New Strategies For Control Research Articles

Wolbachia Infection through Hybridization to Enhance an Incompatible Insect Technique-Based Suppression of Aedes albopictus in Eastern Spain.

The emergence of insecticide resistance in arbovirus vectors is putting the focus on the development of new strategies for control. In this regard, the exploitation of Wolbachia endosymbionts is receiving increasing attention due to its demonstrated effectiveness in reducing the vectorial capacity of Aedes mosquitoes. Here, we describe the establishment of a naïve Wolbachia infection in a wild Aedes albopictus population of eastern Spain through a hybridization approach to obtain males capable of sterilizing wild females. The obtained lines were compared with the Wolbachia donor, Ae. albopictus ARwP, previously artificially infected with Wolbachia wPip, regarding immature and adult survival, female fecundity, egg fertility, and level of induced sterility. Our results did not show significant differences between lines in any of the biological parameters analyzed, indicating the full suitability of the hybrids to be used as a control tool against Ae. albopictus. In particular, hybrid males induced 99.9% sterility in the eggs of wild females without the need for any preliminary treatment. Being harmless to non-target organisms and the environment, the use of this bacterium for the control of Ae. albopictus deserves further exploration. This is especially relevant in areas such as eastern Spain, where this mosquito species has recently spread and may represent a serious threat due to its competence as a vector for dengue, chikungunya, and Zika viruses.

Optimization of RST Controller for Speed Control of Linear Induction Motor Using Genetic Algorithm

Background: In this study, a new model of linear induction motor, along with the impact of end-effect on motor performance, is proposed. Moreover, a new strategy of control approach based on the polynomial RST controller is suggested and investigated. Objective: The proposed approach can provide a robust control strategy and overcome the limitations imposed by the proportional-integral (PI) regulator in the FOC technique. RST controller has a two-degree of freedom structure and consists of three polynomials, namely R, S and T, which are determined by the pole placement method and resolving of a Diophantine equation. Despite this, the implementation of this method is usually difficult and becomes more complicated with the complexity of the controlled plants. Methods: This study proposes the genetic algorithm (GA) optimization strategy for tuning RST controller parameters (adjust the controller coefficients) in order to achieve an adequate response time by minimizing the different objective functions, such as steady-state error, settling time, and rise time. Results: The accuracy and control performance of the proposed technique are checked and validated using Matlab /Simulink environment software tool. Simulation results reported that the proposed method (RST-GA) could provide robust solutions with perfect reference tracking and efficient disturbance rejection. Conclusion: These significant results make the proposed approach a promising technique for the design of a high-performance controller, which is highly suitable for industrial and electrical applications.

The stage- and sex-specific transcriptome of the human parasite Schistosoma mansoni

The flatworm Schistosoma mansoni is an important but neglected pathogen that causes the disease schistosomiasis in millions of people worldwide. The parasite has a complex life cycle, undergoing sexual reproduction in a mammalian host and asexual replication in a snail host. Understanding the molecular mechanisms that the parasite uses to transition between hosts and develop into dimorphic reproductively competent adults may reveal new strategies for control. We present the first comprehensive transcriptomic analysis of S. mansoni, from eggs to sexually naïve worms. Focusing on eight life stages spanning free-living water-borne and parasitic stages from both intermediate and definitive hosts, we have generated deep RNA-seq data for five replicates per group for a total of 75 data sets. The data were produced using a single approach to increase the accuracy of stage-to-stage comparisons and made accessible via a user-friendly tool to visualise and explore gene expression (https://lifecycle.schisto.xyz/). These data are valuable for understanding the biology and sex-specific development of schistosomes and the interpretation of complementary genomic and functional genetics studies.

Effects of pH, sodium chloride, and temperature on the growth of Listeria monocytogenes biofilms

AbstractListeria monocytogenes is able to form biofilms on food contact surfaces. Effectiveness of salt concentration, pH, and temperature on the formation of L. monocytogenes biofilms was evaluated individually and in combinations using microtiter plate assay by measuring the optical density. The tested strains differed in their biofilm formation (low, moderate, and strong) ability. At 37 °C, decreasing amounts of biofilms was observed in almost all L. monocytogenes strains when the NaCl concentration increased from 0.05 to 15%, but all strains were able to form biofilm even at 1 °C. There was no significant difference in biofilm formation between pH 4, 5, and 6, except for some strains. When stress conditions were tested in combination, the addition of 15% NaCl significantly inhibited the growth of L. monocytogenes at 1 °C and 4 °C, and the weak biofilm-forming strains were less sensitive to the temperature and to NaCl treatments than the strong biofilm-forming strains. These results enhance our knowledge of the application of NaCl, temperature, and pH stresses in the food industry and provide basis to develop new strategies for control of biofilm formation of this pathogen.

