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The objective of this study was to determine the effects of mercury chloride (HgCl2) on laying performance, egg quality, hepatic and renal histopathology, and serum biochemical profiles in laying hens. A total of 768 Hy-line brown laying hens aged 40 weeks were randomly allocated to four groups (8 pens per group and 24 hens per pen). The concentrations of mercury (Hg) in four groups were 0.280, 3.325, 9.415, and 27.240 mg/kg. Results revealed that dietary Hg could significantly reduce laying performance (P < 0.05) and egg quality (P < 0.05) and was dose-dependently deposited in albumen, yolk, eggshell, and whole egg. Meanwhile, the thicknesses of palisade layer, mammillary layer, and total layer, and the percent of palisade layer were significantly decreased (P < 0.05), while the percent of mammillary layer was sharply increased (P < 0.05) in eggshell. In addition, with increasing dietary dosage of Hg, accumulation of Hg in viscera was significantly increased (P < 0.05), and histopathological damages in liver and kidney were more and more severe. Serum alanine aminotransferase, aspartate aminotransferase, and globulin were significantly increased (P < 0.05), while serum albumin and albumin to globulin ratio were significantly decreased (P < 0.05) in 27.240 mg/kg Hg group. Blood urea nitrogen, uric acid, and creatinine were significantly increased (P < 0.05) in 3.325, 9.415, and 27.240 mg/kg Hg groups. These results suggested that dietary HgCl2 could reduce laying performance and egg quality with hepatic and renal function disorders in laying hens.

Multiple strategies involving the parasite-host-vector triad are necessary to control leishmania sis. One option is to prevent or reduce transmission of the pathogen by the phlebotomine sand fly vectors. In this sense, it is essential to explore compounds that may influence the vectorial capacity of the insect and reduce its longevity. We investigated the effect of anti- Leishmania drugs administered via the sugar meal on longevity, blood feeding, oviposition, and parasite load on the third day of infection of the sand flies, to identify the most promising candidates for vector infection tests. We identified compounds that affected the longevity of sand flies (three pterocarpanquinones – LQB-475, LQB-181, and LQ-03; one hydroxyethylpiperazine, PMIC-4, and Pentamidine), reduced oviposition of females after blood feeding (LQB-181 and PMIC-4), but did not decrease infection rates or parasite loads. The results provide the effect of antiparasitic drugs from the perspective of the insect vector.

The mosquito species Aedes aegypti is one of the main vectors of arboviruses, including dengue, Zika and chikungunya. Considering the deficiency or absence of vaccines to prevent these diseases, vector control remains an important strategy. The use of plant natural product-based insecticides constitutes an alternative to chemical insecticides as they are degraded more easily and are less harmful to the environment, not to mention their lower toxicity to non-target insects. This review details plant species and their secondary metabolites that have demonstrated insecticidal properties (ovicidal, larvicidal, pupicidal, adulticidal, repellent and ovipositional effects) against the mosquito, together with their mechanisms of action. In particular, essential oils and some of their chemical constituents such as terpenoids and phenylpropanoids offer distinct advantages. Thiophenes, amides and alkaloids also possess high larvicidal and adulticidal activities, adding to the wealth of plant natural products with potential in vector control applications.

Plant volatile organic compounds (VOCs) mediate many interactions, and the function of common VOCs is especially likely to depend on ecological context. We used a genetic mapping population of wild tobacco, Nicotiana attenuata, originating from a cross of 2 natural accessions from Arizona and Utah, separated by the Grand Canyon, to dissect genetic variation controlling VOCs. Herbivory-induced leaf terpenoid emissions varied substantially, while green leaf volatile emissions were similar. In a field experiment, only emissions of linalool, a common VOC, correlated significantly with predation of the herbivore Manduca sexta by native predators. Using quantitative trait locus mapping and genome mining, we identified an (S)-(+)-linalool synthase (NaLIS). Genome resequencing, gene cloning, and activity assays revealed that the presence/absence of a 766-bp sequence in NaLIS underlies the variation of linalool emissions in 26 natural accessions. We manipulated linalool emissions and composition by ectopically expressing linalool synthases for both enantiomers, (S)-(+)- and (R)-(−)-linalool, reported to oppositely affect M. sexta oviposition, in the Arizona and Utah accessions. We used these lines to test ovipositing moths in increasingly complex environments. The enantiomers had opposite effects on oviposition preference, but the magnitude of the effect depended strongly both on plant genetic background, and complexity of the bioassay environment. Our study reveals that the emission of linalool, a common VOC, differs by orders-of-magnitude among geographically interspersed conspecific plants due to allelic variation in a linalool synthase, and that the response of a specialist herbivore to linalool depends on enantiomer, plant genotype, and environmental complexity.

