Autophagy in protists and their hosts: When, how and why?

Pathogenic protists are a group of organisms responsible for causing a variety of human diseases including malaria, sleeping sickness, Chagas disease, leishmaniasis, and toxoplasmosis, among others. These diseases, which affect more than one billion people globally, mainly the poorest populations, are characterized by severe chronic stages and the lack of effective antiparasitic treatment. Parasitic protists display complex life-cycles and go through different cellular transformations in order to adapt to the different hosts they live in. Autophagy, a highly conserved cellular degradation process, has emerged as a key mechanism required for these differentiation processes, as well as other functions that are crucial to parasite fitness. In contrast to yeasts and mammals, protist autophagy is characterized by a modest number of conserved autophagy-related proteins (ATGs) that, even though, can drive the autophagosome formation and degradation. In addition, during their intracellular cycle, the interaction of these pathogens with the host autophagy system plays a crucial role resulting in a beneficial or harmful effect that is important for the outcome of the infection. In this review, we summarize the current state of knowledge on autophagy and other related mechanisms in pathogenic protists and their hosts. We sought to emphasize when, how, and why this process takes place, and the effects it may have on the parasitic cycle. A better understanding of the significance of autophagy for the protist life-cycle will potentially be helpful to design novel anti-parasitic strategies.

Experimental Infection of Ticks: An Essential Tool for the Analysis of Babesia Species Biology and Transmission.

Babesiosis is one of the most important tick-borne diseases in veterinary health, impacting mainly cattle, equidae, and canidae, and limiting the development of livestock industries worldwide. In humans, babesiosis is considered to be an emerging disease mostly due to Babesia divergens in Europe and Babesia microti in America. Despite this importance, our knowledge of Babesia sp. transmission by ticks is incomplete. The complexity of vectorial systems involving the vector, vertebrate host, and pathogen, as well as the complex feeding biology of ticks, may be part of the reason for the existing gaps in our knowledge. Indeed, this complexity renders the implementation of experimental systems that are as close as possible to natural conditions and allowing the study of tick-host-parasite interactions, quite difficult. However, it is unlikely that the development of more effective and sustainable control measures against babesiosis will emerge unless significant progress can be made in understanding this tripartite relationship. The various methods used to date to achieve tick transmission of Babesia spp. of medical and veterinary importance under experimental conditions are reviewed and discussed here.

Molecular survey of Besnoitia spp. (Apicomplexa) in faeces from European wild mesocarnivores in Spain.

Numerous studies have unsuccessfully tried to unravel the definitive host of the coccidian parasite Besnoitia besnoiti. Cattle infections by B. besnoiti cause a chronic and debilitating condition called bovine besnoitiosis that has emerged in Europe during the last two decades, mainly due to limitations in its control associated with the absence of vaccines and therapeutical tools. Although the exact transmission pathways of B. besnoiti is currently unknown, it is assumed that the parasite might have an indirect life cycle with a carnivore as definitive host. Current lack of studies in wildlife might underestimate the importance of free-living species in the epidemiology of B. besnoiti. Thus, the aim of the present study is to assess the presence of Besnoitia spp. in free-ranging mesocarnivores in Spain. DNA was searched by PCR on faeces collected from wild carnivores as a first approach to determine which species could be considered as potential definitive host candidates in further research. For this purpose, a total of 352 faecal samples from 12 free-living wild carnivore species belonging to the Canidae, Felidae, Herpestidae, Mustelidae, Procyonidae and Viverridae families were collected in seven Spanish regions. PCR testing showed that Besnoitia spp. DNA was present in four faecal samples from red foxes collected in western Spain, an area with the greatest density of extensively reared cattle and associated with high incidence of bovine besnoitiosis in the country. To date, this is the first report of a B. besnoiti-like sequence (99.57% homology) from carnivore faeces in a worldwide context. Red foxes might contribute to the epidemiology of B. besnoiti, although further studies, mostly based on bioassay, would be needed to elucidate the accuracy and extent of these interesting findings.

Life History of Bedellia somnulentella (Lepidoptera: Bedelliidae) Feeding on Ipomoea batatas (Solanales: Convolvulaceae) Leaves and Survey of Parasitoids in Brazil.

