envelope and morphological changes that occur after egg-laying. (A) Surface layers investing a fertilized, mature egg (eg) in the ovary. El a' and Elb': two sublayers of the envelope, vitelline membrane (vm). flc: follicle cell, y: yolk. (B) The egg envelope 5-10 min after egg-laying. Electron- dense materials seem to be secreted by the embryos (small arrows). (C) The egg envelope about 10 min after egg-laying. Sublayer Elb' begins to fuse to Ela'. The envelope adhesive, but plasticity i
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 7. Origin of the egg envelope and morphological changes that occur after egg-laying. (A) Surface layers investing a fertilized, mature egg (eg) in the ovary. El a' and Elb': two sublayers of the envelope, vitelline membrane (vm). flc: follicle cell, y: yolk. (B) The egg envelope 5-10 min after egg-laying. Electron- dense materials seem to be secreted by the embryos (small arrows). (C) The egg envelope about 10 min after egg-laying. Sublayer Elb' begins to fuse to Ela'. The envelope adhesive, but plasticity is very weak. (D) The egg envelope 10-30 min after egg-laying. The sublayers of El are not distinguishable, and plasticity increases. Small arrows show a possible secretion from the egg. The middle layer (E2) begins to form. (E) The envelope 80 min after egg-laying: sublayers have reappeared. The expanded envelope becomes the funiculus. E2 becomes thicker. Small arrows: possible secretion from the embryo to make E2. reached a first peak at 40 min after egg-laying and then decreased until 70 min after egg-laying. But at this time, plasticity again increased rapidly, attaining another peak 90 min after egg-laying. After 90 min a stretched envelope (Fig. IF) regained its form somewhat when the tension was released. Over the next few hours, envelope plasticity grad- ually decreased again. The size of the eggs did not change through the attachment process. Egg attachment to transplanted setae. Two segments of an ovigerous seta were removed from a non-incubating female and inserted among the egg clusters of another female that had been laying eggs. The donated segments were removed from the host female after 5 min and after I h. and examined with a stereomicroscope. The setal seg- ment removed after 5 min had nearly 50 eggs attached to its hairs (Fig. 10A), and the attachment was similar to those of intact females (Figs. 6B and 8A). However, neither the coat nor the funiculus were for
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
