Insect Feeding Research Articles

Unveiling symbiotic bacterial communities in insects feeding on the latex-rich plant Ficus microcarpa.

The diversity and health of insects that feed on plants are closely related to their mutualistic symbionts and host plants. These symbiotic partners significantly influence various metabolic activities in these insects. However, the symbiotic bacterial community of toxic plant feeders still needs further characterisation. This study aims to unravel bacterial communities associated with the different species of insect representing three insect orders: Thysanoptera, Hemiptera, and Lepidoptera, along with their predicted functional role, which exclusively feeds on latex-rich plant species Ficus microcarpa. By using 16S rRNA gene high-throughput sequencing, the analysis was able to define the major alignment of the bacterial population, primarily comprising Proteobacteria, Firmicutes, Bacteroidota, Actinobacteriota, and Acidobacteriota. Significant differences in symbiotic organisms between three insect groups were discovered by the study: hemipterans had Burkholderia and Buchnera, and lepidopterans had Acinetobacter. At the same time, Pseudomonas was detected in high abundance in both lepidopteran and thysanopteran insects. Furthermore, these symbionts exhibit consistent core functions, potentially explaining how different insects can consume the same host plant. The identified core functions of symbionts open avenues for innovative approaches in utilising these relationships to develop environment-friendly solutions for pest control, with broader implications for agriculture and environmental conservation.

Cicada nymph trace fossils from South American Maastrichtian paleosols

The Cretaceous was a pivotal Period in the evolution of major insect groups, including cicadas. Insect diversification led to an increased complexity in the paleosol ichnofabrics due to the emergence of chambers associated with reproductive and feeding behaviors. Therefore, any new record of trace fossils attributed to cicadas from the Cretaceous period represent a significant advancement in understanding the diversification of this group and the emergence of insect feeding chambers, throughout the geological record. This work describes the record of the ichnogenus Feoichnus attributed to feeding chambers of cicada nymphs (Hemiptera: Cicadidae) from Maastrichtian paleosols developed in floodplain deposits of The Marília Formation (Bauru Basin, Brazil). The described Feoichnus chambers are elongated, hemispherical, and upwardly concave, with a lining covering the inner surface of the wall. The inner surface exhibits thin, irregular ridges and grooves, likely associated with fine roots. Feoichnus occurs in association with Beaconites antarcticus and root traces found within the feeding chamber, it could be indicating the movement of the trace maker and the feeding chamber from one root to another. These characteristics indicate the xylem-feeding behavior of Feoichnus trace maker in accordance with extant cicada nymph ecology. The presence of Beaconites antarcticus associated with Feoichnus and rhizoliths probably represents the foraging behavior of cicada nymphs and the displacement of feeding chambers in well-drained, rooted soils. Therefore, the cicada nymph could be the trace maker of both traces representing feeding and locomotion behavior. This contribution expands the knowledge about plant–insect interactions and insect groups that compose the Cretaceous paleosols ichnofabrics from South America.

Complicated gene network for regulating feeding behavior: novel efficient target for pest management.

Feeding behavior is a fundamental activity for insects, which is essential for their growth, development and reproduction. The regulation of their feeding behavior is a complicated process influenced by a variety of factors, including external stimuli and internal physiological signals. The current review introduces the signaling pathways in brain, gut and fat body involved in insect feeding behavior, and provides a series of target genes for developing RNA pesticides. Additionally, this review summaries the current challenges for the identification and application of functional genes involved in feeding behavior, and finally proposes the future research direction. © 2024 Society of Chemical Industry.

Historical invasion rates vary among insect trophic groups.

