The eight-legged confidant: Narrativizing octopuses and non-human aging.

This article follows an increased interest in the octopus in both popular science and fiction. Octopuses have long held fascination and are commonly tied to processes of aging: Even though their life expectancy tends to be lower than that of humans, they are often framed as "old", not only by appearing as mythical creatures from an unknown past but also by appearing wise and intelligent. Whereas the octopus has been framed as Other, prominently by inspiring the aesthetics of alien life forms, recent examples have underlined the possibility of inter-species contact and communication. This article traces these moments of contact and investigates the role of aging in such fictional encounters. By focusing on two recent examples, Shelby Van Pelt's Remarkably Bright Creatures (2022) and Gina Chung's Sea Change (2023), it illustrates the ways that contemporary fiction narratively links the octopus to older age and discusses forms of non-human aging.

Evaluation of Octopus maya enzyme activity of the digestive gland and gastric juice.

As the demand for Octopus maya grows, sustainable farming practices become essential to prevent overexploitation, so that farming can be developed as a sustainable alternative to traditional fishing. Understanding the digestive dynamics of the octopus is essential for devising optimal dietary formulations in aquaculture. Despite the progress in understanding cephalopod digestion, little is known about the specific functioning of the digestive enzymes responsible for breaking down protein substrates. This knowledge gap underscores the need for further research to support sustainable O. maya population management. In this paper, dietary formulations are identified for cephalopods by characterizing O. maya digestive enzymes present in the digestive gland and gastric juice. The investigation revealed that acidic proteases showed a peak activity at higher temperatures than alkaline proteases. Inhibitors confirmed the presence of H, L, and D cathepsins. The lower activation energy of alkaline enzymes compared to acidic ones observed highlights an intriguing aspect of O. maya's digestive physiology. This research provides valuable insights into O. maya digestive enzyme functions, representing a significant advancement in formulating diets crucial for successful octopus farming that may help to fully understand its physiology.

Fine structure of the gonadal tissue of the horned octopod Eledone cirrhosa (Lamarck, 1798) (Mollusca - Octopoda) during sexual maturity.

The horned octopod Eledone cirrhosa, a medium-sized species found in Arabian Gulf off Saudi Arabia, was collected monthly from the Arabian Gulf off Dammam city during January to December 2022. Samples were dissected and prepared for examination using transmission electron microscopy. During genital maturation, seminiferous tubules are established in the testis, with active spermatogonia dividing. Spermatocytes 1 are observed in the tubule, followed by an increase in spermatogonia and spermatocytes in August. Spermiogenesis begins, with spherical spermatids evolving into elongated spermatids. In September, active spermatogonia, meiotic divisions, and increased spermiogenesis continue. Spermatozoa appear in Needham's pouch, indicating sexual maturity. The ovary undergoes various stages of development, with oocytes at stage I in June and July, followed by stage II in October and November. In stage III, follicular cords invade the oocyte's cytoplasm, forming numerous lipid inclusions and protein granules. The cytoplasm contains cisternae of endoplasmic reticulum and a poorly developed Golgi apparatus. Stage IV occurs in November, characterized by the maximum development of follicular cords and the beginning of vitellogenesis. The ooplasm contains numerous lipid inclusions, a syncytium, and secretory cells. From December, stage V oocytes are mainly present, indicating the activity phase of maximum secretion. Yolk platelets accumulate in the oocyte ooplasm, and chorion forms at the zona pellucida. In January, the first smooth eggs are found in some octopuses' ovary, with their proportion increasing steadily. This study aimed to investigate the mitogenic action of gonadotropin and identify the periods of intense cell multiplication during the sexual cycle using cytological methods.

Highly Adaptive Kirigami-Metastructure Adhesive with Vertically Self-Aligning Octopus-like 3D Suction Cups for Efficient Wet Adhesion to Complexly Curved Surfaces.

