Search Results (41)

Root-lesion nematodes of the genus Pratylenchus are among the most economically significant plant-parasitic nematodes worldwide. During nematological surveys conducted in natural and agricultural ecosystems in California, several known species, P. bolivianus, P. hippeastri, P. pinguicaudatus, P. scribneri, P. thornei, and P. vulnus, as well as two undescribed species, P. chizhovi sp. n. and P. gracilis sp. n., were recovered. Pratylenchus chizhovi sp. n. is characterized by a slightly offset lip region with three annuli narrowing anteriorly, a short stylet (14.5–17.0 µm) with rounded knobs, a lateral field with four incisures, a spherical spermatheca lacking sperm, a vulva with somewhat prominent lips, a subcylindrical tail with a truncate-rounded, smooth terminus, and unknown males. Pratylenchus gracilis sp. n. is characterized by a lip region offset with three annuli narrowing anteriorly, a short stylet (15–18 µm) with rounded knobs, a lateral field with four incisures, an oval to rounded spermatheca containing some sperm cells, a vulva with somewhat prominent lips, a subcylindrical tail with a rounded, smooth terminus, and males present. Phylogenetic relationships of California Pratylenchus species and other members of the genus were inferred using 18S rRNA, D2–D3 of 28S rRNA, and the mitochondrial COI gene sequences. This study provides an updated assessment of Pratylenchus species diversity in California, highlighting both previously described taxa and newly discovered species. Full article

In honeybees (Apis mellifera L.), the queen ensures the reproduction of the colony. Environmental contamination that could alter this function could compromise the survival of the colony. Ionizing radiation could be such a factor, but its effects have never been studied in queens. The effects of gamma irradiation on queen bees were evaluated under laboratory conditions. The queens were irradiated for 14 days at dose rates of 0.1, 13, and 3500 µGy/h, and mortality, reproductive potential, and several physiological biomarkers were investigated. Irradiation did not affect the survival of the queens or the number of sperm stored in the spermatheca. However, sperm viability and reproductive potential decreased significantly at 13 and 3500 µGy/h. Among the biomarkers analyzed (antioxidant defenses, detoxification, metabolism, immunity, neural activity), no significant differences were observed between the modalities, with the exception of an increase in thoracic LDH activity at 13 µGy/h, confirmed by multivariate analyses indicating metabolic changes. These results show that ionizing radiation does not induce lethality at the tested dose rates, but significantly impaired fertility and metabolism of queen bees, with potential consequences for colony stability, whose ecological significance remains to be confirmed under field conditions. Full article

The development of males and females of the cephalopod Amphioctopus fangsiao is asynchronous. The male produces sperm after maturity for storage in a spermatophore prior to mating. After mating, the sperm enter the female spermatheca for storage until ovulation occurs, a period that lasts for 8 months. This is a biologically uncommon phenomenon because sperm cells generally fail to maintain their ability to fertilize for a long time after being ejaculated. However, the molecular mechanisms of this phenomenon are still not clear. Sperm cells are stored in the male spermatophore and the female spermatheca, each of which provides a suitable environment. To determine the molecular basis of the sperm storage mechanisms in A. fangsiao, protein profiles from spermathecal fluid and seminal plasma were characterized separately using mass spectrometry-based proteomics. The antioxidant enzymes superoxide dismutase (SOD), glutathione S-transferase (GST), and Thioredoxin (Trx), and the glycolytic enzymes lactate dehydrogenase (LDH), hexokinase (HK), pyruvate dehydrogenase kinase (PDK), and ATP synthase were significantly enriched in the spermathecal fluid. Catalase (CAT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), triosephosphate isomerase (TIM), phosphoglycerate kinase (PGK), and Chitinase were significantly enriched in the seminal plasma. The antimicrobial proteins transforming growth factor beta regulator 1 (TBRG1) and interleukin enhancer binding factor 2 (ILF2) and the extracellular matrix-related proteins transforming growth factor beta induced protein (TGFBIp) and thrombospondin type-1 domain-containing protein 4 (THSD4) were also significantly expressed in the spermathecal fluid. These proteins may be crucial for successful long-term sperm storage. We measured the activities of four antioxidant enzymes based on the proteomic results, supporting the antioxidant mechanism during the sperm storage process. This study enhances our understanding of the sperm storage ability of A. fangsiao. Full article

