Oviposition of fruit flies (Diptera: Tephritidae) and its relation with the pericarp of citrus fruits / Oviposição de moscas-das-frutas (Diptera: Tephritidae) e sua relação com o pericarpo de frutos cítricos

Abstract Fruit flies (Diptera: Tephritidae) represent a threat to fruit growing worldwide, mainly the citrus culture, however, biological studies show that fruit flies are not perfectly adapted to this host. This study investigated oviposition of Anastrepha fraterculus (Wiedemann, 1830) and Ceratitis capitata (Wiedemann, 1824) and its relation with the pericarp of citrus fruits. We evaluated the relationship between depth of oviposition of A. fraterculus and C. capitata and epicarp thickness of orange [Citrus sinensis (L.) Osbeck)] 'Navelina' and tangerine [C. reticulata (L.)] 'Clemenules' and the influence of fruit mesocarp of tangerine 'Clemenules' on oviposition of these species. The study was conducted under controlled conditions of temperature (25 ± 2 °C), relative humidity (70 ± 10% RH) and photophase (12 h). A. fraterculus and C. capitata laid their eggs in the flavedo region of orange 'Navelina' and between the albedo and flavedo of tangerine 'Clemenules'. When fruits with mesocarp exposed were offered, there was no oviposition by both fruit fly species. The results show that epicarp thickness of citrus fruits did not influence oviposition of A. fraterculus and C. capitata as oviposition did not occur only in the presence of the mesocarp, suggesting that other factors are involved in oviposition of these species.

Resumo As moscas-das-frutas (Diptera: Tephritidae) representam um risco à fruticultura mundial, especialmente na cultura dos citros, entretanto estudos biológicos demonstram que as moscas-das-frutas não estão perfeitamente adaptadas à estes hospedeiros. Este estudo investigou a oviposição de Anastrepha fraterculus (Wiedemann, 1830) e Ceratitis capitata (Wiedemann, 1824) e sua relação com o pericarpo de frutos cítricos. Foi avaliada a relação entre a profundidade de oviposição de A. fraterculus e de C. capitata e a espessura do epicarpo dos frutos de laranjeira [Citrus sinensis (L.) Osbeck)] 'Navelina' e tangerineira [C. reticulata (L.)] 'Clemenules' e a influência do mesocarpo de frutos de tangerineira 'Clemenules' na oviposição destas espécies. O estudo foi conduzido em condições controladas de temperatura (25 ± 2 °C), umidade relativa (70 ± 10%) e fotofase (12 horas). A. fraterculus e C. capitata depositaram ovos no flavedo de frutos de laranjeira 'Navelina' e entre o flavedo e o albedo de frutos de tangerineira 'Clemenules'. Quando oferecido frutos com mesocarpo exposto, não houve oviposição por ambas as espécies de mosca. Os resultados demonstram que a espessura do epicarpo de frutos cítricos não influenciou a oviposição de A. fraterculus e de C. capitata, a qual não ocorreu na presença apenas do mesocarpo, sugerindo que outros fatores estão envolvidos na oviposição por estas espécies.

Eggs viability of Aedes aegypti Linnaeus (Diptera, Culicidae) under different environmental and storage conditions in Manaus, Amazonas, Brazil / Viabilidade de ovos de Aedes aegypti (Diptera, Culicidae) em diferentes condições de armazenamento em Manaus, Amazônia, Brasil

