Larval Feeding Research Articles

AM fungus plant colonization rather than an Epichloë endophyte attracts fall armyworm feeding.

Most cold-season grasses can be colonized by belowground arbuscular mycorrhizal (AM) fungi and foliar grass endophytes (Epichloë) simultaneously while also be attacked by insect herbivores. The colonization of AM fungi or the presence of grass endophytes is associated with increased resistance by the host plant. However, studies on how these two symbionts affect host plants and mitigate insect pest attack are currently lacking. In a glasshouse study we investigated the effects of an AM fungus (Acaulospora delicata), a foliar grass endophyte (Epichloë), and the insect pest Spodoptera frugiperda (fall armyworm, FAW) on plant growth, defense enzyme activity, and hormone concentrations of the important pasture grass Lolium perenne. Additionally, we assessed the selective behavior of FAW larvae in response to these interactions using olfactometer tests. Our results showed that the AM fungus and its co-colonization with Epichloë endophytes increased aboveground biomass, while Epichloë endophytes alone had no significant impact on ryegrass aboveground biomass. In contrast, FAW reduced aboveground biomass. The Epichloë endophytes and FAW significantly decreased the mycorrhizal colonization rate by 21.67% and 30.16%, respectively. Interestingly, compared to non-mycorrhizal plants, AM fungus colonized plants were more attractive to FAW larvae feeding, and the defense enzyme activity was not discernibly affected by any experimental treatments. The interactions of the AM fungus and Epichloë endophyte increased the jasmonic acid concentrations by 24.29% and decreased trasylol activity by 11.75% in the host plants under FAW attack. Neither the AM fungus nor Epichloë endophyte influenced the relative growth rate (RGR) of FAW. Overall, the AM fungus had a greater positive effect on plant growth than the Epichloë endophyte, regardless of FAW larvae infestation.

Evaluation of the Control Efficacy of Bt Maize Expressing Cry1Ab and Vip3Aa Proteins Against Agrotis ypsilon (Rottemberg)

Bt maize is the main means to control many lepidopteran pests in the world, but its control efficacy against Agrotis ypsilon (Rottemberg), an important insect pest of maize seedlings, remains unclear until now. The interaction between the insect and Bt transgenic maize events (DBN9936 (expressing Cry1Ab), DBN9501 (expressing Vip3Aa), and DBN3601T (expressing Cry1Ab and Vip3Aa)) was investigated using bioassay and insect behavioral tests. The results show that the Cry1Ab contents in different tissues of DBN9936 were 47.78–82.60 μg·g−1, and the Vip3Aa contents in DBN9501 were 15.29–27.78 μg·g−1. The contents of Cry1Ab and Vip3Aa in DBN3601T were 32.08–79.08 and 10.16–17.52 μg·g−1, respectively. There was no significant difference in total Bt protein content between the leaves and stems; however, that the content in both was significantly higher than that in the roots. The larvae were most sensitive to the Vip3Aa protein, and the corrected mortalities of larvae feeding on DBN9501 and DBN3601T were greater than 89.65% at the seedling stage, significantly higher than those feeding on DBN9936 (16.46–76.13%). The corrected mortalities of the third to the fifth instar larvae feeding on Bt maize root were as follows: DBN3601T (54.00–96.60%) > DBN9501 (24.67–70.88%) > DBN9936 (6.67–53.31%). The results of behavioral tests for Bt/non-Bt maize plant selection indicated that the larvae mainly fed on non-Bt maize while showing antifeedant behavior toward Bt maize, and the moth preferred to lay eggs on undamaged or slightly damaged Bt maize. It is concluded that DBN3601T maize has a strong control efficacy for A. ypsilon, which can play an important role in building an integrated pest management strategy for the insect.

