Anoplophora glabripennis, an invasive longhorned beetle, has the potential to damage fruit trees in Japan.

Invasive Anoplophora glabripennis recently became established in Japan and has caused heavy damage to several street-tree species. Overseas, A. glabripennis infests trees of the genera Acer and Populus as common host plants, and Malus, Pyrus, and Prunus (Rosaceae), including apple, pear, and plum trees; it therefore poses a potential risk to the production of economically valuable fruits in Japan. Fruit farms in areas already invaded by A. glabripennis are now threatened with tree infestation. We aimed to determine the potential damage to major fruit species in Japan. In the laboratory, we determined if the adult beetle is attracted to the odor of each of these tree species' branches; two confirmed host plant species and five Rosaceae fruit species, as well as its feeding preferences among branches of one host plant and the five fruit trees and its oviposition preferences among them. Among the fruit species, cherry branch had the highest rate of odor orientation by males. The feeding-preference assay showed that, besides the host plant, Japanese pear was the most consumed among the fruit trees. The potential risk of A. glabripennis laying eggs on fruit-tree branches was high for Japanese pear and above zero for plum, apple, and cherry branches.

Chemical Composition, Repellent, and Oviposition Deterrent Potential of Wild Plant Essential Oils against Three Mosquito Species.

In this study, the chemical composition, repellent, and oviposition deterrent effects of five plant essential oils (EOs) extracted from Lantana camara (Verbenaceae), Schinus terebinthifolia (Anacardiaceae), Callistemon viminalis (Myrtaceae), Helichrysum odoratissimum (Asteraceae), and Hyptis suaveolens (Lamiaceae) were evaluated against Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus. When tested at 33.3 µg/cm2, L. camara, S. terebinthifolia, C. viminalis, and H. odoratissimum were effective repellents against Ae. aegypti (89%, 91%, 90%, and 51% repellency, respectively), but they were less repellent against An. gambiae (66%, 86%, 59%, and 49% repellency, respectively). Interestingly, L. camara, S. terebinthifolia, C. viminalis, and H. odoratissimum exhibited 100% repellency against Cx. quinquefasciatus at 33.3 µg/cm2. In time-span bioassays performed at 333 µg/cm2, the EO of L. camara exhibited 100% repellence against Ae. aegypti and An. gambiae for up to 15 min and against Cx. quinquefasciatus for 75 min. The oviposition bioassays revealed that L. camara exhibited the highest activity, showing 85%, 59%, and 89% oviposition deterrence against Ae. aegypti, An. gambiae, and Cx. quinquefasciatus, respectively. The major compounds of L. camara, S. terebinthifolia, and C. viminalis were trans-ß-caryophyllene (16.7%), α-pinene (15.5%), and 1,8-cineole (38.1%), respectively. In conclusion, the L. camara and S. terebinthifolia EOs have the potential to be natural mosquito repellents.

Thermo-physiological changes and reproductive investment in a liolaemid lizard at the extreme of the slow-fast continuum.

Gravid female lizards often experience reduced thermal preferences and impaired locomotor performance. These changes have been attributed to the physical burden of the clutch, but some authors have suggested that they may be due to physiological adjustments. We compared the thermal biology and locomotor performance of the lizard Liolaemus wiegmannii 1 week before and 1 week after oviposition. We found that gravid females had a thermal preference 1°C lower than that of non-gravid females. This was accompanied by a change in the thermal dependence of maximum running speed. The thermal optimum for locomotor performance was 2.6°C lower before oviposition than after. At relatively low temperatures (22 and 26°C), running speeds of females before oviposition were up to 31% higher than for females after oviposition. However, at temperatures above 26°C, females achieved similar maximum running speeds (∼1.5 m s-1) regardless of reproductive stage. The magnitude of the changes in thermal parameters and locomotor performance of L. wiegmannii females was independent of relative clutch mass (clutches weighed up to 89% of post-oviposition body mass). This suggests that the changes are not simply due to the clutch mass, but are also due to physiological adjustments. Liolaemus wiegmannii females simultaneously adjusted their own physiology in a short period in order to improve locomotor performance and allocated energy for embryonic development during late gravid stage. Our findings have implications for understanding the mechanisms underlying life histories of lizards on the fast extreme of the slow-fast continuum, where physiological exhaustion could play an important role.