In a survey of Bajiaozhai National Forest Park (Guilin, China), several specimens of an Euseius sp. were collected. These specimens were very similar to Euseius nicholsi and Euseius oolong, based on morphological observations. However, some morphological characters, such as the body size, number of solenostomes on the dorsal plate, calyx shape of the spermatheca, the shape and number of metapodal platelet, teeth number on the fixed digit, length of setae j3, and macroseta Seg IV, Sti IV, and St IV were different between these specimens and E. nicholsi and E. oolong. To ascertain whether these morphological differences were interspecific or intraspecific variations, molecular analyses were conducted using mitochondrial DNA COI, 12S rRNA, and nuclear ITS markers. Based on the three molecular markers, minimal genetic distances were observed (COI 0–4%, 12S rRNA 0–2%, and ITS 0%) among the putative Euseius sp., E. nicholsi (collected from Bauhinia purpurea in IZGAS and from Eurya macartneyi and Ficus hispida in Shaoguan City), and E. oolong (collected from B. purpurea in IZGAS). Amblyseius swirskii was used as the outgroup. Using the maximum likelihood method, the phylogenetic tree showed that these specimens of Euseius sp., E. nicholsi, and E. oolong clustered in a single clade. Therefore, we propose that this putative Euseius sp. is E. nicholsi, and E. oolong is a junior synonym of E. nicholsi. This study demonstrates the importance of integrative taxonomy for the proper identification of phytoseiid mites. Full article

In most mosquito species, reproduction requires mating between the female and the male, followed by the female blood-feeding, completing oogenesis, and laying eggs. Warmer environmental temperature and aging both reduce mosquito fecundity and fertility, and warmer temperature accelerates the aging-dependent decline in reproduction such that reproductive impairment manifests earlier in life. To shed light on how this warming-based acceleration of reproductive senescence occurs, we investigated how temperature (27 °C, 30 °C, and 32 °C) and aging interactively shape female and male reproductive tissue size in the African malaria mosquito, Anopheles gambiae. In blood-fed females, we discovered that warmer temperature accelerates the aging-dependent decrease in the size of the ovaries but not the spermatheca. In males, we discovered that warmer temperature lessens and delays the aging-dependent increase in the size of the male accessory glands but not the testes. Next, we measured the expression of reproductive genes in females and males. In female reproductive tissues, warmer temperature accelerates the aging-dependent decrease in the expression of vitellogenin and the aging-dependent increase in the expression of MISO and HPX15. In male reproductive tissues, warmer temperature accelerates an aging-dependent decrease in the expression of Plugin, TGase3, phLP, and CYP315A1. Altogether, these data shed light on how physical and transcriptional changes underpin the warming-based acceleration of an aging-dependent decline in mosquito fecundity and fertility. Full article

To solve the technical bottleneck caused by the absence of a feasible method for removing the spermatheca in social insects, we developed a microsurgical technique specifically designed for bumblebee females. In this study, the invention of this technique is based on the anatomical characteristics of the sting chamber of bumblebees and uses a bespoke scalpel to precisely remove the spermatheca, which is small in size and deeply embedded within the body. During the removal operation, a small wound was observed and a small amount of hemolymph flowed out. The wound healed very quickly and the survival rate of treated individuals was high. The results showed that there was no significant impact on the critical life activities of queens and workers, including longevity, mating behavior, oviposition capacity, and overwintering survival rate after the spermatheca was removed using this technique. These findings further confirm the feasibility and applicability of the technique and provide strong technical support for exploring the evolutionary dynamics and potential function of the spermatheca in social insects. Full article