Globalization has spread thousands of invasive insect species into new world regions,1,2,3 causing severe losses in ecosystem services. Previous work proposed that plant invasions facilitate insect invasions through the creation of niches for non-native herbivores.3,4,5,6 Despite the impact of insect invasions, a comprehensive understanding is lacking on how invasion success varies among insect feeding groups. We therefore compiled the predominant larval trophic groups (herbivores, predators, parasites, detritivores, and brood-carers) for 5,839 non-native insect species in nine world regions to compare (1) proportions of species in each group between non-native species and the world's fauna, (2) how invasion success for each trophic group has changed over the last three centuries, and (3) how historical herbivore invasions are related to plant invasions over time and parasite invasions are related to herbivores. We find that herbivores represent a significantly larger proportion (52.4%) among non-native insects compared with the world fauna (38.4%), whereas proportions of non-native detritivores (including fungivores), predators, and brood-carers are significantly lower; parasite proportions do not significantly differ. Predators and detritivores dominated among invasions in the 18th century but subsequently diminished, likely due to changing invasion pathways, whereas proportions of herbivores, parasites, and brood-carers increased over time. We found herbivore invasions to lag 80 years behind plant invasions, whereas parasitoids appear to co-invade with their herbivore hosts. The dominance of herbivores among non-native insects and their strong cross-correlation with plant invasions further strengthens the hypothesis that plant invasions drive the global rise in numbers of non-native insects.

Cotton Bollworm (H. armigera) Effector PPI5 Targets FKBP17-2 to Inhibit ER Immunity and JA/SA Responses, Enhancing Insect Feeding.

The cotton bollworm causes severe mechanical damage to plants during feeding and leaves oral secretions (OSs) at the mechanical wounds. The role these OSs play in the invasion of plants is still largely unknown. Here, a novel H. armigera effector peptidyl prolyl trans-isomerase 5 (PPI5) was isolated and characterized. PPI5 induces the programmed cell death (PCD) due to the unfolded protein response (UPR) in tobacco leaf. We reveal that PPI5 is important for the growth and development of cotton bollworm on plants, as it renders plants more susceptible to feeding. The GhFKBP17-2, was identified as a host target for PPI5 with peptidyl-prolyl isomerase (PPIase) activity. CRISPR/Cas9 knock-out cotton mutant (CR-GhFKBP17-1/3), VIGS (TRV: GhFKBP17-2) and overexpression lines (OE-GhFKBP17-1/3) were created and the data indicate that GhFKBP17-2 positively regulates endoplasmic reticulum (ER) stress-mediated plant immunity in response to cotton bollworm infestation. We further confirm that PPI5 represses JA and SA levels by downregulating the expression of JA- and SA-associated genes, including JAZ3/9, MYC2/3, JAR4, PR4, LSD1, PAD4, ICS1 and PR1/5. Taken together, our results reveal that PPI5 reduces plant defense responses and makes plants more susceptible to cotton bollworm infection by targeting and suppressing GhFKBP17-2 -mediated plant immunity.

Phloem sap from melon plants contains extracellular vesicles that carry active proteasomes which increase in response to aphid infestation.

The morphogenesis of higher plants requires communication among distant organs throughout vascular tissues (xylem and phloem). Numerous investigations have demonstrated that phloem also act as a distribution route for signalling molecules being observed that different macromolecules translocated by the sap, including nucleic acids and proteins, change under stress situations. The participation of extracellular vesicles (EVs) in this communication has been suggested, although little is known about their role. In fact, in the last decade, the presence of EVs in plants has originated a great controversy, where major concerns arose from their origin, isolation methods, and even the appropriate nomenclature for plant nanovesicles. Phloem sap exudates from melon plants, either aphid-free or infested with Aphis gossypii, were collected by stem incision. After sap concentration (Amicon), phloem EVs (PhlEVs) were isolated by size exclusion chromatography. PhlEVs were characterised using Nanoparticle Tracking Analysis, Transmission electron microscopy and proteomic analysis. Here we confirm the presence of EVs in phloem sap in vivo and the detection of changes in the particles/protein ratio and composition of PhlEVs in response to insect feeding, revealing the presence of typical defence proteins in their cargo as well as components of the proteasome complex. PhlEVs from infested plants showed lower particles/protein ratio and almost two times more proteolytic activity than PhlEVs from aphid-free plants. In both cases, such activity was inhibited in a dose-dependent manner by the proteasome inhibitor MG132. Our results suggest that plants may use this mechanism to prepare themselves to receive infectious agents and open up the possibility of an evolutionary conserved mechanism of defence against pathogens/stresses in eukaryotic organisms.

Influence of the Chemical Properties of Cereal Grains on the Structure and Metabolism of the Bacteriome of Rhyzopertha dominica (F.) and Its Development: A Cause-Effect Analysis.

