Oviposition behavior of the parasitoid Telenomus remus (Hymenoptera: Scelionidae) on eggs of Spodoptera frugiperda (Lepidoptera: Noctuidae).

Telenomus remus (Hymenoptera: Scelionidae) is an efficient parasitoid of Spodoptera eggs. However, biological control programs require taxonomic, bioecological and behavioral studies of biological agents. Although the performance of T. remus in pest control has been evaluated, little is known about its behavioral aspects that can influence IPM tactics. The aim of this study was therefore to study the parameters related to the oviposition behavior of T. remus on Spodoptera frugiperda (Lepidoptera: Noctuidae) eggs. The experiment was conducted in the laboratory, where 17 females were transferred individually to arenas containing a mass of S. frugiperda eggs. Oviposition behavior was recorded for 30 minutes. The average walking speed of the females was 0.116 mm.s-1 and the total distance covered was 203.3 mm. The females remained on the egg masses for an average of 16.7 min, which corresponds to more than half of the total time. The average number of parasitized eggs was 15.1 per female in 30 minutes. Females with larger antennae had lower values for average speed and total distance covered. The results of the parameters evaluated show the standard oviposition behavior of T. remus females on S. frugiperda eggs and help us to better understand the species.

The effect of addition of calcium mineral in feed containing fishery wastes on egg production and hatching performance of Mojosari ducks.

Calcium (Ca) is an essential mineral for eggshell formation and muscle contraction, and a lack of it can result in poor egg quality and decreased egg output in laying ducks. This study aims to see how feeding the mineral Ca in a ration containing Shrimp head meal and Bilis fish head affects the laying performance and quality of hatching eggs in Mojosari ducks. A total of 105 female and 15 male Mojosari ducks, aged 78 weeks, were raised for three months and randomly divided into 15 flocks (each flock containing seven females and one male duck). There were three kinds of treatment, namely P0 (control, without mineral), P1 (ratio of Shrimp head meal and Bilis fish head 2:1 + 1% mineral), and P2 ((ratio of Shrimp head meal and Bilis fish head 1:2 + 1% mineral). The findings revealed that adding mineral Ca to feed, including Shrimp head meal and Bilis fish head, had no significant influence (P>0.05) on laying Mojosari duck performance in terms of feed intake, egg production, egg weight, egg quality, ducklings produced, and income over feed cost (IOFC). Furthermore, Ca addition in the ration did not result in substantial increases (P>0.05) in fertility, hatchability, or egg size characteristics. Based on the findings of this study, feeding ducks with shrimp head meal and Bilis fish head can be used as an alternate calcium-free feed formulation.

Mathematical Modeling of Mating Probability and Fertile Egg Production in Helminth Parasites.

In this work, we obtained a general formulation for the mating probability and fertile egg production in helminth parasites, focusing on the reproductive behavior of polygamous parasites and its implications for transmission dynamics. By exploring various reproductive variables in parasites with density-dependent fecundity, such as helminth parasites, we departed from the traditional assumptions of Poisson and negative binomial distributions to adopt an arbitrary distribution model. Our analysis considered critical factors such as mating probability, fertile egg production, and the distribution of female and male parasites among hosts, whether they are distributed together or separately. We show that the distribution of parasites within hosts significantly influences transmission dynamics, with implications for parasite persistence and, therefore, with implications in parasite control. Using statistical models and empirical data from Monte Carlo simulations, we provide insights into the complex interplay of reproductive variables in helminth parasites, enhancing our understanding of parasite dynamics and the transmission of parasitic diseases.

In vitro anthelmintic activity and colocalization analysis of hydroxycinnamic acids obtained from Chamaecrista nictitans against two Haemonchus contortus isolates.