The microlepidoptera, Bedellia somnulentella (Zeller), is an important pest of sweetpotato, Ipomoea batatas (L.) Lam. Damage by B. somnulentella occurs in the larval stage and when consuming the foliar mesophyll of I. batatas make the leaves brown, wrinkled, and reducing the photosynthetic area and the yield. The detection and management of this pest depends on knowing its biological cycle and identifying its natural enemies. The objectives of this study were to determine the life history of B. somnulentella feeding on I. batatas leaves and to survey parasitoids of this pest in the field. The duration and viability of B. somnulentella egg, larva, prepupa, pupa, and adult stages were evaluated under laboratory conditions. Cephalic capsule width was measured to determine the number of B. somnulentella instars, based on the Dyar rule and analyzed by the Akaike statistical model (AIC). The developmental period of B. somnulentella was 32.5 ± 0. 21 d with a viability of 75, 84, 100, and 84% for the egg, larva, prepupa, and pupa stages, respectively. The identification of this pest on the plants is possible from the third instar and in the pupal and adult stages. The parasitoid Conura sp. (Hymenoptera: Chalcididae) was identified parasitizing pupae of B. somnulentella and could be considered a potential natural enemy for the integrated management of this pest.

Phenology and thermal requirements of the species Cyperus difformis L. in southern Brazil

Cyperus difformis L. is a Cyperaceae, annual, of natural occurrence in marshy environments in southern Brazil, considered a weed in irrigated rice crops. Studies on its development are scarce, especially regarding its cycle and thermal requirements. Therefore, the objective of this work was to determine the base temperature, the thermal sum and the duration of the different sub-periods of the biological cycle of the species. The experiment was carried out at the Campus of the Universidade Federal de Santa Maria – UFSM, Santa Maria, Rio Grande do Sul, in four sowing seasons. In a completely delineated design and factorial scheme involving five soil water conditions (water depth and 50% soil water retention capacity [WRC]) from the sowing, water depth and 50% WRC introduced 21 days after emergence and 100% WRC during the whole cycle, with six repetitions each. Each experimental unit consisted of a cultivated in pot plant with 11 L capacity filled with soil. The cycle of the plants was subdivided into the sowing-emergence sub-periods, emergence-emission of the floral tassel and emission of the floral-maturing physiological tassel, being estimated the thermal requirements for the species. The conditions of the soil water condition the base temperature, the sum of the degree-days and the duration of the species cycle. The base temperature varies for each treatment, the sum of degrees-day decreases with the water deficit and the plants under flood accelerate the biological cycle.

Ecological relationships of Haemagogus spegazzinii (Diptera: Culicidae) in a semiarid area of Brazil

Abstract INTRODUCTION: Haemagogus are mosquitoes with diurnal habits that live preferentially in forest areas. In Brazil, they are considered the primary vectors of wild yellow fever. METHODS: The ecological relationships between Haemagogus spegazzinii, the environment, and some of its activities in the semiarid region of Rio Grande do Norte were analyzed by collecting eggs with ovitraps, actively searching in tree holes, capturing adults in Shannon traps, and conducting an investigation for viral infections. RESULTS: A total of 2420 eggs, 271 immature specimens (larvae and pupae), and 206 adults were collected. Egg collection depended on rainfall and relative humidity, with oviposition occurring between January and May. Larvae were found in five plant species, including Tabebuia aurea (craibeira), with 160 larvae collected. We observed shared breeding sites between Hg. spegazzinii and the following species: Aedes albopictus, Aedes terrens, Culex spp., and Toxorhynchites theobaldi. Adults exhibited greater activity between 5 pm and 6 pm, when 191 (92.7%) specimens were captured, while only 1 (0.5%) was collected between 7 pm and 8 pm. The relationship between Hg. spegazzinii and rainfall was significant, with positive correlations with accumulated rainfall 5, 10, 15, 20, and 30 days before mosquito collection. We found that the species was infected with the DENV-2 virus. CONCLUSIONS: This work contributes new information on the bioecology of Hg. spegazzinii, with data on the main reproduction periods, oviposition, breeding sites, activity times, and the relationship between the species and meteorological variables in the Caatinga of northeastern Brazil.