An essential requirement for biomedical devices is the capability of conformal adaptability on diverse irregular 3D (three-dimensional) nonflat surfaces in the human body that may be covered with liquids such as mucus or sweat. However, the development of reversible adhesive interface materials for biodevices that function on complex biological surfaces is challenging due to the wet, slippery, smooth, and curved surface properties. Herein, we present an ultra-adaptive bioadhesive for irregular 3D oral cavities covered with saliva by integrating a kirigami-metastructure and vertically self-aligning suction cups. The flared suction cup, inspired by octopus tentacles, allows adhesion to moist surfaces. Additionally, the kirigami-based auxetic metastructure with a negative Poisson's ratio relieves the stress caused by tensile strain, thereby mitigating the stress caused by curved surfaces and enabling conformal contact with the surface. As a result, the adhesive strength of the proposed auxetic adhesive is twice that of adhesives with a flat backbone on highly curved porcine palates. For potential application, the proposed auxetic adhesive is mounted on a denture and performs successfully in human subject feasibility evaluations. An integrated design of these two structures may provide functionality and potential for biomedical applications.

The hard life of an octopus embryo is seen through gene expression, energy metabolism, and its ability to neutralize radical oxygen species.

The reproductive process in Octopus maya was analyzed to establish the amount of reactive oxygen species that the embryos inherit from females, during yolk synthesis. At the same time, respiratory metabolism, ROS production, and the expression of some genes of the antioxidant system were monitored to understand the ability of embryos to neutralize maternal ROS and those produced during development. The results indicate that carbonylated proteins and peroxidized lipids (LPO) were transferred from females to the embryos, presumably derived from the metabolic processes carried out during yolk synthesis in the ovary. Along with ROS, females also transferred to embryos glutathione (GSH), a key element of the antioxidant defense system, thus facilitating the neutralization of inherited ROS and those produced during development. Embryos are capable of neutralizing ROS thanks to the early expression of genes such as catalase (CAT) and superoxide dismutase (SOD), which give rise to the synthesis of enzymes when the circulatory system is activated. Also, it was observed that the levels of the routine metabolic rate of embryos are almost as high as those of the maximum activity metabolism, which leads, on the one hand, to the elevated production of ROS and suggests that, at this stage of the life cycle in octopuses, energy production is maximum and is physically limited by the biological properties inherent to the structure of embryonic life (oxygen transfer through the chorion, gill surface, pumping capacity, etc.). Due to its role in regulating vascularization, a high expression of HIf-1A during organogenesis suggests that circulatory system development has begun in this phase of embryo development. The results indicate that the routine metabolic rate and the ability of O. maya embryos to neutralize the ROS are probably the maximum possible. Under such circumstances, embryos cannot generate more energy to combat the free radicals produced by their metabolism, even when environmental factors such as high temperatures or contaminants could demand excess energy.

Gonadal Transcriptome Sequencing Analysis Reveals the Candidate Sex-Related Genes and Signaling Pathways in the East Asian Common Octopus, Octopus sinensis.

The East Asian common octopus (Octopus sinensis) is an economically important species among cephalopods. This species exhibits a strict dioecious and allogamous reproductive strategy, along with a phenotypic sexual dimorphism, where the third right arm differentiates into hectocotylus in males. However, our understanding of the molecular mechanisms that underlie sex determination and differentiation in this species remains limited. In the present study, we surveyed gene-expression profiles in the immature male and female gonads of O. sinensis based on the RNA-seq, and a total of 47.83 Gb of high-quality data were generated. Compared with the testis, we identified 8302 differentially expressed genes (DEGs) in the ovary, of which 4459 genes were up-regulated and 3843 genes were down-regulated. Based on the GO enrichment, many GO terms related to sex differentiation were identified, such as sex differentiation (GO: 0007548), sexual reproduction (GO: 0019953) and male sex differentiation (GO: 0046661). A KEGG classification analysis identified three conserved signaling pathways that related to sex differentiation, including the Wnt signaling pathway, TGF-ß signaling pathway and Notch signaling pathway. Additionally, 21 sex-related DEGs were selected, of which 13 DEGs were male-biased, including Dmrt1, Foxn5, Foxj1, Sox30, etc., and 8 DEGs were female-biased, including Sox14, Nanos3, ß-tubulin, Suh, etc. Ten DEGs were used to verify the expression patterns in the testis and ovary using the RT-qPCR method, and the results showed that the expression level shown by RT-qPCR was consistent with that from the RNA-seq, which confirmed the reliability of the transcriptome data. The results presented in this study will not only contribute to our understanding of sex-formation mechanisms in O. sinensis but also provide the foundational information for further investigating the molecular mechanisms that underline its gonadal development and facilitate the sustainable development of octopus artificial breeding.