Assembly and Analysis of Haemonchus contortus Transcriptome as a Tool for the Knowledge of Ivermectin Resistance Mechanisms.

Haemonchus contortus (Hc) is an important parasitic nematode of small ruminants. In this study we assembled the transcriptome of Hc as a model to contribute to the knowledge about the profile of the differential gene expression between two Mexican Hc strains under different anthelmintic resistance statuses, one susceptible and the other resistant to ivermectin (IVMs and IVMr, respectively), in order to improve and/or to have new strategies of control and diagnosis. The transcript sequence reads were assembled and annotated. Overall, ~127 Mbp were assembled and distributed into 77,422 transcript sequences, and 4394 transcripts of the de novo transcriptome were matched base on at least one of the following criteria: (1) Phylum Nemathelminthes and Platyhelminthes, important for animal health care, and (2) ≥55% of sequence identity with other organisms. The gene ontology (GO) enrichment analysis (GOEA) was performed to study the level of gene regulation to IVMr and IVMs strains using Log Fold Change (LFC) filtering values ≥ 1 and ≥ 2. The upregulated-displayed genes obtained via GOEA were: 1993 (for LFC ≥ 1) and 1241 (for LFC ≥ 2) in IVMr and 1929 (for LFC ≥ 1) and 835 (for LFC ≥ 2) in IVMs. The enriched GO terms upregulated per category identified the intracellular structure, intracellular membrane-bounded organelle and integral component of the cell membrane as some principal cellular components. Meanwhile, efflux transmembrane transporter activity, ABC-type xenobiotic transporter activity and ATPase-coupled transmembrane transporter activity were associated with molecular function. Responses to nematicide activity, pharyngeal pumping and positive regulation of synaptic assembly were classified as biological processes that might be involved in events related to the anthelmintic resistance (AR) and nematode biology. The filtering analysis of both LFC values showed similar genes related to AR. This study deepens our knowledge about the mechanisms behind the processes of H. contortus in order to help in tool production and to facilitate the reduction of AR and promote the development of other control strategies, such as anthelmintic drug targets and vaccines.

Cultivar Susceptibility to Olive Knot Disease and Association with Endophytic Microbiota Community

Olive knot disease (OKD) induced by the bacterium Pseudomonas savastanoi pv. savastanoi seriously affects olive production in the Mediterranean basin. Nowadays, the only strategies to control the disease are pruning and the application of cupric products. An essential strategy to enhance protection is represented by the identification of resistant cultivars, which represents a crucial opportunity for future investments and breeding. We undertook a three-year-long survey at the International Olive Germplasm Collection of “Villa Zagaria” (Sicily, Italy) on thirty-six Sicilian cultivars that were monitored for symptom development. Cultivars with different levels of susceptibility were divided into five clusters. Moreover, in order to investigate possible interactions with endophytic microbial communities, two cultivars with contrasting susceptibilities, Zaituna (highly resistant) and Giarraffa (highly susceptible), were selected for an amplicon-based metagenomic analysis. Distinct endophytic communities colonized the two cultivars, suggesting an interaction between the resident bacterial community and the pathogen. Significantly higher bacterial richness was detected in the shoots of the susceptible cv. Giarraffa, although it had lower diversity. The opposite trend was observed for fungal communities. Among the microbes resulted to be enriched in cv. Giarraffa, it is important to underline the presence of Pseudomonas among the bacterial genera, and Alternaria, Neofusicoccum, Epicoccum, Ascochyta, and Elsinoe among the fungal genera, which include many species often described as plant pathogens and biocontrol agents. Starting from this basic information, new strategies of control, which include breeding for resistance and integrated disease management, can be envisaged.

