Immature Stages Research Articles

Insecticide resistance status and bar-codingof dengue vectors in three districts of Tamil Nadu, India.

Occurrence and distribution of vector population are crucial for entomological study in context of prevention, control and elimination of vector-borne diseases. To update some entomological aspects in three districts of Tamil Nadu state namely Kumbakonam, Nagapattinam and Thriuvarur districts, the study was undertaken. The objective of the study was to understand the prevalence of mosquitoes; to assess insecticide resistance and phylogenetic analysis of dengue vectors [Aedes (Ae.) aegypti and Ae.albopictus]. The immature stages of mosquitoes were collected from different localities by standard WHO methods marking with GPS and mapping was done using ArcGIS 10.4 software for all three districts. Insecticide resistance test was conducted using WHO susceptibility test kits. The F1 generation of female adult mosquitoes of Ae. aegypti and Ae. albopictus were exposed to DDT 4% and Malathion 5% with the control paper of Risella oil and olive oil respectively. Further, genomic DNA of individual mosquito was isolated, and the sequencingwas done through Eurofins, Bangalore, India. The FASTA sequence was analyzed and the phylogenic tree was constructed using the Maximum likelihood method in Molecular Evolutionary Genetics Analysis (MEGA) software (version 10.0). A totally 5307 specimens were collected through expanded survey in all three study areas. The collection yielded 16 species from six genera of mosquitoes. In total collection, the Ae. albopictus was the dominant species in Kumbakonam and Thiruvarur districts and Ae. aegypti was dominant in Nagapattinam district. The predominant breeding sources were discarded tyre with rainwater, plastic cups, coconut shells, aluminum vessels, sliver containers, bottles, grinding stones and earthen pots etc. The study revealed high pupal indices in all three study areas. Insecticide resistance monitoring revealed possible resistance in Ae. aegypti against DDT in all three districts whereas against Malathion, possible resistance was recorded in Kumbakonam and Nagapattinam and in Thiruvarur district, the species was found to be susceptible. Ae. albopictus showed resistance against DDT in all three districts but susceptible to Malathion. The sequences obtained for Dengue vectors showed 99% similar with Genbank. The phylogenetic tree was constructed using COI region sequences. Certainly, observed the different genetic relationship among Ae. aegypti and Ae. albopictus between the study areas. The study confirmed the presence of Ae. aegypti and Ae. albopictus in all three districts. The study further revealed that these vectors are susceptible to Malathion but resistance to DDT. The continue surveillance of dengue vector and monitoring of insecticide resistance will strengthen the control programme for appropriate vector control measurements.

Description of immature stages of Neolycus Bourgeois, 1883 and Rhyncheros LeConte, 1881 (Coleoptera: Lycidae: Lycinae) from the New World

ABSTRACT The study of immature stages of the Lycidae family is currently limited. Only approximately 2% of the described species have documented larvae in different instars and pupae, with a focus mainly on the fauna of the Old World. During fieldwork in Hidalgo, Mexico, we collected adult pairs of Neolycus fernandezi Dugès 1878 and Rhyncheros simulans. We kept the adults in laboratory conditions and obtained the eggs and first instar larvae. The comparison of chaetotaxies between N. fernandezi and R. simulans provides useful characters for differentiating genera. Additionally, the morphological characters of the first larval were compared with those described for Lycostomus ferrugineus Fabricius, 1798, L. formosanus Pic, 1937, as well as Calopteron terminale (Say, 1823). These comparisons revealed differences in the shape of the epicranium, relationship between the length of the maxillary palpomere and mala, prementum division, prosternum amplitude, pronotum shape, and abdominal spiracular plate division. The knowledge of the immature stages of two species within the Lycini tribe is significant since the egg and first instar larval of any American species belonging to this tribe have yet to be identified.

Quantitative and Qualitative Production of Species Cucumis metuliferus and the Potential for Adaptation in the Context of Current Climate Change.