Multitrait genetic parameter estimates in a Tenebrio molitor reference population: high potential for breeding gains.

To address multiple issues impacting the climate imbalance, insects, and in particular Tenebrio molitor, represent now a promising alternative for producing high-quality protein products with low environmental impact. As with any new species farmed on an industrial scale, insect breeding production must be improved through the accumulation of knowledge on rearing techniques and genetic management. Little information on the inheritance of agronomically interesting traits, dedicated to Tenebrio molitor, is available. This study aims to decipher the genetic parameters (heritability and genetic correlations) of reproduction, larval growth and survival, pupation rate and developmental time from a reference population made up of 1 931 sib-groups reared under pedigree, in controlled and stable environments and generated with single pair mating. Considering all sib-groups, 29 599 offspring have been generated and phenotyped over four generations to support this study and provide enough data to estimate, under linear animal models, the additive genetic and common environmental effects. Phenotypic analyses underlined an important variability among sib-groups and individuals, as for the total oviposition during 4 weeks counting (0-680 eggs, min - max, respectively) or larval body mass 63 days posteclosion (36.3-206.8 mg, min - max, respectively). Moderate to important heritability values have been obtained and ranged from 0.17 to 0.54 for reproduction phenotypes, 0.10-0.44 for growth parameters, 0.06-0.22 for developmental time and 0.10-0.17 for larval survival rates. The proportion of phenotypic variance explained by the environmental part varyies from 0.10 to 0.36 for reproductive traits, from 0.17 to 0.38 for growth parameters, from 0.06 to 0.36 for developmental time and 0.17-0.22 for survival rates. Genetic correlations underline relationships among phenotypes such as the trade-off between developmental time from egg to pupae and pupae weight (r2 = 0.48 ± 0.06). These important phenotypic variations coupled with promising heritability values pave the road for future breeding programs in Tenebrio molitor.

Orthologs of NOX5 and EC-SOD/SOD3: dNox and dSod3 Impact Egg Hardening Process and Egg Laying in Reproductive Function of Drosophila melanogaster.

The occurrence of ovarian dysfunction is often due to the imbalance between the formation of reactive oxygen species (ROS) and the ineffectiveness of the antioxidative defense mechanisms. Primary sources of ROS are respiratory electron transfer and the activity of NADPH oxidases (NOX) while superoxide dismutases (SOD) are the main key regulators that control the levels of ROS and reactive nitrogen species intra- and extracellularly. Because of their central role SODs are the subject of research on human ovarian dysfunction but sample acquisition is low. The high degree of cellular and molecular similarity between Drosophila melanogaster ovaries and human ovaries provides this model organism with the best conditions for analyzing the role of ROS during ovarian function. In this study we clarify the localization of the ROS-producing enzyme dNox within the ovaries of Drosophila melanogaster and by a tissue-specific knockdown we show that dNox-derived ROS are involved in the chorion hardening process. Furthermore, we analyze the dSod3 localization and show that reduced activity of dSod3 impacts egg-laying behavior but not the chorion hardening process.

Assessment of the occurrence of the second generation of Mythimna loreyi Duponchel (Lepidoptera: Noctuidae) using temperature-dependent developmental and oviposition models.

A significant crop pest, Mythimna loreyi, migrates annually to Korea and has been frequently observed in rice and corn fields. However, the phenology of this pest, particularly in relation to its ecological interactions and host crop seasons in Korea, remains poorly understood. This study aims to clarify the timing of the second generation of M. loreyi in Korea to enhance pest management strategies. To achieve this, we developed temperature-dependent models for developmental and ovipositional rates, studying these processes across five constant temperatures (15, 20, 25, 30, and 35°C). Our models, which showed a high correlation with observed data (r2 ≥ 0.93), include a theoretical approach that combines the developmental variation of immatures with the necessary degree-days for 50% egg laying and complete egg development. These predictions allow for the forecasting of the second generation's occurrence, with relatively small deviations (one to three days) observed at two different field sites. The insights from this study are critical for both understanding the ecology of M. loreyi and for informing practical management decisions, such as optimal placement of barriers to prevent immigration and strategies for controlling local populations.

