Search Results (189)

Honeybees (Apis mellifera) are pollinators for most crops in nature and a core species for the production of bee products. Body size and body weight are crucial breeding traits, as colonies possessing individuals with large body weight tend to be healthier and exhibit high productivity. In this study, small interfering RNA (siRNA) targeting 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) was incorporated into the feed for feeding worker bee larvae, thereby achieving the silencing of this gene’s expression. The research further analyzed the impact of the RNA expression level of the 15-PGDH gene on the juvenile hormone (JH) titer and its subsequent effects on the body weight and size of worker bees. The results show that inhibiting the expression of 15-PGDH in larvae could significantly increase JH titer, which in turn led to an increase in the body weight of worker bees (1.13-fold higher than that of the control group reared under normal conditions (CK group); p < 0.01; SE: 7.85) and a significant extension in femur (1.08-fold longer than that of the CK group; p < 0.01; SE: 0.18). This study confirms that 15-PGDH can serve as a molecular marker related to body weight and size in honey bees, providing an important basis for molecular marker-assisted selection in honey bee breeding. Full article

The fall armyworm (FAW), Spodoptera frugiperda, is a highly polyphagous pest posing a major threat to Poaceae crops, particularly corn (Zea mays), in China. However, its ability to adapt to Job’s tears (Coix lacryma-jobi), an edible and medicinal Poaceae species, under continuous rearing remains insufficiently understood. In this study, FAW survival, development, and reproduction were assessed over eight generations on two cultivars of Job’s tears, ‘Cuiyi 1’ and ‘Puyi 6’. Feeding and oviposition preferences were also examined in FAW populations reared on ‘Puyi 6’ by offering corn and ‘Puyi 6’ as hosts. Sustained rearing for five to eight generations on both cultivars significantly increased population fitness, with greater improvements observed in the ‘Puyi 6’ group. FAW reared on corn or ‘Puyi 6’ for two generations exhibited strong preferences for corn, whereas those reared on ‘Puyi 6’ for five to eight generations showed no significant host preference. These findings suggest that transgenerational adaptation markedly improved FAW performance and acceptance of Job’s tears, underscoring the need for intensified monitoring of FAW dynamics during the cultivation of Job’s tears. Full article

Tetranychus urticae, commonly known as the two-spotted spider mite, is a highly adaptable and polyphagous arthropod in the family Tetranychidae, capable of feeding on over 1200 plant species, including strawberries (Fragaria × ananassa Duch.). The fitness and microbiota of herbivorous arthropods can vary significantly across different plant species and cultivars. In this study, we investigated the fecundity, longevity, growth rate, and microbiota composition of T. urticae reared on seven Chinese strawberry cultivars: Hongyan (HY), Yuexiu (YX), Tianshi (TS), Ningyu (NY), Xuetu (XT), Zhangjj (ZJ), and Xuelixiang (XLX). Our findings revealed significant differences among cultivars: mites reared on the XT cultivar exhibited the highest fecundity (166.56 ± 7.82 eggs), while those on XLX had the shortest pre-adult period (7.71 ± 0.13 days). Longevity was significantly extended in mites reared on XLX, XT, and NY cultivars (25.95–26.83 days). Microbiota analysis via 16S rRNA sequencing showed that Proteobacteria dominated (>89.96% abundance) across all mite groups, with Wolbachia as the predominant symbiont (89.58–99.19%). Male mites exhibited higher bacterial diversity (Shannon and Chao1 indices) than females, though Wolbachia abundance did not differ significantly between sexes or cultivars. Functional predictions highlighted roles of microbiota in biosynthesis, detoxification, and energy metabolism. These findings underscore the influence of host plant variety on T. urticae fitness and microbiota composition, suggesting potential strategies for breeding resistant strawberry cultivars and leveraging microbial interactions for pest management. Full article

The consumption and farming of insects are gaining global attention as sustainable alternatives to conventional protein sources. Industrial processing of insects into powders or pastes complicates species identification, raising concerns about product authenticity, food safety, and potential fraud. In Western countries, particularly in Europe, the sector is expanding under a stringent regulatory framework, especially regarding rearing substrates, which hinders economic development. This study aimed to assess the species authenticity of commercial insect-based food and feed products and detect the presence of animal-derived DNA from unauthorized substrates. A total of 119 samples (pure insect meals and processed products) were collected from various origins. Species-specific real-time PCR assays targeted Tenebrio molitor, Hermetia illucens, Alphitobius diaperinus, Acheta domesticus, Bombyx mori, and Gryllodes sigillatus, alongside assays for ruminant, porcine, and poultry DNA. High-throughput sequencing (HTS) using metabarcoding confirmed and broadened species detection. Most samples contained the declared species; however, cases of mislabeling, substitution, and cross-contamination were observed. A few insect meals contained animal DNA which could suggest potential use of prohibited substrates. These findings highlight the urgent need for standardized authentication methods and improved transparency to ensure regulatory compliance, consumer trust, and sustainable development of the insect-based sector. Full article