Sardinia as a 100% renewable power system: A frequency stability study

This paper investigates a real complex power system supplied by a 100% renewable generation, focusing on the primary frequency regulation. The grid and the power production park are represented by means of an electro-mechanical model in a free open-source environment. The lack of synchronous generators in the grid, due to the conventional power plants shutdowns, requires higher performances from renewable power plants (RPPs) in terms of synchronization and inertial response. Doubly fed induction generators (DFIGs) are identified as the promising power plants able to lessen inertial issues. DFIG system control is investigated in the present paper, according to the recent studies in the literature, implementing a new strategy of control in case of avoiding maximum power point tracker (MPPT) operation. The 100% renewable 112-bus Sardinia islanded power system is the case study of this paper. Four scenarios were selected to show the primary frequency response in the most critical under and upper frequency events among the year. The simulations revealed that the most severe frequency nadir in the simulation reached a decrease of 0.37 Hz. DFIGs control system appeared robust in terms of inertial response and capability of reaching new stable operating point.

Soil-Borne Nematodes: Impact in Agriculture and Livestock and Sustainable Strategies of Prevention and Control with Special Reference to the Use of Nematode Natural Enemies.

Soil-borne parasitic nematodes cause severe deterioration in the health of crops and supply animals, leading to enormous economic losses in the agriculture and livestock industry worldwide. The traditional strategy to control these parasites has been based on chemically synthesised compounds with parasiticidal activity, e.g., pesticides and anthelmintic drugs, which have shown a negative impact on the environment. These compounds affect the soil’s beneficial microbiota and can also remain as toxic residues in agricultural crops, e.g., fruits and legumes, and in the case of animal products for human consumption, toxic residues can remain in milk, meat, and sub-products derived from the livestock industry. Other alternatives of control with much less negative environmental impact have been studied, and new strategies of control based on the use of natural nematode enemies have been proposed from a sustainable perspective. In this review, a general view of the problem caused by parasitic nematodes affecting the agriculture and livestock industry, traditional methods of control, and new strategies of control based on eco-friendly alternatives are briefly described, with a special focus on a group of natural nematode antagonists that have been recently explored with promising results against plagues of importance for agricultural and livestock production systems.

Review Pollution: Pedagogy for a Post-Truth Society

Consumer reviews on platforms like Amazon are summarized into star ratings, used to weight search results, and consulted by consumers to guide purchase decisions. They are emblematic of the interactive digital environment that has purportedly transferred power from marketers to ‘regular people,’ and yet they represent the infiltration of promotional concerns into online information, as has occurred in search and social media content. Consumers’ ratings and reviews do promotional work for brands—not just for products but the platforms that host reviews—that money can’t always buy. Gains in power by consumers are quickly met with new strategies of control by companies who depend on reviews for reputational capital. Focusing on ecommerce giant Amazon, this article examines the complexities of online reviews, where individual efforts to provide product feedback and help others make choices become transformed into an information commodity and promotional vehicle. It acknowledges the ambiguous nature of reviews due to the rise of industries and business practices that influence or fake reviews as a promotional strategy. In response are yet other business practices and platform policies aiming to provide better information to consumers, protect the image of platforms that host reviews, and punish ‘bad actors’ in competitive markets. The complexity in the production, regulation, and manipulation of product ratings and reviews illustrates how the high stakes of attention in digital spaces create fertile ground for disinformation, which only emphasizes to users that they inhabit a ‘post-truth’ reality online.

The Rcs System in Enterobacteriaceae: Envelope Stress Responses and Virulence Regulation.

The bacterial cell envelope is a protective barrier at the frontline of bacterial interaction with the environment, and its integrity is regulated by various stress response systems. The Rcs (regulator of capsule synthesis) system, a non-orthodox two-component regulatory system (TCS) found in many members of the Enterobacteriaceae family, is one of the envelope stress response pathways. The Rcs system can sense envelope damage or defects and regulate the transcriptome to counteract stress, which is particularly important for the survival and virulence of pathogenic bacteria. In this review, we summarize the roles of the Rcs system in envelope stress responses (ESRs) and virulence regulation. We discuss the environmental and intrinsic sources of envelope stress that cause activation of the Rcs system with an emphasis on the role of RcsF in detection of envelope stress and signal transduction. Finally, the different regulation mechanisms governing the Rcs system’s control of virulence in several common pathogens are introduced. This review highlights the important role of the Rcs system in the environmental adaptation of bacteria and provides a theoretical basis for the development of new strategies for control, prevention, and treatment of bacterial infections.

