Egg-laying Process Research Articles

Role of TRPV channels in texture discrimination during Bactrocera dorsalis egg-laying behaviour.

Deciding where to lay an egg is critical for the survival of insects' offspring. Compared with our understanding of the chemosensory assessment of egg-laying sites, the mechanisms of texture detection are largely unknown. Here, we show that Bactrocera dorsalis, a notoriously agricultural pest laying its eggs within ripening fruits, can discriminate substrate texture during the egg-laying process. Exposure to drugs targeting transient receptor potential vanilloid (TRPV) mechanosensory channels abolished their oviposition preference for hard textures. BdorNan and BdorIav are two members of the TRPV subfamily, and their transcripts were detected in the labellum, the foreleg tarsi and the ovipositor. Then, we successfully obtained knockout strains of each gene using the CRISPR/Cas9 technique. The results showed that BdorNan is required for the discrimination of stiffness difference. BdorIav knockout had no significant effect on the ability of B. dorsalis to choose harder substrates. Our study thus reveals that BdorNan plays a substantial role in the texture assessment of egg-laying behaviour in B. dorsalis.

Morphology of arthropods discovered in pitchers of Nepenthes at Aceh Singkil District, Indonesia

Abstract. Tarigan MRM, Faisal M, Manalu K, Khairuna, Tambunan EPS, Rahmadina, Asy’ari H, Ritonga YE. 2024. Morphology of arthropods discovered in pitchers of Nepenthes at Aceh Singkil District, Indonesia. Biodiversitas 25: 2888-2900. Nepenthes plants create unique microhabitats and are home to diverse arthropod communities. These plants, known for their complex and specialized structures, attract various species of arthropods and contribute to the region's biodiversity. The study of arthropod morphology is critical to understanding the complex interactions within these microhabitats as well as broader ecosystem dynamics. Although this plant has great ecological importance and conservation significance, detailed morphological studies of the arthropods living on it are still rare. This study aimed to identify the families of arthropods trapped in the upper and lower pitchers of Nepenthes. This study used descriptive methods to reveal the morphology of arthropods found in Nepenthes pitchers in Aceh Singkil District, Indonesia. Arthropods were obtained from the upper and lower pitchers of N. ampullaria, N. gracilis, N. mirabilis, N. rafflesiana, N. reinwardtiana, N. x hookeriana, and N. x trichocarpa. Samples were obtained through direct observations conducted between October to December 2023. The results showed the presence of arthropod families, namely Culicidae, Formicidae, Gryllidae, Calliphoridae, Coccinellidae, Curculionidae, Rhyaparochromidae, Blattellidae, Salticidae, and Araneidae. However, Culicidae and Formicidae were observed to be the most abundant and Gryllidae was observed to be the least abundant. A mutualistic symbiosis was established, in which ants used the tendrils of Nepenthes to lay eggs and collected nectar generated by the honey glands, while the egg-laying process helped in the breakdown of the pitcher. This discovery suggests that the plants provided a habitat for Culicidae and a conducive environment for Formicidae larvae. However, Araneidae, Rhyparochromidae, Salticidae, Curculionidae, and Coccinellidae are not attracted to petals and peristomes. Gryllidae and Blattellidae were present in Nepenthes pitchers as a result of their close association with the plant and UV color-trapping mechanism. The study of the morphology of arthropods found in Nepenthes pitchers has several overall implications. First, it contributes to our understanding of ecological interactions in Nepenthes plants, providing insight into predator-prey dynamics, nutrient cycling, and plant evolution. Second, it underscores the importance of Nepenthes plants as a microhabitat that supports diverse arthropod communities, and highlights the ecological role of arthropods in nutrient-poor environments. This research also informs conservation efforts, emphasizing the need to protect Nepenthes plant habitat to maintain biodiversity.

