Egg Hatching Rate Research Articles

Gene flow stimulates recovery of reproductive fitness in a captive bred insect

Abstract Captive breeding can be a useful tool for the management of threatened species, but such programs often begin with a bottleneck which may lower reproductive fitness by increasing inbreeding and allowing deleterious alleles to increase in frequency by reducing effective population size. Dryococelus australis, the Lord Howe Island stick insect, is a critically endangered insect that has been bred at the Melbourne Zoo in Melbourne, Australia, since shortly after the species was rediscovered in 2001. We analysed a long‐term dataset of phenotypic measurements from this captive breeding program to determine whether reproductive fitness has declined in captivity. We found a clear signal of decline in direct (egg hatching success) and indirect (egg and nymph size) fitness indicators over time. We compared a captive line descended from the original program founders to a new hybrid line that has recent wild ancestry. The hybrid line showed an immediate improvement in egg hatch rate, suggesting the potential for genetic rescue. Egg and nymph size did not show as dramatic a change, although this line had only existed for just over a single generation at the time of data collection. These results argue strongly for the regular sourcing of new genetic material from the wild D. australis population to counteract fitness declines in captivity. Aside from benefiting the captive population, this would also improve the prospects of establishing new wild populations in the future, using individuals sourced from captivity.

Inheritance and Fitness Cost of Laboratory-Selected Resistance to Cry1Ab in Hyphantria cunea Drury (Lepidoptera: Arctiidae)

Transgenic poplars have been used to control quarantine pests worldwide, such as the fall webworm (Hyphantria cunea, FW). However, the studies on the resistance mechanism of FW to Cry toxins are limited. This study obtained an FW strain with 45-fold resistance to Cry1Ab toxin by continuous screening in the laboratory. The resistance to Cry1Ab was autosomally completely recessive, and it had approximately 40-fold cross-resistance to Cry1Ac but no cross-resistance to Cry2Ab toxin. Analysis of indoor population life tables for the resistant and susceptible strains found no significant difference in the net reproduction rate (R0) between the two strains. The resistant strain had an insignificantly longer larval development duration and a comparable pupation rate, pupal weight, emergence rate, eggs laidper female, and egg hatching rate compared to the susceptible strain. This indicated that there was no fitness cost for Cry1Ab resistance. Our study helps in evaluating the risk of resistance to Cry1Ab toxin and the mechanisms of resistance to Cry1Ab toxin in FW.

Pathogenicity and sub-lethal activity of orally administered entomopathogenic fungi against two adult mosquito species, Aedes aegypti (Diptera: Culicidae) and Anopheles stephensi (Diptera: Culicidae)

Entomopathogenic fungi (EPF) are known for their efficacy in controlling adult mosquito populations by penetrating through their cuticle. However, the effect of oral administration of EPF on the biological parameters of Aedes aegypti and Anopheles stephensi remains largely unexplored. This study aimed to assess the effect of orally administrated EPF isolates on the survival, feeding behavior, fecundity, fertility, follicle development and host-searching behavior in response to yeast-generated CO2 of Ae. aegypti and An. stephensi. An initial screening of 50 isolates involved exposure of adult Ae. aegypti and An. stephensi by integument inoculation. Subsequently, the entomopathogenic effect of the five highly virulent isolates was confirmed through oral administration revealing Beauveria pseudobassiana 42–51 as a potent mosquito killer. B. pseudobassiana 42–51 was administered orally to evaluate sub-lethal effects. The results showed a 63 % and 43 % reduction in blood feeding of Ae. aegypti and An. stephensi, respectively. Furthermore, a decrease in egg hatching rate was observed, with a reduction of 83% for Ae. aegypti and 74% for An. stephensi on the seventh day following fungal administration, showing decreased hatchability in both species. Poor and abnormal follicle development was observed in both mosquito species. Also, the host-searching behavior was evaluated by attraction to CO2 utilizing a Y-tube olfactometer. A tendency of reduction in the attraction rate towards the odor was observed three days post-fungal administration. These findings underscore the significant impact of oral administration of B. pseudobassiana 42–51 on mosquitoes, highlighting not only its lethal effects but also sub lethal impacts on their biology. Moreover, this fungus may exhibit the potential to simultaneously control both mosquito species and serve as a biocontrol agent for the management of vector-borne diseases.