Estudo epidemiológico de gestantes atendidas pelo sistema único de saúde com ênfase na toxoplasmose

Objetivo: identificar a correlação dos fatores de risco associados í incidência da toxoplasmose nas gestantes atendidas pelo Sistema Único de Saúde em municí­pio de médio porte no Estado do Paraná. Método: estudo transversal quantitativo, de janeiro a fevereiro de 2019, com gestantes acompanhadas em 17 UBS, as quais responderam questionário socioeconômico, hábitos alimentares, de higiene e aspectos relacionados ao ambiente e í doença. Análise estatí­stica pelo programa EpiInfo versão 7.0. Incluí­das no estudo 143 gestantes. Resultados: a análise mostrou que o consumo de verduras/legumes crus (p=0,9; OR=1,71), carne crua ou mal passada (p=0,87; OR=0,82), possuir gato na residência (p=0,56; OR=1,16), ter baixa escolaridade (p=0,17; OR=0,36) e ter baixa renda familiar (p=0,45; OR=0,51) não teve associação significativa com a sororeatividade para Toxoplasma gondii. Possuir cachorro na residência (p<0,001; OR=0,16) mostrou uma relação positiva entre dados, porém sem representatividade de risco para essas gestantes. Conclusões: necessidade de estudos que auxiliem na formulação de novas estratégias para o controle e tratamento desta infecção.

Alta prevalencia de infecciones asintomáticas de malaria en la frontera Ecuador Colombia

La malaria es una enfermedad que afecta a las zonas tropicales del mundo, siendo un importante problema de salud pública. En los últimos 18 años la incidencia en Ecuador ha disminuido, lo que lo ubicó entre los países con capacidad de eliminar la malaria hasta el 2020. Sin embargo, a partir del 2015 se ha presentado un incremento en el número de casos afectando principalmente a la población más vulnerable de las áreas fronterizas del país. La presencia de infecciones asintomáticas, las infecciones sub microscópicas y asintomáticas constituyen un problema para la eliminación de la enfermedad. En este trabajo se estudió la epidemiología de la malaria en las comunidades del norte de la provincia de Esmeraldas, fronterizas con Colombia, con muestras sanguíneas del 2017 y se aplicó una encuesta epidemiológica de conocimientos, actitudes y prácticas de malaria (CAP) a los jefes de familia. La prevalencia total de malaria en las zonas de estudio obtenida mediante técnicas moleculares fue de 5.83%. Todas las infecciones fueron asintomáticas. La población encuestada presentó un conocimiento básico respecto a la malaria, pero la falta de prácticas para prevenir la malaria es un factor importante que podría dificultar la eliminación de la malaria. Este estudio proporciona información sobre el estado de la malaria en las comunidades de estudio del norte de Esmeraldas que facilitará a la formulación de nuevas estrategias para el control y prevención de la enfermedad.

Retracted: P0981ANTIDIABETIC AND RENOPROTECTIVE ROLE OF METFORMIN ON METABOLIC PARAMETERS IN KIDNEY OF DIABETIC AGING RATS.

Abstract Background and Aims The objective of this study was to investigate renoprotective effects of metformin on renal function, mitochondrial and antioxidant enzymes, oxidative stress biomarker, DNA degradation and expression of glucose transporters in of diabetic aging female rats. Method Young (3 months) adult (12 months) and aged (24 months) rats will be diabetic by using alloxan monohydrate. Metformin was administered i.p. at a dose of 200 mg/kg/day for 30 days to both control and diabetic aging rats. A detailed study was carried on membrane fluidity, lipofuscin, antioxidant enzymes and DNA degradation to identify the antidiabetic and antiaging role of metformin using biochemical ,molecular and histiochemical study. Renal function was assessed by measuring proteinuria, enzymuria, expression of glucose transporters, renin-angiotensin system, and activities of polyol pathway enzymes. Results Present study shows that there was a similar pattern of increased lipid peroxidation, lipofuscin, DNA degradation and glucose transporters expression with upregulation of renal angiotensin-converting enzyme and a decrease in membrane fluidity, glutamate dehydrogenase, Na+ K+ ATPse, antixodant enzymes activities in both aging and diabetes. Metformin treatment helped to reverse the age related changes studied, to normal levels, elucidating an anti-aging, antidiabetic and renoprotective action. Metformin effectively countered the diabetes-induced structural abnormalities of renal tissue of aging rats. Conclusion Metformin was found to be an effective treatment in stabilizing and normalizing the renal functions; therefore this therapy can be considered an alternative to be explored further as a means of diabetic and aged related disorders control. The results of this study will be useful for pharmacological modification of the aging process and applying new strategies for control of age related disorders including metabolic syndrome.