Hermetia illucens L. (Diptera: Stratiomyidae), a well-known decomposer of organic wastes, is widely applied to treat food, livestock, and poultry wastes to reduce environmental pollution. It is also used to produce high-protein feed, organic fertilizers, and biomedicine as well as biodiesel. The development of the endo-reproductive system in insects plays a crucial role in their reproduction, which is key in economic insect culture. In this study, we investigate the developmental process of the endo-reproductive system and the effect of mating status on the development of the female reproductive system in adult H. illucens. The results show that the morphological characteristics of the internal reproductive system of adult H. illucens differed with age and mating status. Males exhibited a higher testicular dimension at 2–5 days old, with testicular length and width reaching their maximum at 3 days old, displaying significant differences across ages (p < 0.05). The developmental period of the ovaries varied with time and was classified into five distinct stages. The morphological characteristics of the endo-reproductive system of adult females at different mating status showed differences. The spermatheca of the unmated female was translucent, while that of the mated female exhibited cloudiness and became lighter in color with age. The length and width of the spermatheca of the mated female were larger than that of unmated females (p < 0.05). However, the length and width of the spermathecae of the mated and unmated females reached their maximum at 5 days old. Mating status affected the development of eggs; mated females oviposited matured eggs at 5 days old, while unmated females oviposited matured eggs at 9 days old. The results suggest that mating status can promote the development of eggs in H. illucens. Additionally, the maturity level or mating status can be determined based on the morphology of the endo-reproductive system and its contents. Full article

The male annihilation technique (MAT) plays a crucial role in the pest management program of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). However, a suitable method for real-time and accurate assessment of MAT’s control efficiency has not been established. Laboratory investigations found that motile sperms can be observed clearly under the microscope when the spermathecae dissected from mated females were torn, and no sperms were found in the spermathecae of virgin females. Furthermore, it was confirmed that sperms can be preserved in the spermathecae for more than 50 days once females have mated. Laboratory results also indicated that proportion of mated females decreased from 100% to 2% when the sex ratio (♀:♂) was increased from 1:1 to 100:1. Further observation revealed that there were no significant differences in the superficial area of the ovary or spermatheca between mated females and virgin females. Field investigations revealed that the proportion of mated females (PMF) could reach 81.2% in abandoned mango orchards, whereas the PMF was less than 36.4% in mango orchards where MAT was applied. This indicates that the PMF of the field population can be determined by examining the presence of sperms in the spermathecae. Therefore, we suggest that this method can be used to monitor the control efficiency when MAT is used in the field. Full article

The key to success in the application of the sterile insect technique (SIT) relies on the ability of released, sterile males to outcompete their fertile wild male counterparts to mate with wild females. However, many insect species exhibit multiple-mating behavior, which can be a way for females to select paternity for their progeny. This study aims to recognize the consequences of potential double-matings during an SIT program and to detect any evidence of sperm selection favoring sperm from fertile mates. This report provides a descriptive analysis of the storage and use of sperm by female Aedes albopictus. Stable isotopes were used to mark the sperm of fertile and sterile males. Mated females were allowed to oviposit before dissecting the spermathecae to link the presence of each type of sperm to the sterility of the eggs laid. It was found that sperm in females inseminated by both males was distributed in the three spermathecae with no obvious pattern, mostly mixed but also separately, and no evidence of any mechanism for sperm selection, sperm precedence, or sperm competition in Ae. albopictus females could be found. The fact that only a few double-mated females were double-inseminated and could also produce semi-sterile eggs, together with the finding that the sperm of sterile males appeared to be no less viable than that of fertile males, is an encouraging outcome for SIT approaches. Full article