In the present study, the effects of sublethal concentrations of buprofezin on life-table traits of S. furcifera were evaluated for two consecutive generations (F0 and F1). Our results exhibited that the fecundity, life span (longevity) and hatchability of the F0 and F1 generations were significantly decreased at LC 30 compared to the control. However, copulation was not significantly affected for the F0 or F1 generations at sublethal concentrations. The female life span was affected negatively at both treatments in F0 and at LC 30 in F1, compared to the control. Furthermore, significant effects of the sublethal concentrations were found on the developmental rate of all instars except the 3 rd instar of F1. However, the pre-adult period, total pre-oviposition period (TPOP) and adult pre-oviposition period (APOP) significantly increased in F1 individuals at LC 30 and LC 10 compared to the control. Our findings revealed that demographic characters (survival rate, intrinsic rate of increase ( ri ), finite rate of increase (λ), net reproductive rate ( R 0 ), and gross reproductive rate ( GRR )) of the F1 generation (from F0 parents) significantly decreased compared to the untreated group; however, the generation time ( T ) increased at LC 10 . Therefore, the results suggested that buprofezin could adversely affect individuals in the successive generation.

Aedes aegypti, the primary vector of viruses such as dengue, chikungunya, and yellow fever, poses a global health challenge. Traditional vector control strategies predominantly rely on broad-spectrum insecticides, which not only contribute to development of resistance in mosquitoes but also pose significant risks to non-target organisms and the environment. Here, we assessed the potential of cigarette butt (CB) extract for the management of A. aegypti population. Globally, 4.5 trillion CBs are being wasted annually, which is expected to rise to nine trillion by 2025. So, repurposing this waste for vector control offers an innovative approach. This study evaluated the potential of CB extract to deter ovipositing females and to assess larval mortality of A. aegypti using three concentrations of CB extract (1 CB, 2 CBs, and 3 CBs) against a control (water only). Our results revealed that highest concentration (3 CBs) significantly repelled the egg-laying females and resulted in 100% mortality of younger mosquito larvae (1st and 2nd instars) within 24 h of exposure, whereas complete mortality in mature larvae (3rd and 4th instars) was observed within 48 h of exposure. GC–MS analysis of CB extracts, using acetone and methanol as solvents, revealed both qualitative and quantitative differences in the chemical composition. Identified compounds include nicotine, phthalic acid, terephthalic acid, and acetonyl dimethyl carbinol. This study presents an innovative solution for recycling cigarette butt waste to control A. aegypti population at both adult and larval stages and highlights the potential to utilize CB waste into integrated vector management programs.

Trichogramma chilonis (Ishii) is an important egg parasitoid of Helicoverpa species in tomato growing areas of Pakistan. Different insecticides are used for the management of H. armigera , but these insecticides have significantly reduced the effectiveness of T. chilonis . Therefore, this research aims to understand the compatibility of the selected insecticides with biological control strategies involving T. chilonis for managing Helicoverpa armigera in tomato-growing areas. For this purpose, the effects of five insecticides namely Novaluron, Bifenthrin, Emamectin Benzoate, Chlorantraniliprole and Imidacloprid were assessed against T. chilonis under laboratory conditions. The assays involved direct applications of different insecticides on Sitotroga cerealella eggs and their subsequent effect of T. chilonis life history parameters. A total of 200 eggs were used in each treatment. The results revealed that all the tested insecticides had subsequent negative effects on T. chilonis performance. The results showed that the insecticides Imidacloprid and Chlorantraniliprole led to low mean fecundity, minimum number of male and female adults emergence and prolonged the total pre-oviposition period of T. chilonis as compared to Bifenthrin and Novaluron. The bootstrap results recorded the highest value of the net reproductive rate ( R 0 ), intrinsic rate of increase ( r ) and the finite rate of increase (λ) of T. chilonis in host eggs treated with Bifenthrin and Novaluron as compared to the other tested chemicals. The results regarding percent parasitism showed that maximum percent parasitism was noted in control, Bifenthrin and Novaluron, while the insecticides Imidacloprid and Chlorantraniliprole resulted in minimum % parasitism (63.5% and 71%) respectively. The study revealed that Bifenthrin and Novaluron are relatively more compatible with the T. chilonis in the different integrated pest management programs for H. armigera as compared to other tested chemicals.

