Search Results (80)

The teak defoliator, Hyblaea puera, native to South Asia and Southeast Asia (e.g., India, Laos, and Myanmar), has recently caused frequent outbreaks in mangrove forests across Guangdong, Guangxi, and other regions of China. Its larvae feed extensively on the leaves of Avicennia marina, severely threatening local mangrove ecosystems. However, accurate morphological identification of H. puera across its eggs, larvae, and pupae remains challenging. Therefore, the development of rapid molecular detection methods is essential for effective pest identification and monitoring, thereby supporting timely management interventions. In this study, mitochondrial protein-coding genes (PCGs) were analyzed from H. puera and related species were analyzed. Sliding window analysis was conducted to estimate nucleotide diversity (Pi), leading to the selection of the cytochrome c oxidase subunit I (COI) gene as the optimal target. Species-specific primers were designed based on the H. puera COI sequence, and two molecular detection assays—SS-PCR and LAMP—were developed. Both assays exhibited high specificity, stability, and sensitivity, successfully amplifying target fragments from H. puera across all tested geographic populations and different developmental stages. The limit of detection of the SS-PCR method was 83 fg/µL DNA, while that of the LAMP method reached 8.3 fg/µL DNA. The newly developed assays offer reliable and robust tools: the SS-PCR method is suitable for precise, large-scale detection in laboratory settings, whereas the LAMP assay is preferable for rapid, field-based detection of H. puera. These methods contribute to the early detection and effective management of H. puera populations, thereby safeguarding mangrove ecosystems. Full article

Two biological control agents, Archanara neurica (Hübner) and Lenisa geminipuncta (Haworth) (Lepidoptera: Noctuidae), are being released in Canada for the control of invasive common reed, Phragmites australis australis (Cav.) Trin. Ex Steud (hereafter Phragmites). The release of larvae implanted in cut Phragmites stems is the most reliable way to establish agents at new sites, but the number of larvae that can be used for releases is limited by the short period of time over which egg hatch occurs. We conducted a cold storage experiment to assess whether the timing of egg hatch can be manipulated without affecting hatch success. Additionally, we conducted visual assessments of developing eggs to determine whether hatch timing can be predicted based on early signs of development. Eggs hatched indoors had lower hatch rates than eggs hatched in outdoor conditions. For A. neurica and L. geminipuncta, eggs could be held in cold storage for 11 and 8 weeks, respectively, without affecting hatch rates. Eggs of both species began hatching 4–7 days after the appearance of visible signs of larval development. Manipulating the timing of hatch in A. neurica and L. geminipuncta will increase the number of larval releases that can be conducted during the spring and allow the timing of releases to be optimized. Full article

Common methods for detecting Drosophila suzukii (spotted-wing drosophila, SWD) in fruit, such as microscopy, physical extraction, and incubation, are time-consuming and may underrepresent egg and first instar larvae counts, the smallest life stages of SWD. To address these limitations, we evaluated a quantitative real-time PCR (qPCR) protocol to detect and quantify SWD eggs using a linear model of the log-transformed ratio of eggs to sample volume (µL) in Tris buffer and fruit tissue. Compared to traditional approaches, this method reduces identification time from several weeks to approximately five hours. We observed a negative linear correlation between qPCR cycle threshold and egg concentration in both standard and fruit tissue samples, with similar model fits (R² = 0.7215 for field fruit tissue; R² = 0.874 for standard samples). This DNA-based protocol improves infestation detection speed and accuracy by enabling rapid, species-specific identification of D. suzukii in fruit tissue, addressing limitations of morphological identification of eggs and larvae. Further refinement for fruit tissue could enhance real-world applicability. Rapid detection may enable timely assessment of varietal resistance to SWD and support safer control strategies targeting early life stages, helping to prevent pest development and fruit degradation. Full article