Cucumis metuliferus E. Meyer ex Naudin belongs to the family Cucurbitaceae. It is an annual vegetable species known as horned melon or kiwano. Fruits are recommended for the daily diet because they provide vitamins, minerals, and phytochemicals to alleviate malnutrition and improve human health. In this study, kiwano was cultivated in the climatic conditions of Southwestern Romania, which is characterized by warm summers, lower precipitation, and high temperatures, ensuring optimal conditions for growth and development. The fruits were harvested at three stages of consumption: immature stage (green), intermediate stage (white-yellow) or the mature stage (yellow-orange). They were also subjected to analysis on the productive yield and physical-chemical properties. The results showed that the number of fruits ranged from 13.9 to 15.3 fruits/plant, and their average weight had values from 204 g to 234 g, depending on the harvest stage. The results obtained for bioactive compounds and antioxidant activity indicated significant differences (p ≤ 0.05), depending on the harvesting stage. The highest values for the antioxidant capacity (140.90 μM TE/100g DPPH) and total polyphenols (48.78 TPC mg/100 g) were recorded in the immature fruit phase, as well as for the carbohydrate content (3.56%), total protein (1.98%), ascorbic acid (4.3 mg/100 g f.w.), and carotene (0.98 mg/100 g) in the mature fruit phase. These results may stimulate interest in the introduction of this species as a niche crop and for consumption as a source of natural antioxidants for the prevention of diseases due to oxidative stress.

Influence of photoperiod on the developmental times of the forensically relevant blow fly species Calliphora vicina (Diptera: Calliphoridae)

Blow flies (Diptera: Calliphoridae) are frequently used in forensic investigations due to their rapid colonization of cadavers. As with other insects, environmental temperature strongly influences their developmental rates. While published research has typically explored not only the impact of the environmental temperature, but also of other factors like tissue type and drug presence on developmental rates, the influence of photoperiod on the developmental rates of forensically relevant blow fly species has remained largely underexplored. Understanding the relationship between photoperiod and developmental times is crucial, as neglecting this aspect could compromise the accuracy of minimum post-mortem interval (minPMI) estimations. The present study investigates the impact of three photoperiod conditions (0:24, 8:16, and 12:12 light:darkness) on the developmental rates of Calliphora vicina, focusing on the duration of the different immature stages and on the total developmental time. Our results revealed significant variation in the intra-puparial stage and total development time across different photoperiods. Notably, a 12:12 photoperiod led to a significantly prolonged intra-puparial stage and total development time compared to the 0:24 photoperiod, suggesting that Calliphora vicina develops faster in total darkness. These findings highlight the importance of considering photoperiod in both laboratory rearing protocols and forensic casework to improve the accuracy and reliability of minPMI estimations. In this regard, preliminary guidelines and recommendations are provided.

The genus Nisotra Baly, 1864 (Coleoptera, Chrysomeliae, Galerucinae, Alticini) in Taiwan, with redescriptions of four Asian species and notes on the immature stages of N.gemella (Erichson, 1834).

Nisotrachrysomeloides Jacoby, 1885, N.dohertyi (Maulik, 1926), N.gemella (Erichson, 1834), and Nisotranigripes Jacoby, 1894 are redescribed with illustrations of aedeagi, antennae, gonocoxae, abdominal ventrite VIII, and spermathecae. Nisotranigripes is recorded for the first time from Taiwan. The immature stages and life history of N.gemella were studied in the laboratory using a novel rearing design. Four synonyms previously proposed are confirmed: Sphaerodermajavana de Motschulsky, 1866, S.orbiculata de Motschulsky, 1866, Nisotrabowringi Baly, 1876, and Podagricahibisci Bryant, 1941 with N.gemella (Erichson, 1834). Lectotypes are designated for Halticagemella Erichson, 1834, N.chrysomeloides Jacoby, 1885, N.bowringi Baly, 1876, and Podagricahibisci Bryant, 1941.