Transcriptome analysis of East Asian common octopus, Octopus sinensis, paralarvae.

BACKGROUND: The genes involved in cephalopod development and their association with hatching and survival during early life stages have been extensively studied. However, few studies have investigated the paralarvae transcriptome of the East Asian common octopus (Octopus sinen sis). OBJECTIVE: This study aimed to identify the genes related to embryonic development and hatching in O. sinensis using RNA sequencing (RNA-seq) and verify the genes most relevant to different embryonic stages. METHODS: RNA samples from hatched and 25 days post-hatching (dph) O. sinensis paralarvae were used to construct cDNA libraries. Clean reads from individual samples were aligned to the reference O. sinensis database to identify the differentially expressed genes (DEGs) between the 0- and 25-dph paralarvae libraries. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to supplement the RNA-seq data for embryogenic developmental stages. RESULTS: A total of 12,597 transcripts were annotated and 5,468 DEGs were identified between the 0- and 25-dph O. sinensis paralarvae, including 2,715 upregulated and 2,753 downregulated transcripts in the 25-dph paralarvae. Several key DEGs were related to transmembrane transport, lipid biosynthesis, monooxygenase activity, lipid transport, neuropeptide signaling, transcription regulation, and protein-cysteine S-palmitoyltransferase activity during the post-hatching development of O. sinensis paralarvae. RT-qPCR analysis further revealed that SLC5A3A, ABCC12, and NPC1 transcripts in 20 and/or 30 days post-fertilization (dpf) embryos were significantly higher (p < 0.05) than those in 10-dpf embryos. CONCLUSION: Transcriptome profiles provide molecular targets to understand the embryonic development, hatching, and survival of O. sinensis paralarvae, and enhance octopus production.

Passive elasticity properties of Octopus rubescens arms.

In this report, passive elasticity properties of Octopus rubescens arm tissue are investigated using a multidisciplinary approach encompassing biomechanical experiments, computational modeling, and analyses. Tensile tests are conducted to obtain stress-strain relationships of the arm under axial stretch. Rheological tests are also performed to probe the dynamic shear response of the arm tissue. Based on these tests, comparisons against three different viscoelasticity models are reported.

An Octopus-Inspired Stimulus-Responsive Structural Color Hydrogel for Uterus Cervical Canal Stent.

Soft-bodied aquatic organisms have exhibited remarkable capabilities in navigating and moving within liquid environments serving as a profound inspiration for the development of bionic robots with intricate movements. Traditional rigid components are being replaced by stimulus-responsive soft materials such as hydrogels and shape memory polymers, leading to the creation of dynamically responsive soft robots. In this study, the development of a bionic robot inspired by the shape of an octopus and the adsorptive properties of its tentacles, specifically tailored for targeted stimulation and pH sensing in the cervix, are presented. This approach involves the design of a soft, water-based Janus adhesive hydrogel patch that adheres to specific parts of the cervix and responds to pH changes through external stimuli. The hydrogel patch incorporates inverse opal microstructures mimicking the legs of an octopus, to facilitate efficient and stable locomotion, unidirectional transport of biofluids, and pH-responsive behavior. This miniature bionic robot showcases controlled adhesion and precise unidirectional fluid transport highlighting its potential for targeted stimulus response and pH sensing in the uterine cervical tract. This breakthrough opens new avenues for medical applications within the expanding field of soft-bodied robotics.