Biology and fertility life table of Bactrocera carambolae on grape and acerola

ABSTRACT Bactrocera carambolae Drew & Hancock (Diptera: Tephritidae), native of Southeast Asia, is present in Brazil but restricted to Amapá, Pará and Roraima, where it has quarantine pest status. The possible dispersion to other fruit producing regions of Brazil could cause damages, including for exportation, due to quarantine restrictions imposed by fruit importing countries. The objective of this work was to describe the biological parameters and calculate the fertility life table of B. carambolae on grape (Vitis vinifera L.) and acerola (Malpighia emarginata DC.). The experiment was conducted in the laboratory under controlled conditions. The mean number of punctures and the mean number of eggs per female on grapes were 1.48 ± 0.05 and 9.87 ± 0.36, respectively. The mean number puparia per fruit was 0.1 ± 0.02 (grape) and 0.5 ± 0.10 (acerola). The pupal viability was 82.4% (grape) and 70.6% (acerola). The mean time ± SE of one generation, in days, was 25.8 ± 1.10 (grape) and 19.7 ± 0.21 (acerola). The mean fecundity was 1663.8 ± 501.01 (grape) and 206.9 ± 26.21 (acerola) with eggs viability of 5.6% (grape) and 12.5% (acerola). The mean longevity, in days, was 77.3 ± 12.13 on grape and 82.4 ± 4.24 on acerola. The study found that B. carambolae completes its biological cycle on grape and on acerola leaving offspring.

The life cycle of Neotropical ground beetle, Abaris basistriata (Coleoptera: Carabidae) reared on different substrates / Ciclo de vida do besouro de solo Neotropical, Abaris basistriata (Coleoptera: Carabidae) criado em diferentes substratos

Abstract Carabids are recognized worldwide as biological control agents of agricultural pests. The objective was to compare the life cycle of Abaris basistriata Chaudoir (Coleoptera: Carabidae) on three substrates: soil, fine vermiculite, or paper napkins. The biological cycle of A. basistriata presented different durations in soil and paper. The viability of eggs and larvae survival of the first and second instars were similar on all three substrates, while the third instar and pupa in the soil presented higher survival when compared with vermiculite and paper. The soil substrate was more favorable for the longevity of the carabid beetle. Abaris basistriata showed a shorter pre-oviposition period and a higher oviposition and post-oviposition period in the soil. Fecundity and fertility were higher when A. basistriata was reared on soil. The soil was most favorable substrate for rearing of A. basistriata in the laboratory. This information may make this species useful for the biological control.

Resumo Os carabídeos são reconhecidos mundialmente como agentes de controle biológico de pragas agrícolas. O objetivo foi comparar o ciclo de vida de Abaris basistriata Chaudoir (Coleoptera: Carabidae) em três substratos: solo, vermiculita fina, ou guardanapos de papel. O ciclo biológico de A. basistriata apresentou diferentes durações no solo e no papel. A viabilidade dos ovos e a sobrevivência das larvas do primeiro e segundo instares foram semelhantes nos três substratos, enquanto que o terceiro instar e a pupa apresentaram maior sobrevivência no solo quando comparados com vermiculita e papel. O substrato solo foi mais favorável à longevidade do carabídeo. Abaris basistriata mostrou menor período de pré-oviposição e maior período de oviposição e pós-oviposição no solo. A fecundidade e a fertilidade foram maiores quando A. basistriata foi criado no solo. O solo foi o substrato mais favorável para a criação de A. basistriata no laboratório. Estas informações são importantes e podem tornar essa espécie útil para o controlo biológico.

Quiescence in Aedes aegypti: Interpopulation Differences Contribute to Population Dynamics and Vectorial Capacity.