Taking it with a grain of salt: tolerance to increasing salinization in Culex pipiens (Diptera: Culicidae) across a low-lying delta.

BACKGROUND: Salinity, exacerbated by rising sea levels, is a critical environmental cue affecting freshwater ecosystems. Predicting ecosystem structure in response to such changes and their implications for the geographical distribution of arthropod disease vectors requires further insights into the plasticity and adaptability of lower trophic level species in freshwater systems. Our study investigated whether populations of the mosquito Culex pipiens, typically considered sensitive to salt, have adapted due to gradual exposure. METHODS: Mesocosm experiments were conducted to evaluate responses in life history traits to increasing levels of salinity in three populations along a gradient perpendicular to the North Sea coast. Salt concentrations up to the brackish-marine transition zone (8 g/l chloride) were used, upon which no survival was expected. To determine how this process affects oviposition, a colonization experiment was performed by exposing the coastal population to the same concentrations. RESULTS: While concentrations up to the currently described median lethal dose (LD50) (4 g/l) were surprisingly favored during egg laying, even the treatment with the highest salt concentration was incidentally colonized. Differences in development rates among populations were observed, but the influence of salinity was evident only at 4 g/l and higher, resulting in only a 1-day delay. Mortality rates were lower than expected, reaching only 20% for coastal and inland populations and 41% for the intermediate population at the highest salinity. Sex ratios remained unaffected across the tested range. CONCLUSIONS: The high tolerance to salinity for all key life history parameters across populations suggests that Cx. pipiens is unlikely to shift its distribution in the foreseeable future, with potential implications for the disease risk of associated pathogens.

Life table parameters of Amblyseius largoensis, Amblyseius swirskii and Proprioseiopsis lenis (Acari: Phytoseiidae) fed on eggs and larvae of Frankliniella occidentalis.

The immature development and reproduction of the predatory mites Amblyseius largoensis (Muma), Proprioseiopsis lenis (Corpuz and Rimando), and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) were investigated using both thrips eggs and first instars of the western flower thrips, Frankliniella occidentalis Pergande, as prey in a controlled laboratory environment at 25 °C and 60% relative humidity. When provided with thrips eggs as food, A. largoensis exhibited a notably shorter immature development period for both males (7.05 days) and females (6.51 days) as compared with A. swirskii (8.05 and 7.19 days, respectively) and P. lenis (8.10 days and 7.05 days, respectively). Amblyseius largoensis also displayed a higher oviposition rate (2.19 eggs/female/day) than A. swirskii and P. lenis (1.79 and 1.78 eggs/female/day, respectively). Moreover, it exhibited the highest fecundity (25.34 eggs/female), followed by P. lenis (24.23 eggs/female) and A. swirskii (22.86 eggs/female). These variations led to A. largoensis having the highest intrinsic rate of increase (rm) at 0.209, followed by A. swirskii at 0.188, and P. lenis at 0.165. However, when the predatory mites were provided with first instars of F. occidentalis, A. swirskii demonstrated a faster immature development period for both males (7.67 days) and females (7.59 days) as compared with P. lenis (9.00 days and 7.86 days, respectively) and A. largoensis (8.47 days and 8.61 days, respectively). While the oviposition rates of P. lenis (1.92 eggs/female/day) and A. swirskii (1.90 eggs/female/day) were similar when feeding on this prey, A. largoensis produced fewer eggs (1.83 eggs/female/day). Further, A. swirskii exhibited the highest fecundity (31.93 eggs/female), followed by A. largoensis (25.71 eggs/female) and P. lenis (23 eggs/female). Consequently, the intrinsic rate of increase (rm) on thrips first instars was highest in A. swirskii (0.190), followed by A. largoensis (0.186), and P. lenis (0.176). In summary, our findings indicate that in terms of life history parameters A. largoensis performs optimally when feeding on thrips eggs, whereas A. swirskii performs best when preying on the mobile first instars of the thrips. These insights into the dietary preferences and reproductive capabilities of the studied predatory mite species have important implications for their potential use as biological control agents against F. occidentalis in agricultural settings.

Supplemental effect of Pediococcus acidilactici CNCM I-4622 probiotic on the laying characteristics and calcium and phosphorus metabolism in laying hens.