3D octopus kinematics of complex postures: Translation to long, thin, soft devices and their potential for clinical use.

INTRO/BACKGROUND: Octopuses are capable of complex arm movements. Unfortunately, experimental barriers and lack of a robust analysis method made it difficult to quantify the three-dimensional (3D) kinematics of soft, flexible bodies, such as the octopus arm. This information is not only crucial for understanding the posture of the animal's arm but also for the development of similarly designed soft, flexible devices. OBJ/GOAL: The primary goal of this work was to create a method to comprehensively quantify complex, 3D postures of octopus (Octopus Bimaculoides) arms in a manner that is conducive and translatable to octopus arm-inspired devices for health monitoring and rehabilitation. METHODS: In this study, 3D underwater motion capture was used to collect kinematic data on both live octopuses and disembodied arms that still had neural activity. A new method was developed to define how arm curvature and regional segments were oriented relative to each other in 3D. This included identification of the bend within a segment along with the computation of the relative orientation between segments, thus permitting the complete quantification of complex arm motions. RESULTS: By comparing vector-based and radius of curvature-based approaches to magnitude of curvature, it was clear that the vector-based approach was less dependent on the length of a segment and that its reported ranges of motion were translatable for outcome measures associated with clinical use. The new approach for the relative orientation of each segment of the octopus arm resulted in the capability of describing the octopus arm in many unique postures, such as straight, simple bending, and complex bending as it utilized the three rotational angles. OUTCOME/IMPACT: This method and its application to octopus arms will yield new information that can be used to better communicate and track not only octopus arm movements but in the development of complex, segmented, soft-bodied devices that can be used in health monitoring and rehabilitation.

Expression profile and immunomodulatory roles of methionine-enkephalin and delta opioid receptor in Octopus ocellatus.

In this study, the expressions and distributions of methionine-enkephalin (Met-enk) and δ opioid receptor in the nervous system of Octopus ocellatus, and the immune regulatory mechanisms of Met-enk on O. ocellatus were explored. The distributions and expressions of Met-enk and δ opioid receptor were assessed by immunohistochemistry and enzyme-linked immunosorbent assay. UV-spectrophotometer, microplate reader, and flow cytometer were used to examine the effects of different concentrations of Met-enk on phagocytosis, antioxidant effects, and body surface mucus immunity of O. ocellatus hemocytes. The data were used to study the mechanisms of Met-enk immunity regulation in O. ocellatus. According to the results, the expression levels of Met-enk and δ opioid receptor in O. ocellatus lymphocytes were higher than those in hemocytes. The expression levels of Met-enk in the ganglia of O. ocellatus decreased in the following order: pedal ganglia > cerebral ganglia > visceral ganglia > optic ganglia > stellate ganglia. Moreover, the phagocytic activity of O. ocellatus hemocytes was enhanced with increasing Met-enk concentration. With increasing Met-enk concentration, the expressions of nitric oxide, total nitric oxide synthase, inducible nitric oxide synthase, catalase, hydrogen peroxide, myeloperoxidase, reduced glutathione, α-naphthy acetate esterase, and methionine aminopeptidases decreased in serums of O. ocellatus in the experimental group compared to the blank group. Similarly, the content of reduced glutathione in the hemocytes of O. ocellatus was also lower in the experimental group than in the blank group; however, the expressions of other substances were higher compared to the blank group. Furthermore, α-naphthy acetate esterase, myeloperoxidase, and hydrogen peroxide expressions in mucus immunity trials of the body surface were lower in the experimental group compared to the blank group. These results indicate that the distributions and expressions of Met-enk and δ opioid receptor in the nervous system of O. ocellatus were related to axoplasmic transport and immune regulation mechanisms. Met-enk participates in cellular immunity, humoral immunity, and mucus immunity in the form of neurotransmitters, thereby regulating the immune response of O. ocellatus.