Abstract The viability of Aedes aegypti eggs was assessed in the Amazon region. The eggs were maintained under different conditions: indoors (insectarium) and outdoors (natural environment), as well as in different storage types (plastic cup, paper envelope, plastic bag) for different days. Egg viability was measured as the mean of hatchings observed from egg-bearing sheets of filter paper immersed in water, using three sheets randomly selected from each storage type and at both sites. There were significant differences in the viability of Ae. aegypti eggs with respect to the location (F=30.40; DF=1; P<0.0001), storage type (F=17.66; DF=2; P<0.0001), and time of storage (F=49.56; DF=9; P<0.0001). The interaction between storage site versus storage type was also significant (F=15.96; DF=2; P<0.0001). A higher hatching mean was observed for the eggs kept in the insectarium than for those outdoors (32.38 versus 7.46). Hatching rates of egg batches stored for 12 to 61 days ranged between 84 and 90%. A reduction was observed between 89 and 118 days, with values of 63 and 48%, respectively. With respect to type of storage, mean egg hatching was higher for the eggs in plastic cups (44.46). It was concluded that the viability of the eggs of Ae. aegypti in the Amazon region remains high up to 4 months, after which it declines drastically, although in this study hatching occurred for up to 8 months in very low percentages.

Resumo Testou-se a viabilidade dos ovos de Ae. aegypti na região amazônica armazenados em copos plásticos, envelopes de papel e sacos plásticos que foram mantidos em área interna e em área externa por dias diferentes. Verificaram-se diferenças significativas na viabilidade dos ovos considerando-se a localização (F=30,40; GL=1; P<0,0001), os tipos de armazenamento (F=17,66; GL=2; P<0,0001) e os tempos (F=49,56; GL=9; P<0,0001) e na interação localização versus tipo de armazenamento (F=15,96; GL=2; P<0,0001). A média de eclosão dos ovos armazenados no insetário foi maior: 32,38, do que a dos lotes armazenados na área externa: 7,46. As taxas de eclosão dos ovos armazenados de 12 a 61 dias ficaram entre 90% e 84% com reduções a partir de 89 e 118 dias, quando atingiu de 63% e 48%, respectivamente. Em relação aos tipos de armazenamento a média de ovos dos copos foi significativa (44,46). Conclui-se que a viabilidade dos ovos de Ae. aegypti na região amazônica é mantida em níveis elevados até 4 meses, e a partir daí ocorrem reduções drásticas, com eclosões até 8 meses em percentuais muito baixos.

Reproductive cycle of the endemic and threatened fish Puntius shalynius (Cypriniformes: Cyprinidae) in Meghalaya, India / Ciclo reproductivo del pez endémico y amenazado Puntius shalynius (Cypriniformes: Cyprinidae) en Meghalaya, India

Abstract:Puntius shalynius is a highly endemic freshwater minor carp that is economically important and is threatened because of its ornamental value. The present investigation evaluated this barb gonadal maturation, based on morphology and spawning of this species in the Umiam river, Meghalaya, India. The population of this indigenous fish has declined due to its fragmented distribution and exploitation as an ornamental fish. The reproductive cycle of P. shalynius was studied for the first time. A total of 609 fish samples were randomly collected from the river for a period of two years during January 2010 and December 2011. Five maturity phases (rest, primary growth, secondary growth, ripe and spent) were observed on the basis of ovarian and testicular macroscopic evaluation throughout the annual cycle. Peak spawning activity was observed in the month of June/ July and it coincided with the start of the monsoon season. The study showed that the fish spawns once in a year with single spawning peak and that the species is a low fecund fish. It is important to conserve this species for its unique ecological value and urgent management policies should promote its sustainable utilization. Rev. Biol. Trop. 65 (1): 255-265. Epub 2017 March 01.

ResumenPuntius shalynius es un pez de agua dulce altamente endémico que posee importancia económica y esta amenazado por su valor ornamental. En esta investigación se evaluó la maduración de las gónadas de este pez basado en la morfología y desove de esta especie en el río Umiam, Meghalaya, India. La población de esta especie nativa ha decrecido debido a su distribución fragmentada y explotación como pez ornamental. El ciclo reproductivo de P. shalynius se estudió por primera vez. En el río se recolectó al azar una muestra de 609 peces por un período de dos años entre enero 2010 y diciembre 2011. Se observaron cinco estadios de madurez (descanso, crecimiento primario, crecimiento secundario, maduro, agotamiento) basados en la evaluación macroscópica testicular y ovárica durante el ciclo anual. La actividad máxima del desove se observó entre junio y julio lo que coincidió con el comienzo de la época de monzones. El estudio demostró que estos peces desovan una vez al año con un único punto máximo y que la especie es de baja fecundidad. Es importante la conservación de esta especie por su valor ecológico único y se deben promover políticas de manejo urgentes para su uso sostenible.