The close link between intestinal microbiota and bone health ('gut-bone' axis) has recently been revealed: the modulation of the amount and nature of bacteria present in the intestinal tract has an impact on bone health and calcium (Ca) metabolism. Probiotics are known to favorably impact the intestinal microbiota. The objective of this study was to investigate the effect of Pediococcus acidilactici CNCM I-4622 (PA) on laying performance, egg/eggshell quality, Ca metabolism and bone mineralization and resistance in relatively old layers (50 wks old at the beginning of the experiment) during 14 weeks. 480 Hy Line brown layers were divided into 2 groups (CON and PA: 3 layers/rep, 80 rep/group) and fed with a diet formulated to be suboptimal in calcium (Ca) and phosphorus (P) (- 10% of the requirements). The total egg weight was improved by 1.1% overall with PA, related to an improvement of the weight of marketable eggs (+ 0.9%). PA induced a decreased % of downgraded eggs, mainly broken eggs (- 0.4 pts) and FCR improvement (- 0.8% for all eggs, - 0.9% for marketable eggs). PA also led to higher Haugh units (HU: + 7.4%). PA tended to decrease crypt depth after the 14 weeks of supplementation period in the jejunum (- 25.2%) and ileum (- 17.6%). As a consequence, the VH/CD ratio appeared increased by PA at the end of the trial in the jejunum (+ 63.0%) and ileum (+ 48.0%). Ca and P retention were increased by 4 pts following PA supplementation, translating into increased bone hardness (+ 19%), bone cohesiveness (+ 43%) and bone Ca & P (+ 1 pt) for PA-supplemented layers. Blood Ca and P were respectively improved by 5% and 12% with PA. In addition, blood calcitriol and osteocalcin concentrations were respectively improved by + 83% and + 3% in PA group at the end of the trial, compared to CON group. There was no difference between the 2 groups for ALP (alkaline phosphatase) and PTH (parathyroid hormone). PA significantly decreased the expression of the following genes: occludin in the small intestine, calbindin 1 in the ovarian tissue and actin B in the bone. PA therefore improved zootechnical performance of these relatively old layers, and egg quality. The parallel increase in Ca and P in the blood and in the bone following PA supplementation suggests an improvement of the mineral supply for eggshell formation without impacting bone integrity, and even increasing bone resistance.

Impact of climate change on the reproductive diapause and voltinism of the carrot weevil, Listronotus oregonensis.

The impacts of climate change on the development of insects are of great concern due to potential alterations in population dynamics and pest pressure. The carrot weevil, Listronotus oregonensis, is a major agricultural pest, and its development is influenced by temperature and photoperiod. In this study, our aim was to investigate the impact of temperature increases on the voltinism and reproductive diapause of the carrot weevil under field conditions and bioclimatic models. Field observations were conducted over two growing seasons using structures that allowed for temperature increases. The developmental stages of the carrot weevil, including female reproductive status, oviposition and larval stage, were monitored weekly to measure the proportion of individuals undergoing an additional generation. Concurrently, bioclimatic models were used to simulate the probability of a second generation under current (1981-2010) and future (2041-2070) climates, considering a lower and a higher change in emission scenarios. Results showed that rising temperatures led to an increase in the proportion of carrot weevils undergoing inhibition of the reproductive diapause and a higher number of eggs laid in the field. The models indicated a substantial rise in the probability of a second generation developing, from 24% to 37% to 62%-99% under current and future climates, respectively. These findings demonstrate the potential for significant alterations in carrot weevil population dynamics, resulting in increased pest pressure on crops. Further research is needed to fully understand the implications of these findings and to develop effective adaptation measures to mitigate the negative impacts of global warming on insect populations and agriculture.

Monitoring cotton squares with opened and/or yellowed bracts to determine the need and efficency of chemical control against the cotton boll weevil.