The diabetes drug metformin reverses cognitive impairment and membrane functions in diabetic aging female rat brain: A link with diabetes and Alzheimer’s disease

The objective of this study was to investigate effects of metformin on body weight, blood glucose levels, glucose transporter (GLUT1), interleukin 1 β (IL-1β) and protein kinase B expression, antioxidant enzymes, expression of synaptic molecules, biomarkers of oxidative stress, lipid peroxidation, membrane fluidity and acetylcholinesterase (AChE) in diabetic aging brain of female rats. Male Wistar rats, young (3 months) adult (12 months) and aged (24 months) were diabetic by using alloxan monohydrate. Metformin was administered i.p. at a dose of 200mg/kg/day for 30 days to both control and diabetic aging rats. A detailed study was carried on expression of inflammatory cytokines, insulin receptor pathology and synapse, GLUT 1, biomarkers of oxidative stress and AChE activity. Present study shows that there was a similar pattern of increased expression of interleukin, protein kinase B, lipid peroxidation, blood glucose, insulin receptor expression and RNS levels with AChE activity, and a decrease in membrane fluidity, antioxidant enzymes activity and (GLUT1) expression in brain of both aging and diabetes. On the other hand, metformin treated groups exhibited significant reduction in helped to reverse the age related changes studied, to normal levels. Metformin treatments improved attention and memory functions with enhanced the levels of synaptic molecules synaptophysin and synapsin I. Our data showed that exogenous administration of metformin brought these changes to near normalcy in diabetic aging female rats. The results illuminate mechanisms of neuroprotection by metformin, and applying new strategies for control of neurodegenerative diseases including metabolic syndrome and Alzheimer’s disease.

A neural network model predicts community-level signaling states in a diverse microbial community.

Signal crosstalk within biological communication networks is common, and such crosstalk can have unexpected consequences for decision making in heterogeneous communities of cells. Here we examined crosstalk within a bacterial community composed of five strains of Bacillus subtilis, with each strain producing a variant of the quorum sensing peptide ComX. In isolation, each strain produced one variant of the ComX signal to induce expression of genes associated with bacterial competence. When strains were combined, a mixture of ComX variants was produced resulting in variable levels of gene expression. To examine gene regulation in mixed communities, we implemented a neural network model. Experimental quantification of asymmetric crosstalk between pairs of strains parametrized the model, enabling the accurate prediction of activity within the full five-strain network. Unlike the single strain system in which quorum sensing activated upon exceeding a threshold concentration of the signal, crosstalk within the five-strain community resulted in multiple community-level quorum sensing states, each with a unique combination of quorum sensing activation among the five strains. Quorum sensing activity of the strains within the community was influenced by the combination and ratio of strains as well as community dynamics. The community-level signaling state was altered through an external signal perturbation, and the output state depended on the timing of the perturbation. Given the ubiquity of signal crosstalk in diverse microbial communities, the application of such neural network models will increase accuracy of predicting activity within microbial consortia and enable new strategies for control and design of bacterial signaling networks.

Towards active self-management of umbilical linking ROV and USV for safer submarine missions

This article focuses on the active management of the umbilical of a Remotely Operated Vehicle (ROV) for shallow water exploration. The objective is to increase the ROV maneuverability by exploiting the mechanical model of the cable that links the ROV to an Unmanned Surface Vehicle (USV). The efforts applied on the umbilical are studied in simulation. The numerical models implemented under SimulinkTM and VortexTM are used to define new strategies of control for the winch, the USV and the ROV in order to manage the umbilical.

Survival and drifting patterns of grass carp eggs and larvae in response to interactions with flow and sediment in a laboratory flume.