This study assessed the in vitro anthelmintic activity of ethyl acetate extract (Cn-EtOAc) and its bioactive fractions (CnR3 and CnR5) obtained from Chamaecrista nictitans aerial parts against two Haemonchus contortus (Hc) isolates, one resistant (strain HcIVM-R) and another susceptible (strain HcIVM-S) to ivermectin. Ferulic acid and p-coumaric acid were identified in the bioactive fractions; therefore, their commercial standards were also assessed. A colocalization analysis between the ferulic acid commercial standard and eggs of the HcIVM-R strain was performed using confocal laser scanning microscopy and the ImageJ program. The ovicidal effects of the Cn-EtOAc extract, bioactive fractions and commercial compounds were tested through the egg hatching inhibition (EHI) assay on H. contortus isolates HcIVM-R and HcIVM-S. The Cn-EtOAc caused 88 % and 92 % EHI at 5000 µg/mL on HcIVM-R and HcIVM-S, respectively. Fractions CnR3 and CnR5 displayed the highest ovicidal activity against HcIVM-S, with effective concentrations (EC90) of 2134 and 601 µg/mL, respectively. Meanwhile, the commercial standards ferulic acid and p-coumaric acid also resulted in higher effectiveness on the same strain, with EC90 of 57.5 and 51.1 µg/mL. A colocalization analysis of ferulic acid and eggs of HcIVM-R revealed that this compound is localized to the cuticle surface of the embryo inside the egg parasite. The results demonstrated that both ferulic and p-coumaric acids interrupt the egg-hatching processes of the two Hc isolates. Both phenolic acids isolated from C. nictitans and commercial standards exhibited the best anthelmintic effect on HcIVM-S. These findings indicate that the phenolic acids were less effective in egg hatch inhibiting on the HcIVM-R strain compared to the HcIVM-S strain.

Temporal resource continuity for egg parasitoids of Dalbulus maidis (Hemiptera: Cicadellidae) during winter on irrigated maize crops and edge grasses.

Little is known about winter-season parasitism of eggs of the corn leafhopper Dalbulus maidis DeLong (Hemiptera: Cicadellidae), an important pest of maize throughout the Americas. Our study, conducted in Mexico, aimed to characterize winter-season parasitism of corn leafhopper eggs on maize crops cultivated with drip irrigation and on wild grasses that grow on the edges of maize crops when maize is not present. Maize leaves baited with D. maidis eggs were used to trap the egg parasitoids in the field. In the first year (2022), parasitism of D. maidis eggs was investigated in maize fields planted contiguously on different dates (asynchronous planting). In the second year (2023), parasitism of D. maidis eggs was evaluated in edge grasses and in adjacent maize crops planted on the same date (synchronous). The highest percentage of parasitism (53%), percentage of emergence, and total abundance of egg parasitoids were found in asynchronous maize fields. Here, Anagrus virlai Triapitsyn (Hymenoptera: Mymaridae), Paracentrobia subflava (Girault) (Hymenoptera: Trichogrammatidae), and Pseudoligosita sp. (Hymenoptera: Trichogrammatidae) wasps were found parasitizing the D. maidis eggs, with P. subflava being the most abundant. In wild edge grasses, only P. subflava was found, showing low levels of parasitism, while in synchronous maize, P. subflava increased its percentage of parasitism (up to 37%), percentage of emergence, and abundance, during winter. These results suggest that P. subflava acts as an efficient biological control agent of D. maidis in irrigation-grown maize crops during the winter season, and that edge grasses are overwinter habitats for P. subflava.

Ovicidal activity of diaryl dichalcogenides and ivermectin on Fasciola hepatica: A novel candidate for a blending-based therapeutic strategy.

Fasciolosis is a food and waterborne disease caused by Fasciola spp., representing a global health burden to various hosts, including humans and other animals. This study investigates the in vitro activity of tellurium- and selenium-containing diaryl dichalcogenides: diacetal ditelluride (LQ07), diacetal diselenide (LQ62), and diacetyl diselenide (LQ68) alone and in combination with ivermectin (IVM) against eggs of Fasciola hepatica. The eggs were exposed for 12 h with each organochalcogen (OC) (0.1 - 2 mmol l-1) and IVM (0.01 - 2 mmol l-1) following an incubation of 15 days, allowing embryonation. The inhibitory concentration of 50 % (IC50) of each OC or IVM was tested with the IC10, IC30, and IC50 of IVM or each OC, respectively. LQ07, LQ62, and LQ68, as well as IVM, demonstrated a concentration-dependent ovicidal activity. The peak ovicidal activity of 99.74 % was achieved when IVM was tested at 2.0 mmol l-1. LQ62 and LQ68 demonstrated greater ovicidal activity, having an IC50 < 0.32 mmol l-1 being 6.25-fold more toxic than IVM alone. The percentage of dead eggs was significantly higher in the IVM group (early mortality), as Se-containing OCs led to the (miracidia) embryonation of the eggs with no hatching (late mortality). Blending Se-containing OCs and IVM showed an additive effect of up to 27 % against F. hepatica eggs. The present data contribute to the potential use of blending-based therapeutic strategies to combat F. hepatica infections in eradication programs worldwide. The combinations may also act against multidrug-resistant strains, reinstating drug-based parasite control.