The technique of terrestrial sampling of boll weevil (BW) populations is expensive and inefficient over large areas, but may be cheaper and more efficient without involving the manipulation of cotton squares. The aim of this study was to develop a technique to sampling cotton squares based on the observation of opened and/or yellowing bracts to determine the need and efficacy of chemical control of BW in cotton crops. The first experiment aimed to estimate the ratio between the number of cotton squares with opened and/or yellowed bracts and that of squares with BW oviposition punctures. The second experiment, aimed to determine the efficacy of chemical control for BW by sampling cotton squares with opened and/or yellowed bracts. The ratio between the number of opened and/or yellowed bracts and the number of cotton squares with oviposition punctures was 2:1. The level and efficiency of chemical control of BW, based on the percentage and sampling of cotton plants with opened and/or yellowed bracts, was 5% and did not differ from the one based on the observation of cotton plants with 10% cotton squares with oviposition punctures by BW females. The control level based on sampling cotton plants with open and/or yellowing bracts was 5%. The efficiency of chemical insecticides using this economic threshold against the BW did not differ from that based on sampling cotton plants with 10% of cotton squares with oviposition punctures by BW females. This indicates that the chemical control of cotton boll weevil can be carried out based on cotton squares with open and/or yellowed bracts.

The influence of oviposition status on measures of transmission potential in malaria-infected mosquitoes depends on sugar availability.

BACKGROUND: Like other oviparous organisms, the gonotrophic cycle of mosquitoes is not complete until they have selected a suitable habitat to oviposit. In addition to the evolutionary constraints associated with selective oviposition behavior, the physiological demands relative to an organism's oviposition status also influence their nutrient requirement from the environment. Yet, studies that measure transmission potential (vectorial capacity or competence) of mosquito-borne parasites rarely consider whether the rates of parasite replication and development could be influenced by these constraints resulting from whether mosquitoes have completed their gonotrophic cycle. METHODS: Anopheles stephensi mosquitoes were infected with Plasmodium berghei, the rodent analog of human malaria, and maintained on 1% or 10% dextrose and either provided oviposition sites ('oviposited' herein) to complete their gonotrophic cycle or forced to retain eggs ('non-oviposited'). Transmission potential in the four groups was measured up to 27 days post-infection as the rates of (i) sporozoite appearance in the salivary glands ('extrinsic incubation period' or EIP), (ii) vector survival and (iii) sporozoite densities. RESULTS: In the two groups of oviposited mosquitoes, rates of sporozoite appearance and densities in the salivary glands were clearly dependent on sugar availability, with shorter EIP and higher sporozoite densities in mosquitoes fed 10% dextrose. In contrast, rates of appearance and densities in the salivary glands were independent of sugar concentrations in non-oviposited mosquitoes, although both measures were slightly lower than in oviposited mosquitoes fed 10% dextrose. Vector survival was higher in non-oviposited mosquitoes. CONCLUSIONS: Costs to parasite fitness and vector survival were buffered against changes in nutritional availability from the environment in non-oviposited but not oviposited mosquitoes. Taken together, these results suggest vectorial capacity for malaria parasites may be dependent on nutrient availability and oviposition/gonotrophic status and, as such, argue for more careful consideration of this interaction when estimating transmission potential. More broadly, the complex patterns resulting from physiological (nutrition) and evolutionary (egg-retention) trade-offs described here, combined with the ubiquity of selective oviposition behavior, implies the fitness of vector-borne pathogens could be shaped by selection for these traits, with implications for disease transmission and management. For instance, while reducing availability of oviposition sites and environmental sources of nutrition are key components of integrated vector management strategies, their abundance and distribution are under strong selection pressure from the patterns associated with climate change.

Cananga odorata L., Illicium verum, and Foeniculum vulgare essential oils impair the reproduction of the cattle tick Rhipicephalus microplus (Acari: Ixodidae).

This study aimed to evaluate the acaricidal potential of the essential oils of Cananga odorata L. (ylang-ylang), Illicium verum (star anise), and Foeniculum vulgare (sweet fennel) in Rhipicephalus microplus engorged females. The essential oils were extracted by hydrodistillation, and the females were immersed in each essential oil at concentrations ranging from 10 µL/mL to 50 µL/mL, using 10% dimethyl sulfoxide as a solvent. Tick mortality was evaluated after seven and 14 days, and the following parameters were determined: female weight before oviposition, preoviposition period, egg mass weight, egg production index, incubation period, hatching rate, fecundity, percentage of reduction in oviposition, percentage of reduction in hatching and product efficacy. Lethal concentration (LC50) values were 34.42 µL/mL (28.34-40.86) for C. odorata and 40.60 µL/mL (32.58-58.21) for F. vulgare. This parameter was not calculated for I. verum because there was insufficient mortality at the concentrations evaluated. The greatest efficacy was observed in the group treated with 40 µL/mL F. vulgare essential oil (97.17%), followed by I. verum (91.35%) and C. odorata (86.19%) at the same concentration. Efficacy results were associated with a greater reduction in egg mass weight and lower hatching rates. Although the essential oils caused a slight acaricidal impact, they showed significant effects on the reproductive performance of R. microplus engorged females. Thus, the results of this study indicate that these essential oils can be used in the development of new acaricidal formulations.

