Egg-Laying in the Cuttlefish Sepia officinalis

Abstract

This chapter reviews studies about egg-laying in the cuttlefish Sepia officinalis. Egg masses are spawned in specific mating and spawning coastal areas where mates aggregate between April and June in the English Channel and all year long in the Mediterranean Sea. Environmental cues are clearly involved in the aggregation process, but chemical communication also plays a determining role in these complex mechanisms. The successive steps of egg-laying are orchestrated by three classes of regulatory peptides: (1) neuropeptides that integrate environmental cues, (2) ovarian regulatory peptides that modulate the activity of the genital tract, and (3) sex pheromones expressed and released by the oviduct gland. After egg-laying, embryo protection is ensured for 8-10 weeks by a multilayer capsule secreted by the accessory sex glands. The oviduct gland secretes the inner layer of the egg case. The main nidamental gland secretes the main polysaccharides and glycoproteins, such as Sepia Egg Case Proteins, involved in capsule formation and in embryo protection. The accessory nidamental gland expresses specific proteins inherent in the structural organization of the gland, and hosts symbiotic bacteria. Similarly to salivary glands, this gland secretes immune factors possibly associated with gamete and/or embryo protection.

First Evidence of Microplastics in the Yolk and Embryos of Common Cuttlefish (Sepia officinalis) from the Central Adriatic Sea: Evaluation of Embryo and Hatchling Structural Integrity and Development

“…Cuttlefish eggs are surrounded by the eggshell capsule, a multilayer envelope secreted in synergy by the female oviductal gland, nidamental gland, and ink sac which acts as a protective barrier with limited permeabilization to gases and other chemicals (e.g., trace elements) [32]. During organogenesis, which represents the last phase of embryonic development, the egg capsule becomes permeable allowing the entrance of water and solutes within the egg [33]. MPs suspended in the aquatic environment could pass through the egg capsule and thus reach the ooplasm.…”

Structural and Functional Characterization of Orcokinin B-like Neuropeptides in the Cuttlefish (Sepia officinalis)

“…The females are considered to be mature when ovulation starts, that is, when the mature oocytes are released into the genital coelom by the ovary. Egg-laying usually starts before mating, so the oocytes are stored in the genital coelom, and proximal oviduct contractions are inhibited by factors of ovarian origin, expressed and secreted by the oocytes [ 1 , 2 , 3 , 4 ].…”