Studying the effect of the pesticides Tondexir and Emamectin benzoate on some biological aspects of the southern cowpea beetle Callosobruchus maculatus

The study aimed to evaluate the effectiveness of Tondexir and Emamectin benzoate pesticides on the southern cowpea beetle, Callosobruchus maculatus. Experiments were conducted using three different concentrations (1, 1.5, 2) ml/1 liter (distilled water) of Tondexir and Emamectin benzoate on 10 selected insects (5 males, 5 females) placed on 10 grams of treated cowpea seeds. The results showed that Tondexir effectively eliminated C. maculatus, achieving a 100% mortality rate after 5 days at a concentration of 2 mL. In contrast, the biopesticide Emamectin benzoate showed high mortality rates for adult southern cowpea beetles, reaching 100% after one day at the same concentration. This confirms the effectiveness and superiority of Emamectin benzoate compared to the control group, which did not show any fatalities. Different concentrations of pesticides had varying effects on spawning rates, with significant differences observed between the treatment and control groups. These results indicate the effect of the pesticides Tondexir and Emamectin benzoate on the egg-laying process of the Southern Cowpea beetle. The study showed that different concentrations of Tondexir and Emamectin benzoate did not lead to egg hatching, while the control group showed a high hatching rate of about 90-93%. This confirms the ability of these pesticides to combat the southern cowpea beetle. In conclusion, the study highlighted the effectiveness of Emamectin benzoate in combating the Southern Cowpea beetle, as the pesticide Emamectin benzoate showed superior results. It also greatly affected egg productivity and hampered the egg-hatching process. These results indicated the possibility of using tondexir and Emamectin benzoate as effective substances to control Callosobruchus maculaus in Cowpea crops.

Canid attacks on sea turtles along the Northeastern Brazilian Coast

Abstract The aim of the present study was to report canid attacks on sea turtles in northeastern Brazil. The study was conducted on the Sergipe-Alagoas Basin coastline between March 2010 and October 2019. Injured-stranded sea turtles or carcasses were recorded through systematic beach monitoring. The specimens were submitted for clinical or postmortem assessments, providing evidence for the identification of injuries caused by canids. In the study period, 9841 stranded sea turtles were recorded, with the diagnosis of canid attacks in 55 (0.55%) events. Lepidochelys olivacea was the species with the largest number of events (90.90%), followed by Chelonia mydas (7.27%), and Caretta caretta (1.81%). The attacked sea turtles were clinically healthy, with a good body score and no apparent diseases; most were in the reproductive stage. The injuries were mainly found on the front flippers, with considerable loss of musculature affecting the brachial plexus, with the rupture of large blood vessels, and in some cases, exposure of the humerus or oesophagus. Thus, these events hampered the reproductive cycle, limiting the egg-laying process and preventing the hatching of hundreds of new turtles. Therefore, mitigating measures should be implemented, addressing the consequences of abandoning pets and their unsupervised presence on beaches.

Ethogram and classification of the mating and egg-laying behaviour of the Southeast Asian apple snail Pilavirescens (Deshayes, 1824) (Mollusca, Gastropoda, Caenogastropoda, Ampullariidae).

The status of the indigenous Southeast Asian apple snails belonging to the genus Pila is of concern due to their fast rate of population decline, possibly as a result of multiple factors including habitat loss or disturbance and the introduction of globally-invasive apple snails, Pomacea spp. Conservation actions, including captive breeding of the native Pila species, have been suggested as urgent remedial practices, but the lack of knowledge regarding the fundamental reproductive biology of indigenous Pila spp. makes such practices difficult. In the present study, observations on the mating and egg-laying behaviour of an economic valuable apple snail native to Southeast Asia, P.virescens, were conducted using video recording to examine and describe their reproductive behaviour under a laboratory condition. A total of 15 types of mating and seven egg-laying behaviour were recorded. The mating sequence which subsequently resulted in egg laying was comprised of seven types of major sequential behaviour: mate probing, mounting, shell circling, positioning, insemination posture, sheath withdrawal and dismounting. Rejection of mating attempts by the female was frequently observed. Egg laying occurred during either day or night. A sequence of seven distinct types of behaviour were performed during oviposition: climbing, positioning, forming a temporary tube, mucous secreting, egg depositing, leaving and resting. Overall, these results provide an understanding of the egg-laying behavioural process and highlight its complexity in P.virescens. In addition, detailed ethograms of mating and egg-laying behaviour were derived. These will promote further systematic comparative studies of the reproductive behaviour of apple snails.