The TCTP is essential for ovarian development and oviposition of Rhipicephalus haemaphysaloides.

Tick infestations transmit various infectious agents and result in significant socioeconomic consequences. Currently, the primary focus of tick control efforts is identifying potential targets for immune intervention. In a previous study, we identified a highly conserved protein abundant in tick haemolymph extracellular vesicles (EVs) known as translationally controlled tumour protein (TCTP). We have found that native TCTP is present in various tissues of the Rhipicephalus haemaphysaloides tick, including salivary glands, midgut, ovary, and fat body. Notably, TCTP is particularly abundant in the tick ovary and its levels increase progressively from the blood-feeding stage to engorgement. When the TCTP gene was knocked down by RNAi, there was a noticeable delay in ovarian development, and the reproductive performance, in terms of egg quantity and survival, was also hindered. Our investigations have revealed that the observed effects in ovary and eggs in dsRNA-treated ticks are not attributable to cell death mechanisms like apoptosis and autophagy but rather to the reduction in the expression of vitellogenin (Vg1, Vg2, and Vg3) and ferritin (ferritin 1 and ferritin 2) proteins crucial for ovarian development and embryo survival in ticks. Additionally, phylogenetic analysis and structural comparisons of RhTCTP and its orthologues across various tick species, vertebrate hosts, and humans have shown that TCTP is conserved in ticks but differs significantly between ticks and their hosts, particularly in the TCTP_1 and TCTP_2 domains. Overall, TCTP plays a vital role in tick reproductive development and presents itself as a potential target for tick control in both humans and animals.

Differential effects of plant-beneficial fungi on the attraction of the egg parasitoid Trissolcus basalis in response to Nezara viridula egg deposition.

There is increasing evidence that plant-associated microorganisms play important roles in defending plants against insect herbivores through both direct and indirect mechanisms. While previous research has shown that these microbes can modify the behaviour and performance of insect herbivores and their natural enemies, little is known about their effect on egg parasitoids which utilize oviposition-induced plant volatiles to locate their hosts. In this study, we investigated how root inoculation of sweet pepper (Capsicum annuum) with the plant-beneficial fungi Beauveria bassiana ARSEF 3097 or Trichoderma harzianum T22 influences the olfactory behaviour of the egg parasitoid Trissolcus basalis following egg deposition by its host Nezara viridula. Olfactometer assays showed that inoculation by T. harzianum significantly enhanced the attraction of the egg parasitoid, while B. bassiana had the opposite effect. However, no variation was observed in the chemical composition of plant volatiles. Additionally, fitness-related traits of the parasitoids (wasp body size) were not altered by any of the two fungi, suggesting that fungal inoculation did not indirectly affect host quality. Altogether, our results indicate that plant inoculation with T. harzianum T22 can be used to enhance attraction of egg parasitoids, which could be a promising strategy in manipulating early plant responses against pest species and improving sustainable crop protection. From a more fundamental point of view, our findings highlight the importance of taking into account the role of microorganisms when studying the intricate interactions between plants, herbivores and their associated egg parasitoids.

The egg-counter: a novel microfluidic platform for characterization of Caenorhabditis elegans egg-laying.