Biology and fertility life table of Eriopis connexa, Harmonia axyridis and Olla v-nigrum (Coleoptera: Coccinellidae) / Biologia e tabela de vida de fertilidade de Eriopis connexa, Harmonia axyridis e Olla v-nigrum (Coleoptera: Coccinellidae)

Abstract The coccinellids Eriopis connexa (Germar), Harmonia axyridis (Pallas) and Olla v-nigrum (Mulsant) are important natural biological control agents. The purpose of this paper was to study the biology and create a fertility life table of these three coccinellid species. For the biology study, 50 insects/species were used and kept in groups of 10 in glass vials (2300cm3). For the three species studied, the viability of the total cycle varied from 45 to 50%. O. v-nigrum was the species which presented the longest oviposition period. However, H. axiridis demonstrated the best reproductive performance and ability of population growth in each generation. In conclusion, the use of commercially obtained pollen and A. kuenhiella eggs enables the development of coccinellids E. connexa, H. axyridis and O. v-nigrum under laboratory conditions, since the insects completed their biological cycle and originated adults with good reproductive performance.

Resumo Os coccinelídeos Eriopis connexa (Germar), Harmonia axyridis (Pallas) e Olla v-nigrum (Mulsant) são importantes agentes de controle biológico natural. O objetivo deste trabalho foi estudar a biologia e a tabela de vida de fertilidade dessas três espécies de coccinelídeos. Para a biologia foram utilizados 50 insetos/espécie, mantidos em grupo de 10 em recipientes de vidro de (2300cm3). Para as três espécies estudadas, a viabilidade do ciclo total variou de 45 a 50%. O. v-nigrum foi a espécie que apresentou maior período de oviposição. No entanto, H. axiridis foi àquela que demonstrou maior performance reprodutiva e capacidade de aumento populacional a cada geração. Em conclusão, a utilização de pólen comercial e ovos de A. kuenhiella possibilita o desenvolvimento dos coccinelídeos E. connexa, H. axyridis e O. v-nigrum em condições de laboratório, pois, os insetos completaram o ciclo biológico e originaram adultos com boa performance reprodutiva.

Physiological and biochemical characterization of egg extract of black widow spiders to uncover molecular basis of egg toxicity

BACKGROUND: Black widow spider (L. tredecimguttatus) has toxic components not only in the venomous glands, but also in other parts of the body and its eggs. It is biologically important to investigate the molecular basis of the egg toxicity. RESULTS: In the present work, an aqueous extract was prepared from the eggs of the spider and characterized using multiple physiological and biochemical strategies. Gel electrophoresis and mass spectrometry demonstrated that the eggs are rich in high-molecular-mass proteins and the peptides below 5 kDa. The lyophilized extract of the eggs had a protein content of 34.22% and was shown to have a strong toxicity towards mammals and insects. When applied at a concentration of 0.25 mg/mL, the extract could completely block the neuromuscular transmission in mouse isolated phrenic nerve-hemidiaphragm preparations within 12.0 ± 1.5 min. Using whole-cell patch-clamp technique, the egg extract was demonstrated to be able to inhibit the voltage-activated Na+, K+and Ca2+ currents in rat DRG neurons. In addition, the extract displayed activities of multiple hydrolases. Finally, the molecular basis of the egg toxicity was discussed. CONCLUSIONS: The eggs of black widow spiders are rich in proteinous compounds particularly the high-molecular-mass proteins with different types of biological activity The neurotoxic and other active compounds in the eggs are believed to play important roles in the eggs' toxic actions.