Rhyzopertha dominica causes significant economic losses in stored cereals. Insects' digestive tract microbiome is crucial for their development, metabolism, resistance, and digestion. This work aimed to test whether the different chemical properties of different wheat and barley grain cultivars cause disturbances in insect foraging and rearrangements of the structure of the R. dominica microbiome. The results indicated that grain cultivars significantly influence the microbiome, metabolism, and insect foraging. Most observed traits and microbiome structures were not correlated at the species level, as confirmed by ANOSIM (p = 0.441). However, the PLS-PM analysis revealed significant patterns within barley cultivars. The study found associations between C18:2 fatty acids, entomopathogenic bacteria, an impaired nitrogen cycle, lysine production of bacterial origin, and insect feeding. The antioxidant effects also showed trends towards impacting the microbiome and insect development. The findings suggest that manipulating grain chemical properties (increasing C18:2 and antioxidant levels) can influence the R. dominica microbiome, disrupting their foraging behaviours and adaptation to storage environments. This research supports the potential for breeding resistant cereals, offering an effective pest control strategy and reducing pesticide use in food production.

Interactions between invasive pests and pathogens in a native chestnut forest

The introduction in the same area of different invasive species can result in novel interactions, with unpredictable consequences. We carried out a study in Galicia (northwestern Iberian Peninsula) with the aim of clarifying the interactions between two invasive species Cryphonectria parasitica and Dryocosmus kuriphilus. In 2018, we selected five chestnut plots affected by both species. We compared trees affected only by the insect and trees affected by both the insect and the fungus with respect to attack level, gall characteristics, female size and fecundity, and concentrations of nitrogen, water and secondary metabolites. We also evaluated female preferences in a greenhouse assay. There were higher levels of attack in trees affected by both invaders. However, the greenhouse assay showed that ovipositing females do not preferentially choose trees attacked by the fungus. The presence of the fungus had no effect on the size, wall thickness, or hardness of D. kuriphilus galls, but larvae were smaller in trees also affected by the fungus. The fecundity of females was strongly related to the presence of chestnut blight; the number of eggs per female was almost double in trees affected by the fungus. There were no relations between blight and the nitrogen or water content in the galls, where the insects feed. There were also no effects of chestnut blight on the concentration of terpenes or phenols, but condensed tannins were higher in trees with chestnut blight. The higher tannins induced by chestnut blight may directly or indirectly benefit gall wasps. Positive relationships between condensed tannin concentration and reproductive performance of other gall makers were previously reported. Tannins can also improve the negative effects of environmental conditions inside the gall. Our results indicate that the presence of chestnut blight can increase the suitability of chestnut trees for the invasive insect, D. kuriphilus, through the increase in tannins due to the presence of the fungus.

Intraguild Predation or Spatial Separation? The efficacy and Interactions of Two Natural Enemy Species for the Biological Control of Pear Psyllid (Cacopsylla pyri)

AbstractPear psyllid (Cacopsylla pyri) is a persistent pest to the pear industry; with an estimated cost of £5 million per annum in the UK alone. This phloem feeding insect is resistant to a large proportion of approved pesticides, necessitating the use of alternative control strategies. Many pear growers practice integrated pest management (IPM) of pear psyllid, focusing on maximizing natural enemy populations, whilst minimizing the use of agrochemical sprays. The anthocorid Anthocoris nemoralis and the European earwig Forficula auricularia are particularly effective at controlling pear psyllid populations during the summer months. Despite the effectiveness of both natural enemies, there is a lack of understanding on whether both species should be promoted together or separately, due to the risk of intraguild predation (IGP) or interference competition. Furthermore, abiotic factors including temperature may influence both behaviors, altering activity level and niche overlap. Although IGP and interference competition have been documented between multiple species of natural enemies neither have been studied between these two specific predators. Using microcosm experiments, olfactometer assays and survival analyses this study demonstrated whether A. nemoralis and F. auricularia can be used in synchrony to control pear psyllid. Results indicated that IGP is present; F. auricularia will consume A. nemoralis when predators are not spatially separate and in absence of psyllid prey. There was no evidence for interference competition, although both predators consumed more prey at higher temperatures. This confirms that pear growers can encourage both predators for the control of pear psyllid without losing predation efficacy.