Laboratory maintenance of mosquitoes is important for studying vector biology and transmission of diseases, and for testing vector control tools. Standard operating procedures require feeding larvae with commercial fish meal. However, for many insectaries in sub-Saharan Africa, the commonly used feeds are imported and accompanied by procurement challenges. Changing the larval feed abruptly without allowing the larvae to adapt to new brands of feed also leads to a decrease in mosquito colonies in the laboratory. We investigated locally acquired beans, maize, and dried herrings as alternate feeds for mosquito larvae reared under laboratory conditions. Four replicates for each treatment were prepared, each containing 100 first instar larvae of Anopheles gambiae Tiassalé mosquitoes. The larvae were introduced into 500 mL of dechlorinated tap water and maintained under standard environmental insectary conditions. The larvae were provided with 40 mg of the designated powdered feed—beans, maize, and herring fish—in single and combined treatments. Tetra^® goldfish meal was included as a control. The larval mortality, developmental time, and number of pupae were recorded to evaluate the effectiveness of the feeds. Adult mosquitoes were weighed and measured to assess fitness, and females from each treatment were blood-fed and allowed to lay eggs to evaluate fertility. Larval survival differed significantly across diets (Kruskal–Wallis, p = 0.01), with maize-fed larvae showing the highest mortality (41.3%) and those with herring-based diets the lowest. Pupation and adult emergence were poorest in the maize and maize–bean groups, while the maize–herring combination achieved the highest emergence (92.6%, p = 0.03). Although overall differences were detected among the groups, conservative pairwise tests did not pinpoint specific group contrasts, but effect size estimates suggested biologically meaningful patterns. Generally, adult body weight and wing length did not differ by treatment except in maize-fed males (β = 0.371 mm, p = 0.022). Herring fish-based diets consistently supported larval survival, timely development, and robust fecundity, whereas maize-based diets were nutritionally inadequate. These findings highlight herring fish-based diets as a sustainable and cost-effective alternative to commercial feeds for maintaining Anopheles mosquito colonies, with potential to strengthen vector research capacity in resource-limited laboratories. Full article

This study investigated the population dynamics of Vespa orientalis L. (Hymenoptera: Vespidae) across two consecutive seasons (2023–2024) in selected apiaries, with a focus on nest composition (eggs, larvae, and pupae) and the effectiveness of various bait traps for capturing the species. Monthly monitoring revealed the highest population peaks in October and the lowest in December. Notable inter-seasonal variations in population density were observed across the studied sites. The average number of individuals per nest varied between seasons, reflecting fluctuations in colony development and environmental factors. In 2023, the mean counts of cells, eggs, larvae, and pupae per nest were 30.14, 18.77, 13.33, and 20.88, respectively, while in 2024, they were 10.55, 14.81, 18.02, and 30.43. Among the tested attractants, grape juice proved the most effective, capturing an average of 511.67 hornets, followed by black honey (422.33 hornets), whereas the capturing trap caught only 5 hornets. These findings provide insights into the seasonal activity and reproductive status of V. orientalis and support the development of environmentally friendly capture strategies. Full article

Glyptapanteles porthetriae (Hymenoptera: Braconidae) is a solitary larval endoparasitoid of the spongy moth, Lymantria dispar (Lepidoptera: Erebidae). Previous studies suggested that only the spring generation of the wasp parasitizes early instars of L. dispar, while subsequent generations develop in larvae of unidentified alternative hosts and overwinter exclusively as endoparasitic larvae within these hosts. In a declining outbreak population of L. dispar in Austria, we observed two successive generations of G. porthetriae developing in spongy moth larvae during spring and early summer. The high abundance of parasitoids in the third outbreak year prompted us to test alternative hypotheses proposing a univoltine, monophagous life cycle with strong specialization on L. dispar. We exposed various developmental stages of L. dispar embryonic larvae to wasp females and evaluated potential dormancy induction in G. porthetriae larvae or pupae by assessing developmental parameters and respiratory activity under different environmental conditions. G. porthetriae did not develop from L. dispar individuals exposed in the egg stage, and no dormancy was observed in G. porthetriae developing in L. dispar larvae. These findings disprove the univoltine, monophagous development hypotheses and highlight the reliance of G. porthetriae on suitable alternative hosts to complete its life cycle. Full article