Reproductive performance of the Mesa silverside (Chirostoma jordani Woolman, 1894) under natural and controlled photoperiods

Chirostoma jordani is a native annual species inhabiting lacustrine waters of the Central Mexico Plateau. It is widely distributed and is currently facing high environmental pressures. Five experiments were performed to study the reproductive performance of this species. Four of the experiments were conducted in 270-L indoor recirculation tanks. Two males and one female at the first stage of reproduction were included in each test. A photoperiod of 14 light hours and 10 dark hours was used. In a fifth experiment, 10 females and 15 males were kept in an outdoor 3,000-L recirculation tank under natural photoperiod. The number of spawns, fertilised eggs and 30-day-old juveniles were counted and the survival rate was calculated. The results indicated significant differences (P< 0.05) between treatments. Higher spawn numbers and greater egg production were observed under controlled photoperiod, and higher numbers of juveniles and a higher survival rate were observed under natural photoperiod. The trials exhibited different patterns of egg production during the experiment. The egg production in the natural-photoperiod trials followed a polynomial curve model. In contrast, the trials under the controlled photoperiod showed an irregular pattern of increases and decreases in egg production.

Comportamiento reproductivo del pez Opistognathus rosenblatti (Perciformes: Opistognathidae) en cautiverio / Reproductive behavior of Opistognathus rosenblatti (Perciformes: Opistognathidae) in captivity

The Blue Spotted Jawfish O. rosenblatti, is an endemic species from the Gulf of California, included in the local list of protected species. With few biological reports, this species is appreciated in the aquarium industry due to its coloration and digging behaviour, and has a considerable value. With the aim to generate valuable biological information, eight fishes were caught at Loreto Natural Marine Protected Area. Captured fishes were juveniles, and just three of them were kept in an aquarium conditioned with gravel, pieces of shells and coral as substrata. Temperature and photoperiod conditions were stable, and they were supplied with a variety of live and inert feeds. Fishes reached maturity in eight months, according to literature reports, displaying mature male courtship coloration and upward movements in the water column. Fishes spawned several times over more than two years in captivity. Presences of egg masses, or some evidence of egg shell or larvae, were registered in 50 occasions. Male took care of eggs in his shelter, but never in his mouth. Egg masses had an average of 3 592 eggs, with a hatching rate close to 99%. Eggs were apparently rounded having three diameter measurements with significant differences (1.17mm mean higher diameter, SD=0.054; 1.13mm mean lower diameter, 0.058; 0.99mm mean height, 0.045; n=125). Most of corion eggs had four, rarely six filaments; with a single oil drop (0.30mm mean diameter, 0.021, n=59). Incubation lasted 10.4 days (9-14), depending on water temperature (21.0-25.3°C). Egg hatching occurred after darkness, emerging newly hatched larvae of 4.51mm mean notochord length (0.082, n=30), with reserves exhausted, eyes pigmented and mouth opened, ready to eat. This study represents the first report on this species courtship displaying, spawning and some basic characteristics of eggs masses and larvae in captivity. Also, their flexibility and adaptability of individual behaviour to particular environment conditions, lead to consider worth their commercial culture, as already occur with other species of this family.

El bocón manchas azules O. rosenblatti, es una especie endémica del Golfo de California con un elevado valor comercial, del cual existe poca información referente a su biología. Los peces alcanzaron la edad adulta después de ocho meses de cautiverio. Manifestaron ascensos en la columna de agua, típicos de los desplantes de cortejo en su hábitat natural. Asimismo se registro en 50 ocasiones la presencia de masas ovígeras o alguna evidencia de desgove. El macho cuidó los huevos dentro de su refugio, pero nunca en su cavidad bucal. En promedio, depositaron 3 592 huevos, con una viabilidad de eclosión superior al 99%. La eclosión se da de noche y se liberan larvas de 4.51mm de longitud promedio del notocordio. Este estudio presenta el primer registro de su cortejo, su desove e información sobre características elementales de las masas ovígeras y sus larvas, las cuales fueron obtenidas en cautiverio. De tal manera que, la flexibilidad y adaptabilidad de su comportamiento individual a condiciones particulares del ambiente, significan que vale la pena su cultivo comercial, como ya se realiza con otras especies de la misma familia.