Solid-state fermentation of hemp waste: enhancing the performance of Hermetia illucens larvae and altering the composition of hemp secondary metabolites

Solid-state fermentation (SSF) can increase the nutritional quality of low value substrates for insects. In this study, SSF using different fungal species was applied on a hemp waste substrate, and the fermentation was followed by a black soldier fly larvae (BSFL) feeding experiment during which 300 larvae were grown on 200 g (20.1% DM) substrate for 7–9 days depending on the treatment. Besides assessing the BSFL performance parameters, the presence of hemp cannabinoids, flavonoids, and terpenes was assessed through the process and compared among the treatments. The results show that BSFL growth parameters varied depending on the fungal species used. Fermenting the substrate with Ganoderma lucidum can lead to an increase in the BSFL dry yield (4.54 g) compared to the untreated substrate (2.86 g), likely due to enhancing carbon accessibility in the substrate. SSF using Trichoderma reesei increased the cannabidiol and ∆9-tetrahydrocannabinol mass fractions in the substrate, and consequently in the produced BSFL biomass, while decreasing the amounts of acidic cannabinoids. Both Hypsizygus ulmarius and Pleurotus ostreatus effectively removed cannabinoids from the substrate. This study confirms that pre-treating hemp wastes via SSF can enhance their nutritional value and/or reduce bioactive secondary metabolites, with different fungal species offering different and complementary performances in achieving different biotechnological goals.

In vitro evaluation of anthelmintic activity of biocompatibile carbon quantum dot nanocomposite against egg and larval stages of equine strongyles

BackgroundStrongyle nematodes pose a major challenge in veterinary parasitology, causing significant economic losses in livestock due to resistance to conventional treatments. Current anthelmintics, like Ivermectin, often encounter resistance issues. This study aims to address these gaps by synthesizing Carbon Quantum Dots (CQDs) and Copper-Doped CQDs (Cu@CQDs) using glucose extract, and evaluating their nematicidal properties against strongyles in vitro. We assessed the nematicidal effects of CQDs and Cu@CQDs through larval feeding inhibition of first-stage larvae (L1), egg hatch inhibition (EHI), and the mobility and mortality of infectious larvae (L3s). Additionally, we conducted ultrastructural examinations of eggs and larvae and evaluated oxidative/nitrosative stress indicators, including total antioxidant status (TAS), protein carbonylation (PCO), lipid peroxidation (MDA), and oxidative DNA damage in homogenized samples of L3s.ResultsThe synthesized CQDs displayed semi-spherical morphology with diameters under 30 nm. Cu@CQDs at 12.5 µg/ml achieved over 90% EHI and larval motility inhibition. Fluorescence microscopy confirmed over 90% larval feeding inhibition at the same concentration. Both CQDs and Cu@CQDs induced oxidative stress, indicated by decreased TAS and increased MDA, PCO, and oxidative DNA damage. Scanning Electron Microscopy showed that CQDs and Cu@CQDs penetrated the larvae cuticle, altered the tegument, caused larval mortality, and resulted in egg deformities.ConclusionsGiven the potential for resistance to Ivermectin, seeking suitable alternatives is essential. Cu@CQDs exhibit effects similar to Ivermectin, indicating their potential as novel antiparasitic agents against strongyles. These findings emphasize the importance of exploring alternative treatments to address resistance and enhance nematode control efficacy.Graphical

Microbial ecology of sandflies—the correlation between nutrition, Phlebotomus papatasi sandfly development and microbiome

The role and the impact of the microbial component on the biology, ecology, and development of sandflies is largely unknown. We evaluated the impact of larval nutrition on laboratory-reared sandflies in correlation to the abundance of food, light starvation, and food with/without live microbiome, by monitoring the survival and development of immature stages, and the longevity of adult sandflies. Within this study we examined 360 larvae, 116 pupae, and 120 adult flies of Phlebotomus papatasi for the microbial gut content. The data showed that the presence of a live and diverse microbiome plays a role in the development and survival of larvae. The mortality rate of the larvae was higher, and larval development was longer for sandflies maintained on microbiome-depleted medium, in comparison to the larvae fed with medium containing alive and complex microbiome. Actively feeding larvae reduce microbial abundance and diversity of the medium. The microbial content of the larval gut depends on the composition of the rearing medium, indicating a potential attraction to certain bacteria. The microbial content of the pupa gut was severely diminished, with overall survival of two bacterial species in adult insects - Ochrobactrum intermedium (found in 95% of dissected adults) and Bacillus subtilis (16%). Further microbial studies may aid in developing biological control methods for sandfly larval or adult stages.