Biocontrol Efficacy of Bacillus thuringiensis Strain 00-50-5 Against the Root-Knot Nematode Meloidogyne enterolobii in Pepper

The root-knot nematode Meloidogyne enterolobii is a major constraint to pepper production in tropical regions. In the long-term practice of root-knot nematode management, bacterial nematicides have attracted increasing attention as effective biocontrol agents. In this study, we evaluated the efficacy of Bacillus thuringiensis strain 00-50-5 (Bt 00-50-5) against M. enterolobii through in vitro, greenhouse and field trials. The cell-free supernatant of Bt 00-50-5 exhibited potent nematicidal activity against second-stage juveniles (J2s) of M. enterolobii, with mortality rates of 98.0% and 100% after 24 h and 36 h of exposure, respectively. In addition, Bt 00-50-5 showed inhibitory effects on the hatching of M. enterolobii eggs, resulting in a remarkable 96.6% reduction in the egg hatching rate after 6 days compared to the control. The pot trials showed that both pepper root galls and egg masses were reduced, and plant growth was improved after treatment with Bt 00-50-5. The field trials showed that the gall index was significantly reduced, with a 66.3% and 68.2% reduction in disease index in 2020–2021 and 2021–2022, respectively, and pepper yield was improved, with a 96.2% and 93.1% increase in yield in 2020–2021 and 2021–2022, respectively, compared to the control. These results indicate the potential use of Bt 00-50-5 as an effective biocontrol agent against M. enterolobii.

Exposure to Cyantraniliprole Adversely Impacts Fitness of Harmonia axyridis: Acute Toxicity and Sublethal Effects on Development, Fecundity and Antioxidant Responses.

Extensive utilization of pesticides and their persistent residues inadvertently pose threats to the effectiveness and fitness of biocontrol agents in agroecosystems. However, these ecological consequences are generally disregarded when executing integrated pest management strategies (IPM). Cyantraniliprole (CNAP) serves as a wide-spectrum diamide insecticide and its sublethal effects have been well characterized on multiple insect pests, whereas its impacts on beneficial natural enemies remain unfathomed. Herein we exposed Harmonia axyridis, a predacious generalist, to lethal and sublethal concentrations of CNAP via dipping treatment (egg stage) and topical applications (1st-instar stage + adult stage). The acute toxicity tests revealed that LC50 of CNAP were 90.11, 86.11 and 240.50 mg/L against embryos, 1st instar nymphs and female adults, respectively, with safety factors ranging from 1.14 to 5.34, suggesting its medium toxicity for H. axyridis and larval stage was the most susceptible. The embryonic, larval and pupal durations of coccinellids ecdysed from CNAP-treated eggs and 1st instars were all elongated under sublethal concentrations, of which LC30 triggered more pronounced and significant retardations relative to control. Besides, exposed coccinellids displayed substantially diminished pupal mass and pupation rate, most notably for insects molted from the 1st-instar stage upon CNAP sublethal treatments. With respect to reproductive performance, LC10 and LC30 of CNAP all significantly suppressed female fecundity, as evidenced by reduced vitellin content, a prolonged pre-oviposition period (POP), mitigated laid eggs and the egg hatching rate. Specifically, there existed positive correlations between vitellin level (Vn) and number of eggs deposited by per female, indicative of CNAP affecting fecundity by regulation of Vn. In addition, the antioxidant system was also profoundly disrupted by CNAP, with compromised POD activity at different concentrations over time and induced hormesis of SOD/CAT activities post LC10 exposure. Activities of SOD and TAC were enhanced to exert protective functions during the first 48 h, while defense collapsed at 72 h following LC30 treatments that depleted all enzymatic activities. We speculated that fitness trade-offs may occur between reproductive capacity and antioxidant defenses to sustain physiological homeostasis in response to CNAP stress. Collectively, this study evaluated the ecological risk of CNAP and unmasked its adverse implications for overall fitness of H. axyridis, which highlighted rational application of agrochemicals to conserve biocontrol agents when implementing IPM strategies for sustainable pest control.