Phenotypic plasticity and fitness in egg parasitoids

Several proxies can be used to estimate the fitness of egg parasitoids: size, longevity, fecundity, mating ability and vagility. All these proxies are positively correlated with the lifetime fitness gain of an individual. However, the phenotypic plasticity, which is the ability of a genotype to produce distinct phenotypes depending on environmental conditions, may alter the value of these proxies. Host related factors (host species and quality), competition and duration of development will influence the proxies expressed by a given phenotype. When the phenotype is modified by the temperature at which an individual develops, the resulting phenotype will vary based on the life history strategy of the parasitoid. While in koinobiont species an increase in size is positively correlated with longevity and fecundity, the reverse occurs with idiobiont parasitoids. Using size as a proxy could thus be misleading depending on the factors that influence the size of the adult.

Carbohydrates detection in the hepatic egg - granuloma system using lectin histochemistry

This study aims to evaluate the egg-granuloma system in hepatic tissues using lectin histochemistry in experimental Schistosomiasis. Eight Swiss mice were infected with a local strain of Schistosoma mansoni, being submitted forty days later to a perfusion after which slices of liver were prepared. The tissue samples were incubated with the following peroxidase conjugated lectins: Peanut agglutinin (PNA), Wheat Germ agglutinin (WGA), and Concanavalin A (Con A). All lectins recognized the glycoconjugates in the adult worm tegument. In the hepatic tissue, WGA presented the highest staining followed by PNA and Con A. The PNA presented the most intense staining of the egg-granuloma system while WGA stained the hepatic sinusoid cells and Con A bound preferentially the fibrosis rings of granuloma and the surrounding hepatic parenquima. WGA and PNA indicated the presence of residues of N-acetyl-glucosamine and galactose in the surface of Schistosoma mansoni eggs in the hepatic granulomas. In conclusion, using PNA, Con A and WGA our study presented different aspects of the egg-granuloma and Tegument of Schistosoma mansoni as well as indicated differences in the peri-ovular granulomas indicating alterations in the cellular mechanism of expression of surface carbohydrates during progression of the Schistosomiasis.

El objetivo del estudio fue evaluar el sistema de los huevos de los granulomas en los tejidos hepáticos, utilizando histoquímica de lectinas esquistosomiasis. Ocho ratones suizos experimentales fueron infectados con una cepa local de Schistosoma mansoni y luego a los cuarenta días fueron sometidos a la perfusión y se prepararon cortes de hígado. Las muestras de los tejidos fueron incubadas con las siguientes peroxidasas lectinas conjugadas: aglutinina de maní (PNA), aglutinina de germenn de trigo (WGA), Concanavalin A (Con A). Todas las lectinas reconocieron las glicoconjugadas en el tegumento del gusano adulto. El tejido hepático con WGA presentó mayor coloración seguido de PNA y Con A. El PNA presentó la más intensa tinción de los huevos mientras el granuloma del sistema WGA tiñó las células hepáticas sinusoides y las Con A estuvieron siempre presentes en los anillos de la fibrosis y alrededor de los granulomas hepáticos del parénquima. WGA y PNA indicaron la presencia de residuos de N - acetil - glucosamina y galactosa en la superficie de los huevos de Schistosoma mansoni en los granulomas hepáticos de esquistosomiasis.

Population biology and feeding habits of the nephropid lobster Metanephrops thomsoni (Bate, 1888) in the East China Sea.