The strategy of Aedes aegypti to prolong embryonic viability by quiescence has severe implications for geographic expansion and maintenance of mosquito populations in areas under control measures. We evaluated the effects of quiescence on biological parameters directly or indirectly associated with population dynamics and vectorial capacity in populations of this mosquito species from two Brazilian municipalities characterized as dengue, chikungunya, and Zika transmission areas. Egg viability, initial hatching time, post-embryonic development time, adult emergence rate, sexual proportion, adult size, fecundity, and fertility were analyzed using eggs stored for 10, 40, 70, 100, 130, and 160 d. Quiescence time reduced overall egg viability and post-embryonic development time in both municipalities but was more costly in Aracaju (100 d, 8 d) than in Recife (130 d, 7.5 d). Emergence rates increased in Recife when the eggs were older, but not in Aracaju. Significant deviations in sexual proportion, with male predominance, were observed in both populations. Initial hatch, fecundity, fertility, and adult size did not significantly influence egg quiescence time. These results indicate intrinsic and differential characteristics for each A. aegypti population, suggesting a differential cost of quiescence for population dynamics parameters that can indirectly affect vectorial capacity and control measures.

Porcine Endogenous Retrovirus (PERV) - Molecular Structure and Replication Strategy in the Context of Retroviral Infection Risk of Human Cells.

The xenotransplantation of porcine tissues may help overcome the shortage of human organs for transplantation. However, there are some concerns about recipient safety because the risk of porcine endogenous retrovirus (PERV) transmission to human cells remains unknown. Although, to date, no PERV infections have been noted in vivo, the possibility of such infections has been confirmed in vitro. Better understanding of the structure and replication cycle of PERVs is a prerequisite for determining the risk of infection and planning PERV-detection strategies. This review presents the current state of knowledge about the structure and replication cycle of PERVs in the context of retroviral infection risk.

The metabolic effects of mercury during the biological cycle of vines (Vitis vinifera).

Mercury (Hg) is a major environmental pollutant that can be disposed to the environment by human activities, reaching crops like vineyards during irrigation with contaminated waters. A 2-year study was performed to monitor Hg variations during reproductive and vegetative stages of vines after Hg supplementation. Variations were focused on total Hg concentration, the molecular weight of Hg fractions and Hg-proteins associations in roots, stems and leaves. Total Hg concentrations increased during reproductive stages and decreased during vegetative stages. Variations in length of these stages were observed, according to an extension of the vegetative period. Six months post Hg administration, in roots, stems and leaves, initial Hg proteic fractions of 200 kDa were catabolized to 66 kDa fractions according to a transition from reproductive to vegetative stages. However, 24 months after Hg supplementation, the 66 kDa Hg proteic fraction was continuously determined in a prolonged senescence. Accordingly, the identified proteins associated to Hg show catabolic functions such as endopeptidases, hydrolases, glucosidases and nucleosidases. Stress associated proteins, like peroxidase and chitinase were also found associated to Hg. During the reproductive periods of vines, Hg was associated to membrane proteins, such as ATPases and lipid transfer proteins, especially in roots where Hg is absorbed.

Aspectos biológicos de Archaeoprepona demophon muson (Fruhstorfer, 1905) (Lepidoptera: Nymphalidae, Charaxinae) en la Amazonía peruana

El objetivo de este trabajo fue elucidar el ciclo biológico de la mariposa diurna Archaeoprepona demophon muson, determinar las especies de plantas con las que se relaciona, caracterizar su hábitat y contribuir al conocimiento sobre sus enemigos naturales. El trabajo de campo se desarrolló en dos áreas cercanas a la ciudad de Iquitos (Perú). Para describir el ciclo biológico se utilizó 20 huevos recientemente depositados en las hojas de su planta hospedera. La duración del ciclo, desde huevo hasta adulto fue de 85.40 ± 4.66 días en condiciones de laboratorio. El periodo de huevo se extendió por 5.60 ± 0.52 días. La larva pasa por cinco estadíos: el primero duró 8.61 ± 0.77 días, el segundo 6.12 ± 0.68 días, el tercero 11.44 ± 0.73 días, el cuarto 8.13 ± 0.34 días, y el quinto 27.37 ± 1.29 días. El periodo de la prepupa duró 3.60 ± 0.51 días y el de pupa 14.13 ± 2.62 días; los adultos nacieron aproximadamente entre las 9:00 a 11:00 h. La hembra vivió 41.00 ± 6.35 días y el macho 19.25 ± 4.49 días. Las plantas alimenticias utilizadas fueron Siparuna bifida (Poepp. & Endl.) A.DC., Pouteria caimito (Ruiz & Pav.) Radlk. y Musa x paradisiaca L. Registramos dos enemigos naturales, una araña y un hongo