Discovery of novel nematicidal active ingredient 2,4,7-trichloroquinazoline as a potential succinic dehydrogenase inhibitor

Plant-parasitic nematodes seriously affect the growth and yield of crops, causing huge economic losses to world agriculture. One of the effective ways to manage nematode diseases is the use of nematicides. Compound B1 was found to have good nematicidal activity in the biological test. Therefore, some compounds with similar structures to B1 were tested for better nematicidal activities. Among them, the LC50 of compound C3 against pine wood nematode (Bursaphelenchus xylophilus), rice stem nematode (Aphelenchoides besseyi), and sweet potato stem nematode (Ditylenchus destructor) were 4.6, 22.4, and 16.9 mg/L, respectively, which are markedly better than tioxazafen (103.9, 56.2, and 61.0 mg/L). Compound C3 was capable of not only significantly promoting oxidative stress in Bursaphelenchus xylophilus (B. xylophilus), but also curtailing population growth by influencing the frequency of head swing frequency, feeding behaviors, reproductive capabilities, and egg hatching rates. Furthermore, Compound C3 has demonstrated a favorable binding affinity to the succinic dehydrogenase (SDH) protein and has significantly dampened the activity of the SDH in B. xylophilus. Therefore, compound C3 can be used as a potential lead compound to discover new nematicides.

Spirodiclofen toxicity in Tetranychus urticae and safety to natural enemies Proprioseiopsis asetus and Amblyseius swirskii

Proprioseiopsis asetus and Amblyseius swirskii are excellent natural enemies of plant-feeding mites and small pests. In order to clarify the safety of the acaricide spirodiclofen to the predatory mites P. asetus and A. swirskii, here, we investigated the toxicity of the acaricide on the pest mite T. urticae (nymphs and adult females) and on both species of predatory mites, P. asetus and A. swiskii (eggs, nymphs, and female adults) by using the spray, slide-dip, and leaf residual toxicity methods, compared the selective toxicity and assessed the safety to these natural enemies. The results demonstrated that the corrected mortality in P. asetus and A. swirskii female adults was <5% at recommended spirodiclofen concentrations in the spray method. In the leaf residual toxicity method, P. asetus and A. swirskii egg-hatching rates did not differ significantly from the pure water control group. In the slide-dip method, spirodiclofen lethal concentration 50 (LC50) in P. asetus and A. swirskii female adults was noted to be 9,494.875 and 3,064.187 mg·L−1, respectively. In the spray method, spirodiclofen LC50 in P. asetus and A. swirskii nymphs was found to be 4,292.664 and 1,081.609 mg·L−1, respectively, and that in T. urticae female adults and nymphs was 55.189 and 40.862 mg·L−1, respectively. Spiroclofen selective toxicity ratios (STRs) in P. asetus female adults–T. urticae and P. asetus nymphs–T. urticae were 172.013 and 105.053, respectively, indicating that spiroclofen has a high positive selectivity toward the pest T. urticae and its natural enemy P. asetus. In contrast, spiroclofen STRs in A. swirskiis female adults–T. urticae and A. swirskiis nymphs–T. urticae were 55.522 and 26.470, respectively, indicating spiroclofen has a moderate positive selectivity toward the pest T. urticae and its natural enemy A. swirskii. In the safety evaluation, the spirodiclofen safety factor for P. asetus female adults and nymphs was 158.248–237.37 and 71.544–107.317, respectively, whereas that for A. swirskii female adults and nymphs was 50.070–76.605 and 18.027–27.040 respectively. All spirodiclofen safety factor values were much higher than 5, indicating that spirodiclofen is highly safe for P. asetus and A. swirskii; in particular, spirodiclofen is safer for P. asetus than for A. swirskii.

Limonene enhances rice plant resistance to a piercing-sucking herbivore and rice pathogens.

Terpene synthases (TPSs) are key enzymes in terpenoids synthesis of plants and play crucial roles in regulating plant defence against pests and diseases. Here, we report the functional characterization of OsTPS19 and OsTPS20, which were upregulated by the attack of brown planthopper (BPH). BPH female adults performed concentration-dependent behavioural responses to (S)-limonene showing preference behaviour at low concentrations and avoidance behaviour at high concentrations. Overexpression lines of OsTPS19 and OsTPS20, which emitted higher amounts of the monoterpene (S)-limonene, decreased the hatching rate of BPH eggs, reduced the lesion length of sheath blight caused by Rhizoctonia solani and bacterial blight caused by Xanthomonas oryzae. While knockout lines of OsTPS19 and OsTPS20, which emitted lower amounts of (S)-limonene, were more susceptible to these pathogens. Overexpression of OsTPS19 and OsTPS20 in rice plants had adverse effects on the incidence of BPH, rice blast, and sheath blight in the field and had no significant impacts on rice yield traits. OsTPS19 and OsTPS20 were found to be involved in fine-tuning the emission of (S)-limonene in rice plants and play an important role in defence against both BPH and rice pathogens.