High levels of sinigrin trigger synthesis of fatty acids in Plutella xylostella (L.).

Diamondback moth (Lepidoptera: Plutellidae; Plutella xylostella L.) is a specialist insect of the Brassicaceae family, damaging economically important crops, such as cabbage and cauliflower. Glucosinolates, also known as 'mustard oil bombs' are present in all Brassicaceae members, of which sinigrin (allyl-glucosinolate or 2-propenyl-glucosinolate) is a major aliphatic compound. During herbivory, glucosinolates are converted to toxic isothiocyanates that deter insect pests. P. xylostella possesses glucosinolate sulfatases that desulfate them. Such a conversion renders them unfit for degradation to toxic products. Changes in the larval performance prompted us for RNA sequencing to understand probable adaptation mechanism under sinigrin stress. Differentially expressed genes were found to be related to larval cuticle proteins. Further, gene ontology and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses depict genes belonging to the categories, integral component of membrane, cellular processes and those involved in biosynthesis of fatty acids. Upregulation of cuticular genes viz. larval cuticle protein-17 (LCP-17), cuticular protein-19 (2CP-19) and ATP binding cassette transporter C7 (ABCC7), ABCC16 was validated by qRT-PCR. Liquid chromatography quadrupole time of flight mass spectrometry analysis of whole larvae feeding on sinigrin and their separated cuticle, depicted abundance of fatty acids. Changes in the topography of the larval cuticle were evident by scanning electron microscopy. Expression of PxABCH1 was corroborated to its role in the transport of cuticular lipids. Notably, molecular docking of PxABCH1 with cuticular fatty acids showed favorable binding interactions. To summarize, integrated transcriptomic and metabolomic analyses suggest that in response to a diet containing a high dose of sinigrin, P. xylostella re-programs metabolic pathways related to fatty acid biosynthesis that directly influence insect development.

Radiocaesium and radiostrontium transfer to an insect herbivore and an insect detritivore through holometabolous development: A comparison between the cabbage butterfly (Pieris brassicae) and the black soldier fly (Hermetia illucens).

The presence of the long-lived radionuclides 137Cs and 90Sr in ecosystems is a major environmental concern because bioavailable forms of the radionuclides are readily transferred to living organisms. The present study investigated how holometabolous insect development influences the fate of radiocaesium and radiostrontium by examining the behaviour of tracers (134Cs and 84Sr) and stable elements during the larval feeding stage (21-23days old), the pupal stage, and the adult stage. We aimed to evaluate the degree to which an herbivore or a detritivore food chain could serve as transfer pathways to higher trophic levels in terms of accumulation potential, and during which stage of development the accumulation potential is highest. We used the Cabbage butterfly (Pieris brassicae) and the Black soldier fly (Hermetia illucens) as model insects in the herbivore food chain and the detritivore food chain, respectively. Both food chains showed similar patterns of radiocaesium transfer to the larvae, with concentration ratios of 0.26 to 1.15. Radiocaesium levels then gradually decreased during the transition from larva to adult. We also found strontium in the larvae of both model insects. However, while the transfer to P. brassicae was low and the majority of retained strontium was removed prior to the pupal stage, we found that strontium biomagnified in H. illucens larvae and pupae, showing high accumulation potentials. Overall, our results suggest that radiocaesium transfer to terrestrial holometabolous insects is predominantly determined by radiocaesium levels in their diet, whereas radiostrontium transfer is influenced by the insects' dietary need for calcium and the concentration of calcium in the diet.

Neural Network for AI-Driven Prediction of Larval Protein Yield: Establishing the Protein Conversion Index (PCI) for Sustainable Insect Farming

The predictive capabilities of artificial intelligence for predicting protein yield from larval biomass present valuable advancements for sustainable insect farming, an increasingly relevant alternative protein source. This study develops a neural network model to predict protein conversion efficiency based on the nutritional composition of larval feed. The model utilizes a structured two-layer neural network with four neurons in each hidden layer and one output neuron, employing logistic sigmoid functions in the hidden layers and a linear function in the output layer. Training is performed via Bayesian regularization backpropagation to minimize mean squared error, resulting in a high regression coefficient (R = 0.9973) and a low mean-squared error (MSE = 0.0072401), confirming the precision of the model in estimating protein yields. This AI-driven approach serves as a robust tool for predicting larval protein yields, enhancing resource efficiency and promoting sustainability in insect-based protein production.