Functional Annotation of Some Hypothetical Genes in the Schistosoma Parasite Based on Reciprocal Best Structural-hit Relationship

Background: The Schistosoma parasite is responsible for several overlooked tropical diseases, which cause significant economic losses in livestock. This parasite is increasingly found in the central areas of the northern provinces of Iran. To generate an effective treatment, it is crucial to understand thoroughly how the parasite’s genes work. Currently, the roles of numerous genes in these parasites are unknown, so their identification and targeting of them are challenging. Conventional techniques for assigning functions to proteins depend on the similarity of their sequences. Yet, this method does not always recognize similarities between distantly related proteins. Research has shown that taking the protein’s structure in the process of predicting its function can be helpful in pinpointing proteins whose functions are not known yet. Methods: In our study, we utilized two advanced technologies, AlphaFold and Foldseek, to deduce the functions of theoretical proteins in the Schistosoma parasite. We accomplished this by contrasting the structure of Schistosoma proteins with those of Caenorhabditis elegans, a closely related model organism, using Foldseek to identify reciprocal best matches. Our research involved an in-depth examination of two specific predictions, evaluating evidence for functional resemblances, such as patterns of protein interactions and similarities in functional domains. Results: Our results indicate that one of the analyzed genes is likely involved in embryogenesis, while the other might be connected to the egg-laying process of the Schistosoma parasite. Conclusion: Function of some hypothetical proteins can be inferred bases on their structural similarities to annotated proteins, especially proteins with a low sequence similarity to annotated proteins.

Ovarian Transcriptomic Analysis of Ninghai Indigenous Chickens at Different Egg-Laying Periods.

Egg production is an essential indicator of poultry fertility. The ovary is a crucial organ involved in egg production; however, little is known about the key genes and signaling pathways involved in the whole egg-laying cycle of hens. In order to explore the mechanism of egg production at different stages of the egg-laying process, ovarian tissues from four chickens were randomly selected for transcriptome analysis at each of the three ages (145 d, 204 d, and 300 d in the early, peak, and late stages of egg laying). A total of 12 gene libraries were constructed, and a total of 8433 differential genes were identified from NH145d vs. NH204d, NH145d vs. NH300d and NH300d vs. NH204d (Ninghai 145-day-old, Ninghai 204-day-old, and Ninghai 300-day-old), with 1176, 1653 and 1868 up-regulated genes, and 621, 1955 and 1160 down-regulated genes, respectively. In each of the two comparison groups, 73, 1004, and 1030 differentially expressed genes were found to be co-expressed. We analyzed the differentially expressed genes and predicted nine genes involved in egg production regulation, including LRP8, BMP6, ZP4, COL4A1, VCAN, INHBA, LOX, PTX3, and IHH, as well as several essential egg production pathways, such as regulation adhesion molecules (CAMs), calcium signaling pathways, neuroactive ligand–receptor interaction, and cytokine–cytokine receptor interaction. Transcriptional analysis of the chicken ovary during different phases of egg-lay will provide a useful molecular basis for study of the development of the egg-laying ovary.

Research Note: Comparison on laying behavior and clutch traits among Zhedong white geese (Anser cygnoides), Sichuan white geese (Anser cygnoides), and Hungarian geese (Anser anser)

Egg laying is an important reproductive behavior of female poultry. Here, we investigated the laying behavior and clutch traits of different goose breeds, specifically, Zhedong white geese (Anser cygnoides), Sichuan white geese (Anser cygnoides) and Hungarian geese (Anser anser). A total of 108 geese in their first laying year were selected. Their laying rhythm was monitored daily by video cameras during the egg-laying period. The results showed that the prenatal behavior included nest hunting, nest site selection and nesting, as well as laying behavior included prenatal crouching, anal contraction until oviposition and postnatal resting. There were some differences in laying times among the 3 breeds. Approximately 70% of the eggs were laid between 03:00 and 12:00 in Zhedong white geese and Sichuan white geese, while the Hungarian geese laid throughout the day. Also, the clutch length and the oviposition interval differed among these 3 breeds. Their average clutch lengths were approximately 14.07, 12.14 and 19.15 days in Zhedong white geese, Sichuan white geese, and Hungarian geese, respectively. While their oviposition intervals showed 2 peaks (39 and 47 h), 3 peaks (41, 50 and 53 h), and 1 peak (46 h). Moreover, there were significant correlation between egg yield and clutch length in Zhedong white geese (r = 0.951), Sichuan white geese (r = 0.987) and Hungarian geese (r = 0.991), respectively. Taken together, the difference in laying behavior among the breeds was mainly reflected in laying time and oviposition intervals, Zhedong white geese and Sichuan white geese have egg laying time preference and short oviposition intervals, which was helpful not only to understand egg-laying process, but also to manage egg-laying geese scientifically and improve egg production.