Characteristics of a Spray-Dried Porcine Blood Meal for Aedes aegypti Mosquitoes.

Research into mosquito-borne illnesses faces hurdles because feeding fresh animal blood to rear female mosquitoes presents logistical, economic, and safety challenges. In this study, a shelf-stable additive (spray-dried porcine blood; SDPB) hypothesized to supply accessible hemoglobin was evaluated within an alternative meal (AM) containing whey powder and PBS for rearing the yellow fever mosquito Aedes aegypti. LC-MS/MS proteomics, microbial assays, and particle reduction techniques confirmed and characterized the functionality of hemoglobin in SDPB, while engorgement, fecundity, egg viability, and meal stability bioassays assessed AM performance. Chemical assays supported hemoglobin as the phagostimulant in SDPB with aggregates partially solubilized in the AM that can be more accessible via particle reduction. Unpaired two-tailed t-tests indicate that the AM stimulates oogenesis (t11 = 13.6, p = 0.003) and is stable under ambient (1+ y; t12 = 0.576, p = 0.575) and aqueous (14 d; t12 = 0.515, p = 0.639) conditions without decreasing fecundity. Egg hatch rates for the ninth generation of AM-reared Ae. aegypti were 50-70+%. With further development, this meal may serve as a platform for mass rearing or studying effects of nutritional additives on mosquito fitness due to its low cost and stability. Future work may examine tuning spray drying parameters and resulting impacts on hemoglobin agglomeration and feeding.

Evaluation of biological traits, morphometric characteristics, feeding preferences, and infestation potential of pulse beetle (Callosobruchus maculatus fab.) on various pulse crops

The pulse beetle, Callosobruchus maculatus (Fab.), is a major invasive pest of stored legume seeds in Pakistan. This study aimed to investigate the biology, morphometrics, feeding potential, and seed damage caused by the beetle on different pulses under laboratory conditions in 2023. The insect laid the highest number of eggs on Vigna unguiculata (8.53±0.95), followed by V. radiata (7.55±0.78), V. mungo (6.66±0.75), Phaseolus vulgaris (6.61±0.63), and Cicer arietinum (5.02±0.37). The mean egg incubation periods were recorded as follows: black gram (5.60±0.54), cowpeas (5.50±0.21), chickpea (4.00±0.72), green gram (4.00±0.37), and kidney bean (0.00±0.00) days, respectively. The egg hatching rates were (39.30%) green gram, (36.10%) cowpeas, (19.50%) chickpea, (5.10%) black gram, and (0.00%) for kidney beans. Notably, while (23.30%) of the eggs were laid on kidney beans, none hatched, and no adults emerged due to the smooth surface of the seed coat. The larvae and pupae development period lasted (24-27) days on black gram, (23-25) days on white gram, (19-21) days on cowpeas, and (18-20) days on green gram. Adult females survived for (14-15) days on cowpeas, (10-15) days on green gram, (12-14) days on black gram, and (10-11) days on chickpea. The mean fecundity was recorded at (6.12±3.17) eggs when two males fertilized one female and (8.73±4.22) eggs when one male fertilized two females. Cowpea seeds were identified as the preferred food source for C. maculatus compared to other pulses. Therefore, effective control of this pest is crucial to protect legume crops.

Reproductive parameters of a new biocontrol agent, Eupeodes americanus (Diptera: Syrphidae) and comparison with the commercialized Aphidoletes aphidimyza (Diptera: Cecidomyiidae).