This study investigated the effects of feeding striped beakfish (Oplegnathus fasciatus) newly hatched larvae on the survival and growth of kawakawa (Euthynnus affinis) larvae and juveniles, as well as their relative growth patterns. Fertilized eggs of kawakawa were reared in 1 m³ experimental tanks until 13 days post-hatch (dph). From 3 to 8 dph, larvae were fed enriched rotifers, and from 9 to 12 dph, they were assigned to two experimental groups: one receiving only a formulated diet and the other receiving a combination of the formulated diet and 10,000 striped beakfish newly hatched larvae every day in each tank. The group fed newly hatched larvae exhibited approximately 36% greater growth than the group fed only the formulated diet. However, survival at 13 dph was approximately 34% lower, suggesting that further investigation is needed to determine the optimal feeding quantity of newly hatched larvae. The relative growth patterns of larvae and juveniles reared in a commercial 30 m³ tank showed morphological traits characteristic of scombrid fish, such as a longer preanal length and upper jaw length. Growth patterns varied at three key body lengths (notochord length or standard length; 3, 8–10, and 30 mm), as well as at their corresponding standard lengths. In kawakawa, the upper jaw exhibited early accelerated growth compared to other scombrid species. This characteristic is believed to facilitate the early onset of piscivory under captive conditions. Full article

Plant–herbivore–parasitoid systems are poorly studied in the tropics. Enicospilus carmenae Campos and Palacio sp. nov. are described, originating from southern Mexico in the Yucatan Peninsula and establishing a new tri-trophic interaction. This species is a koinobiont larval endoparasitoid of the American silkworm moth caterpillar Zanola verago (Cramer) (Lepidoptera: Apatelodidae) feeding on the shrub Piper neesianum C.DC. (Piperaceae) in a semi-evergreen forest. The host plant P. neesianum had no herbivore records to date, and a single collection event yielded the rearing of a new species of Enicospilus (Ichneumonidae, Ophioninae). Morphological, molecular (COI), biological, ecological, and geographical data are integrated to delineate the new species. Full article

Current feeding protocols used in commercial hatcheries of Mediterranean fish species are, for a species-dependent period after hatching, based on live feeds which have often raised issues of biosecurity, stability, availability, price and nutrients content. Instead, dry feeds can offer stability in nutritional value, price and supply. The aim of the present study was to evaluate an alternative feeding protocol by co-feeding live and dry feed at first feeding red seabream larvae (on 3 days post-hatching—3 dph, DF3) and to compare it to a standard feeding protocol (i.e., dry feed introduced on 22 dph, DF22). Larvae productivity and functional development of the digestive system were evaluated under actual production conditions in a commercial hatchery. Additionally, post-larvae efficiency during pre-growing was evaluated under controlled laboratory conditions. The results obtained showed that the experimental protocol (DF3) promoted larval growth without affecting larval survival and the efficiency of the digestion processes. After pre-growing, DF3-produced juveniles showed a decreased incidence of spinal cord malformations, while the initially gained growth advantage was maintained. The present study shows the feasibility of an alternative feeding protocol for red seabream intensive larviculture and points out the critical role that larval rearing may have for later production stages. Full article

Wireworms are a major threat to potatoes. Agronomic prevention is always the first IPM strategy to be implemented. This work assesses whether a bioactive cover crop, sunn hemp (Crotalaria juncea L.), a tropical leguminous plant, reduces wireworm damage risk when cultivated as a crop preceding potatoes. The effects of Crotalaria plants (alive, chopped, and incorporated) on wireworms and tuber-damage prevention were studied in semi-natural (pots) and open-field conditions. The survival of a set number of reared wireworms feeding on Crotalaria plants or potato tubers in soil with incorporated Crotalaria chopped tissues was assessed. Wireworm damage on tubers was assessed in fields where Crotalaria had been cultivated, chopped, and incorporated the previous year. The tuber damage assessment involved counting all the erosions/scars caused by wireworm feeding. The prevalent wireworm species studied was Agriotes sordidus. Our research is the first to demonstrate that Crotalaria as a cover crop can significantly reduce potato damage by wireworms. A major role is likely played by the high pyrrolizidine alkaloid content in Crotalaria juncea tissues, but this has to be specifically proven. Crotalaria juncea may thus represent an effective means for use alone or with complementary ones to produce potatoes with low wireworm damage without using synthetic insecticides. Full article