Climate change consequences on the systemic heart of female Octopus maya: oxidative phosphorylation assessment and the antioxidant system.

There is evidence that indicates that temperature modulates the reproduction of the tropical species Octopus maya, through the over- or under-expression of many genes in the brain. If the oxygen supply to the brain depends on the circulatory system, how temperature affects different tissues will begin in the heart, responsible for pumping the oxygen to tissues. The present study examines the impact of heat stress on the mitochondrial function of the systemic heart of adult O. maya. The mitochondrial metabolism and antioxidant defense system were measured in the systemic heart tissue of female organisms acclimated to different temperatures (24, 26, and 30°C). The results show that acclimation temperature affects respiratory State 3 and State 4o (oligomycin-induced) with higher values observed in females acclimated at 26°C. The antioxidant defense system is also affected by acclimation temperature with significant differences observed in superoxide dismutase, glutathione S-transferase activities, and glutathione levels. The results suggest that high temperatures (30°C) could exert physical limitations on the circulatory system through the heart pumping, affecting nutrient and oxygen transport to other tissues, including the brain, which exerts control over the reproductive system. The role of the cardiovascular system in supporting aerobic metabolism in octopus females is discussed.

Developing isotopic proxies to reconstruct the metabolic rates and thermal histories of octopus.

Understanding an animal's metabolic rate and thermal history is pivotal for ecological research. Recent studies have proposed the use of stable carbon and oxygen isotopes (δ13C and δ18O) in biogenic carbonates as proxies of metabolic rate and experienced temperature, respectively, to overcome the challenges of directly measuring these data in the field. Our study represents the first experimental investigation to develop δ13C and δ18O proxies in octopus. Octopus berrima hatchlings were raised in captivity, at varying water temperatures, for up to 110 days. O. berrima statoliths were then subsequently analysed for δ13C and δ18O values. The proportion of metabolically derived carbon, or respired carbon (Cresp), increased as the octopus grew (slope = 0.076, R2 = 0.72), suggesting an influence of somatic growth rate and body mass on δ13C values. Additionally, we identified an inverse correlation between δ18O values and environmental temperature (slope = -0.163, R2 = 0.91), which was subsequently used to develop a thermal reconstruction model. Our experiment aids in interpreting stable isotopic values in statoliths and their application as temperature and metabolic proxies in wild-caught octopus. Such proxies will increase our monitoring capabilities of these ecologically and commercially significant cephalopods and contribute to their conservation and effective management.

Signaling Ligand Heterogeneities in the Peduncle Complex of the Cephalopod Mollusc Octopus bimaculoides.

INTRODUCTION: The octopus peduncle complex is an agglomeration of neural structures with remarkably diverse functional roles. The complex rests on the optic tract, between the optic lobe and the central brain, and comprises the peduncle lobe proper, the olfactory lobe, and the optic gland. The peduncle lobe regulates visuomotor behaviors, the optic glands control sexual maturation and maternal death, and the olfactory lobe is thought to receive input from the olfactory organ. Recent transcriptomic and metabolomic studies have identified candidate peptide and steroid ligands in the Octopus bimaculoides optic gland. METHODS: With gene expression for these ligands and their biosynthetic enzymes, we show that optic gland neurochemistry extends beyond the traditional optic gland secretory tissue and into lobular territories. RESULTS: A key finding is that the classically defined olfactory lobe is itself a heterogeneous territory and includes steroidogenic territories that overlap with cells expressing molluscan neuropeptides and the synthetic enzyme dopamine beta-hydroxylase. CONCLUSION: Our study reveals the neurochemical landscape of the octopus peduncle complex, highlighting the unexpected overlap between traditionally defined regions.