Asian seabass (Lates calcarifer) larval rearing using cyclopoid copepod (Apocyclops royi) live feed: A new approach

BackgroundThe Apocyclops species are gaining importance as suitable live feed for augmenting growth and survival of marine finfish larvae. In the present study, as a new approach Apocyclops royi is mass cultured using monoalgal diet (Chloroidium saccharophilum) and its nutritive value is assed and used as supplementary diet in the Asian seabass Lates calcarifer larval rearing.ResultsMass culture of A. royi with C. saccharophilum diet reached population density of 12,700 ± 454 ind./L on 21 days culture period. A. royi showed high ratio of DHA:EPA and EPA: ARA. Rearing experiments of the Asian seabass (Lates. calcarifer) 11 DPH larvae with copepod, Artimia nauplii and their combination diets recorded faster growth and maximum survival (90%) with A. royi + Artemia nauplii diet compared to A. royi and Artemia nauplii lone feeds. Seabass larval length and weight gain showed significant (p < 0.05) difference among the three dietary treatments. Significantly high content of essential fatty acids in the L. calcarifer larvae have been reported in A. royi + Artemia nauplii fed seabass larvae compared to individual A. royi and Artemia nauplii fed larvae.ConclusionsOur finding highlights the importance of incorporating A. royi as a supplementary feed for seabass larvae, which will bring improvement in their growth and survival leading to sustainable seed production of this fish.

Tomato Defenses Under Stress: The Impact of Salinity on Direct Defenses Against Insect Herbivores.

Abiotic stressors, such as salt stress, can reduce crop productivity, and when combined with biotic pressures, such as insect herbivory, can exacerbate yield losses. However, salinity-induced changes to plant quality and defenses can in turn affect insect herbivores feeding on plants. This study investigates how salinity stress in tomato plants (Solanum Lycopersicum cv. Better Boy) impacts the behavior and performance of a devastating insect pest, the tomato fruitworm caterpillar (Helicoverpa zea). Through choice assays and performance experiments, we demonstrate that salt-stressed tomato plants are poor hosts for H. zea, negatively affecting caterpillar feeding preferences and growth rates. While changes in plant nutritional quality were observed, the primary factor influencing insect performance appears to be direct ionic toxicity, which significantly impairs multiple life history parameters of H. zea including survival, pupation, adult emergence, and fecundity. Plant defense responses show complex interactions between salt stress and herbivory, with two proteinase inhibitor genes - PIN2 and AspPI, showing a higher induced response to insect herbivory under salt conditions. However, plant defenses do not seem to be the main driver of reduced caterpillar performance on salt-treated plants. Furthermore, we report reduced oviposition by H. zea moths on salt-treated plants, which was correlated with altered volatile emissions. Our findings reveal that H. zea exhibits optimal host selection behaviours for both larval feeding and adult oviposition decisions, which likely contribute to its success as an agricultural pest. This research provides insights into the complex interactions between abiotic stress, plant physiology, and insect behaviour, with potential implications for pest management strategies in saline agricultural environments.

Change Your Diet: How CO2, Plant Phenology and Genotype Alter Grapevine Quality and Affect Performance and Larval Transcriptome of an Insect Herbivore.