Population biology and feeding habits of the nephropidlobsterMetanephrops thomsoni (Bate) was studied from a field survey sampled with bottom trawls in the East China Sea. The female/male ratio was 1.06:1. Three size-class groups were discriminated for both sexes, which may correspond to one to three year-old cohorts. The average stage fecundity was 471 in each brood. Larger than two-year-size-class females are multi broods during the breeding season. Gut analysis showed that this lobster is a common camivore and mainly consume crustaceans and fishes, regardless of sex and carapace length size.

Reproduction and growth of the freshwater prawn, Palaemon paucidens (Decapoda: Palaemonidae) in a lake of Korea.

This study analyzed the reproduction and growth of freshwater prawn, Palaemon paucidens De Haan 1844 from Suk-dang lake(Korea). The analysis of the sex ratio showed a higher proportion of males than that of females. The average size of the eggs was 6.12 (+/-0.55) mm3 in the non-eyed stage (stageA) and 7.20 (+/-0.86)mm3 in the eyed stage (stage B). The reproductive output (RO) calculated with the dried-body weight of an incubating female and the weight of the eggs in dried condition was 26.97% (n = 17) of the average females weight. Incubating prawn appeared in April, and the gonadosomatic indices(GSI) showed the highest value during three months from January to March. Based on the month when there was a high proportion of incubating females with a high GSI, the estimated spawning season of P. paucidens was April. The maturity of the female was evaluated by the development of the ovaries and the existence of eggs. The average body length when 50% of the females in the group reached maturity was 8.55 (+/-2.74) mm. The analysis of the length-frequency distribution showed that the life span of P. paucidens ranged from 12 to 13 months. Females mature faster than males.

Long-term storage and viability of Ochlerotatus albifasciatus (Diptera: Culicidae)

The viability of Ochlerotatus albifasciatus (Macquart) eggs stored at room temperature and at 5ºC was studied over 31 months. After 12, 18 and 31 months of storage, eggs were acclimatized at 22ºC for ten days, and then inundated twice every seven days. The effect of the storage period on the percentage of hatching was analyzed by one way ANOVA. Differences on the hatching response between the first and second flooding were analyzed by paired t-test. Differences on the hatching response between the two storage conditions were analyzed by Mann-Whitney rank test. Results showed that (1) Oc. albifasciatus eggs were able to survive and hatch over 31 months; (2) the percent hatching of eggs stored at 5ºC was higher than that of eggs stored at room temperature; and (3) low temperatures and long periods without water favor installment hatching.

Hatching rates of resting eggs of 'Cladocera' (Crustacea; Branchiopoda) at a tropical bay, Brazil

The aim of this study was to determine the development time of embryos and to estimate the hatching rates of resting eggs of cladocerans found in the sediment of Guanabara Bay, Rio de Janeiro, Brazil, under experimental conditions. Eggs were sorted by species (Penilia avirostris - Sididae; Pleopis polyphemoides and Pseudevadne tergestina - Podonidae) and incubated at a temperature of 25 °C, salinity 35 and photoperiod 12 hours light/ 12 hours dark. Hatching rates were about 38 percent for Pseudevadne tergestina and 28 percent for Pleopis polyphemoides. Embryos of resting eggs of Penilia avirostris developed comparatively slowly (hatching after 86 days of incubation), with a hatching rate of only 5 percent. It was observed that development and hatching of resting eggs of marine cladocerans suggest that pulses of recruitment may exist, thus contributing to the rapid appearance and maintenance of planktonic populations of these crustaceans in Guanabara Bay.