This study investigates the role of lysosomal acid lipase (LIPA) in sex hormone regulation and gonadal development in Macrobrachium nipponense. The full-length Mn-LIPA cDNA was cloned, and its expression patterns were analyzed using quantitative real-time PCR (qPCR) in various tissues and developmental stages. Higher expression levels were observed in the hepatopancreas, cerebral ganglion, and testes, indicating the potential involvement of Mn-LIPA in sex differentiation and gonadal development. In situ hybridization experiments revealed strong Mn-LIPA signaling in the spermatheca and hepatopancreas, suggesting their potential role in steroid synthesis (such as cholesterol, fatty acids, cholesteryl ester, and triglycerides) and sperm maturation. Increased expression levels of male-specific genes, such as insulin-like androgenic gland hormone (IAG), sperm gelatinase (SG), and mab-3-related transcription factor (Dmrt11E), were observed after dsMn-LIPA (double-stranded LIPA) injection, and significant inhibition of sperm development and maturation was observed histologically. Additionally, the relationship between Mn-LIPA and sex-related genes (IAG, SG, and Dmrt11E) and hormones (17β-estradiol and 17α-methyltestosterone) was explored by administering sex hormones to male prawns, indicating that Mn-LIPA does not directly control the production of sex hormones but rather utilizes the property of hydrolyzing triglycerides and cholesterol to provide energy while influencing the synthesis and secretion of self-sex hormones. These findings provide valuable insights into the function of Mn-LIPA in M. nipponense and its potential implications for understanding sex differentiation and gonadal development in crustaceans. It provides an important theoretical basis for the realization of a monosex culture of M. nipponense. Full article

The endangered terrestrial firefly Pyrocoelia pectoralis (Olivier) is endemic to China. Populations of P. pectoralis have decreased dramatically due to urbanization and pollution. Breeding and re-introduction to a suitable habitat may save the species from becoming extinct. Because of its polyandrous character, an investigation into the possibility of sperm competition and paternity outcomes from multiple matings was initiated to better understand its reproductive physiology. To achieve these goals, 13 SSR markers were developed. The results of paternity experiments indicate there is a significant difference between P3 and P1 or P2. The female reproductive system has three spermathecae which accept sperm from different matings, and no bursa or spermatophore-digesting organ is developed. Our research established that multiple inseminations with sperm from different males occur, leading to competition between ejaculates. The benefits of such competition include an increasing number of sperm in the ejaculates of competing males and the consequential increase in fertilized eggs (thus, fecundity), and thereby a higher chance of genetic diversity and fitness in the offspring of the firefly P. pectoralis. Full article

This taxonomic study investigates marine tubificids, with a focus on the genera Smithsonidrilus, Heterodrilus, Limnodriloides, and Tubificoides and presenting a new species, Heterodrilus koreanus n. sp., discovered in the around Ulleungdo and Dokdo Islands in the East Sea of the Republic of Korea. The new species, Heterodrilus koreanus n. sp., is characterized by a very long and slender atrium with prostate glands attached to the ventral side, with indistinct ducts and large round ampullae in the spermathecae. The four recorded species are: H. pentcheffi Erséus, 1981, Limnodriloides anxius Erséus, 1990, Smithsonidrilus exspectatus Erséus, 1993, and Tubificoides heterochaetus Michaelsen, 1926. This study not only enhances our comprehension of the intricate morphology within these genera but also contributes to the broader understanding of marine oligochaetes, particularly in the Korean marine ecosystem. Full article