Herbivorous insects need to cope with changing host plant biochemistry caused by abiotic and biotic impacts, to meet their dietary requirements. Larvae of the multivoltine European grapevine moth Lobesia botrana, one of the main insect pests in viticulture, feed on both flowers and berries. The nutritional value and defence compounds of these organs are changing with plant phenology and are affected by climate change which may accordingly alter plant-insect interactions. Here, we assessed the impacts of future elevated atmospheric CO2 concentrations on the host plant quality of different grapevine organs and the larval performance and the transcriptome of L. botrana. Using the Geisenheim VineyardFACE facility, where 'Riesling' and 'Cabernet Sauvignon' were cultivated in the field under ambient or elevated (ca. + 20%) atmospheric CO2 concentrations, we found that nutrient (amino acids and sugars) and defence compound (phenolic compounds) concentrations of inflorescences and ripening berries differed strongly due to plant phenology and less due to cultivar and CO2 concentration. Assessing global gene expression after feeding on the respective organs, we found that larval transcriptomic plasticity largely mirrored the plant biochemical plasticity. Larval relative growth rate differed between treatments in a plant phenology-dependent manner. Grape berries contained higher amino acid concentrations and altered phenolics profiles after larval feeding. In the near future, the grapevine-L. botrana interaction will probably change less because of elevated CO2 concentrations than it does currently during one season. Changes associated with plant phenology, however, may be relevant for contemporary pest management.

Characterization of sulfakinin and its role in larval feeding and molting in Spodoptera frugiperda.

Feeding and molting are particularly important physiological processes for insects, and it has been reported that neuropeptides are involved in the nervous regulation of these 2 processes. Sulfakinin (SK) is an important neuropeptide that is widely distributed among insects and plays a pivotal role in regulating feeding, courtship, aggression, and locomotion. In this study, we investigated the involvement of SK in feeding and molting on a highly notorious pest insect, the fall armyworm, Spodoptera frugiperda. SK transcript levels were found in all larval stages and there was a predominant expression of SK in the brain of 5th instar larvae. By immunostaining, SK was detected in 2 pairs of cells in the median protocerebrum. But during prolonged periods of starvation, there was a significant reduction in SK messenger RNA levels; however, subsequent refeeding led to a notable increase. To investigate the role of SK in feeding and molting, SK was silenced in S. frugiperda larvae through RNA interference. This resulted in a significant increase in food intake, weight gain, and the molting process happened more rapidly in the double-stranded SK-treated larvae compared to the controls. Conversely, injection of sulfated SK peptide (sSK) caused opposite effects. Interestingly, SK-knockdown in larvae resulted in increased levels of 20-hydroxyecdysone and also of the expression of some of it signaling pathway genes. Altogether, this study highlights the important role played by SK in regulating feeding and molting in S. frugiperda.

A seasonal matrix population model for ixodid ticks with complex life histories and limited host availability.

Many vector-borne diseases are sensitive to changes in land use and climate; hence, it is important to understand the factors that govern the vector populations. Ixodid ticks, which serve as vectors for multiple diseases, have a slow life cycle compared with many of their hosts. The observable questing population represents only a fraction of the total tick population and may include overlapping cohorts in each stage. The duration of each life stage (larvae, nymph, and adult) is variable and depends on factors such as the seasonal timing of questing, development, and host availability. Mathematical models are therefore essential to mediate how complex life cycle transitions and host interactions underpin the seasonal dynamics of the questing tick population. In this study, we develop a seasonal matrix population model for ixodid ticks feeding on a small and large host. The model has 17 stages representing the main life history stages (eggs, larvae, nymphs, and adults) combined with status of feeding, seasonal timing of feeding, and overwintering. The probability of finding a host depends on tick instar and host type, and density regulation is incorporated through limited host capacity. Using a life history representing Ixodes ricinus in Northern Europe as a baseline, we extract seasonal numbers of different parts of the tick population and calculate life history outcomes such as generation time and mean and variance of lifespan and of lifetime reproductive output. These results are compared with an alternative scenario of a southern life history. Secondly, we investigate (1) effects of seasonality in the small host availability on the seasonal numbers of tick stages and (2) effects of varying host availability and utilization of small versus large hosts by larvae and nymphs, on the seasonal numbers of questing ticks. Our results suggest that the small host availability is an important regulating factor through the feeding of larvae. Our model incorporates complex mechanisms underlying the seasonal composition of the tick population. It can be applied to different ixodid tick species and provides a framework for future investigations into intra- and interspecific variation in life history and population dynamics.

The hidden drivers: Unraveling the impact of density, moisture, and scale on Hermetia illucens rearing.