Reproduction is a fundamental process that shapes the demography of every living organism yet is often difficult to assess with high precision in animals that produce large numbers of offspring. Here, we present a novel microfluidic research platform for studying Caenorhabditis elegans' egg-laying. The platform provides higher throughput than traditional solid-media behavioral assays while providing a very high degree of temporal resolution. Additionally, the environmental control enabled by microfluidic animal husbandry allows for experimental perturbations difficult to achieve with solid-media assays. We demonstrate the platform's utility by characterizing C. elegans egg-laying behavior at two commonly used temperatures, 15 and 20 °C. As expected, we observed a delayed onset of egg-laying at 15 °C degrees, consistent with published temperature effects on development rate. Additionally, as seen in solid media studies, egg laying output was higher under the canonical 20 °C conditions. While we validated the Egg-Counter with a study of temperature effects in wild-type animals, the platform is highly adaptable to any nematode egg-laying research where throughput or environmental control needs to be maximized without sacrificing temporal resolution.

The impact of yeast-encapsulated orange oil in Aedes aegypti oviposition.

The yeast-encapsulated orange oil (YEOO) is a novel larvicide under development against vector mosquitoes. Despite its efficiency against Aedes aegypti (L.) in small scale experiments, its applicability in vector control can be influenced by other effects on mosquito behaviour or physiology. For this reason, the impact of YEOO particles in mosquito oviposition was evaluated in laboratory and semi-field conditions. Oviposition assays with one gravid Aedes aegypti female were carried under laboratory and semi-field conditions with natural light and temperature fluctuation. For all ovitraps, the number of eggs was manually counted in the wooden paddle and in the solution of each ovitrap. The proportion of eggs between substrates (wooden paddle and solution) varied between conditions, with females in laboratory presenting a lower preference to lay eggs in paddles when compared with studies in semi-field. This behaviour shifts in laboratory can create challenges to extrapolate results from laboratory to the field. Here, studies in both conditions indicate a similar impact of YEOO particles in Aedes aegypti oviposition. The potential treatment concentration of YEOO particles presents a strong repellent/deterrent effect (-0.559 > OAI > -0.760) within the initial 72h of application when compared with water, and weak repellent/deterrent signal (OAI = -0.220) when compared against inactivated yeast. Control ovitraps with water were more positive for egg presence than treated ovitraps, while ovitraps with YEOO particles and inactivated yeast present similar number of positive ovitraps. It is possible that the repellent/deterrent action is partially driven by the delivery system, since most times Citrus sinensis EO oviposition repellent/deterrent signal is weak, and it seem influenced by solvent/delivery used. However, it is unclear how the yeast wall that protect/surrounds the orange oil will negatively affect oviposition since live yeast are normally consider an attractant for mosquito oviposition.

Identifying suitable methods for evaluating the sterilizing effects of pyriproxyfen on adult malaria vectors: a comparison of the oviposition and ovary dissection methods.

BACKGROUND: Nets containing pyriproxyfen, an insect growth regulator that sterilizes adult mosquitoes, have become available for malaria control. Suitable methods for investigating vector susceptibility to pyriproxyfen and evaluating its efficacy on nets need to be identified. The sterilizing effects of pyriproxyfen on adult malaria vectors can be assessed by measuring oviposition or by dissecting mosquito ovaries to determine damage by pyriproxyfen (ovary dissection). METHOD: Laboratory bioassays were performed to compare the oviposition and ovary dissection methods for monitoring susceptibility to pyriproxyfen in wild malaria vectors using WHO bottle bioassays and for evaluating its efficacy on nets in cone bioassays. Blood-fed mosquitoes of susceptible and pyrethroid-resistant strains of Anopheles gambiae sensu lato were exposed to pyriproxyfen-treated bottles (100 µg and 200 µg) and to unwashed and washed pieces of a pyriproxyfen long-lasting net in cone bioassays. Survivors were assessed for the sterilizing effects of pyriproxyfen using both methods. The methods were compared in terms of their reliability, sensitivity, specificity, resources (cost and time) required and perceived difficulties by trained laboratory technicians. RESULTS: The total number of An. gambiae s.l. mosquitoes assessed for the sterilizing effects of pyriproxyfen were 1745 for the oviposition method and 1698 for the ovary dissection method. Fertility rates of control unexposed mosquitoes were significantly higher with ovary dissection compared to oviposition in both bottle bioassays (99-100% vs. 34-59%, P < 0.05) and cone bioassays (99-100% vs. 18-33%, P < 0.001). Oviposition rates of control unexposed mosquitoes were lower with wild pyrethroid-resistant An. gambiae s.l. Cové, compared to the laboratory-maintained reference susceptible An gambiae sensu stricto Kisumu (18-34% vs. 58-76%, P < 0.05). Sterilization rates of the Kisumu strain in bottle bioassays with the pyriproxyfen diagnostic dose (100 µg) were suboptimal with the oviposition method (90%) but showed full susceptibility with ovary dissection (99%). Wild pyrethroid-resistant Cové mosquitoes were fully susceptible to pyriproxyfen in bottle bioassays using ovary dissection (> 99%), but not with the oviposition method (69%). Both methods showed similar levels of sensitivity (89-98% vs. 89-100%). Specificity was substantially higher with ovary dissection compared to the oviposition method in both bottle bioassays (99-100% vs. 34-48%) and cone tests (100% vs.18-76%). Ovary dissection was also more sensitive for detecting the residual activity of pyriproxyfen in a washed net compared to oviposition. The oviposition method though cheaper, was less reliable and more time-consuming. Laboratory technicians preferred ovary dissection mostly due to its reliability. CONCLUSION: The ovary dissection method was more accurate, more reliable and more efficient compared to the oviposition method for evaluating the sterilizing effects of pyriproxyfen on adult malaria vectors in susceptibility bioassays and for evaluating the efficacy of pyriproxyfen-treated nets.