O objetivo do presente estudo foi determinar o tempo de desenvolvimento de embriões e estimar as taxas de eclosão de ovos de resistência de cladóceros encontrados no sedimento da baía de Guanabara, Rio de Janeiro, Brasil, sob condições experimentais. Os ovos foram separados por espécie (Penilia avirostris - Sididae; Pleopis polyphemoides e Pseudevadne tergestina - Podonidae) e incubados a 25 °C, salinidade 35 e fotoperíodo 12 horas claro 12 horas escuro. As taxas de eclosão foram de aproximadamente 38 por cento para Pseudevadne tergestina e de 28 por cento para Pleopis -polyphemoides. Os embriões dos ovos de resistência de Penilia avirostris desenvolveram-se de forma relativamente lenta (eclodindo apenas 86 dias após o início da incubação), com uma taxa de eclosão de apenas 5 por cento. Foi observado que o desenvolvimento e a eclosão dos ovos de resistência de cladóceros marinhos sugerem que podem ocorrer em pulsos, contribuindo assim para o rápido aparecimento e manutenção destes crustáceos na baía de Guanabara.

Successful hatching from eggs carried by females and naturally removed from incubant males in Belostoma spp. water bugs (Heteroptera: Belostomatidae)

Within Belostomatinae water bug species (Heteroptera, Belostomatidae) it has been hitherto believed that the completion of embryonic development is successful only if eggs are incubated on male hemelytra. Nevertheless, we found egg successful hatching from a back-brooding Belostoma elegans (Mayr) and B. micantulum (Stål) females, as well as from fertilized eggs kicked off from four back-brooder B. elegans males. One "encumbered" B. elongatum Montandon female was also recorded, but eggs did not hatch after she removed them.

Se considera que el desarrollo embrionario y la emergencia de las ninfas de las especies de Belostomatinae (Heteroptera, Belostomatidae) se cumplen con éxito si los huevos son incubados sobre el espacio dorsal de machos adultos. No obstante, hemos registrado eclosiones exitosas a partir de dos hembras grávidas portando huevos sobre su dorso; una de ellas de la especie Belostoma elegans (Mayr), la otra de B. micantulum (Stål). Se registra la eclosión de huevos, previamente removidos del área de postura por los propios machos incubantes de B. elegans (N=4) y la presencia de una hembra de B. elongatum Montandon, portando huevos sobre sus hemiélitros, los cuales no eclosionaron después de haber sido removidos por la propia hembra.

Variation in the hatching response of Ochlerotatus albifasciatus egg batches (Diptera: Culicidae) in temperate Argentina

Egg hatching of winter-collected Ochlerotatus albifasciatus was studied for six months. Batches of eggs were divided into two groups, one of them was stored in the laboratory at 23ºC and 12:12 photoperiod, and the other in the field under dead leaves. Every month, from July to December, eggs from the two groups were flooded under both laboratory and field conditions. Unhatched eggs were returned to the original condition and flooded two more times separated by ten-day intervals. Results show that egg diapause is expressed in different intensities, not only on eggs exposed to different conditions but also in those exposed to the same condition, even when they were laid by the same female. Successive inundations yielded incomplete hatches of eggs, and favored the hatching response in the next flooding. Low environmental temperatures before and during the flooding depressed hatching response. This shows that eggs need a warm period before flooding as well as warm temperatures during flooding, to hatch. As drought period was longer hatching response increased, but this was also accompanied by warmer environmental conditions. The experiment performed in laboratory did not show that increment. Field studies showed that a layer of dead leaves protected eggs from extreme temperatures.

Fecundidad, fertilidad e índice gonadosomático de Poecilia reticulata (Pisces: Poeciliidae)en Heredia, Costa Rica / Fertility, fecundity and gonadosomatic index of Poecilia reticulata (Pisces: Poeciliidae) in Heredia, Costa Rica