Arthropods discovered in lower and upper pitchers of Nepenthes at Rampa-Sitahuis Hill, North Sumatra, Indonesia

Abstract. Tarigan MRM, Corebima AD, Zubaidah S, Rohman F. 2021. Arthropods discovered in lower and upper pitchers of Nepenthes at Rampa-Sitahuis Hill, North Sumatra, Indonesia. Biodiversitas 22: 5358-5366. This research aimed to identify the families of arthropods trapped in the upper and lower pitchers of Nepenthes in Rampa Sitahuis Hill Area, North Sumatra, Indonesia. This descriptive qualitative research used an experimental method of data analysis. The arthropods were obtained from the upper and lower pitchers of N. rafflesiana, N. gracilis, N. eustachya, N. ampullaria, and N. sumatrana. Consequently, ten families of arthropods, namely Culicidae, Formicidae, Araneidae, Calliphoridae, Rhyparochromidae, Salticidae, Curculionidae, Blattellidae, Coccinellidae, and Tridactylidae were identified. Culicidae and Formicidae were the most abundant arthropods trapped in Nepenthes’ lower and upper pitchers because Nepenthes functioned as a microhabitat and breeding ground for Culicidae (adult mosquitoes) and Formicidae (ant larvae). Thus, these species established a mutualistic symbiosis in which ants used the tendrils of Nepenthes to lay their eggs and collected nectar generated by the honey glands, while the egg-laying process aids in the pitcher’s breakdown process.

Transcriptome analysis reveals key genes and pathways associated with egg production in Nandan-Yao domestic chicken

BackgroundEgg production is a very important economic trait in chicken breeding, but its molecular mechanism is unclear until now. Nandan-Yao chicken (Gallus gallus domesticus) is a native breed in Guangxi province, China, which is famous for good meet quality, but with low egg production. MethodsTo explore the molecular regulation related to egg production, high egg production (HEP) and low egg production (LEP) were divided according to the total egg number at 55 weeks, and the concentration of serum sex hormones was tested to evaluate the physiological function of ovary and uterus. RNA sequencing (RNA-Seq) was used to explore the transcriptome from the ovary and uterus of Nandan-Yao chicken. ResultsThe levels of serum sex hormone showed that concentrations of estradiol (E2), follicle-stimulating hormone (FSH), and luteotropic hormone (LH) were significantly higher in HEP than those in LEP (P < 0.01), while the concentration of testosterone (T) was significantly lower in HEP (P < 0.01). RNA-Seq analysis identified 901 and 2763 differentially expressed genes (DEGs) in ovary and uterus, respectively. Enrichment analysis showed that DEGs were significantly involved in the regulation of tight junction in the ovary (P < 0.05), while in uterus, DEGs were mainly enriched in the phagosome, ECM-receptor interaction, cell adhesion molecules (CAMs), focal adhesion, cardiac muscle contraction, cytokine-cytokine receptor interaction, and the regulation of MAPK signaling pathway (P < 0.05). Protein network interaction and function analyses revealed that FN1, FGF7, SOX2 identified from the ovary, and UQCRH, COX5A, FN1 from the uterus might be key candidate genes for egg production in Nandan-Yao chicken. ConclusionsOur study provided key candidate genes and pathways involved in the egg-laying process of Nandan-Yao chicken and could help to further understand the molecular mechanisms of chicken reproduction.

Biological features of egg productivity of black African ostriches under a semi-intensive keeping

The study of egg-laying patterns and defining ways of increasing egg-laying productivity is a necessary condition for the development and increased efficiency of ostrich breeding. Therefore, some studies deal with egg productivity of ostriches of different age groups (group 1 - age 8-9 years, group 2 - age 4-5 years) for their long-term keeping under a semi-intensive system forest-steppe zone of Ukraine. The sex ratio in the families was 1: 2-3. Behavioral patterns of poultry during the breeding season are close to natural ones. Older individuals are characterized with a longer productive period (January-October) than younger ones (March-September). According to the most extended daylight hours at this time of year, the higher level of egg-laying performance is established in May and summer months. The females’ egg-laying performance analysis shows their significant individual features - 9-42 eggs were obtained from one female. It is worth mentioning that the productivity period’s duration does not continuously regulate the number of eggs. There is a high positive correlation between the duration of the egg-laying process and total egglaying performance in group 1 (r = 0.7981); in group 2 � there is no relation between these features (r = -0.0843). The variability of egg-laying cycles of ostrich females has been confirmed, and it requires further studies. According to the intensity of lying during the breeding season, there are differences between younger and older poultry groups. The first two months and the last month of egg-laying are the least productive for all. It was established that the egg weight of older females is higher compared to young ones, with a potential difference between the groups (P&gt; 0.999) and a significant level of individual variability (Cv = 1.78-8.06%). This indicates the necessity of successive work with the herd to optimize egg weight, as a significant variation in egg weight affects the duration of incubation and embryonic development of ostriches. It also leads to the elongation of the “hatch window” that causes heterogeneity of ostrich weight. New data allow characterizing the peculiarities of ostrich physiology, their ability to adapt to industrial conditions of breeding at farms located in the northern part of the forest-steppe zone of Ukrai.