Salivary Protein Sfapyrase of Spodoptera frugiperda Stimulates Plant Defence Response.

Plants have developed various resistance mechanisms against herbivorous insects through prolonged coevolution. Plant defence responses can be triggered by specific compounds present in insect saliva. Apyrase, a known enzyme that catalyzes the hydrolysis of adenosine triphosphate (ATP) and adenosine diphosphate (ADP) into adenosine monophosphate (AMP) and inorganic phosphorus, has recently been identified in some herbivorous insects. However, whether insect salivary apyrase induces or inhibits plant responses remains poorly understood. In this study, we identified an apyrase-like protein in the salivary proteome of the fall armyworm, Spodoptera frugiperda, named Sfapyrase. Sfapyrase was primarily expressed in the salivary gland and secreted into plants during insect feeding. Transient expression of Sfapyrase in tobacco and maize enhanced plant resistance and resulted in decreased insect feeding. Knockdown of Sfapyrase through RNA interference led to increased growth and feeding of S. frugiperda. Furthermore, we showed that Sfapyrase activates the jasmonic acid signalling pathway and promotes the synthesis of secondary metabolites, especially benzoxazinoids, thereby enhancing resistance to S. frugiperda. In summary, our findings demonstrated that Sfapyrase acts as a salivary elicitor, inducing maize jasmonic acid defence responses and the production of insect-resistant benzoxazinoids. This study provides valuable insights into plant-insect interactions and offers potential targets for developing innovative insect pest management strategies.

Utility of Cry1Ja for Transgenic Insect Control.

Insect control traits are a key component of improving the efficacy of insect pest management and maximizing crop yields for growers. Insect traits based on proteins expressed by the bacteria Bacillus thuringiensis (Bt) have proven to be very effective tools in achieving this goal. Unfortunately, the adaptability of insects has led to resistance to certain proteins in current commercial products. Therefore, new insecticidal traits representing a different mode of action (MoA) than those currently in use are needed. Cry1Ja has good insecticidal activity against various lepidopteran species, and it provides robust protection against insect feeding with in planta expression. For Bt proteins, different MoAs are determined by their binding sites in the insect midgut. In this study, competitive binding assays are performed using brush border membrane vesicles (BBMVs) from Helicoverpa zea, Spodoptera frugiperda, and Chrysodeixis includens to evaluate the MoA of Cry1Ja relative to representatives of the various Bt proteins that are expressed in current commercial products for lepidopteran insect protection. This study highlights differences in the shared Cry protein binding sites in three insect species, Cry1Ja bioactivity against Cry1Fa resistant FAW, and in planta efficacy against target pests. These data illustrate the potential of Cry1Ja for new insect trait development.

Floral resource availability declines and florivory increases along an elevation gradient in a highly biodiverse community.

Flower-visitor interactions comprise a continuum of behaviors, from mutualistic partners to antagonistic visitors. Despite being relatively frequent in natural communities, florivory remains unexplored, especially when comprising abiotic factors, spatio-temporal variations and global environmental changes. Here, we addressed the variation of florivory driven by changes in elevation and temporal flower availability. We expect decreased floral resources as elevation increases -due to environmental constraints- which may affect plant-florivore interactions. Yet, if floral resources decrease but florivores remain constant, then we may expect an increase in florivory with increasing elevation in the community. The flowering phenology of plant individuals was recorded in the Neotropical campo rupestre vegetation, in southeastern Brazil. Damages by florivores were recorded in plots at elevations ranging from 823 to 1411 m using two response variables as a proxy for florivory: the proportion of attacked flowers per plant and the proportion of petal removal on single flowers. Flower attack increased with elevation and damages were intensified in species with longer flowering periods. Conversely, longer flowering periods resulted in higher levels of petal removal when decreasing elevation. The temporal availability of flowers affected florivory, with the proportion of attacked flowers being more intense when there are less flowered individuals in the community. Petal removal on single flowers was intensified in plots with a larger number of individuals flowering, and with more species co-flowering. This study brings one of the broadest records of a commonly neglected interaction of insects feeding on floral structures, quantifying the combined effect of floral display and availability along an elevation gradient in a highly biodiverse mountaintop community. These findings contribute to filling in the gap in the understanding of florivory dynamics, focusing on a tropical mountaintop scenario facing imminent environmental changes and excessive natural resource exploitation.