The aim of this study was to elucidate the life cycle of the butterfly Archaeoprepona demophon muson, determine the species of plants to which it relates, characterize its habitat and contribute to the knowledge about their natural enemies. Fieldwork was conducted in two areas near Iquitos (Peru). For the description of the life cycle 20 eggs laid on leaves of it host plant were used. The cycle from egg to adult lasted 85.40 ± 4.66 days under laboratory conditions. The egg period took 5.60 ± 0.52 days. The larva goes through five stages: the first one lasts 8.61 ± 0.77 days; the second 6.12 ± 0.68; the third 11.44 ± 0.73; the fourth 8.13 ± 0.34; and the fifth 27.37 ± 1.29. The prepupa lasted 3.60 ± 0.51 days and the pupa 14.13 ± 2.62; adults were born approximately between 9:00 to 11:00 h. The female lived 41.00 ± 6.35 days and the male 19.25 ± 4.49 days. The host plants were Siparuna bifida (Poepp. & Endl.) A.DC., Pouteria caimito (Ruiz & Pav.) Radlk. and Musa × paradisiaca L. We report two natural enemies, a spider and a fungus

The life cycle of Neotropical ground beetle, Abaris basistriata (Coleoptera: Carabidae) reared on different substrates

Abstract Carabids are recognized worldwide as biological control agents of agricultural pests. The objective was to compare the life cycle of Abaris basistriata Chaudoir (Coleoptera: Carabidae) on three substrates: soil, fine vermiculite, or paper napkins. The biological cycle of A. basistriata presented different durations in soil and paper. The viability of eggs and larvae survival of the first and second instars were similar on all three substrates, while the third instar and pupa in the soil presented higher survival when compared with vermiculite and paper. The soil substrate was more favorable for the longevity of the carabid beetle. Abaris basistriata showed a shorter pre-oviposition period and a higher oviposition and post-oviposition period in the soil. Fecundity and fertility were higher when A. basistriata was reared on soil. The soil was most favorable substrate for rearing of A. basistriata in the laboratory. This information may make this species useful for the biological control.

Resumo Os carabídeos são reconhecidos mundialmente como agentes de controle biológico de pragas agrícolas. O objetivo foi comparar o ciclo de vida de Abaris basistriata Chaudoir (Coleoptera: Carabidae) em três substratos: solo, vermiculita fina, ou guardanapos de papel. O ciclo biológico de A. basistriata apresentou diferentes durações no solo e no papel. A viabilidade dos ovos e a sobrevivência das larvas do primeiro e segundo instares foram semelhantes nos três substratos, enquanto que o terceiro instar e a pupa apresentaram maior sobrevivência no solo quando comparados com vermiculita e papel. O substrato solo foi mais favorável à longevidade do carabídeo. Abaris basistriata mostrou menor período de pré-oviposição e maior período de oviposição e pós-oviposição no solo. A fecundidade e a fertilidade foram maiores quando A. basistriata foi criado no solo. O solo foi o substrato mais favorável para a criação de A. basistriata no laboratório. Estas informações são importantes e podem tornar essa espécie útil para o controlo biológico.