First Record of Telenomus dilophonotae (Hymenoptera, Scelionidae), Parasitizing Eggs of Erinnyis ello (Lepidoptera, Sphingidae) in Western Paraná, Brazil, with Molecular Characterization and Records of Occurrences.

There are few records for Telenomus dilophonotae Cameron, 1913 (Hymenoptera, Scelionidae) from South America. In Brazil, the first occurrence was reported in Bahia in rubber crops, Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. - Arg., there parasitizing eggs of Erinnyis ello Linnaeus, 1758 (Lepidoptera, Sphingidae). It was also found parasitizing the same host in cassava, Manihot esculenta Crantz (Euphorbiaceae). This is the first record of occurrence of T. dilophonotae in the state of Paraná, parasitizing eggs of E. ello in areas of cassava production in the western region of Paraná, this being the southernmost record of the species. Here, photographs, the first sequence of DNA barcode of this species of parasitoid wasp, and a distribution map are provided.

Horismenus saturnus n. sp. (Hymenoptera, Eulophidae) a New Parasitoid Wasp from Eggs of Saturniidae (Lepidoptera) from the Atlantic Forest, Minas Gerais, Brazil.

A new species of Horismenus Walker, H. saturnus Schoeninger & Hansson (Hymenoptera: Eulophidae), is described from material reared from eggs of an unidentified species of Saturniidae (Lepidoptera). The new species is compared to H. cupreus (Ashmead, 1894), a species it is very similar to, and to H. ancillus (Brèthes), a species with the same type of host as H. saturnus. A total of 30 adult specimens developed from the eggs of Saturniidae. This is the second record of a Horismenus species parasitizing eggs of Saturniidae and the first record of this host from Brazil. Here, we provide a diagnosis and description of the new species including morphological and molecular characters, and multiple illustrations.

New Technique for Identification of Ichthyoplankton and Its Application in Biomonitoring Studies, Management and Conservation of Neotropical Fish.

Despite significant advancements in ichthyoplankton collection and data processing, challenges persist in the taxonomic identification of these organisms, particularly their eggs. To overcome these challenges, a novel technique has been developed to facilitate the identification of live eggs collected directly in wild. This user-friendly technique includes the collection, processing of the material, and field incubation. Sampling must be conducted using a pelagic net towed at low speed, preferably during early evening. The material processing involves pre-sorting and sorting to remove eggs and larvae. The separated eggs, kept in an aerated bowl, can be identified based on their morphological and meristic characteristics. Unidentified eggs can be placed in plastic bags with oxygen and incubated directly in the aquatic environment for 48-72 h. After this incubation period, the hatched larvae at the yolk-sac or preflexion stage, are identified to the lowest possible taxonomic level. Depending on the study's purpose, hatched larvae and field-collected larvae can be transported to research centers for further development, released back into the natural environment, or fixed to complete the collection. The application of this technique supports management and monitoring programs by identifying spawning areas through egg identification, forming broodstock, and replenishing threatened species, thereby enhancing scientific collections of ichthyoplankton. Additionally, it reduces mortality in ichthyoplankton techniques, including endangered species. Therefore, we believe that this novel taxonomic technique for identifying live ichthyoplankton represents a paradigm shift in the monitoring, management, and conservation of fish, as well as in ecological stewardship and advances in this area of research.

Phylogenetic variations in a novel family of hyperstable apple snail egg proteins: insights into structural stability and functional trends.