Effect of temperature on the biological parameters of pink bollworm, Pectinophora gossypiella Saunders (Lepidoptera: Gelechiidae)

Pink bollworm (PBW) Pectinophora gossypiella is an important pest cotton worldwide. There are multiple factors which determines the occurrence and distribution of P. gossypiella across different cotton growing regions of the world, and one such key factor is ‘temperature’. The aim was to analyze the life history traits of PBW across varying temperature conditions. We systematically explored the biological and demographic parameters of P. gossypiella at five distinct temperatures; 20, 25, 30, 35 and 40 ± 1 °C maintaining a photoperiod of LD 16:8 h. The results revealed that the total developmental period of PBW shortens with rising temperatures, and the highest larval survival rates were observed between 30 °C and 35 °C, reaching 86.66% and 80.67%, respectively. Moreover, significant impacts were observed as the pupal weight, percent mating success, and fecundity exhibited higher values at 30 °C and 35 °C. Conversely, percent egg hatching, larval survival, and adult emergence were notably lower at 20 °C and 40 °C, respectively. Adult longevity decreased with rising temperatures, with females outliving males across all treatments. Notably, thermal stress had a persistent effect on the F1 generation, significantly affecting immature stages (egg and larvae), while its impact on reproductive potential was minimal. These findings offer valuable insights for predicting the population dynamics of P. gossypiella at the field level and developing climate-resilient management strategies in cotton.

Assembling a Coculture System to Prepare Highly Pure Induced Pluripotent Stem Cell-Derived Neurons at Late Maturation Stages.

Generation of human induced pluripotent stem cell (hiPSC)-derived motor neurons (MNs) offers an unprecedented approach to modeling movement disorders such as dystonia and amyotrophic lateral sclerosis. However, achieving survival poses a significant challenge when culturing induced MNs, especially when aiming to reach late maturation stages. Utilizing hiPSC-derived motor neurons and primary mouse astrocytes, we assembled two types of coculture systems: direct coculturing of neurons with astrocytes and indirect coculture using culture inserts that physically separate neurons and astrocytes. Both systems significantly enhance neuron survival. Compared with these two systems, no significant differences in neurodevelopment, maturation, and survival within 3 weeks, allowing to prepare neurons at maturation stages. Using the indirect coculture system, we obtained highly pure MNs at the late mature stage from hiPSCs. Transcriptomic studies of hiPSC-derived MNs showed a typical neurodevelopmental switch in gene expression from the early immature stage to late maturation stages. Mature genes associated with neurodevelopment and synaptogenesis are highly enriched in MNs at late stages, demonstrating that these neurons achieve maturation. This study introduces a novel tool for the preparation of highly pure hiPSC-derived neurons, enabling the determination of neurological disease pathogenesis in neurons at late disease onset stages through biochemical approaches, which typically necessitate highly pure neurons. This advancement is particularly significant in modeling age-related neurodegeneration.

Evaluation of Generational Implications of Metabolic Resistance Development in Malaria Mosquitoes against Permethrin Insecticides

Enzymes mediated resistance development and their activities are well documented in Anopheles gambiae vectors. However, biological consequences of such resistance development in malaria vectors are obscure. The present study aims to determine the implications of such response in An. gambiae (Kisumu) population following exposure to a concentration of Permethrin selection pressure across multiple generations. Adult Kisumu mosquitoes exposed to 0.2 µg/ CDC bottle over generations were compared with unexposed control populations by way of resistance status, cost of fitness, and correlating metabolic enzymes. Data obtained were analysed using SPSS. Analysis of Variance was employed to determine statistical differences at 95%. Fecundity rates of the mosquito population dropped progressively over generations. With increase in activity of metabolic enzymes, resistance status of the mosquito population progressed significantly (P< 0.05) over generations with 5.0 µg (18.00±0.00; 72%) at f4 generation. Mosquito resistance development is therefore a disadvantage to malaria vectors as it reduces ovipository capability, and increases longevity of immature stages (life cycle) with filial generations.

The Asian rock-dwelling antlions Gatzara Navás, 1915 and Nepsalus Navás, 1914 (Neuroptera: Myrmeleontidae): new advancements in systematics, biogeography and life history.