A series of laboratory experiments was conducted to better understand the behavior of grass carp eggs and larvae in moving water in order to develop and implement new strategies for control and prediction of their dispersal and drift at early life stages. Settling velocity and density of a representative sample of eggs were estimated, and three trials of flume experiments with different flow conditions were conducted with live eggs in a temperature-controlled setting with a mobile sediment bed. In these trials, egg and larval stages were continuously analyzed over periods of 80 hours; and eggs and larvae interactions with the flow and sediment bed were monitored and characterized qualitatively and quantitatively. Survival rates were quantified after each trial, highlighting physical causes for increased mortality. Detailed flow analysis was correlated to the observed drifting and swimming behavior of eggs and larvae, to estimate distributions across the water depth, as well as traveling and swimming speeds. Evidence of the influence of mean and turbulent flow in the suspension and transport of eggs are reported, and swimming patterns of larvae at different developmental stages are described. These findings support the development of new strategies for monitoring the spread of grass carp eggs and larvae in rivers, and provide new inputs to predict conditions favorable for spawning and hatching, allowing for mitigation measures at early life stages, which are critical to control their dispersal.

Trypsin and ascorbic acid have a synergistic effect on the quality of apple processing by protecting apple cells from oxidative damage

Flesh browning is fundamentally important to the quality of minimally processed fruit. The development of browning is associated with reactive oxygen species accumulation in the fruit tissue. The novel superoxide scavenging activity of trypsin has been shown in our previous work. In the current study, the effects of mixtures of trypsin and ascorbic acid (AsA) on the processing quality of apple homogenate were evaluated. In the presence of trypsin and AsA, the browning of apple homogenate was significantly impeded, and changes in the titration of acid and in the concentration of soluble solids were also delayed. The mixture of trypsin and AsA could significantly reduce cell membrane damage and the activity of peroxidase. Above all, trypsin could protect the cells of the fruit due to its superoxide scavenging activity. The utilization of trypsin will provide a new strategy for controlling quality in the processing of apples or other fruits and vegetables. Practical applications Pure, natural fruit juice with fruit flavor, especially pure, cloudy juice with a variety of natural nutrients, is increasingly widely accepted. Eliminate or inhibit the free radical accumulation is one of the most efficient methods to control the browning of apple tissue. Trypsin had a significant effect on the superoxide anion scavenging activity and showed a good protective effect on the cells. This article investigates the antioxidant and cell protective activity of trypsin–ascorbic acid (AsA) mixture during the processing of apple homogenate. The application of trypsin provides a new strategy for the quality control of fruit juice. Food additives with trypsin have a broad market and development potential.

Spontaneous topological charging of tactoids in a living nematic

Living nematic is a realization of an active matter combining a nematic liquid crystal with swimming bacteria. The material exhibits a remarkable tendency towards spatio-temporal self-organization manifested in formation of dynamic textures of self-propelled half-integer topological defects (disclinations). Here we report on the study of such living nematic near normal inclusions, or tactoids, naturally realized in liquid crystals close to the isotropic-nematic (I–N) phase transition. On the basis of the computational analysis, we have established that tactoid’s I–N interface spontaneously acquire negative topological charge which is proportional to the tactoid’s size and depends on the concentration of bacteria. The observed negative charging is attributed to the drastic difference in the mobilities of +1/2 and −1/2 topological defects in active systems. The effect is described in the framework of a kinetic theory for point-like weakly-interacting defects with different mobilities. Our dedicated experiment fully confirmed the theoretical prediction. The results hint into new strategies for control of active matter.

The influence of a light and dark cycle on the egg laying activity of Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae).

BACKGROUNDThe epidemiological importance of the mosquito Aedes aegypti as a vector of multiple human pathogens has generated a growing number of studies on the physiology and behaviour of its blood-feeding females. The activity of oviposition is one of the critical elements contributing to the expansion of Ae. aegypti's populations. Although there is a vast literature about oviposition behaviour, significant specific knowledge about egg viability and female fertility under light and dark conditions is still lacking.OBJECTIVESWe studied, in controlled laboratory conditions, the effect that light and dark cycles have on the efficiency of oviposition by Ae. aegypti females.METHODSPhysiological assays were performed using synchronised eggs obtained from forced egg laying. The number and viability of eggs was analysed under three different light/dark regimes: LD12:12 (12 h of light and 12 h of dark), DD (constant darkness) and LL (constant light).FINDINGS and CONCLUSIONSOur results show that females prefer to lay their eggs in dark conditions, but maximising the number and viability of eggs requires the occurrence of a light/dark cycle. Ongoing research on this theme has the potential of contributing to the proposition of new strategies for control based on the failure of egg laying and hatching.