The relationship between protein stability and functional evolution is little explored in proteins purified from natural sources. Here, we investigated a novel family of egg proteins (Perivitellin-1, PV1) from Pomacea snails. Their remarkable stability and clade-related functions in most derived clades (Canaliculata and Bridgesii) make them excellent candidates for exploring this issue. To that aim, we studied PV1 (PpaPV1) from the most basal lineage, Flagellata. PpaPV1 displays unparalleled structural and kinetic stability, surpassing PV1s from derived clades, ranking among the most hyperstable proteins documented in nature. Its spectral features contribute to a pale egg coloration, exhibiting a milder glycan binding lectin activity with a narrower specificity than PV1s from the closely related Bridgesii clade. These findings provide evidence for substantial structural and functional changes throughout the genus' PV1 evolution. We observed that structural and kinetic stability decreased in a clade-related fashion and was associated with large variations in defensive traits. For instance, pale PpaPV1 lectin turns potent in the Bridgesii clade, adversely affecting gut morphology, while giving rise to brightly colored PV1s providing eggs with a conspicuous, probably warning signal in the Canaliculata clade. This work provides a comprehensive comparative analysis of PV1s from various apple snail species within a phylogenetic framework, offering insights into the interplay among their structural features, stability profiles and functional roles. More broadly, our work provides one of the first examples from natural evolution showing the crucial link among protein structure, stability and evolution of new functions.

Morphological changes in eggs and embryos of Aedes aegypti (Diptera: Culicidae) exposed to predicted climatic scenarios for the year 2100 in the Central Amazon.

According to the IPCC, by the year 2100, rises in global temperature could reach up to 5 °C above current averages. On a planet-wide scale, this is one of the effects of climate changes that could have repercussions on the biological cycle of Aedes aegypti, the main arbovirus vector in urban environments and a transmitter of the arboviruses that cause dengue, Zika, chikungunya and urban yellow fever. The objective of this study was to evaluate morphological changes in Ae. aegypti eggs and embryos maintained in a climate change simulator. For this, specimens obtained from an insectarium were kept in four chambers that simulated the range of environmental scenarios predicted by the IPCC for the year 2100. The eggs obtained from each room were collected and transported to the laboratory for morphometric and morphological analysis, using confocal and scanning microscopy. Aedes aegypti eggs (n=20) were used to obtain the following variables: total width, total length, length-width ratio and diameter of the micropylar disc. Additionally, 20 embryos were used to obtain the data on head capsule length, width and length-width ratio. The data were subjected to a normality test and the means of each variable were compared using ANOVA and Tukey's post-hoc test, considering (p ≤ 0.05). A significant reduction (p < 0.05) was observed mainly in the mean lengths under the current-extreme scenario (587.5 and 553.6 µm, respectively), as well as in the widths under the current-mild scenario (171 and 158.4 µm, respectively). The length of the cephalic capsule was also affected, showing significant differences in the means under the current-intermediate scenario (189.5 and 208.5 µm, respectively), as well as in the widths between the current-intermediate scenarios (173.7 and 194.9 µm, respectively). The results suggest significant changes in the morphometry of Ae. aegypti eggs and embryos as a result of the climatic influences to which the adults were subjected, which may have an impact on vector population density and, consequently, on arbovirus dynamics in urban environments.

Attracting Scelionidae egg parasitoids to enhance stink bug egg parasitisation in soybean crops using methyl salicylate and (E,E)-α-farnesene.