The antlion genera Gatzara and Nepsalus (Myrmeleontidae: Dendroleontinae) inhabit mountain forests and are characterised by camouflaging larvae. Both genera remain poorly known despite recent findings on systematics and distribution. We report the discovery of new specimens and the previously unknown larvae of the rare species Gatzara jubilaea Navás, 1915, Nepsalus insolitus (Walker, 1860) and N. decorosus (Yang, 1988). These provide new evidence regarding the affinities of these species, and updated knowledge of the distribution, larval morphology and biology. Moreover, a new species of Nepsalus , N. maclachlani Badano, Zheng & Liu, sp. nov. is described from Sri Lanka based on historical museum collections. The discovery of the immature stages of Gatzara shows that the larvae of this genus share the same specialised ecological characteristics and habits as those of Nepsalus but are less morphologically derived. We also reconstruct a molecular phylogeny of this lineage, estimating the divergence time and biogeographical history by adding the new samples. The evolution of the Gatzara + Nepsalus lineage is associated with two major mountain ranges on the southern Tibetan Plateau, i.e. the Himalayas and the Hengduan Mountains. ZooBank: urn:lsid:zoobank.org:pub:68E68211-DFC1-4D98-997B-8A23BA8F9B69.

Evaluation of diagnostic techniques for early detection of heartworm in experimentally infected dogs: identification of Dirofilaria immitis-derived microRNA in the initial 28 weeks post-inoculation

BackgroundDirofilaria immitis, commonly known as heartworm (HW), is a parasitic nematode transmitted by various mosquito species, leading to heartworm disease (HWD) in dogs. Diagnosis of HW typically involves antigen or microfilariae detection, or visualization of adult worms through imaging or post mortem examination. Polymerase chain reaction (PCR) and micro RNA (miRNA) detection have been explored for HW diagnosis.MethodsThree dogs, previously experimentally infected with HW, underwent blood sampling every 4 weeks for 7 months. Samples were assessed for antigen presence after heat treatment, PCR amplification, and microfilaria examination using Giemsa-stained thick smears. Additionally, whole blood aliquots underwent miRNA deep sequencing and bioinformatic analysis.ResultsHeartworm antigen was detectable after heat treatment at 20 weeks post-inoculation and via PCR at 24 weeks, with microfilariae observed in peripheral blood smears at 28 weeks. However, deep miRNA sequencing revealed that the miRNA candidate sequences are not consistently expressed before 28 weeks of infection.ConclusionsWhile ancillary molecular methods such as PCR and miRNA sequencing may be less effective than antigen detection for detecting immature larval stages in an early stage of infection, our experimental findings demonstrate that circulating miRNAs can still be detected in 28 weeks post-infection.Graphical

Comparative Analysis of mRNA and lncRNA Expression Profiles in Testicular Tissue of Sexually Immature and Sexually Mature Mongolian Horses.

Testicular development and spermatogenesis are tightly regulated by both coding and non-coding genes, with mRNA and lncRNA playing crucial roles in post-transcriptional gene expression regulation. However, there are significant differences in regulatory mechanisms before and after sexual maturity. Nevertheless, the mRNAs and lncRNAs in the testes of Mongolian horses have not been systematically identified. In this study, we first identified the testicular tissues of sexually immature and sexually mature Mongolian horses at the tissue and protein levels, and comprehensively analyzed the expression profiles of mRNA and lncRNA in the testes of 1-year-old (12 months, n = 3) and 10-year-old (n = 3) Mongolian horses using RNA sequencing technology. Through gene expression analysis, we identified 16,582 mRNAs and 2128 unknown lncRNAs that are commonly expressed in both sexually immature and sexually mature Mongolian horses. Meanwhile, 9217 mRNAs (p < 0.05) and 2191 unknown lncRNAs (p < 0.05) were identified as differentially expressed between the two stages, which were further validated by real-time fluorescent quantitative PCR and analyzed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). The analysis results showed that genes in the sexually immature stage were mainly enriched in terms related to cellular infrastructure, while genes in the sexually mature stage were enriched in terms associated with hormones, metabolism, and spermatogenesis. In summary, the findings of this study provide valuable resources for a deeper understanding of the molecular mechanisms underlying testicular development and spermatogenesis in Mongolian horses and offer new perspectives for future related research.