The Asian tiger mosquito Aedes albopictus is a highly invasive species capable of transmitting human pathogens. For population management, the sterile insect technique (SIT) is considered an effective and sustainable alternative to conventional methods, such as insecticides and reducing or eliminating breeding sites. The use of symbiotic bacteria to improve the application of SIT or design combined SIT/incompatible insect technique (IIT) approaches is currently considered. In this context, exploring the microbiota of local mosquito populations is crucial for identifying interesting components. This study employed 16S rRNA sequencing and microbiological methods to characterize the diversity of laboratory and wild Ae. albopictus in Greece. Differences were recorded between wild and lab-reared mosquitoes, with laboratory samples exhibiting higher diversity. Laboratory treatment, sex, and developmental stage also resulted in variations between communities. Populations reared in the same facility developed mostly similar bacterial profiles. Two geographically distant wild populations displayed similar bacterial profiles, characterized by seasonal changes in the relative abundance of Pantoea and Zymobacter. Wolbachia was dominant in most groups (63.7% relative abundance), especially in field-caught mosquitoes. It was identified with two strains, wAlbA (21.5%) and wAlbB (42.2%). Other frequent taxa included Elizabethkingia, Asaia, and Serratia. Blood feeding favored an increase in Serratia abundance. Various Enterobacter, Klebsiella, Aeromonas, and Acinetobacter strains were isolated from larval and adult mosquito extracts and could be further characterized as diet supplements. These findings suggest that the microbiota of local populations is highly variable due to multiple factors. However, they retain core elements shared across populations that may exhibit valuable nutritional or functional roles and could be exploited to improve SIT processes. Full article

Aquaculture play a vital role in enhancing human nutrition by producing commercially valuable fish, with gilthead seabream (Sparus aurata) being a key species in the Mediterranean region. In seabream larviculture, disinfection is commonly used to control pathogens and prevent microbial imbalances. However, this process may also remove beneficial microbiota that contribute to ecosystem stability. This study aims to investigate the impact of tank disinfection operations on the bacterial communities associated with seabream larvae and their rearing water in a commercial hatchery using 16S rRNA amplicon sequencing. For further comparison, the bacterial communities present in eggs and feed were also analyzed for comparison. Results showed that the use of different disinfectants significantly altered the bacterial composition of the larvae, while the duration of the dry period had no measurable effect. Across all larval samples, the phylum Pseudomonadota dominated, with members of the genus Psychrobacter consistently detected regardless of disinfection treatment. This suggests that Psychrobacter may be transmitted from eggs or acquired through the feed, mainly rotifers and Artemia nauplii. In contrast, the bacterial communities in the rearing water were more diverse and showed only minor differences in relative abundance across disinfection methods. Full article

With over 40 species, Eupeodes Osten Sacken, 1877, is a common aphidophagous hoverfly genus (Diptera: Syrphidae: Syrphinae) with a worldwide distribution. The immature stages of Eupeodes are well known, since 23 species have been reared, but only 8 species have been described. All known immature stages of Eupeodes species have predatory feeding habits, mainly on aphids and other soft-bodied Hemiptera, for which some of its species are commonly used as agents of biological control programs. In this work, the puparium of Eupeodes bucculatus (Rondani, 1857) is detailed and re-described, and the complete morphology of all immature stages of the life cycle of Eupeodes corollae (Fabricius, 1794) is documented by using stereomicroscope and scanning electron microscope techniques. An update to the taxonomic key for the known larvae/puparium of Eupeodes species is also provided. Full article

Edible insects are a significant component of traditional diets in Madagascar, where food insecurity and malnutrition persist. This study examines the production parameters and nutritional composition of four laboratory-farmed edible grasshopper species commonly consumed by Malagasy people with the aim of upscaling their farming to mitigate malnutrition. The grasshopper species include: vlei grasshopper (Paracinema tricolor), rice grasshopper (Oxya hyla), emerald-legged grasshopper (Eyprepocnemis smaragdipes), and Madagascan slant-faced grasshopper (Acrida madecassa). The study involved the assessment of production parameters (survival rate, developmental time, feed consumed, feed conversion ratio, biomass yield, fecundity, and hatchability). The study also involved analysis of the nutritional content (moisture, protein, fat, ash, fibre, carbohydrates, minerals, amino acids, fatty acids, and vitamins) to evaluate the potential dietary contribution of these grasshoppers. The result show P. tricolor had superior survival, faster development, low feed intake, and higher fecundity and hatchability when compared to other species of grasshoppers. Acrida madecassa showed the highest biomass yield and feed conversion ratio followed by P. tricolor. The results further show that all four species are rich in protein, essential fatty acids, and key minerals, particularly calcium, phosphorus, iron, and zinc. P. tricolor exhibited the highest protein and fat content. Moreover, P. tricolor showed the highest ash content, suggesting a superior mineral profile. Acrida madecassa showed the highest fibre content, reflecting its richness in chitin. These findings provide valuable insights into the nutritional role of grasshoppers in Malagasy diets. Furthermore, they offer reference values for selecting and optimizing the nutrient composition of insect species that are safe and easy to rear, which could serve as a sustainable alternative to wild collection. Future research should explore the bioavailability of nutrients in these species and identify suitable practices to mass rear these species to improve food security in Madagascar. Full article