There is an energy deficiency during the later stage of embryonic development, as the metabolic demands show an “explosive increase”. Vegetable oils are already used for in ovo feeding in poultry to provide energy for the embryos. What would be the effectiveness of animal oils used as alternative energy sources for the chicken embryo? To find out more, BSF larvae oil was used for in ovo feeding of the chicken embryo in this study. A total of 2300 Arbor Acres chicken eggs were used for incubation. On the tenth day of incubation, 2268 eggs were selected after candling and then divided into three groups for in ovo feeding in the yolk sac on the 11th, 14th, and 17th days of incubation. Each group was divided into seven lots, such as CON−, CON+, L0.1, L0.2, L0.3, L0.4, and L0.5. The CON− and CON+ were not injected. L0.1, L0.2, L0.3, L0.4, and L0.5 were pierced and then received the injection of 0.1 mL, 0.2 mL, 0.3 mL, 0.4 mL, and 0.5 mL of BSF maggot oil per egg, respectively. After hatching, 48 chicks from each lot of each group were housed in cages and then fed the same diet for six weeks. A better hatch rate and growth performance were observed for lots L0.1 and L0.2 compared to the other lots on the 14th and 17th days of incubation (p < 0.05). The injected lots showed reduced levels of low-density lipoprotein (LDL) cholesterol (p < 0.05). The injection of 0.1 mL BSF maggot oil on the 17th day of incubation had 0% embryonic mortality and 100% hatching success. In conclusion, BSF larvae oil can be used as an energy source for in ovo injection, with a dose of 0.1 mL on the 17th day of incubation being most effective and recommended. Full article

Early life nutrition is a critical factor influencing subsequent performance and quality, including skeletal development, in farmed Atlantic cod (Gadus morhua). This study investigated the effects of a novel start-feed protocol utilizing barnacle nauplii and plankton eggs and two experimental microdiets on larval survival, growth, skeletal anomalies, and organ ontogeny. Atlantic cod larvae were reared using three feeding protocols (COM, D1, and D2): COM used enriched rotifers and a commercial microdiet, while D1 and D2 protocols incorporated blue mussel eggs (Cryo-µ) and barnacle nauplii (Cryo-S, Cryo-L), followed by inert microdiets that differed in their phospholipid (PL) source (D1 richer in vegetable PL; D2 richer in marine PL). Larvae were sampled up to 66 days post hatching (dph) for morphometric, skeletal anomaly, and histological analyses. Survival averaged 21.3% and was unaffected by the diets. The control group had slightly higher standard length and dry weight at 66 dph compared to the experimental groups. However, larvae fed the D1 protocol exhibited a significantly lower overall prevalence of skeletal anomalies (52%) compared to the control group (91%). Moreover, D1 showed a lower occurrence of severe anomalies and a significantly reduced prevalence of scoliosis compared to both D2 and COM groups. Histology showed that group D1 achieved an overall accelerated organ ontogeny, with greater villi length and goblet cell abundance in the anterior intestine at 66 dph. In conclusion, the novel D1 feeding protocol, incorporating barnacle nauplii and a microdiet richer in vegetable phospholipids, enhanced larval quality by effectively reducing skeletal anomalies and accelerating internal organ development. Full article

Paroxetine (PRX) is a common antidepressant, also frequently used by pregnant women to treat depression and anxiety associated with pregnancy; thus, we should increase warnings about its intake. The increased presence of paroxetine in the environment raises concerns about unintended exposure to it, with consequences for embryonic development. However, the effect of PRX on early embryonic development, particularly on the embryonic brain, is still poorly studied, so this study aimed to investigate its toxicological profile on embryonated eggs of Danio rerio. Embryos of D. rerio were exposed to 1, 10, and 100 μg/L of PRX using the ZFET test. The results showed that exposure to PRX does not interfere with embryonic development but causes adverse effects in larvae, including heartbeats and an inflammatory state, with production of ROS and apoptotic cells on their head. Finally, the immunofluorescence assay for the biomarker acetylcholinesterase showed a decrease in its activity in exposed groups. Therefore, paroxetine is able to reach the nervous system during embryonic development with negative consequences. Full article

Haemonchus contortus and Haemonchus placei infect different species of ruminants, but when small ruminants and cattle share the same pasture, cross-infections can occur. Weather conditions and the herbage microenvironment influence the development and survival of larvae during the free-living stage. Development of free-living stages (eggs, L1, L2, and L3) for both nematode species in sheep faeces deposited on short grass (4 cm) and tall grass (60 cm) ground was evaluated during nine days at the beginning of the rainy season. Rainfall occurred during five of the nine days assessed, and the tall and short grass environments demonstrated different temperatures, with a maximum of 34.0 °C to 42.0 °C and 31.0 °C to 38.0 °C and a minimum of 12.0 °C to 17.0 °C and 10.0 °C to 24.5 °C for the short and tall grass, respectively. Due to the development of eggs into infective larvae (L3), decreased egg counts were observed over time in faecal samples from both species and environments. However, some eggs were still present in samples until eight days post-deposition among tall grass. In both environments, the development times for all larval stages were similar. Small numbers of H. contortus larvae were found in the soil and grass, whereas no H. placei larvae were found. In conclusion, the trend of development in different environments was similar for both nematode species; however, the tall grass environment provided better conditions for the development of larval stages of both Haemonchus species. Full article