Sugar assimilation underlying dietary evolution of Neotropical bats

Dietary specializations in animals lead to adaptations in morphology, anatomy and physiology. Neotropical bats, with their high taxonomic and trophic diversity, offer a unique perspective on diet-driven evolutionary adaptations. Here we assess the metabolic response to different dietary sugars among wild-caught bats. We found that insectivorous bats had a pronounced metabolic response to trehalose, whereas bats with nectar and fruit-based diets showed significantly higher blood glucose levels in response to glucose and sucrose, reaching levels over 750 mg dl−1. The genomic analysis of 22 focal species and two outgroup species identified positive selection for the digestive enzyme trehalase in insect eaters, while sucrase–isomaltase showed selection in lineages with omnivorous and nectar diets. By examining anatomical and cellular features of the small intestine, we discovered that dietary sugar proportion strongly impacted numerous digestive traits, providing valuable insight into the physiological implications of molecular adaptations. Using hybridization chain reaction (HCR) RNA fluorescence in situ hybridization, we observed unusually high expression in the glucose transporter gene Slc2a2 in nectar bats, while fruit bats increased levels of Slc5a1 and Slc2a5. Overall, this study highlights the intricate interplay between molecular, morphological and physiological aspects of diet evolution, offering new insights into the mechanisms of dietary diversification and sugar assimilation in mammals.

Exploring the effects of entomopathogenic nematode symbiotic bacteria and their cell free filtrates on the tomato leafminer Tuta absoluta and its predator Nesidiocoris tenuis

The use of biocontrol agents, such as predators and entomopathogenic nematodes, is a promising approach for the effective control of the tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidaean), an oligophagous insect feeding mainly on Solanaceae species and a major pest of field- and greenhouse-grown tomatoes globally. In this context, the effects of two entomopathogenic nematode species Steinernema carpocapsae (Weiser) (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora (Poinar) (Rhabditida: Heterorhabditidae), as well as their respective bacterial symbionts, Xenorhabdus nematophila and Photorhabdus luminescens (Enterobacterales: Morganelaceae), which were applied as bacterial cell suspensions and as crude cell-free liquid filtrates on T. absoluta larvae, were investigated. The results showed that of all treatments, the nematodes S. carpocapsae and H. bacteriophora were the most effective, causing up to 98 % mortality of T. absoluta larvae. Regarding bacteria and their filtrates, the bacterium X. nematophila was the most effective (69 % mortality in young larvae), while P. luminescens and both bacterial filtrates showed similar potency (ca. 48–55 % mortality in young larvae). To achieve a holistic approach of controlling this important pest, the impact of these factors on the beneficial predator Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) was also studied. The results demonstrated that although nematodes and especially S. carpocapsae, caused significant mortality on N. tenuis (87 %), the bacterial cell suspensions of X. nematophila and P. luminescens and crude cell-free liquid filtrates had minimum impact on this beneficial predator (∼11–30 % mortality).

Plant viruses exploit insect salivary GAPDH to modulate plant defenses

Salivary proteins of insect herbivores can suppress plant defenses, but the roles of many remain elusive. One such protein is glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the saliva of the Recilia dorsalis (RdGAPDH) leafhopper, which is known to transmit rice gall dwarf virus (RGDV). Here we show that RdGAPDH was loaded into exosomes and released from salivary glands into the rice phloem through an exosomal pathway as R. dorsalis fed. In infected salivary glands of R. dorsalis, the virus upregulated the accumulation and subsequent release of exosomal RdGAPDH into the phloem. Once released, RdGAPDH consumed H2O2 in rice plants owing to its –SH groups reacting with H2O2. This reduction in H2O2 of rice plant facilitated R. dorsalis feeding and consequently promoted RGDV transmission. However, overoxidation of RdGAPDH could cause potential irreversible cytotoxicity to rice plants. In response, rice launched emergency defense by utilizing glutathione to S-glutathionylate the oxidization products of RdGAPDH. This process counteracts the potential cellular damage from RdGAPDH overoxidation, helping plant to maintain a normal phenotype. Additionally, salivary GAPDHs from other hemipterans vectors similarly suppressed H2O2 burst in plants. We propose a strategy by which plant viruses exploit insect salivary proteins to modulate plant defenses, thus enabling sustainable insect feeding and facilitating viral transmission.