The black soldier fly (Hermetia illucens) is a saprophagous insect known for bioconverting organic waste, potentially offering environmental benefits, such as contributing to waste reduction and nutrient cycling. The performance of larvae varies significantly with factors substrate moisture, larval density, and scale of production. Three experiments were conducted using a mix of spent mushroom substrate (SMS) and chicken feed (CF). In the first experiment, 250 larvae were reared on 100 g dry matter (DM) feed at moisture levels of 65-75%. Results showed that the average individual larval weight, total biomass, and feed conversion ratio (FCR) improved with increased moisture. In the second experiment, 300 and 350 larvae/box were tested at 70% and 75% moisture. The highest average individual larval fresh weight (158.6 mg) was observed at 70% moisture with 250 larvae, while the highest biomass was achieved at 75% moisture with 300 larvae. Finally, different scales (10-2,500 g feed with 25-6,500 larvae) were tested with a similar feeding rate. The highest individual larval weight was recorded at the 100 g scale, with no clear correlation between weight and scale. However, the 50 g scale achieved the highest substrate reduction (33.2%). Overall, this study underscores the need to adjust moisture, density, and scale to nutrient conversion efficiency when using SMS, CF or other diets. The optimal results for the SMS feed mix were observed at 75% substrate moisture, 250 larvae per 100 g DM, and at approximately 2 larvae per cm2.

Optimizing Feeding and Pupation Bioassays to Assess the Effects of Insecticidal and Repellent Treatments on Aethina tumida Larval Development and Pupation Success.

European honey bee (Apis mellifera) colonies are an ideal host to the invasive beetle Aethina tumida, providing a nutrient rich environment that is protected from the elements and facilitates beetle reproduction. Although various management techniques and chemical treatments for A. tumida have been developed, understanding the efficacy of these treatments and techniques is limited. Throughout this study, several methods for impairing A. tumida development and delivering insecticidal, repellent, or antifungal treatments were examined. A series of A. tumida larval feeding bioassays developed and optimized feeding gel pellet for delivery of insecticidal treatments, revealing that A. tumida larvae are sensitive to the two common in-hive varroa mite (Varroa destructor) treatments: coumaphos (EC50 = 25.6 ppm) and tau-fluvalinate (EC50 = 21.2 ppm). Feeding bioassays also demonstrated that A. tumida were more sensitive to the pyrethroid compounds permethrin (EC50 = 3.37 ppm), deltamethrin (EC50 = 2.69 ppm), and bifenthrin (EC50 = 0.365 ppm), which have been previously used to control this beetle. Feeding bioassays also revealed that the antifungal drug Amphotericin B was palatable to A. tumida larvae via feeding, but was also injected into A. tumida larvae and adults. Two types of pupation bioassays were also developed to test the effects of several insecticidal and repellent treatments on pupation burrowing and pupation success. Overall, this work details specific toxicity information regarding common insecticidal treatments found in the apiary setting study and provides groundwork and methods for testing insecticidal compounds on A. tumida larvae in in the future.

Refining larval feeding regimes for the x-ray tetra (Pristella maxillaris) to minimize reliance on live feeds

Refining larval feeding regimes for the x-ray tetra (Pristella maxillaris) to minimize reliance on live feeds

Comfort in stratification and trophic flexibility: argentine anchovy, Engraulis anchoita, larvae life traits in relation to their food sources

Fish larvae feeding success is crucial for adult recruitment, which affects both fisheries and ecosystem regulation processes. Engraulis anchoita is a species of great ecological and fishing relevance in the South-West Atlantic Ocean, with a wide latitudinal distribution and active spawning throughout the year and strongly associated with frontal areas. E. anchoita larvae have been described as exclusively feeding on small copepods and their early developmental stages. In this study, the diet, nutritional condition, and daily growth of E. anchoita larvae were estimated in different environmental scenarios in the South-West Atlantic Ocean. Carbon and Nitrogen stable isotopes analysis, otolith microstructure analysis, and RNA/DNA index determination were performed. The larval diet, which was evaluated based on the availability of potential prey, varied with respect to the water column stability. It was observed that the larvae tend to feed on microphytoplankton in stratified waters and on calanoid copepods in waters with a homogeneous vertical structure. The growth and nutritional condition indexes responded to ontogeny, presenting higher values at larger larval sizes. Growth indexes also responded positively to the stratified water column structure in comparison to the homogeneous one. The nutritional condition index was only explained by the size of the individuals. This study found that E. anchoita larvae had greater trophic flexibility than previously suspected, as they included microphytoplankton as the main food item under certain oceanographic conditions without negative impacts on their growth or nutritional condition.