The American hoverfly Eupeodes americanus (Wiedemann) (Diptera: Syrphidae) is an aphidophagous predator during its larval stage and is currently being evaluated for inclusion in biocontrol programs as a new biocontrol agent. However, little is known about its reproductive aptitudes. The objective of the present study was to determine the reproductive parameters of E. americanus and to compare them with those of a commercialized and widely used biological control agent for aphids, the aphid midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae). The preoviposition period, oviposition period, adult longevity, lifetime and daily fecundity, egg hatching rate, and fertility were determined for E. americanus females and compared to those of A. aphidimyza. Trials were conducted under laboratory conditions in rearing cages on the broad bean plant Vicia faba L. (Fabaceae), infested with pea aphids Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae). The results revealed that the preoviposition period, oviposition period, and adult longevity were significantly longer in E. americanus than in A. aphidimyza. The daily fecundity and egg-hatching rate were similar in both species. However, lifetime fecundity and fertility were considerably higher in E. americanus than in A. aphidimyza. This study demonstrates that the reproductive capacity of E. americanus is clearly superior to that of A. aphidimyza and therefore supports its inclusion in the aphid pest management program as a new biocontrol agent.

Optimizing and synchronizing Aedes aegypti colony for Sterile Insect Technique application: Egg hatching, larval development, and adult emergence rate

Mosquito Sterile Insect Technique (SIT) programs can be developed in smaller agencies through synchronization of the colony development to take advantage of the natural male early emergence. This paper examined key aspects of Ae. aegypti colony synchronization work, including egg hatching, larval development, and adult emergence to produce sufficient numbers of adult male mosquitoes within a specific timeframe for irradiation and release. Our data indicated that a relatively low percentage of males are required for colony propagation. Additional results highlighted that fresher Ae. aegypti eggs could yield as high as a 93 % hatching success than older eggs when placed under vacuum pressure in yeast infused water for 1.5 h. Eggs that were one-month old hatched (93 %) better than older eggs (0–32 %). A higher egg density in the hatching flask was correlated to a lower hatch rate, and higher larval density was related to unsynchronized pupae and delayed adult emergence. By keeping Ae. aegypti larvae at reasonable density, over 95 % of adults emerged on the first two days of emergence – indicating a high synchronicity. A standardized colony maintenance protocol therefore renders a synchronized larval development and adult male emergence which are critical in SIT programs.

'The Garlic Gambit': an alternative strategy for controlling vine weevil (Otiorhynchus sulcatus F.; Coleoptera: Curculionidae).

Plant protection products derived from plant material are proposed to be a sustainable alternative to conventional synthetic chemical pesticides. This study determines the efficacy of a commercially available bioinsecticide based on garlic (Allium sativum L.; Asparagales: Amaryllidaceae) extract against vine weevil (Otiorhynchus sulcatus F.; Coleoptera: Curculionidae) eggs and larvae in contact, fumigation and a combination of contact and fumigation bioassays under laboratory conditions. Results showed that garlic significantly reduced egg hatch rate compared to the control group when applied as a fumigant. Similarly, the egg hatch rate was reduced compared to the control group when garlic was applied as combined contact and fumigant applications. No effect was observed when the garlic product was applied as a contact application. The bioinsecticide significantly reduced larval survival when either contact or fumigant applications were used. A combined contact and fumigant effect was shown also when vine weevil eggs were exposed to the bioinsecticide for 30 days in plastic containers containing growing media. The number of larvae recovered after this period was significantly reduced compared to the control group. This study demonstrates the potential of garlic-based bioinsecticides, such as Pitcher GR, for vine weevil control. Further studies are, however, needed to determine the efficacy of such bioinsecticides under field conditions and investigate how these products can be most effectively used as a part of a wider vine weevil integrated pest management program.

Functional analysis of novel cystatins from Haemaphysalis doenitzi and evaluation of their roles in cypermethrin and λ-cyhalothrin resistance

Currently, the primary strategy for tick control relies on chemical agents. Pyrethrins, which are botanically derived compounds, have demonstrated efficacy in controlling ticks without posing a risk to human or animal health. However, research into pyrethrins' metabolic mechanisms remains sparse. Cystatin, as a reversible binding inhibitor of cysteine protease, may be involved in the initiation of pyrethrin detoxification of Haemaphysalis doenitzi. In this study, two novel cystatins were cloned, HDcyst-3 and HDcyst-4, the relative expression of which was highest in the Malpighian tubules compared with the tick midguts, salivary glands, and ovaries. Prokaryotic expression and in vitro studies revealed that cystatins effectively inhibit the enzymatic activities of cathepsins B and S. RNAi results showed that the reduction of cystatins significantly decreased the engorgement weight, egg mass weight, and egg hatching rate of adult female ticks, and prolonged feeding time by two days. The control rate of rHDcyst-3 and rHDcyst-4 protein vaccination against female adults were 55.9% and 63.2%, respectively. In addition, the tick immersion test showed that cypermethrin and λ-cyhalothrin had significant acaricidal effects against adult unfed H. doenitzi. The qPCR result indicated that compared with the control group, the expression of HDcyst-3 and HDcyst-4 was markedly decreased in the sublethal cypermethrin and λ-cyhalothrin group at LC50. Enzyme activity showed that cypermethrin and λ-cyhalothrin could significantly induce the activities of glutathione S-transferase (GST), carboxylesterase (CarE), and acetylcholinesterase (AchE). The aforementioned results provided indirect evidence that cystatin plays an important role in pyrethrin detoxification and provides a theoretical basis for future acaricide experiments and pest management.