Getting the Most Out of Your Zombie: Abdominal Sensors and Neural Manipulations Help Jewel Wasps Find the Roach’s Weak Spot

The parasitoid emerald jewel wasp (Ampulex compressa) subdues the American cockroach (Periplaneta americana) with a sting to the 1st thoracic ganglion, followed by a sting to the roach’s brain, causing long-term pacification. The wasp then leads the cockroach to a hole where it lays an egg on the roach middle leg before barricading the entrance and departing. Although many aspects of the wasp’s initial attack have been investigated, few studies have detailed the egg-laying process and the subsequent fate of the larvae. Here I show that larval survival depends on precise egg positioning on the cockroach by the female wasp. Ablation of sensory hairs on the wasp’s abdomen resulted in mislaid eggs, which seldom survived. In addition, the cockroach femur may block the oviposition site. The wasp contended with this challenge with a newly discovered suite of stings, 3 directed into the 2nd thoracic ganglion which resulted in extension of the femur, thus exposing the oviposition site and removing a potential barrier to the wasp’s successful reproduction. When the femur was glued in place, the wasp stung the cockroach over 100 times, in an apparent fixed action pattern triggered by the obscured oviposition target. These findings highlight the importance of proper egg placement by the wasp, and reveal sensors and new neural manipulations that facilitate the process.

Identification of differentially expressed genes associated with egg production in black-boned chicken

ABSTRACT 1. Muchuan black-bone chicken is well known in China for its meat quality and medicinal properties; however, its egg-laying performance is not ideal. To better understand the molecular mechanisms of black-boned chicken egg-laying, high-throughput RNA sequencing was performed to compare differences in the pituitary transcriptome between three high-rate (group H) and three low-rate (group L) egg production chickens. 2. In total, 171 differentially expressed genes (DEGs) were identified between the two groups, of which 113 were upregulated and 58 were downregulated in group L. Some of these genes are known to be related to hormone secretion or the regulation of reproductive processes; these include prolactin-releasing hormone (PRLH), distal-less homeobox 6 (DLX6), interferon regulatory factor 4 (IRF4), and cilia and flagella associated protein 69 (CFAP69). Notably, expression pattern analysis indicated that both PRLH and DLX6 may influence egg-laying performance. 3. The dataset provided a foundation for discovering important genes and pathways involved in the chicken egg-laying process, and may help to improve understanding of the molecular mechanisms of chicken reproduction.

Halogenated organic compounds in the eggs of aquatic birds from the Gulf of Gdansk and Wloclawek Dam (Poland)

Diet is the major route of exposure to environmental contaminants in biota and, after penetration into an organism, xenobiotics continue to accumulate in the body. In birds the egg-laying process acts as a transfer mechanism for the accumulated pollutants and results in the burdening of the next generation at an early stage of development. This transfer has a strong influence on developmental disorders and even breeding success. With this in mind polybrominated diphenyl ethers (PBDE), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans (PCDD/Fs), as well as polychlorinated biphenyls (PCBs), were analyzed in the eggs of aquatic birds from different habitats and with different diet preferences. The highest concentration of PBDE was noted in gull eggs (198.31 ng g−1 dw.) and the lowest in tern eggs (sandwich tern: 76.96 ng g−1 dw.; common tern: 113.73 ng g−1 dw). Deca-BDE was detected only in herring gull eggs from the Wloclawek reservoir. PCDDF/s were found in the eggs of terns from the southern coast of the Baltic Sea and gulls from an inland reservoir (dam) on the River Vistula close to the town of Wloclawek. The highest toxicity (birds Toxic Equivalent Factor) was found in the eggs of terns (sandwich tern – 93.97 pg g−1 dw., common tern – 68.35 pg g−1 dw.), and this was found to be several times higher than in herring gull eggs (18.80 pg g−1 dw.). Non-dioxin like PCBs were ten times higher than other analyzed PCB congeners, but the congener pattern was similar to other studies.