BACKGROUND: Plant volatile organic compounds (VOCs) play a crucial role in mediating interactions between plants, herbivores and natural enemies. Among these VOCs, methyl salicylate and (E,E)-α-farnesene are emitted as herbivore-induced plant volatiles (HIPVs) by soybean plants in response to feeding by the brown stink bug Eushistus heros. These HIPVs function as synomones, influencing the foraging behaviour of the egg parasitoid, Telenomus podisi, the main natural enemy of E. heros, one of the major soybean pests in Brazil. RESULTS: Laboratory experiments showed that two soybean cultivars, BRS 7580 and BRS 7880, produced similar qualitative blends of HIPVs, with methyl salicylate, (E,E)-α-farnesene and (Z)-3-hexenyl acetate being produced by both cultivars. Soybean cultivar BRS 7580 produced a significant lower amount of HIPVs compared to BRS 7880 but this difference did not affect the attractiveness of the egg parasitoid Telenomus podisi. Field experiments using these two cultivars and synthetic applications of methyl salicylate and (E,E)-α-farnesene showed a substantial increase in egg parasitism in all treated areas. Parasitism rates ranged from 50% to 80% in areas where these HIPVs were deployed, compared to only 10% in untreated control areas. CONCLUSIONS: The egg parasitoid Telenomus podisi demonstrated an adept ability in recognising between HIPVs in soybean blends, even in the presence of significant quantitative differences. The results from the field experiment showed the potential of HIPVs in attracting natural enemies to specific target areas within fields. (E,E)-α-Farnesene showed an improved action during the later stages of soybean growth, notably at R6. In addition, this volatile attracted other families of natural enemies. © 2024 Society of Chemical Industry.

Ozone and peroxone disinfection of Toxocara canis eggs in water.

Water pollution in developing countries continues to be a major health problem due to various anthropological activities that contribute to the spread of many parasitic diseases, including those caused by helminths. The aim of this study is to explore the ability of ozone and peroxone to disinfect drinking water contaminated samples with Toxocara canis eggs. The oxidants used were ozone and ozone-hydrogen peroxide combination. The treatment of Toxocara canis eggs was carried out in a 50 ml reactor with an operating volume of 10 ml. The pH conditions (5, 7 and 10) were varied for each treatment. The treatment effect was calculated by counting eggs and examining the condition of the larvae larval condition (whole, broken and hatched larvae) using an optical microscope. The experiment was carried out by exposing the eggs for 60 and 120 minutes to ozone and peroxone. The best results were obtained for helminths treated with the ozone/hydrogen peroxide combination at pH 10, with an inactivation of 79.2%. The synergistic effect of ozone combined with hydrogen peroxide allows higher helminth egg inactivation rates, demonstrating that advanced oxidation processes are a real alternative to apply in the inactivation of Toxocara canis eggs. The results obtained in this study show that the ozone and peroxone treatment could be a useful disinfection process to destroy or inactivate Toxocara canis eggs in processes commonly applied in water treatment.

Fish (eggs) out of water: evolutionary divergence in terrestrial embryonic plasticity in Trinidadian killifish.

Externally laid eggs are often responsive to environmental cues; however, it is unclear how such plasticity evolves. In Trinidad, the killifish (Anablepsoides hartii) is found in communities with and without predators. Here, killifish inhabit shallower, ephemeral habitats in sites with predators. Such shifts may increase the exposure of eggs to air and lead to possible desiccation. We compared egg-hatching plasticity between communities by rearing eggs terrestrially on peat moss or in water. The timing of hatching did not differ between communities when eggs were reared in water. Eggs from sites with predators responded to terrestrial incubation by hatching significantly earlier compared with water-reared eggs. These responses were weaker in sites with no predators. Such divergent trends show that the presence of predators is associated with evolutionary shifts in hatching plasticity. Our results provide evidence for local adaptation in embryonic plasticity at the population scale.

Evaluation of heating and liming treatments in sand samples artificially contaminated with Ancylostoma spp. eggs.

Ancylostoma spp. are found worldwide. Infected dog and cat feces can contaminate soil in public places. Despite prophylactic measures being available, studies on direct remediation of Ancylostoma-contaminated soils are scarce. This study aimed to determine the impact of heat treatment and liming on the viability of Ancylostoma spp. eggs in artificially contaminated sandy soil. Sterilized sand samples were contaminated with Ancylostoma spp. eggs extracted from infected dogs' feces. Samples were heated (trial I) to 70 °C or 80 °C, then sieved after 24 hours (212, 90, 38, and 25 µm). Larval cultures were assessed for larval development following heat treatment. Five quicklime concentrations (trial II; 50, 30, 20, 10 and 5%) were used to treat sand. The effect of liming on larval cultures was assessed by measuring embryonic development. Filariform larvae were exposed to 20% quicklime (25 °C and 37 °C, 20 min). Heat treatment destroys Ancylostoma spp. eggs and prevents in vitro larval development. Liming at 50, 30, and 20% concentrations made embryonic development impossible. However, filariform larvae treated with 20% lime solution retained their motility. Heating at 70 °C and liming at 20% were sufficient to make Ancylostoma spp. egg embryogenesis impossible in experimentally contaminated sand samples.