Selection of appropriate oviposition sites is essential for progeny survival and fitness in generalist insect species, such as Drosphila melanogaster, yet little is known about the mechanisms regulating how environmental conditions and innate adult preferences are evaluated and balanced to yield the final substrate choice for egg-deposition. Female D. melanogaster are attracted to food containing acetic acid (AA) as an oviposition substrate. However, our observations reveal that this egg-laying preference is a complex process, as it directly opposes an otherwise strong, default behavior of positional avoidance for the same food. We show that 2 distinct sensory modalities detect AA. Attraction to AA-containing food for the purpose of egg-laying relies on the gustatory system, while positional repulsion depends primarily on the olfactory system. Similarly, distinct central brain regions are involved in AA attraction and repulsion. Given this unique situation, in which a single environmental stimulus yields 2 opposing behavioral outputs, we propose that the interaction of egg-laying attraction and positional aversion for AA provides a powerful model for studying how organisms balance competing behavioral drives and integrate signals involved in choice-like processes.

The diverse flora of the Atlantic Forest is fertile ground for discovering new chemical structures with insecticidal activity. The presence of species belonging to the genus Baccharis is of particular interest, as these species have shown promise in pest management applications. The objective of this study is to chemically identify the constituents expressed in the leaves of seven species of Baccharis ( B. anomala DC., B. calvescens DC., B. mesoneura DC., B. milleflora DC., B. oblongifolia Pers., B. trimera (Less) DC. and B. uncinella DC.) and to evaluate the toxicological and morphological effects caused by essential oils (EOs) on the larvae and adults of Drosophila suzukii (Diptera: Drosophilidae). Chemical analysis using gas chromatography-mass spectrometry (GC–MS) indicated that limonene was the main common constituent in all Baccharis species. This constituent in isolation, as well as the EOs of B. calvescens , B. mesoneura , and B. oblongifolia , caused mortality in over 80% of adults of D. suzukii at a discriminatory concentration of 80 mg L −1 in bioassays of ingestion and topical application. These results are similar to the effect of spinosyn-based synthetic insecticides (spinetoram 75 mg L −1 ) 120 h after exposure. Limonene and EOs from all species had the lowest LC 50 and LC 90 values relative to spinosyn and azadirachtin (12 g L −1 ) in both bioassays. However, they showed the same time toxicity over time as spinetoram when applied to adults of D. suzukii (LT 50 ranging from 4.6 to 8.7 h) in a topical application bioassay. In olfactometry tests, 92% of D. suzukii females showed repellent behavior when exposed to the EOs and limonene. Likewise, the EOs of B. calvescens , B. mesoneura , and B. oblongifolia significantly reduced the number of eggs in artificial fruits (≅ 7.6 eggs fruit −1 ), differing from the control treatment with water (17.2 eggs fruit −1 ) and acetone (17.6 eggs fruit −1 ). According to histological analyses, the L3 larvae of D. suzukii had morphological and physiological alterations and deformations after exposure to treatments containing EOs and limonene, which resulted in high larval, pupal, and adult mortality. In view of the results, Baccharis EOs and their isolated constituent, limonene, proved to be promising alternatives for developing bioinsecticides to manage of D. suzukii .

The orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), is a significant wheat pest in the Prairie Provinces of Canada and northern regions of the USA. Wheat phenology plays a critical role in wheat midge oviposition. We hypothesized that S. mosellana oviposition behaviour is influenced by volatile organic compounds (VOCs) emitted by wheat at two adjacent wheat growth stages: preanthesis and postanthesis. A higher number of S. mosellana eggs laid on preanthesis than postanthesis spikes in an oviposition choice experiment using the susceptible spring wheat cultivar ‘Roblin’. In preanthesis, wheat emitted higher amounts of Z-3-hexenyl acetate (Z3-06:OAc) than at the postanthesis stage. Higher amounts of methyl ketones such as 2-tridecanone, 2-pentadecanone, and 2-undecanone were emitted by wheat in the postanthesis stage and these VOCs were sensitive to S. mosellana antennae used in the Gas Chromatography-Electroantennographic Detection. Females were attracted to synthetic Z3-06:OAc but were deterred by 2-tridecanone relative to the solvent control in the vertical Y-tube olfactometer. 2-Undecanone and 2-pentadecanone did not show any attractiveness or deterrence. In a no-choice oviposition experiment, fewer eggs were laid in preanthesis wheat exposed to a synthetic VOC blend of Z3-06:OAc, 2-undecanone, 2-tridecanone, and 2-pentadecanone at the concentrations released by postanthesis spikes. This study shows that the reduction of Z3-06:OAc, in the VOC mix, and possibly the increase in 2-tridecanone, are likely responsible for the reduction in oviposition on postanthesis wheat. These results elucidate for the first time the role of specific VOCs mediating S. mosellana oviposition in preanthesis and postanthesis wheat.