The cryopreservation of gametes and embryos is an important element of biodiversity conservation. One species in need of conservation is the honey bee Apis mellifera L. Changing environmental factors, especially the anthropogenic factor, have led to a reduction in the numbers of this insect species. In this study, we provide an example of the creation of a biobank of honey bee drone sperm. For sperm cryopreservation, drones of the most common subspecies of honey bees common in Russia were selected. These were the dark forest bee, Apis mellifera mellifera, from the Republic of Bashkortostan, with three subspecies (A. m. carnica, A. m. carpatica, and A. m. caucasica) from the southern regions of Russia, as well as two breeding stocks, the Far Eastern bee and Prioksky bee. For subspecies identification, morphometric and genetic methods were used. The subspecies of the studied samples were confirmed via the analysis of the tRNAleu-COII locus of mitochondrial DNA and nine microsatellite markers of nuclear DNA. It was shown that bees of the Prioksky breeding stock belong to the subspecies A. m. caucasica based on phylogenetic analysis, and the Far Eastern breeding stock is a stable hybrid, descending on the maternal line from the evolutionary lineage C or O. The results of the morphometric analysis are consistent with the results of the genetic analysis. For the cryopreservation of sperm, we used a cryoprotectant solution with honey. As a result, the viability of frozen–thawed sperm decreased by 20.3% compared to fresh sperm, and overall motility decreased 25-fold. The measurement of the sperm concentration in the spermatheca of artificially inseminated queens showed that it varied from 0.22 to 4.4 million/μL. Therefore, the use of honey in sperm cryopreservation has great potential. Full article

This study investigated the potential to use double-stranded RNA insulin-like androgenic gland hormone (dsIAG) to induce sex reversal in Macrobrachium nipponense and identified the molecular mechanisms underlying crustacean reproduction and sex differentiation. The study aimed to determine whether dsIAG could induce sex reversal in PL30-male M. nipponense during a critical period. The sex-related genes were selected by performing the gonadal transcriptome analysis of normal male (dsM), normal female (dsFM), neo-female sex-reversed individuals (dsRM), and unreversed males (dsNRM). After six injections, the experiment finally resulted in a 20% production of dsRM. Histologically, dsRM ovaries developed slower than dsFM, but dsNRM spermathecae developed normally. A total of 1718, 1069, and 255 differentially expressed genes were identified through transcriptome sequencing of the gonads in three comparison groups, revealing crucial genes related to reproduction and sex differentiation, such as GnRHR, VGR, SG, and LWS. Principal Component Analysis (PCA) also distinguished dsM and dsRM very well. In addition, this study predicted that the eyestalks and the “phototransduction-fly” photoperiodic pathways of M. nipponense could play an important role in sex reversal. The enrichment of related pathways and growth traits in dsNRM were combined to establish that IAG played a significant role in reproduction, growth regulation, and metabolism. Finally, complete sex reversal may depend on specific stimuli at critical periods. Overall, this study provides valuable findings for the IAG regulation of sex differentiation, reproduction, and growth of M. nipponense in establishing a monoculture. Full article

Naidids are tiny, transparent freshwater oligochaetes, which are well known for their ability to propagate asexually. Despite the fact that sexually mature individuals and cocoons with embryos are sometimes found in nature, in long-period laboratory cultures, worms reproduce agametically only. In this paper, we showed, for the first time, the expression of Vasa, Piwi, and Pl10 homologs in mature Pristina longiseta worms with well-developed reproductive system structures and germ cells. Although the animals have been propagated asexually by paratomic fission for over 20 years in our lab, some individuals become sexualized under standard conditions for our laboratory culture and demonstrate various stages of maturation. The fully matured animals developed a complete set of sexual apparatus including spermatheca, atrium, seminal vesicles, and ovisac. They also had a clitellum and were able to form cocoons. The cues for the initiation of sexual maturation are still unknown for P. longiseta; nevertheless, our data suggest that the laboratory strain of P. longiseta maintains the ability to become fully sexually mature and to establish germline products even after a long period of agametic reproduction. On the other hand, many of the sexualized worms formed a fission zone and continued to reproduce asexually. Thus, in this species, the processes of asexual reproduction and sexual maturation do not preclude each other, and Vasa, Piwi, and Pl10 homologs are expressed in both somatic and germline tissue including the posterior growth zone, fission zone, nervous system, germline cells, and gametes. Full article