In vitro ovicidal and larvicidal activity of a hydroalcoholic extract and its fractions from Cyrtocarpa procera fruits on Haemonchus contortus.

This study describes the in vitro anthelmintic effect of a hydroalcoholic extract (HA-E) and its fractions from Cyrtocarpa procera fruits against Haemonchus contortus eggs and infective larvae. The HA-E was subjected to bipartition using ethyl acetate, which resulted in an aqueous fraction (Aq-F) and an organic fraction (EtOAc-F). The HA-E and both fractions were tested using the egg hatching inhibition assay (EHIA) and the larval mortality test (LMT). Fractionation of the EtOAc-F was achieved using different chromatographic processes, i.e., open glass column and HPLC analysis. Fractionation of the EtOAc-F gave 18 subfractions (C1R1-C1R18), and those that showed the highest yields (C1R15, C1R16, C1R17 and C1R18) were subjected to anthelmintic assays. The HA-E and the EtOAc-F displayed 100% egg hatching inhibition at 3 and 1 mg/mL, respectively, whereas Aq-F exhibited 92.57% EHI at 3 mg/mL. All subfractions tested showed ovicidal effect. Regarding the larval mortality test, HA-E and EtOAc-F exhibited a larvicidal effect higher than 50% at 50 and 30 mg/mL, respectively. The subfractions that showed the highest larval mortality against H. contortus were C1R15 and C1R17, with larval mortalities of 53.57% and 60.23% at 10 mg/mL, respectively. Chemical analysis of these bioactive subfractions (C1R15 and C1R17) revealed the presence of gallic acid, protocatechuic acid, and ellagic acid. This study shows evidence about the ovicidal and larvicidal properties of C. procera fruits that could make these plant products to be considered as a natural potential anthelmintic agents for controlling haemonchosis in goats and sheep.

The multispecies stinkbug iflavirus Halyomorpha halys virus detected in the multispecies stinkbug egg parasitoid microwasp, Telenomus podisi (Ashmead) (Hymenoptera: Platygastridae).

Wasps are important parasitoids of stinkbugs and frequently exposed to various types of microorganisms through environmental contact and fecal-oral transmission route. Many parasitize stinkbug eggs and are commercially used in the field to control insect population. The parasitoid T. podisi is known for its high parasitism capacity and ability to target multiple species of stinkbugs. In this study we asked whether T. podisi exposed to eggs infected by a multispecies asymptomatic stinkbug virus, the Halyomorpha halys virus (HhV) would get infected. HhV is a geographically distributed multispecies iflavirus previously found to infect four stinkbug hosts, including three Brazilian species, Chinavia ubica, Euschistus heros and Diceraeus melacanthus, and T. posidi can parasitize all of them. As results, RT-PCR screening revealed positive samples for the HhV genome in two out of four tested pools of T. podisi, whereas the antigenome, indicative of replicative activity, was not detected. The wasps were raised in E. heros eggs that presented both the genome and the antigenome forms of the HhV genome. Subsequent RNA-deep sequencing of HhV positive T. podisi RNA pools yielded a complete genome of HhV with high coverage. Phylogenetic analysis positioned the isolate HhV-Tp (isolate Telenomus podisi) alongside with the stinkbug HhV. Analysis of transcriptomes from several hymenopteran species revealed HhV-Tp reads in four species. However, the transmission mechanism and the ecological significance of HhV remain elusive, warranting further studies to illuminate both the transmission process and its capacity for environmental propagation using T. podisi as a potential vector.

Temporal dynamics of the egg bank of Aedes aegypti (Diptera: Culicidae) in the winter-spring transition in a temperate region.