Scavenging H2O2 of plant host by saliva catalase of leafhopper vector benefits viral transmission.

Catalase (CAT) is the main reactive oxygen species (ROS)-scavenging enzyme in plants and insects. However, it remains elusive whether and how insect saliva CAT suppresses ROS-mediated plant defense, thereby promoting initial virus transmission by insect vectors. Here, we investigated how leafhopper Recilia dorsalis catalase (RdCAT) was secreted from insect salivary glands into rice phloem, and how it was perceived by rice chaperone NO CATALASE ACTIVITY1 (OsNCA1) to scavenge excessive H2O2 during insect-to-plant virus transmission. We found that the interaction of OsNCA1 with RdCAT activated its enzymatic activity to decompose H2O2 in rice plants during leafhopper feeding. However, initial insect feeding did not significantly change rice CATs transcripts. Knockout of OsNCA1 in transgenic lines decreased leafhopper feeding-activated CAT activity and caused higher H2O2 accumulation. A devastating rice reovirus activated RdCAT expression and promoted the cosecretion of virions and RdCAT into leafhopper salivary cavities and ultimately into the phloem. Virus-mediated increase of RdCAT secretion suppressed excessive H2O2, thereby promoting host attractiveness to insect vectors and initial virus transmission. Our findings provide insights into how insect saliva CAT is secreted and perceived by plant chaperones to suppress the early H2O2 burst during insect feeding, thereby facilitating viral transmission.

Unraveling the Chicken Meat Volatilome with Nanostructured Sensors: Impact of Live and Dehydrated Insect Larvae Feeding.

Incorporating insect meals into poultry diets has emerged as a sustainable alternative to conventional feed sources, offering nutritional, welfare benefits, and environmental advantages. This study aims to monitor and compare volatile compounds emitted from raw poultry carcasses and subsequently from cooked chicken pieces from animals fed with different diets, including the utilization of insect-based feed ingredients. Alongside the use of traditional analytical techniques, like solid-phase microextraction combined with gas chromatography-mass spectrometry (SPME-GC-MS), to explore the changes in VOC emissions, we investigate the potential of S3+ technology. This small device, which uses an array of six metal oxide semiconductor gas sensors (MOXs), can differentiate poultry products based on their volatile profiles. By testing MOX sensors in this context, we can develop a portable, cheap, rapid, non-invasive, and non-destructive method for assessing food quality and safety. Indeed, understanding changes in volatile compounds is crucial to assessing control measures in poultry production along the entire supply chain, from the field to the fork. Linear discriminant analysis (LDA) was applied using MOX sensor readings as predictor variables and different gas classes as target variables, successfully discriminating the various samples based on their total volatile profiles. By optimizing feed composition and monitoring volatile compounds, poultry producers can enhance both the sustainability and safety of poultry production systems, contributing to a more efficient and environmentally friendly poultry industry.

Insecticidal Activities of Securidaca longepedunculata Fresen Extracts and Feeding Behavior of Schizaphis graminum Rondani: Electropenetrography Approach.