Assessing the Efficacy of Acanthoic Acid Isolated from Acanthopanax koreanum Nakai in Male Infertility: An In Vivo and In Silico Approach.

Acanthoic acid, a diterpene isolated from the root bark of Acanthopanax koreanum Nakai, possesses diverse pharmacological activities, including anti-inflammatory, anti-diabetic, gastrointestinal protection, and cardiovascular protection. This study is the first to investigate the egg-hatching rates of Drosophila melanogaster affected by acanthoic acid. Notably, male flies supplemented with 10 μM acanthoic acid exhibited a strong increase in hatching rates compared with controls under adverse temperature conditions, suggesting a potential protective effect against environmental stressors. Molecular docking simulations revealed the binding affinities and specific interactions between acanthoic acid and proteins related to male infertility, including SHBG, ADAM17, and DNase I, with binding affinity values of -10.2, -6.8, and -5.8 kcal/mol, respectively. Following the docking studies, molecular dynamic simulations were conducted for a duration of 100 ns to examine the stability of these interactions. Additionally, a total binding energy analysis and decomposition analysis offered insights into the underlying energetic components and identified key contributing residues.

The effect of transport temperature and duration on survival and growth of house cricket nymphs and eggs

Abstract The transport of live insects is becoming increasingly common within the food and feed industry. However, very little information is available as to its effects on the insects themselves. The aim of this study was to monitor how variation in transport conditions, such as duration of transport and external temperature and humidity, directly and indirectly affect the survival and growth of nymphs of the house cricket, Acheta domesticus. In addition, we investigated the effect of external temperature on the viability of eggs upon completion of a transport event. We investigated how four different temperatures (5 °C, 15 °C, 25 °C, 35 °C) and four possible transport durations (1, 2, 3, 6 days) affected survival and growth of the cricket nymphs. To gain insight into the potential transport of eggs, its effect on egg hatch-rate was studied by storing eggs at three different temperatures (6 °C, 18 °C and 30 °C) before moving the eggs to optimal hatching conditions. We found that humidity remained constant inside the transport boxes and was different from the exterior humidity. Temperature had a significant effect on nymph survival and growth. The extreme temperatures negatively affected nymph survival, and increased temperature was correlated with increased growth. The development of eggs was also sensitive to temperature, and transport of eggs at suboptimal temperatures prolonged incubation time considerably. Finally, based on the results of this study, we discuss temperature optimisation as the most critical factor to consider during transport of live house cricket nymphs and eggs.

The impact of non-lethal doses of pyriproxyfen on male and female Aedes albopictus reproductive fitness.

Control of the mosquito Aedes albopictus is confounded by its behavior due to females preferring to oviposition in small natural and artificial containers that are often difficult to remove or treat with insecticides. Autodissemination strategies utilizing highly potent insect growth regulators (IGRs) have emerged as promising tools for the control of this container-inhabiting species. The intended goal of autodissemination approaches is to use mosquitoes to self-deliver an IGR to these cryptic oviposition locations. Previous studies have focused on the efficacy of these approaches to impact natural populations, but little focus has been placed on the impacts on mosquitoes when exposed to non-lethal doses of IGRs similar to the levels they would be exposed to with autodissemination approaches. In this study, the impact of non-lethal doses of pyriproxyfen (PPF) on the reproductive fitness of Ae. albopictus was investigated. Female and male Ae. albopictus mosquitoes were exposed to non-lethal doses of PPF and their fecundity and fertility were measured. To examine the impact of non-lethal doses of PPF, the expression of the ecdysone-regulated genes USP, HR3, and Vg, which are involved in vitellogenesis, was determined. Our results demonstrated a significant reduction in female fecundity and in the blood feeding and egg hatching rates upon exposure to non-lethal doses of PPF. Oocyte development was also delayed in PPF-treated females. Furthermore, exposure to non-lethal doses of PPF altered the expression of the genes involved in vitellogenesis, indicating disruption of hormonal regulation. Interestingly, PPF exposure also reduced the sperm production in males, suggesting a potential semi-sterilization effect. These findings suggest that non-lethal doses of PPF could enhance the efficacy of autodissemination approaches by impacting the reproductive fitness of both males and females. However, further research is needed to validate these laboratory findings in field settings and to assess their practical implications for vector control strategies.