In temperate regions, the populations of Aedes aegypti (L.) (Diptera: Culicidae) remain in the egg stage during the winter. In Buenos Aires, Argentina, a temperate region in the southern limit of Ae. aegypti distribution, the start of the next reproductive season and the rate of increase of the adult population depend on the egg bank that remains after the winter. This study aimed to analyze the mortality, field-hatching, and survival of eggs exposed to field conditions representative of those that occur in nature. In addition, the post-exposure hatching response of the eggs was assessed. Four egg batches were exposed to natural conditions starting in mid-winter and were recovered progressively after 3, 6, 9, and 12 weeks. One egg batch (initial control) was not exposed in the field and remained under laboratory conditions. After the exposure period, the recovered intact, collapsed, and hatched eggs were counted. Intact eggs were immersed three times in the laboratory to study their hatching response. Progressive increases in the proportion of lost (presumably by predation), dead, and hatched eggs in successive egg batches were recorded. Field-hatching was recorded from late winter onwards. The first hatchings occurred in conditions probably not favorable to complete development into reproductive adults. A progressive decrease in live eggs was observed, with 51% of the recovered eggs alive after 12 weeks of exposure. In the laboratory, the hatching response in the first immersion was low for the initial control and for the eggs exposed for 3 weeks, and increased for successive cohorts. The results confirm that the survival of Ae. aegypti eggs in the winter-spring transition ensures persistence throughout the next favorable season in Buenos Aires City. The observed inhibition to hatch of the first batches might relate to a photoperiod-induced diapause, as observed in previous studies.

Bionomics, reproductive traits and assessment of forensic relevance of Peckia (Peckia) chrysostoma (Wiedemann, 1830) (Diptera: Sarcophagidae).

Peckia (Peckia) chrysostoma (Wiedemann, 1830) (Diptera: Sarcophagidae) is a colonizer of cadavers in the Neotropical Region. Nevertheless, data on development for the P. (P.) chrysostoma (e.g., instar duration) and behavioral strategies used by the species for locating and colonizing a corpse are scant. We aimed to explore bionomic and reproductive aspects of the flesh fly P. (P.) chrysostoma, and in this article we: (a) provide quantitative data on the life cycle of P. (P.) chrysostoma; (b) present bionomic measurements (length and weight) of larvae and pupae; (c) describe intrauterine egg and larvae development; and (d) analyze the ovo/larviposition behavior by gravid females. Females showed ovaries with discernible eggs and larvae between 8 and 10 days (x̅ = 23.3 eggs/female). This study reports the first observation of egg deposition, an atypical behavior for the species. The average development time for immature stages was 22.24 h and 21.36 h for 1st and 2nd respectively, and 3rd showed an average development time of 80.47 h. Pupa had the longest duration (x̅ = 295.69 h). A direct increase was observed in weight (P < 0.05) and length (P < 0.05) throughout time. The average survival time of males and females is approximately 30 days. This study expands the knowledge on P. (P.) chrysostoma, such as facultative ovoviviparity under laboratory conditions and the life cycle, which may benefit future studies for accuracy in entomology-based estimation of minimum post-mortem interval (min PMI).

Effects of pasture management and supplementation on the productive performance of recently lambed ewes.

The hypothesis was tested that the performance of lactating ewes is affected by the supplementation level and pasture management. Two supplementation levels (0.5 and 1.0% of body weight, BW) and two pasture managements (mowed and non-mowed) were tested. Forty adult ewes (2 years old) with an average weight at lambing of 62.97 ± 7.0 kg (day 0) and an average the body condition score of 2.5 points (day 0) were evaluated. Verminosis was monitored with periodic deworming. The number of eggs per gram of feces (EPG) of ewes at lambing was used as a covariate for performance assessments. Ewes lost an average of 7.5 kg over the 90 days post-partum (12% BW). The weaning rate was 53%. The body condition of the ewes was influenced by the post-partum period. The ewes mobilized their body reserves in the first 30 days of lactation. Mowing management negatively affected the nutritive value of the forage. Supplementation with 0.5% BW was sufficient for nutritional management post-partum. Pasture management (mowed vs. not mowed) cannot prevent post-partum weight loss. Supplementation levels and pasture management altered the morphological and chemical components of the pasture.