Prospecting for fine scale establishment of exotic stem borer pupal parasitoid (Xanthopimpla stemmator Thunberg) in Kenya

Lepidopteran stem borers are an important constraint to cereal production in Sub- Saharan Africa. The exotic Chilo partellus (Swinhoe) is one of the most economically important stem borer pest causing extensive losses on cereal crops in Kenya. This pest has also displaced indigenous species of stem borers while expanding its range in warm, mid and high altitude areas. In order to exert control on various developmental stages of this pest, both Cotesia flavipes Cameron (larval endoparasitoid) and Xanthopimpla stemmator Thunberg (pupal endoparasitoid) were imported and released in 2002 in the Eastern region of Kenya. This study was conducted to assess the establishment status, spread and impact of X. stemmator on C. partellus following its release in Kenya. Stem borer sampling was done on farms where the biocontrol agents had been released and on transects radiating outwards from them every 15km to assess spread. A total of 100 maize plants were inspected for stem borer infestation and destructive sampling done on 10 maize stems per farm to collect immature stem borer stages. Emerging parasitoids and adult moths were identified, counted and recorded. Results of this study showed that C. partellus was the most dominant stem borer species (constituted 71.2%) followed by Sesemia calamistis and Busseola fusca (26.0 and 2.8% respectively). A decrease in overall stem borer infestation (22.47±7.42%) with no significant difference across distances from parasitoid release points (F=0.4; df=3, 51; p&gt;0.05) was also recorded. Seven parasitoid species were recovered, the most abundant being C. flavipes and this coupled with a significant increase in parasitism (25.27±3.27%) (V=1213, p˂0.05) from pre-release levels. The parasitoid of interest, X. stemmator was not recovered. This suggests a failure to establish though there is need to sample alternative hosts before this is declared. Key words: Classical biological control, lepidoptera, pupal parasitoid, post release survey, Xanthopimpla stemmator, Eastern Kenya

Retinal organoids with X-linked retinoschisis RS1 (E72K) mutation exhibit a photoreceptor developmental delay and are rescued by gene augmentation therapy

BackgroundX-linked juvenile retinoschisis (XLRS) is an inherited disease caused by RS1 gene mutation, which leads to retinal splitting and visual impairment. The mechanism of RS1-associated retinal degeneration is not fully understood. Besides, animal models of XLRS have limitations in the study of XLRS. Here, we used human induced pluripotent stem cell (hiPSC)-derived retinal organoids (ROs) to investigate the disease mechanisms and potential treatments for XLRS.MethodshiPSCs reprogrammed from peripheral blood mononuclear cells of two RS1 mutant (E72K) XLRS patients were differentiated into ROs. Subsequently, we explored whether RS1 mutation could affect RO development and explore the effectiveness of RS1 gene augmentation therapy.ResultsROs derived from RS1 (E72K) mutation hiPSCs exhibited a developmental delay in the photoreceptor, retinoschisin (RS1) deficiency, and altered spontaneous activity compared with control ROs. Furthermore, the delays in development were associated with decreased expression of rod-specific precursor markers (NRL) and photoreceptor-specific markers (RCVRN). Adeno-associated virus (AAV)-mediated gene augmentation with RS1 at the photoreceptor immature stage rescued the rod photoreceptor developmental delay in ROs with the RS1 (E72K) mutation.ConclusionsThe RS1 (E72K) mutation results in the photoreceptor development delay in ROs and can be partially rescued by the RS1 gene augmentation therapy.

Larval and adult morphology of Photuris elliptica Olivier (Coleoptera, Lampyridae) and a Halloweeny case of cave-dwelling firefly larva feeding on bat guano

The predatory firefly Photuris elliptica is common throughout the Atlantic Forest and has been proposed as a biomonitor due to the species’ narrow niche and elevational range. However, the species is only known from adults, and a more effective monitoring of its populations hinges on the lack of knowledge on their immature stages. Recent sampling in ferruginous caves and inserted in other lithologies, on sites in the Atlantic Forest and Cerrado, have led to the capture of firefly larvae later reared to adults in the lab. Firefly larvae have been reported in South American caves before; however, they have only been identified to family due to the adult-biased taxonomy of Lampyridae. Here, we provide an updated diagnosis of Photuris elliptica, describe its immature stages for the first time, and update the distribution of the species. The larvae of Photuris elliptica were observed to interact with guano of several bat species, including that of vampire bats. These observations are consistent with the less specialized feeding preferences of photurine larvae, unlike most other firefly taxa, which specialize in gastropods and earthworms. It is yet unclear whether P. elliptica are cave specialists. However, since its occurrence outside caves remains unknown, protecting cave environments must be considered in conservation strategies for this important biomonitor species.