Heterodera schachtii, a nematode primarily feeding on sugar beet and cruciferous plants, e.g., rapeseed, cabbage, broccoli, mustard, and radish, had a significant impact on Camelina sativa (L.) Crantz. The isolation of H. schachtii cysts from C. sativa roots and a known data gap regarding their development on this plant prompted an investigation into their interaction. A pot experiment conducted under controlled conditions in a growth chamber showed that H. schachtii completes its full development cycle in the roots of spring (UP, Smielowska, Borowska, Omega) and winter (Lemka, Maczuga, Luna, Przybrodzka) camelina cultivars at temperatures of 15, 20, and 25 °C. Female nematodes and cysts were most abundant in the Omega cultivar at 20 °C, averaging 9.25 per plant. Nematode feeding did not affect the height or fresh weight of the plants. Plants of the Przybrodzka cultivar had fewer leaves than the control plants. More siliques were observed on the control plants of the UP cultivar kept at 15 °C and those of the UP and Borowska cultivars at 20 °C. Under natural conditions, the number of eggs and larvae in the soil decreased by approximately 50% during the camelina growth cycle for both spring and winter biotypes. Full article

The fall armyworm, Spodoptera frugiperda, is a serious invasive pest of the family Noctuidae (Lepidoptera) that poses a significant threat to global crop production, with poaceae crops being particularly affected. Previous studies have indicated that, as a voracious insect, the fall armyworm possesses the potential for food source diversification. However, to date, limited research has been conducted on whether plants other than maize (Zea mays L.) and rice (Oryza sativa L.) can serve as potential food resources for the pest. In Yunnan Province, China, the distribution ranges of the fall armyworm and Ficus plants show a significant degree of overlap. Ficus species, including the widely distributed Ficus microcarpa L. f., commonly grow within or near cornfields. Our previous field studies have documented instances of fall armyworms in cornfields exhibiting feeding behavior on F. microcarpa. In this study, maize and F. microcarpa were selected as food resources for fall armyworms to compare larval feeding preferences, development time, survival rate, and reproductive capacity. The results demonstrated that when both maize and F. microcarpa were available simultaneously, fall armyworm larvae consumed both plant species. Further analysis revealed that larvae feeding on F. microcarpa exhibited a significantly longer developmental period from the third stage to pupation (14.08 ± 0.44 d) compared to those feeding on maize (9.21 ± 0.14 d). Moreover, the pupae size, pupae weight, and egg count were reduced by approximately 10%, 30%, and 30%, respectively, in larvae that fed on F. microcarpa. Despite these physiological challenges, our research findings indicated that, despite F. microcarpa not being the primary food source for fall armyworms under natural conditions, fall armyworms feeding on F. microcarpa were still capable of completing the life cycle from the third instar to the second generation when relying solely on F. microcarpa. Therefore, it is crucial to strengthen the observation and monitoring of fall armyworm populations feeding on F. microcarpa and implement targeted control strategies according to specific circumstances, thereby preventing F. microcarpa from acting as a potential host. Full article

The study of substances of botanical origin is fundamental for the development of new effective alternatives for the control of Aedes (Stegomyia) aegypti (Culicidae), a vector of arboviruses in humans. In this study, the potential of two new dillapiole derivatives, propyl ether dillapiole and piperidyl dillapiole, was tested to determine their ability to deter oviposition and their larvicidal and residual effects against Ae. aegypti under simulated field conditions, as alternatives for the control of this mosquito. The ability of these substances to deter oviposition by pregnant Ae. aegypti females was assessed in the laboratory, and then the larvicide and residual effects of different concentrations were tested under simulated field conditions. The determination of the enzymatic activity in exposed larvae was carried out using sublethal concentrations. The LC₅₀ values of propyl ether dillapiole after 24 and 48 h were 24.60 µg/mL and 14.76 µg/mL, and those of piperidyl dillapiole were 31.58 µg/mL and 24.85 µg/mL, respectively. After 48 h of exposure to aged, treated water, the mortality of propyl ether dillapiole (100 µg/mL) and piperidyl dillapiole (200 µg/mL) fell to 81.7% and 75% on the second day, and to 73.3% and 66.7% on the fourth day, respectively. The concentrations of 100 µg/mL of propyl ether dillapiole and 200 µg/mL of piperidyl dillapiole caused oviposition rates of only 3.80% and 4.63% of the eggs of the females, respectively, compared to 22.01% in the negative control (water and DMSO at 2%). In the larvae exposed to propyl ether, piperidyl dillapiole, dillapiole, or the chemical insecticide temephos (positive control), inhibition of acetylcholinesterase (AChE) occurred. Propyl ether dillapiole and piperidyl dillapiole have potential for use as alternative forms of control of Ae. aegypti, with propyl ether dillapiole being the most promising molecule. Further studies are needed to understand the effects of these substances on this mosquito and on non-target organisms. Full article