The aphid, Schizaphis graminum Rondani (Hemiptera: Aphididae), is one of the most destructive pests of wheat. It is responsible for significant economic losses in the agricultural sector, with an estimated 45% of wheat fields affected. Plant-based insecticides have seen a rapid increase in popularity in recent years due to their efficacy, cost-effectiveness, biodegradability, and lower toxicity compared to synthetic pesticides. The study aimed to evaluate the toxic potential of S. longipedunculata extracts against S. graminum and investigate the insect's feeding behavior on wheat. Initially macerated in methanol, the different extracts of S. longipedunculata organs were fractionated using n-hexane, chloroform, ethyl acetate, and butanol. The feeding behavior was analyzed by comparing the waveforms generated by the EPG with the control. After 72 h of treatment, the ethyl acetate fraction extracted from root had the highest toxicity against aphids, with mean 26 mortality of S. graminum at LC50 of 330 ppm; 25 mortality S. graminum at LC50 of 400 ppm for leaves; and mean 24.5 mortality S. graminum at LC50 of 540 ppm in stem bark. EPG analysis indicated that the extract fractions enhanced plant tissue resistance by significantly preventing aphid access to the phloem. The toxic effect of the botanical extracts significantly enhanced the chemical composition of the leaf medium, resulting in a drastic reduction in the number of tissue attacks by S. graminum. In summary, besides their toxicity to S. graminum, extracts of S. longipedunculata reinforce the plant's defense mechanisms, significantly reducing the S. graminum population. They also reinforce wheat's defense mechanisms. S. longipedunculata can, therefore, be used as a promising agent in the biological control of S. graminum.

Reducing flea-beetle feeding wounds on canola seedlings with foliar insecticide failed to improve blackleg control

In earlier studies, it was found that Leptosphaeria maculans could readily infect canola via fresh wounds but would require extended leaf wetness to infect intact tissues. We hypothesized that flea beetle feeding wounds might facilitate L. maculans infection under field conditions. Multi-year plot trials were conducted in western Canada to assess the effect of reducing flea beetle feeding wounds on canola seedlings with in-crop insecticide on subsequent blackleg infection. The experiment encompassed susceptible and resistant cultivars seeded into canola stubble from the previous year, with pyrethroid insecticide applied weekly commencing at trace feeding (<5%) to mitigate the insect damage. Fluopyram seed treatment was used as an additional treatment against early blackleg infection. Results from eight station years showed moderate feeding damage by flea beetles and generally high blackleg pressure, with the average disease incidence > 80%. Despite reduced feeding damage due to in-crop insecticide treatment, significant blackleg reduction was not observed. A greenhouse study revealed no correlation between puncture wounds on cotyledons and successful stem infection under high-inoculum conditions, suggesting that reduced insect feeding might not effectively counteract the heavy inoculum pressure resulting from canola residue in field trials. Fluopyram seed treatment did not reduce blackleg substantially, while resistant cultivars consistently exhibited effectiveness. Furthermore, harvested seed from plots with lighter blackleg often displayed lower levels of L. maculans inoculum contamination.

A meta-analysis of the meat physicochemical parameters of broiler chickens fed insect-based diet.

A total of 23 studies were identified in a literature search performed in the Scopus, Science Direct and Google Scholar databases for meta-analysis. The criteria used include studies that were published from 2015 to 2023 and those reporting the effects of insect meal utilisation in poultry diets. Data on live weight (LW), carcass weight (CW), moisture, meat pH, lightness (L*), redness (a*), yellowness (b*), proximate composition (protein, fat and ash content) and shear force in broilers were subjected to OpenMEE software, and data were pooled using a random-effect model. Subgroup analysis and meta-regression were performed to ascertain the influence of dietary insect meals on the response of meat aspects and the source of heterogeneity, respectively, using the following moderators (insect species, dosage level, feeding duration and age at slaughter). The results indicated that dietary insect meal did not affect LW, CW, meat L*, pH, shear force, moisture, fat and ash content. In contrast, dietary insect meal increased the a* of the meat (standardised mean differences (SMDs) = 1.03; 95% confidence intervals (CIs) = 0.484-1.578; p ≤ 0.001), b* (SMD = 1.117; 95% CI = 0.334-1.90; p = 0.005), and meat protein content (SMD = 0.365; 95% CI = 0.031-0.7; p = 0.032). The subgroup analysis showed that insect meal dosage of ≤10% and age at slaughtered ≤35 days had improved the LW, CW and meat L*. In addition, the meat a*, protein and ash content were also influenced by insect species, dosage levels and age at slaughter. In conclusion, ≤10% of either Hermetia illucens or Tenebrio molitor can be included in broiler diets without compromising the LW, CW, meat pH, colour, shear force, moisture, fat and ash content in broilers. The study therefore indicated that insect meals have a bright future as an alternative protein source in poultry diets.