Assessment of development and consumption rate of Macrolophus caliginosus Wagner predator on different prey stages

BackgroundMacrolophus caliginosus Wagner is one of the most important polyphagous predatory mirid bug that attack many agriculture insect pests.MethodsThe present study was carried out to show the effect of different prey stages as Tuta absoluta (eggs and fourth larval stage), Bemisia tabaci (eggs and three nymph stages) and Aphids gossypii (1st nymph stage) on the life cycle and consumption rate of male and females of M. caliginosus as predator under laboratory condition. The experiments were started by collecting the first stage of M. caliginosus nymph and placed separately on acalypha plants situated on saturated cotton pads inside Petri dishes with an excess of each prey.ResultsThe results showed that the developmental period of the total immature stages of M. caliginosus female are affected by type and stage of tested prey. So, the duration of larval stages of female was significantly recorded the longest in case of feeding on eggs of T. absoluta compare to 1st nymph of A. gossypii. In addition to extension the adult longevity of female M. caliginosus, which fed on the 1st nymphal instar of B. tabaci more than the other pests. The consumption rate of total immature stages and adult M. caliginosus female were fed on eggs of B. tabaci was more than the other test pests. While the consumption rate of total immature stages and adult of male M. caliginosus were fed on eggs of B. tabaci was higher than that of the other pests.ConclusionsThe search was given the highlight focus on ability of mirid bugs to consume different insect species “stages” that might be facilitate rear predatory bugs under laboratory condition.

Remarkable sexual dimorphism found in Nosophora insignis (Butler) (Lepidoptera, Crambidae, Spilomelinae)

An unidentified spilomeline moth, “Nosophora sp.” was first illustrated by Inoue (1982) from Japan. Since little is known about the immature stage of “Nosophora sp.”, we attempted to rear this species from eggs. As a result, we found that “Nosophora sp.” can be successfully reared on Quercus serrata Murray and Q. glauca Thunb. Surprisingly, of the adults that emerged, all females showed the “Nosophora sp.” phenotypes, while all males showed the N. insignis (Butler, 1881) phenotypes. We also found that the mitochondrial COI sequences of “Nosophora sp.” and N. insignis are completely identical. Based on these results, we concluded that “Nosophora sp.” and N. insignis represent the sexual dimorphisms of the same species, and redescribed N. insignis.

Molecular differentiation analysis of ten putative species of Fannia (Diptera: Fanniidae) collected in carrion-baited traps from Colombia.

The genus Fannia is the most representative of the Fannidae family of true flies with worldwide distribution. Some species are attracted to decomposing materials and live vertebrate animals, which makes them important in forensics, medical and veterinary fields. However, identifying Fannia species can be difficult due to the high similarity in the external morphology of females and limited descriptions and morphological keys. Herein, molecular markers could provide a complementary tool for species identification. However, molecular identification has still limited application since databases contain few data for neotropical species of Fannia. This study assessed the potential of two molecular markers, the COI-3' region and internal transcribed spacer 2 (ITS2), to differentiate 10 putative species of the genus Fannia from Colombia using distance-based and tree-based approaches. The partial ITS2 and/or COI-3' regions allowed molecular diagnosis of six species, while pairs of species Fannia colazorrensis + F. dodgei and F. laclara + F. aburrae are conflicting. Although these results might suggest that conflicting pair species are conspecific, consistent morphological differences between males do not support this hypothesis. The lack of differentiation at the nuclear and mitochondrial molecular markers for the conflicting species may be due to incomplete evolutionary lineage separation, hybridization, or introgression events. In addition, sexual selection on male morphological traits before species-specific differences in molecular markers emerge may partially explain the results. Our study provides a valuable dataset to identify and confirm some Fannia species molecularly. Further, they could be used to associate females and immature stages with their conspecifics as a baseline to deep into their biology, ecology, distribution and potential applications in forensic and medico-veterinary entomology.