Egg-laying job makes males hot: body temperature measurements in egg-laying tandems of the dragonfly Sympetrum vulgatum using IR camera

Tandem oviposition, where males guide females in contact, requires quite a substantial muscle activity from males and, therefore, stronger heat production within the male thorax compared to the female thorax. In the present study, an infrared camera equipped with a macrolens was applied in the field, in order to estimate temperature in different body regions of male and female dragonflies Sympetrum vulgatum laying eggs in tandems. In both sexes, the thorax was considerably warmer than other body parts. The male thorax was on average 3-4°C warmer than that of the female. These observations support previous data that Sympetrum males have a stronger muscular activity and heat production in tandem during the egg-laying process compared to females. The data provide additional evidence that this kind of contact guarding behavior during oviposition is rather costly for males. The tip of the male abdomen was much warmer than its own abdomen in the middle region. This result might be explained by possible heat transfer from the female head to the male abdomen through the contact between male abdominal appendages and the female head. An alternative explanation might be strong activity of the muscles controlling male anal appendages. Finally, this study also demonstrated a strong potential of IR cameras in field studies of dragonfly behavioral physiology.

Modeling of a negative feedback mechanism explains antagonistic pleiotropy in reproduction in domesticated Caenorhabditis elegans strains.

Most biological traits and common diseases have a strong but complex genetic basis, controlled by large numbers of genetic variants with small contributions to a trait or disease risk. The effect-size of most genetic variants is not absolute and is instead dependent upon multiple factors such as the age and genetic background of an organism. In order to understand the mechanistic basis of these changes, we characterized heritable trait differences between two domesticated strains of C. elegans. We previously identified a major effect locus, caused in part by a mutation in a component of the NURF chromatin remodeling complex, that regulates reproductive output in an age-dependent manner. The effect-size of this locus changes from positive to negative over the course of an animal’s reproductive lifespan. Here, we use a previously published macroscale model of the egg-laying rate in C. elegans to show that time-dependent effect-size is explained by an unequal use of sperm combined with negative feedback between sperm and ovulation rate. We validate key predictions of this model with controlled mating experiments and quantification of oogenesis and sperm use. Incorporation of this model into QTL mapping allows us to identify and partition new QTLs into specific aspects of the egg-laying process. Finally, we show how epistasis between two genetic variants is predicted by this modeling as a consequence of the unequal use of sperm. This work demonstrates how modeling of multicellular communication systems can improve our ability to predict and understand the role of genetic variation on a complex phenotype. Negative autoregulatory feedback loops, common in transcriptional regulation, could play an important role in modifying genetic architecture in other traits.

High-throughput sequencing of pituitary and hypothalamic microRNA transcriptome associated with high rate of egg production

BackgroundMicroRNAs exist widely in viruses, plants and animals. As endogenous small non-coding RNAs, miRNAs regulate a variety of biological processes. Tissue miRNA expression studies have discovered numerous functions for miRNAs in various tissues of chicken, but the regulation of miRNAs in chicken pituitary and hypothalamic development related to high and low egg-laying performance has remained unclear.ResultsIn this study, using high-throughput sequencing technology, we sequenced two tissues (pituitary and hypothalamus) in 3 high- and 3 low-rate egg production Luhua chickens at the age of 300 days. By comparing low- and high-rate egg production chickens, 46 known miRNAs and 27 novel miRNAs were identified as differentially expressed (P < 0.05). Six differentially expressed known miRNAs, which are expressed in both tissues, were used in RT-qPCR validation and SNP detection. Among them, seven SNPs in two miRNA precursors (gga-miR-1684a and gga-miR-1434) were found that might enhance or reduce the production of the mature miRNAs. In addition, 124 and 30 reciprocally expressed miRNA-target pairs were identified by RNA-seq in pituitary and hypothalamic tissues, respectively and randomly selected candidate miRNA and miRNA-target pairs were validated by RT-qPCR in Jiuyuan black fowl. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation illustrated that a large number of egg laying-related pathways were enriched in the high-rate egg production chickens, including ovarian steroidogenesis and steroid hormone biosynthesis.ConclusionsThese differentially expressed miRNAs and their predicted target genes, especially identified reciprocally expressed miRNA-target pairs, advance the study of miRNA function and egg production associated miRNA identification. The analysis of the miRNA-related SNPs and their effects provided insights into the effects of SNPs on miRNA biogenesis and function. The data generated in this study will further our understanding of miRNA regulation mechanisms in the chicken egg-laying process.