Genome-wide identification of toll-like receptors in Octopus sinensis and expression analysis in response to different PAMPs stimulation.

Toll-like receptors (TLRs) are one of the extensively studied pattern recognition receptors (PRRs) and play crucial roles in the immune responses of vertebrates and invertebrates. In this study, 14 TLR genes were identified from the genome-wide data of Octopus sinensis. Protein structural domain analysis showed that most TLR proteins had three main structural domains: extracellular leucine-rich repeats (LRR), transmembrane structural domains, and intracellular Toll/IL-1 receptor domain (TIR). The results of subcellular localization prediction showed that the TLRs of O. sinensis were mainly located on the plasma membrane. The results of quantitative real-time PCR (qPCR) showed that the detected TLR genes were differentially expressed in the hemolymph, white bodies, hepatopancreas, gills, gill heart, intestine, kidney, and salivary gland of O. sinensis. Furthermore, the present study investigated the expression changes of O. sinensis TLR genes in hemolymph, white bodies, gills, and hepatopancreas in different phases (6 h, 12 h, 24 h, 48 h) after stimulation with PGN, poly(I: C) and Vibrio parahaemolyticus. The expression of most of the TLR genes was upregulated at different time points after infection with pathogens or stimulation with PAMPs, a few genes were unchanged or even down-regulated, and many of the TLR genes were much higher after V. parahaemolyticus infection than after PGN and poly(I:C) stimulation. The results of this study contribute to a better understanding of the molecular immune mechanisms of O. sinensis TLRs genes in resistance to pathogen stimulation.

Projected ocean temperatures impair key proteins used in vision of octopus hatchlings.

Global warming is one of the most significant and widespread effects of climate change. While early life stages are particularly vulnerable to increasing temperatures, little is known about the molecular processes that underpin their capacity to adapt to temperature change during early development. Using a quantitative proteomics approach, we investigated the effects of thermal stress on octopus embryos. We exposed Octopus berrima embryos to different temperature treatments (control 19°C, current summer temperature 22°C, or future projected summer temperature 25°C) until hatching. By comparing their protein expression levels, we found that future projected temperatures significantly reduced levels of key eye proteins such as S-crystallin and retinol dehydrogenase 12, suggesting the embryonic octopuses had impaired vision at elevated temperature. We also found that this was coupled with a cellular stress response that included a significant elevation of proteins involved in molecular chaperoning and redox regulation. Energy resources were also redirected away from non-essential processes such as growth and digestion. These findings, taken together with the high embryonic mortality observed under the highest temperature, identify critical physiological functions of embryonic octopuses that may be impaired under future warming conditions. Our findings demonstrate the severity of the thermal impacts on the early life stages of octopuses as demonstrated by quantitative proteome changes that affect vision, protein chaperoning, redox regulation and energy metabolism as critical physiological functions that underlie the responses to thermal stress.

HOST SWITCHING IN DICYEMIDS (PHYLUM DICYEMIDA).

Dicyemids (phylum Dicyemida) are the most common and most characteristic endosymbionts in the renal sacs of benthic cephalopod molluscs: octopuses and cuttlefishes. Typically, 2 or 3 dicyemid species are found in a single specimen of the host, and most dicyemids have high host specificity. Host-specific parasites are restricted to a limited range of host species by ecological barriers that impede dispersal and successful establishment; therefore, phylogenies of interacting groups are often congruent due to repeated co-speciation. Most frequently, however, host and parasite phylogenies are not congruent, which can be explained by processes such as host switching and other macro-evolutionary events. Here, the history of dicyemids and their host cephalopod associations were studied by comparing their phylogenies. Dicyemid species were collected from 8 decapodiform species and 12 octopodiform species in Japanese waters. Using whole mitochondrial cytochrome c oxidase subunit 1 (COI) sequences, a phylogeny of 37 dicyemid species, including 4 genera representing the family Dicyemidae, was reconstructed. Phylogenetic trees derived from analyses of COI genes consistently suggested that dicyemid species should be separated into 3 major clades and that the most common genera, Dicyema and Dicyemennea, are not monophyletic. Thus, morphological classification does not reflect the phylogenetic relationships of these 2 genera. Divergence (speciation) of dicyemid species seems to have occurred within a single host species. Possible host-switching events may have occurred between the Octopodiformes and Decapodiformes or within the Octopodiformes or the Decapodiformes. Therefore, the mechanism of dicyemid speciation may be a mixture of host switching and intra-host speciation. This is the first study in which the process of dicyemid diversification involving cephalopod hosts has been evaluated with a large number of dicyemid species and genera.