Biological parameters and fertility life table of Aphis forbesi Weed, 1889 (Hemiptera: Aphididae) on strawberry / Parâmetros biológicos e tabela de vida de fertilidade de Aphis forbesi Weed, 1889 (Hemiptera: Aphididae) em morangueiro

Abstract This study provides the first contribution of the biology and life table of Aphis forbesi Weed, 1889 (Hemiptera: Aphididae), an important strawberry pest throughout the world. This species lives in the crown and leaf petioles of the plant. It is difficulty to rear this species in laboratory due to protocooperation with ants observed only in the field. We studied the life cycle of A. forbesi on the leaves of the Albion strawberry cultivar at 25 ± 2 °C, 60 ± 10% relative humidity, and a 12-h photophase. The experiment was randomised with 100 replicates. The parameters of the fertility life table were calculated using TabVida. In the population studied, 25% and 46% had four and three instars, respectively. A mean of 1.43 nymphs per female per day was generated. The mean reproductive period was seven days and the mean longevity was 10 days. In every 11 days there is a generation of A. forbesi, where each female has the potential to generate between 6 to 9 individuals daily, increasing its population by 1.2 times. The average life cycle was 16.8 days. High viability observed in all instars and the resulting values of R0, rm and λ suggest that A. forbesi has the capacity to increase their numbers in a short period of time, while generating high populations in strawberry crops, requiring differential management.

Resumo Este trabalho apresenta a primeira contribuição ao estudo de biologia e tabela de vida de fertilidade de Aphis forbesi, Weed, 1889 (Hemiptera: Aphididae), uma importante praga de morangueiro no mundo. Esta espécie se desenvolve na coroa e pecíolo do morangueiro. O desenvolvimento desta espécie em laboratório apresentou dificuldades, possivelmente devido à protocooperação com formigas, observada em campo durante coletas. O ciclo de vida de A. forbesi foi estudado em folhas de morangueiro cultivar ‘Albion’ a 25 ± 2 °C, 60 ± 10% umidade relativa, e fotofase de 12 horas. O experimento foi inteiramente casualizado com 100 repetições. Os parâmetros da tabela de vida de fertilidade foram calculados usando o software TabVida. Na população estudada observou-se que as ninfas apresentaram três e quatro instares, sendo 46 e 25% respectivamente, dos indivíduos que completaram o ciclo de vida. Foi gerada uma média de 1,43 ninfas/ fêmea/ dia. O período reprodutivo médio foi de 7 dias e a longevidade média 10 dias. A cada 11 dias ocorre uma geração de A. forbesi onde cada fêmea tem capacidade de gerar de 6 a 9 indivíduos aumentando em 1,2 vezes a população. O ciclo de vida de A. forbesi durou em média 16,8 dias. A alta viabilidade observada em todos os estádios, e os valores de R0, rm e λ sugerem que A. forbesi tem a capacidade de aumentar seu número em um curto período de tempo, gerando altas populações no cultivo do morangueiro, exigindo manejo diferenciado.

Effects of temperature on the life cycle, expansion, and dispersion of Aedes aegypti (Diptera: Culicidae) in three cities in Paraiba, Brazil.

The mosquito Aedes aegypti is the primary vector of dengue and is common throughout tropical and subtropical regions. Its distribution is modulated by environmental factors, such as temperature. This study aimed to evaluate the influence of temperature on the life cycle and expansion of Ae. aegypti populations in the cities of Campina Grande, João Pessoa, and Patos. Samples of Ae. aegypti were collected in the three cities and raised in the laboratory. We assessed the life cycles of the three Ae. aegypti populations under six constant temperatures (16, 22, 28, 33, 36, and 39°C), selected on the basis of historical temperature tendencies of each city. We also used existing climate data to calculate projected temperature increases for all three areas. Our results suggest that Campina Grande, João Pessoa, and Patos will experience, respectively, maximum temperature increases of 0.030°C/year, 0.069°C/year, and 0.061°C/year, and minimum temperature increases of 0.019°C/year, -0.047°C/year, and -0.086°C/year. These projected increases will result in temperatures favorable to the Ae. aegypti life cycle, causing rapid population growth. Therefore, Ae. aegypti populations are likely to expand in the mesoregions represented by these cities.