Implementation of the Fuzzy Logic Mamdani Method in the KUB Chicken Egg Incubator

Poultry farming plays an important role in rural Indonesia's economy, with increasing demand for poultry meat and protein-rich eggs. One of the main challenges for farmers is the limited production of chicken seeds and suboptimal egg incubation methods. Modern egg incubators offer a solution with higher ease and efficiency compared to traditional methods. However, existing machines on the market have weaknesses, such as less accurate temperature and humidity control, and less optimal power source switching. The use of fuzzy logic methods in egg incubators has proven to be more efficient than manual methods, with a hatching success rate of 100% for 10 eggs. Fuzzy logic-based egg incubators start hatching earlier and more on days 18 and 19, while manual methods begin on days 19 and 20. The automatic egg-turning process in fuzzy logic machines saves labor and reduces the risk of error. This research highlights the importance of using accurate sensors and optimal temperature and humidity control systems to improve the success rate of chicken egg hatching. Index Terms—poultry farming; egg hatching; temperature; humidity; fuzzy logic

The Xenorhabdus nematophila LrhA transcriptional regulator modulates production of γ-keto-N-acyl amides with inhibitory activity against mutualistic host nematode egg hatching.

Xenorhabdus bacteria are of interest due to their symbiotic relationship with Steinernema nematodes and their ability to produce a variety of natural bioactive compounds. Despite their importance, the regulatory hierarchy connecting specific natural products and their regulators is poorly understood. In this study, comparative metabolomic profiling was utilized to identify the secondary metabolites modulated by the X. nematophila global regulator LrhA. This analysis led to the discovery of three metabolites, including an N-acyl amide that inhibited the egg hatching rate and length of Steinernema carpocapsae nematodes. These findings support the notion that X. nematophila LrhA influences the symbiosis between X. nematophila and S. carpocapsae through N-acyl amide signaling. A deeper understanding of the regulatory hierarchy of these natural products could contribute to a better comprehension of the symbiotic relationship between X. nematophila and S. carpocapsae.

Incompatible insect technique: insights on potential outcomes of releasing contaminant females: a proof of concept under semi-field conditions.

Releasing large numbers of Aedes albopictus males, carrying the artificially introduced Wolbachia 'wPip' strain, results in a decrease in the reproductive capacity of wild females due to a phenomenon known as cytoplasmic incompatibility (CI). This vector control strategy is referred to as the incompatible insect technique (IIT). However, its widespread implementation faces various challenges, including the complexity of removing fertile females from the males intended for release. Here, we present the results of semi-field experiments comparing the impact of minimal female co-release on two IIT modes: unidirectional CI-based (UnCI IIT) and bidirectional CI-based (BiCI IIT), specifically targeting Ae. albopictus. The contamination of 'wPip' infected females (2%) during male releases significantly weakened the overall effectiveness of IIT, emphasizing the need for thorough sex separation. Specifically, with UnCI IIT, despite the low rate of co-released females, there was a gradual rise in 'wPip' infection frequency, resulting in more compatible mating and subsequently higher rates of egg hatching. Conversely, this pattern was effectively mitigated in BiCI IIT owing to the reciprocal sterility between the wild-type and the 'wPip' infected populations. Through an experimental approach, conducted in a semi-field setting, we have contributed to advancing scientific understanding regarding the potential outcomes of implementing the IIT strategy in the absence of a complete sexing system. The results suggest that safety measures for mitigating the potential impacts of co-released females can be tailored according to the specific type of IIT being utilized. © 2024 Society of Chemical Industry.