This study investigated the effects of dietary carbohydrate levels (control 8.13%, HG1 12.03%, and HG2 14.15%) on growth performance and glutamate metabolism in Chinese perch (S. chuatsi) (initial weight: 39.12 ± 0.25 g) reared at 12–15 °C. Diets were isonitrogenous (49% protein). After 8 weeks, the HG1 group optimized weight gain rate (WGR), specific growth rate (SGR), and protein efficiency ratio (PER), while reducing feed conversion ratio (FCR). HG1 and HG2 groups reduced liver glutamate/glutamine levels while downregulating the expression of key ammonia-metabolizing genes (gs, gdh, and ampd), collectively suppressing glutamate-mediated ammonia excretion. HG1 and HG2 groups enhanced glycolysis (upregulated gk and pk) coupled with suppressed gluconeogenesis (decreased PEPCK and G6Pase activities) in the liver. Concurrent downregulation of proteolytic markers (mafbx and murf1) in the muscle indicated improved protein conservation efficiency in the HG1 and HG2 groups. The HG1 diet optimally enhances growth by promoting glycolysis, reducing ammonia excretion, and improving feed efficiency. The insights gained from this research will be used to refine the low-temperature culture feed for Chinese perch, aiming to decrease ammonia and nitrogen emissions, thereby advancing the practice of low-ammonia emission culture for this species. Full article

Plastic pollution has become a critical environmental issue, with vast amounts of plastic waste accumulating in aquatic and terrestrial ecosystems. Plastic pollution poses significant risks to biodiversity by introducing toxic chemicals and disrupting biological functions. The drone fly, Eristalis tenax, is perhaps the most globally widespread hoverfly. This success is aided by its development as a rat-tailed maggot in a wide array of aquatic environments where it feeds on decaying organic matter. As an adult, E. tenax is a vital pollinator, visiting a wide range of crops and wild plants, and has been shown to vector pollen over hundreds of kilometres during seasonal migrations. Exposure to microplastics during larval stages has the potential to alter the provision of these ecosystem services and to provide a route for the long-distance vectoring of microplastics. To investigate this, we rear E. tenax in water contaminated with different concentrations of microplastic particles. We show that these plastics are retained in the gut from larval through to pupal to adult developmental stages. This contamination resulted in reductions of 33% and 60% in pupal and adult weight when exposed to the highest concentrations of microplastic particles but resulted in no detectable effects on mortality or developmental length. Our results demonstrate the potential for the vectoring of microplastics by this highly mobile species. However, the associated reductions in body size likely have profound consequences for movement capability in terms of foraging and migration and should be further investigated for their impact on ecosystem service provision. Full article

This study explores the potential of utilizing black bullhead (Ameiurus melas Rafinesque, 1820), an invasive freshwater species, as a stocking fish for aquaculture. Fish were mass-removed from Ponjavica Nature Park during two periods (2018–2019 and 2020–2021), with selected individuals reared to evaluate growth, survival, and meat quality. A total of 20,145 individuals were removed in the first period (168 reared), and 15,921 in the second (120 reared). Two rearing systems—cages and recirculating aquaculture systems (RAS)—and four feed types were tested. Results demonstrated the species’ adaptability to intensive aquaculture, with good growth, resilience to high-protein diets, and tolerance to high stocking densities. Cage systems generally showed superior growth performance, while RAS produced higher survival rates. Both systems achieved favorable feed conversion ratios. Meat analysis revealed optimal levels of polyunsaturated fatty acids (PUFAs) in RAS and cage-reared fish, enhancing the species’ nutritional value for human consumption. These findings demonstrate the feasibility of repurposing black bullhead as a sustainable aquaculture resource. This dual-purpose approach addresses ecological concerns while offering economic benefits through increased fish production and affordable, nutritious food availability. Further technological development is needed to optimize production systems for broader implementation. Full article