Cyclic Variations of Ovarian Development, Hormones and Sex Related Genes of Rainbow Trout (Oncorhynchus mykiss) During Different Growth Stages

This study aimed to investigate the reproductive biology of female rainbow trout (Oncorhynchus mykiss). Mature female (n.80) rainbow trout from different reproductive phases were collected. Through a transmission electron microscope (TEM), it was feasible to examine the oocyte at several developmental stages, namely the perinucleolus stage, cortical alveoli stage, vitellogenic stage, mature stage, and postovulatory stage. Progesterone and estradiol levels were measured at their lowest during the immature and spent phases, while reaching their highest levels during the maturing and mature stages. The total amount of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) was greater in mature ovaries compared to immature and maturing ovaries. Gene transcripts related to the production of steroids, specifically star, cyp11a1, cyp17a1 and hsd3b were expressed at low levels during the immature stage and showed a significant rise during the mature stage. The ovarian gene expression patterns during oogenesis exhibited distinct dissimilarities. The fatty acid content, essential for the development of fish ovaries, and the sex steroid hormonal profile, which play a key role in regulating oogenesis, are particularly significant. These results will enhance our comprehension of the reproductive biology and sustainable management of rainbow trout in their natural environment.

Sand Fly larvae are capable of positive chemotaxis: a proof of concept study using Phlebotomus papatasi (Diptera: Psychodidae) as a model species.

Phlebotomine sand flies are important vectors of medical and veterinary importance, transmitting pathogens, such as the Leishmania parasites, responsible for 700,000 to 1 million new cases of leishmaniasis every year. The vast majority of the current sand fly surveillance and control tools are tailored against the adult stages, due to the limited knowledge on the ecology of the larval stages. Since vector control is primarily an ecological problem, an in-depth understanding of the behavior of the target insect pests across all the different life stages of their development is required prior to the development of effective control strategies. It is well known that chemical cues play an important role in insect behavior. While there are numerous studies investigating the behavior of adult sand flies in response to chemical sources, there is currently no information available on the response of their larval stages. In this study, novel bioassays were constructed to investigate the effect of chemical cues (gustatory and olfactory) on the behavior of Phlebotomus papatasi (Scopoli) sand fly larvae. The larvae exhibited a clear food preference within a few hours of exposure in a 2-choice bioassay, while, also, demonstrated positive chemotaxis in response to volatile stimuli emitted from their preferred food source. Identification of the specific chemical compounds (or the combination thereof) eliciting attractance response to sand fly immature stages could lead to the development of innovative, and targeted (larval-specific) tools for the surveillance, and management of these important public health pests.

Entomological investigation of triatomine fauna in rural communities in the state of Piauí, Brazilian semi-arid region

Objective: To describe the characteristics and distribution of triatomine fauna in rural communities of Simplício Mendes municipality, located in the state of Piauí, Brazilian semiarid region. Methods: This is a cross-sectional study and entomological survey conducted from 2022 to 2023. Insects were captured using active search method in all human dwellings, which were georeferenced, followed by characterized of species, sex, developmental stage, and identification of presence of infection by trypanosomatids. Results: All households (n=178) in 10 rural localities of the municipality were investigated, resulting in a household triatomine infestation rate of 14%. A total of 268 insects were collected, predominantly species from the Triatoma brasiliensis complex (n=190), immature developmental stage (n=172), and originating from peridomestic environments (n=250). The rate of triatomines with natural infection by Trypanosoma cruzi was 1.1%. Conclusion: The finding of infestation by species from the T. brasiliensis complex with higher concentration cohabiting extradomestic spaces, wide dispersion, and presence of natural infection by T. cruzi signals conditions for the maintenance of vector-borne transmission of Chagas disease in the municipality.