Comparative study of the morphology of the female seminal receptacles of Ilia nucleus and Persephona mediterranea (Decapoda, Brachyura, Leucosiidae)

Because of the poor knowledge of the morphology of the female reproductive organs of most brachyuran crabs, this study investigated two Atlantic representatives of the family Leucosiidae, Ilia nucleus (Linnaeus, 1758) and Persephona mediterranea (Herbst, 1794), using histological methods and magnetic resonance imaging (MRI). While the vagina conforms to the concave type, the arrangement of the two chambers of the seminal receptacle differs strongly from that of other eubrachyuran sperm storage organs. Both chambers are oriented laterally within the crab's body. This is in contrast to the dorso-ventral orientation described in most other known brachyuran crabs. The lateral chamber is covered by cuticle, whereas the medial chamber is covered by a holocrine glandular epithelium. The oviduct connection is located ventrally, posterior to the vagina. The oviduct orifice is characterized by a transition from the epithelium lining the oviduct to the seminal receptacle's holocrine glandular epithelium. Moreover, muscle fibres are attached to the oviduct orifice and to the sternal cuticle. This musculature can be interpreted as an important feature in the fertilization and egg-laying process by supporting and controlling the inflow of eggs into the seminal receptacle lumen. The results of this study are compared to the morphology of the seminal receptacle of another leucosiid crab, Ebalia tumefacta (Montagu, 1808), and to those of other known eubrachyuran crabs.

Neuropeptidome of the Cephalopod Sepia officinalis: Identification, Tissue Mapping, and Expression Pattern of Neuropeptides and Neurohormones during Egg Laying.

Cephalopods exhibit a wide variety of behaviors such as prey capture, communication, camouflage, and reproduction thanks to a complex central nervous system (CNS) divided into several functional lobes that express a wide range of neuropeptides involved in the modulation of behaviors and physiological mechanisms associated with the main stages of their life cycle. This work focuses on the neuropeptidome expressed during egg-laying through de novo construction of the CNS transcriptome using an RNAseq approach (Illumina sequencing). Then, we completed the in silico analysis of the transcriptome by characterizing and tissue-mapping neuropeptides by mass spectrometry. To identify neuropeptides involved in the egg-laying process, we determined (1) the neuropeptide contents of the neurohemal area, hemolymph (blood), and nerve endings in mature females and (2) the expression levels of these peptides. Among the 38 neuropeptide families identified from 55 transcripts, 30 were described for the first time in Sepia officinalis, 5 were described for the first time in the animal kingdom, and 14 were strongly overexpressed in egg-laying females as compared with mature males. Mass spectrometry screening of hemolymph and nerve ending contents allowed us to clarify the status of many neuropeptides, that is, to determine whether they were neuromodulators or neurohormones.

Morphology and function of the female reproductive system of Ebalia tumefacta (Decapoda, Brachyura, Leucosiidae).

In this article, the morphology and function of the female reproductive organs of Ebalia tumefacta were investigated using histological methods. While the vagina conforms to the concave type, the study reveals a new orientation of seminal receptacle compartments. The seminal receptacle consists of two chambers, which are oriented in anterior-posterior direction. This is in contrast to the dorso-ventral orientation of seminal receptacle chambers in all other known brachyuran crabs. The anterior chamber is lined by cuticle, whereas the posterior chamber is covered with a holocrine glandular epithelium. The oviduct connection is located ventrally, close to the opening of the vagina. The oviduct orifice is characterized by a transition of the epithelium lining of the oviduct to the seminal receptacle holocrine glandular epithelium. Special features are muscle fibers, which are attached to the oviduct orifice and to the sternal cuticle as well. The muscle fibers can be found exactly at that point where the oviduct opens into the seminal receptacle and are secondly attached to the sternum beneath. This musculature is newly described for Eubrachyuran crabs. This musculature can be interpreted as an important feature in the fertilization and egg-laying process in relation to supporting and controling the inflow of eggs into the seminal receptacle lumen. These new discoveries were compared to the known pattern of an Eubrachyuran seminal receptacle.