Living in a dynamic environment: The effects of multi-ways temperature variation on embryo and newborn juveniles of a shallow-water octopus (Amphioctopus fangsiao).

Shallow waters are characterized by fluctuating environmental conditions, modulating marine life cycles and biological phenomena. Multiple variations in water temperature could affect eggs and embryos during spawning events of many marine invertebrate species, yet most of the findings on embryonic development in invertebrates come from experiments based on the constant temperature. In this study, to examine the effects of temperature variation on octopus embryos, Amphioctopus fangsiao, a common shallow-water octopus along the coast of China, was exposed to the constant temperature (18 °C, in situ temperature of the seawater in Lianyungang), ramping temperatures (from 18 to 24 °C), diel oscillating temperatures (18 °C and 20 °C for 12 h each day), and acute increasing temperatures (the temperature increased sharply from 18 °C to 24 °C at embryonic development stage XIX) for 47 days (from embryogenesis to settlement). The results demonstrated that the temperature variations accelerated the development time of A. fangsiao embryos. Temperature fluctuations could cause embryonic oxidative damage and disorder of glycolipid metabolism, thereby affecting the growth performance of embryos and the survival rate of hatchings. Through transcriptome sequencing, the mechanistic adaption of the embryo to environmental temperature variations was revealed. The pathways involved in the TCA cycle, DNA replication and repair, protein synthesis, cell signaling, and nervous system damage repair were significantly enriched, indicating that the embryo could improve heat tolerance to thermal stress by regulating gene expression. Moreover, acute warming temperatures posed the most detrimental effects on A. fangsiao embryos, which could cause embryos to hatch prematurely from the vegetal pole, further reducing the survival of hatchings. Meanwhile, the diel oscillating temperature was observed to affect the normal morphology of the embryo, resulting in embryo deformities. Thus, the constant temperature is critical for balanced growth and defense status in octopuses by maintaining metabolism homeostasis. For the first time, this study evaluates the effects of multiple temperature fluctuations on embryos of A. fangsiao, providing new insights into the physiological changes and molecular responses of cephalopod embryos following dynamic temperature stress.

Soft octopus-inspired suction cups using dielectric elastomer actuators with sensing capabilities.

Bioinspired and biomimetic soft grippers are rapidly growing fields. They represent an advancement in soft robotics as they emulate the adaptability and flexibility of biological end effectors. A prominent example of a gripping mechanism found in nature is the octopus tentacle, enabling the animal to attach to rough and irregular surfaces. Inspired by the structure and morphology of the tentacles, this study introduces a novel design, fabrication, and characterization method of dielectric elastomer suction cups. To grasp objects, the developed suction cups perform out-of-plane deflections as the suction mechanism. Their attachment mechanism resembles that of their biological counterparts, as they do not require a pre-stretch over a rigid frame or any external hydraulic or pneumatic support to form and hold the dome structure of the suction cups. The realized artificial suction cups demonstrate the capability of generating a negative pressure up to 1.3 kPa in air and grasping and lifting objects with a maximum 58 g weight under an actuation voltage of 6 kV. They also have sensing capabilities to determine whether the grasping was successful without the need of lifting the objects.