Cephalopod Sex and Reproduction

DWhatley

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New Findings on the Behaviour of the Horned Octopus Eledone cirrhosa in Captivity
Marcos Regueira, Ángel Guerra, Ángel F. González 2017 (Thalassas: An International Journal of Marine Sciences subscription)
@sirreal - note the spontaneous spawning comment
Abstract
A total of sixteen individuals of horned octopus Eledone cirrhosa were caught using creels by a vessel of the small-scale fishery operating in the Ría of Vigo (NW Spain). Captures took place on the west side of the Cíes Islands (Galician Atlantic Islands Maritime-Terrestrial National Park) in March 2013 between 60 and 70 m depth. All the octopuses were females, ranging 355–950 g in body weight. Animals were kept alive and subsequently transferred to open seawater system. Observations under confined conditions resulted in several behavioural events, summarized as follows: i) visual attack sequence was described and found to be similar to that exhibited by Sepia sp., which involves three main phases: attention, positioning and seizure, ii) after a time of confinement, females spontaneously start to spawn in the artificial dens arranged inside the tanks, although eggs were unviable, and iii) females spawn within a shelter, inside which they remain during eggs development, and block the entrance with stones and other materials they find nearby the burrow. This behaviour has been observed for the first time in E. cirrhosa. These new findings are discussed and compared with previous literature.
 

DWhatley

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Health status of post-spawning Octopus maya (Cephalopoda: Octopodidae) females from Yucatan Peninsula, Mexico
Katina Roumbedakis, Maité Mascaró, Maurício L. Martins, Pedro Gallardo, Carlos Rosas, Cristina Pascual 2017 (hydrobiologia subscription)
The present study aimed to evaluate the health status of Octopus mayafemales on different days after spawning (days 0, 10, 20, 30, and 40). A total of 25 O. maya females were examined in terms of physiological (i.e., weight loss, hepatosomatic and gonadosomatic indexes, and hemocyanin, protein, glucose, cholesterol, and acylglycerides concentrations in plasma) and immunological variables (i.e., total hemocyte count, hemagglutination, and phenoloxidase activity). We hypothesized that O. maya females should maintain their physiological integrity throughout the post-spawning period until the hatching of the offspring. Results showed that the physiological and immunological indicators measured in post-spawning females significantly changed with time. Loss of body weight over time and a decrease in the hepatosomatic and gonadosomatic indexes were observed. Hemolymph components showed variations that reflect the consumption of reserves and coincide with an increased immune process of hemagglutination and phenoloxidase activity in hemocytes. Our results demonstrate that O. maya females are adapted to maintain an adequate state of health to care for their spawn despite the long period of starvation and contribute to the identification of the mechanisms involved in maintaining the integrity of these animals during one of the most critical phases of their life cycle.
 

DWhatley

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Multiple optic gland signaling pathways implicated in octopus maternal behaviors and death
Z. Yan Wang, Clifton W. Ragsdale
(subscription Journal of Experimental Biology 2018 : jeb.185751 doi: 10.1242/jeb.185751 Published 13 August 2018)

Editorial of study findings here:
The grim, final days of a mother octopus September 25, 2018, University of Chicago Medical Center


Abstract
Post-reproductive life in the female octopus is characterized by an extreme pattern of maternal care: the mother cares for her clutch of eggs without feeding until her death. These maternal behaviors are eradicated if the optic glands, the octopus analog of the vertebrate pituitary gland, are removed from brooding females. Despite the optic gland's importance in regulating maternal behavior, the molecular features underlying optic gland function are unknown. Here, we identify major signaling systems of the Octopus bimaculoides optic gland. Through behavioral analyses and transcriptome sequencing, we report that the optic gland undergoes remarkable molecular changes that coincide with transitions between behavioral stages. These include the dramatic up- and down-regulation of catecholamine, steroid, insulin, and feeding peptide pathways. Transcriptome analyses in other tissues demonstrate that these molecular changes are not generalized markers of senescence, but instead, specific features of the optic glands. Our study expands the classic optic gland-pituitary gland analogy and more specifically, it indicates that, rather than a single “self-destruct” hormone, the maternal optic glands employ multiple pathways as systemic hormonal signals of behavioral regulation.
 

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How female squid inseminate their eggs with stored sperm
Yoko Iwata, Noriyosi Sato, Noritaka Hirohashi. Takashi Kasugai, Yoshiro Watanabe, Eiji Fujiwara 2019 (Current Biology subscription)

Summary
How sperm reach ova after mating is one of the central questions in reproductive biology. Many species copulate and store sperm in female reproductive organs until spawning [1]. The way females use stored sperm is closely associated with sperm competition and cryptic female choice. However, it is difficult to observe the process of fertilization in natural spawning, as fertilization usually occurs in some ‘hidden place’ within the female’s body. Here, we report the fertilization process of a squid using a glass plate as a spawning substratum, enabling observation within the female arm crown where the sperm storage organ is located and where fertilization may occur. Additionally, we detail the distribution of sperm around newly spawned eggs. Our observations reveal that: the female places her sperm-storage organ (seminal receptacle) over an egg held within her arm crown and inseminates the eggs one-by-one during attachment to the spawning substratum; sperm pass through a pathway within the jelly layers surrounding an egg; and such direct insemination behavior and the pathway through the egg jelly enables a female squid to externally fertilize her eggs using relatively few sperm. This study is the first to reveal the fertilization process using stored sperm, under female control.
 

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