Leaf trichome-mediated predator effects on the distribution of herbivorous mites within a kidney bean plant.

Some predators prefer to settle on leaf patches with microstructures (e.g., trichomes and domatia), leaving traces on the patches. Herbivorous arthropods, in turn, select leaf patches in response to these traces left by predators. It remains unclear whether traces of predators on leaf patches affect the distribution of herbivorous prey within plants through plant microstructure. Therefore, we examined the distribution of herbivorous mite (Tetranychus urticae) and predatory mite (Phytoseiulus persimilis) by investigating their oviposition pattern. We used a kidney bean plant (Phaseolus vulgaris) with two expanded primary leaves and the first trifoliate leaf, focusing on leaf trichomes as the microstructure. The density of trichomes was higher on the first trifoliate leaf than on the primary leaves and on the abaxial surface of the leaves than on the adaxial surface. Adult female P. persimilis laid more eggs on the first trifoliate leaf to the primary leaves. Although adult female T. urticae preferred to oviposit on the abaxial surface of primary leaves, previous exposure of plants to predators diminished this preference. The altered egg distribution would be a response to the traces of P. persimilis rather than eggs of P. persimilis. Our findings indicate that T. urticae reproduces on leaf patches with traces of predators without altering their oviposition preference. Given that the presence of predator traces is known to reduce the reproduction of T. urticae, it may have a substantial effect on the population of T. urticae in the next generations on kidney bean plants.

The oviposition preference and offspring performance of Aethina tumida (Coleoptera: Nitidulidae).

Given the rapid spread and potential harm caused by the small hive beetle, Aethina tumida (Coleoptera: Nitidulidae) in China, it has become imperative to comprehend the developmental biology of this invasive species. Currently, there is limited knowledge regarding the impact of A. tumida female oviposition site preference on larval growth and development. To examine this, we investigated the ovipositional preference of adult female A. tumida on bee pupae, beebread, banana, and honey through a free choice test. Furthermore, we assessed the impact of these food resources on offspring performance, which included larval development time, survival, wandering larvae weight, emerged adult body mass, reproduction, and juvenile hormone titer. Our results showed that A. tumida females exhibited a strong preference for ovipositing on bee pupae compared to other diets, while showing reluctance toward honey. Moreover, A. tumida larvae that were fed on bee pupae displayed accelerated growth compared to those fed on other diets. Furthermore, A. tumida fed on bee pupae exhibited higher weights for wandering larvae, and emerged adult, increased pupation rates, enhanced fecundity and fertility, as well as a larger number of unilateral ovarioles during the larval stage when compared to those fed on other diets. Overall, the results indicate that the oviposition preferences of A. tumida females are adaptive, as their choices can enhance the fitness of their offspring. This finding aligns broadly with the hypothesis of oviposition preference and larval performance. This study can provide a foundation for the development of attractants aimed at promoting the oviposition of the A. tumida adults.