Gastrointestinal nematodes (GINs) inflict significant economic losses on sheep and goat farming globally due to reduced productivity and the development of anthelmintic resistance. Sustainable control strategies are urgently needed including the exploration of medicinal plants as safer alternatives to chemical anthelmintics. This genus of plants is used for anti-inflammatory, antioxidant, and antimicrobial activities. In this study, we aimed to evaluate the anthelmintic activities of Nepeta racemosa Lam. MeOH extract, n-hexane, dichloromethane (DCM), ethyl acetate (EtOAc), n-buthanol (n-BuOH) and aqueous (H₂O) subextracts, and quantify rosmarinic acid in the active extract by the HPLC method, and perform in silico molecular docking studies of rosmarinic acid to examine its binding interactions with tubulin. The anthelmintic activity of the plant extracts on gastrointestinal nematode eggs and larvae (L3) of the sheep was assessed using in vitro test methods such as the egg hatch assay and larval motility assay, conducted over a 24 h period (1, 2, 3, 4, 6, 8, 24). All extracts exhibited 100% effectiveness in the egg hatch inhibition assay, regardless of concentration (50–1.5625 mg/mL). The EtOAc subextract shows the highest effectiveness at 79.66%, followed by the MeOH extract at 74.00%, water at 64.00%, n-hexane at 67.00%, and DCM at 61.00%, and the lowest effectiveness is observed with n-BuOH at 51.66% in the larval motility assay. The major compound of EtOAc extract, the most active extract of N. racemosa, was determined as rosmarinic acid and its amount in the extract was determined as 14.50 mg/100 mg dry extract. The amount of rosmarinic acid in the MeOH extract was found to be 0.21 mg/100 mg dry extract. n-Hexane, DCM, n-BuOH, and H₂O extracts’ rosmarinic acid content was lower than the LOQ value. As tubulin plays an important role in the mechanism of anthelmintics, the major compound of the most active extract (NR-EtOAc) rosmarinic acid was docked onto the colchicine-binding site of the tubulin (5OV7) protein. Rosmarinic acid showed a similar activity spectrum to the anthelmintic drug albendazole. The discovery of low-cost and low-toxicity anthelmintic compounds is very important. Full article

Bombyx mori (Lepidoptera: Bombycidae) is an important economic insect, which mainly feeds on mulberry leaves and is widely used in many research fields. The growth and development of silkworm larvae are easily affected by the use of chemical insecticides such as novaluron, a benzoylurea insecticide. However, the effect of novaluron exposure on the reproduction of silkworms has not yet been studied. In this study, the effect of trace novaluron on the oviposition of silkworms and histopathological changes were first evaluated, and then the gene expression level changes after novaluron exposure were also determined by employing qRT-PCR. It was found that the number of eggs and the hatching rate of eggs in silkworms decreased significantly after feeding on leaves with a trace amount of novaluron (p ≤ 0.01). Furthermore, novaluron exposure could affect the development of ovary tissue by reducing the number of oocytes and oogonia in the ovaries of silkworms fed with novaluron. In addition, the transcription levels of genes related to ovary development (Vg, Ovo, Otu, Sxl-S and Sxl-L) and hormone regulation (EcR and JHBP2) showed varying degrees of downregulation at 24 h, 48 h, and 72 h after novaluron treatment (p ≤ 0.05). Therefore, we speculated that novaluron can affect the energy metabolism, ovary development, and egg formation of silkworms, thus leading to reproductive disorders of silkworms after novaluron exposure. Full article