Bionomy of two flies of sanitary and forensic importance: Peckia (Sarcodexia) lambens (Wiedemann) and Oxysarcodexia amorosa (Schiner) (Diptera, Sarcophagidae)

ABSTRACTThis study aims to elucidate the bionomy of Peckia(Sarcodexia) lambens and Oxysarcodexia amorosa to provide data for medical, veterinary and forensic entomology analyses. We analyzed larval stage duration (L1–L3), weight of the mature larvae (L3), pupal stage duration, L1–adult duration, adult emergence and viability of larvae and adults of both species. Larval viability of P. (S.) lambens was 82% and the mean duration of the larval stage was 3.51 ± 0.99 days. The mature larvae had a mean weight of 33.67 ± 7.13 mg. The mean duration of the pupal stage was 8.26 ± 0.93 days and the mean duration of the L1–adult was 11.53 ± 1.22 days. Mean lifespan for females and males was 39.33 ± 1.52 and 57.33 ± 4.72 days, respectively. Larval viability of O. amorosa was 76% and mean duration of larval stage was 3.51 ± 0.64 days. Mature larvae had a mean weight of 28.28 ± 3.38 mg. Mean duration of the pupal stage was 10.14 ± 0.63 days and mean duration of the L1–adult was 13.60 ± 0.69 days. Mean lifespan for females and males was 83.66 ± 15.94 and 84.00 ± 19.97 days, respectively. Oxysarcodexia amorosa showed a L1–adult stage longer than P. (S.) lambens; however both species showed low viability. O. amorosa laid more larvae than P. (S.) lambens, this fact may occur because O. amorosa had longer life duration.

Biological aspects of immature stage of Nyssomyia whitmani (Antunes and Coutinho) (Diptera, Psychodidae, Phlebotominae) in laboratory conditions

Nyssomyia whitmani (Antunes and Coutinho, 1939) has been considered as a complex of cryptic species, and some of the populations of this complex plays an important role in the transmission of Leishmania spp. in Brazil. The present study reports the biological aspects concerning the productivity out of eggs and the development time of the descendants of females obtained in Dourados municipality, Mato Grosso do Sul state. The females were captured with modified electric aspirators, fed in hamsters and further individualized in containers for breeding. At the insectary, temperature and relative humidity were maintained on average of 24.5 °C and 67.3%, respectively. From 944 females 3737 eggs were obtained, 748 (20.0%) evolved to the stage of larvae, and 93 (12.4%) of these reached adult stage. The life cycle lasted 80.6 days and the last larval instar was the longest. The use of a higher protein diet revealed a significant improvement in larval development.

Effect of salinity on the behavior of Aedes aegypti populations from the coast and plateau of southeastern Brazil

Mosquito larvae can develop in fresh, salty and brackish water. The larvae of Aedes aegypti develop in fresh water. However, in laboratory studies, tolerance of this species for oviposition and hatchingin brackish water was observed. Immature forms of Ae. aegypti have also been found developing in brackish water in coastal areas. The purpose of the study was to compare the effects of salt on the biological cycle of Ae. aegypti populations from coastal and plateau areas of southeastern Brazil...

Modeling the effects of climate on date palm scale (Parlatoria blanchardi) population dynamics during different phenological stages of life history under hot arid conditions.

The date palm scale (DPS) Parlatoria blanchardi is a serious pest due to the damage it inflicts on its host tree (Phoenix dactylifera). To develop an effective control against DPS in arid regions, it is essential to know its bio-ecology including population dynamics and climatic factors influencing the duration and timing of life history and also the densities of different phenological stages (crawlers, first and second instars nymphs, adult males, and adult females). Monitoring of biological cycle and population dynamics of the pest were achieved through weekly counts of DPS densities on leaflets sampled at different position of date palm trees in an oasis of Ouargla region (Algerian Sahara Desert). Within this hyper-arid region, DPS established four generations per year, the most important was the spring generation. Two overlapping generations occurred in spring-early summer and two in autumn-early winter; these two pairs of generations were interspersed by two phases of high-mortality rates, the first corresponds to winter cold and the second refers to the extreme heat of summer. Statistical analysis of the effects of the studied climatic conditions (minimum, maximum and mean temperatures, precipitation, humidity, wind, rain days, and climatic indices) on the DPS densities at different phenological stages showed great variability from one stage to another. Among these, adult females were the most affected by climate factors. For the total DPS population, high values of minimum temperatures negatively affected population density, while high maximum temperatures, hygrometry, and De Martonne aridity index showed a positive influence.