Metabolic enhancement contributed by horizontal gene transfer is essential for dietary specialization in leaf beetles

Horizontal gene transfer (HGT) from bacteria to insects is widely reported and often associated with the adaptation and diversification of insects. However, compelling evidence demonstrating how HGT-conferred metabolic adjustments enable species to adapt to surrounding environment remains scarce. Dietary specialization is an important ecological strategy adopted by animals to reduce inter- and intraspecific competition for limited resources. Adults of the leaf beetle Plagiodera versicolora (Coleoptera) preferentially consume new leaves; nevertheless, we found that they selectively oviposit on mature leaves, thereby establishing a distinct dietary niche separation between adults and larvae. Based on the de novo assembled chromosome-level genome, we identified two horizontally transferred genes with cellulose degradation potential, belonging to the glycosyl hydrolase 48 family (GH48-1 and GH48-2). Prokaryotic expression of the HGTs confirmed the cellulose degradation capability of the two genes. Knockdown of GH48 significantly hampered the growth and survival rate of larvae feeding on mature leaves compared to wild-type larvae, with no similar effect observed in adults. Replenishing the GH48-expressing bacteria compensated for the knockdown of these two genes and recurred larval adaptability to mature leaves. Taken together, our results highlight the advantage and metabolic enhancement conferred by the two cellulose-degrading HGTs in P. versicolora larvae, enabling their development on cellulose-enriched mature leaves and underscoring the indispensable role of HGTs in facilitating the adaptation of leaf beetles to plants.

A Dual Branch Time-Frequency Multi-Dilated Dense Network for Wood-Boring Pest Activity Signal Enhancement in the Larval Stage

The early identification of forest wood-boring pests is essential for effective pest management. However, detecting infestation in the early stages is difficult, as larvae, such as the emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), usually feed inside the trees. Acoustic sensors can detect the pulse signals generated by larval feeding or movement, but these sounds are often weak and easily masked by background noise. To address this, we propose a dual-branch time-frequency multi-dilated dense network (DBMDNet) for noise reduction. Our model decouples two denoising training objectives: a magnitude masking decoder for coarse denoising and a complex spectral decoder for further magnitude repair and phase correction. Additionally, to enhance global time-frequency modeling, we use three different multi-dilated dense blocks to effectively separate clean signals from noisy data. Given the difficult acquisition of clean larval activity signals, we describe a self-supervised training procedure that utilizes only noisy larval activity signals directly collected from the wild, without the need for paired clean signals. Experimental results demonstrate that our proposed approach achieves the optimal performance on various evaluation metrics while requiring fewer parameters (only 98.62 k) compared to competitive models, achieving an average signal-to-noise ratio (SNR) improvement of 17.45 dB and a log-likelihood ratio (LLR) of 0.14. Furthermore, using the larval activity signals enhanced by DBMDNet, most of the noise is suppressed, and the accuracy of the recognition model is also significantly improved.

Nutritional composition and processing methods of black soldier fly larvae for fish feeding

&lt;p&gt;This review explores the potential of black soldier fly (BSF) larvae as a sustainable alternative to fishmeal and soybean meal in aquaculture. BSF larvae offer a valuable protein, fat, and chitin source while contributing to waste reduction and nutrient recycling. Feed industries can effectively incorporate BSF larvae into fish diets without negatively impacting growth performance or health. However, the optimal inclusion levels and potential challenges associated with BSF-based diets vary among fish species. Future research should focus on further optimizing BSF production and processing methods and investigating the long-term effects of BSF-based diets on fish health and reproductive performance. BSF larvae can significantly promote sustainable and efficient aquaculture practices by addressing these areas.&lt;/p&gt;