Entre setiembre y noviembre de 1998 se determinó la fecundidad,fertilidad e índice gonadosomático de Poecilia reticulata (Peters 1859),a partir de especímenes recolectados en un estanque en Santo Domingo de Heredia,Costa Rica.Las hembras presentaron una longitud total promedio de 34.43 ± 7.26 mm con un ámbito entre 17.80 y 51.50 mm y un peso total promedio de 0.69 ± 0.48 g,con un ámbito entre 0.06 y 2.32 g.Se determinó que esta especie presenta superfetación,matrotrofía y se mantuvo sexualmente activa durante todo el período de estudio.La fertilidad se rigió por la ecuación F =0.527e0.1171Lt (r2 =0.9404)y con una fertilidad promedio para la población de 56.1 ± 43.6,con un ámbito entre 7.98 y 197.58 (huevos +embriones).La fecundidad se rigió por la ecuación Fo = 0.695e0.1076 Lt (r2 =0.9376)con una fecundidad promedio para la población de 48.95 ± 35.99, con un ámbito entre 6.98 y 178.99 (ovocitos +óvulos). El índice gonadosomático en hembras se rigió por la ecuación IGS =0.0014e 0.134 Lt (r 2 =0.8581)y se encontró un índice gonadosomático promedio de 0.25 ± 0.27% con un ámbito entre 0.02 y 1.31%

Between September and November of 1998,1 432 females of Poecilia reticulata were collected in a pond in Santo Domingo,Heredia,Costa Rica.The average total length of females was 34.43 ± 7.26 mm (range 17.80 and 51.50 mm)and the average total weight of 0.69 ± 0.48 g (range 0.06 and 2.32 g). This species is a viviparous matrotrofic and the specimens were sexually mature.The total length-fertility relationship was F =0.527e 0.1171Lt (r2 =0.9404).The average fertility was 56.1 ± 43.6 (eggs +embryos)(range 8.0 and 197.6).The total length-fecundity relationship was Fo =0.695e0.1076 Lt (r2 =0.9376).The average fecundity was of 49.0 ± 36.0 (oocytes +ova)(range 7.0 and 179.0).The total length-gonadosomatic index relationship was IGS =0.0014 e0.134 Lt (r2 =0.8581).The average gonadosomatic index was 0.25 ± 0.27%(range 0.02 and 1.31%)

Competitividad óvulo-embrionaria determinada a través de la cuantificación de los Ýndices perifoliculares en la microarquitectura vascular por Doppler / Ovum-embryo competitiveness determined by the quantification of perifollicular indices in Doppler vascular micro-architecture

OBJECTIVE: To obtain the linear correlation between Doppler flowmetry rates and follicular development and the observed embryo growth in ovarian hyperstimulation cycles in the IVFTE/ICSI results. MATERIAL AND METHODS: A prospective and observational study including 29 patients was carried out. The ovarian reserve was determined--by the ovaries morphometric conditions--as well as basal FSH. These were correlated with pulsatility rates (PR), resistance rates (RR), and the systole/diastole ratio (S/D) and the maximum flow rate (TAmax), using a USG pulse-colour Doppler. All these were correlated to embryo development. Covariance, regression lines and confidence intervals analyses were performed for its statistical determination. RESULTS: A correlation between RR and the formation of mature follicles was observed (p = 0.05), and, at the same time, a negative relationship between FSH and ovarian volume was found. CONCLUSIONS: A series of markers of ovarian reserve have been described, however, none of these is a specific marker when ovum quality is expressed through the administration of ovulation inducers. Considering the data obtained in our study, we can say that Doppler flowmetry rates can indicate follicular expression and the resulting ovum and embryo development.

Factors affecting the hatching of human pinworm ova.

Parasite life-history traits reflect past environmental and host selective pressure that act to produce strategies that maximize successful transmission. Pooled human pinworm eggs were pretreated with 0.9% NaCl, acid digestive enzyme, and alkaline solutions (pH 9.0) and then incubated in 0.9% NaCl at room temperature and 37 degrees C both with and without 5% CO2. Eggs pretreated with both acid and base had the same hatching pattern, which was markedly different to that of the untreated eggs. At room temperature (RT), hatching of the pretreated eggs occurred on the first day and reached its peak rate (>90%) on day 3; at 37 degrees C hatching occurred on the second day and was more than 80% by day 5. Hatching of the untreated eggs was evident on day 2 at RT and between days 3-5 at 37 degrees C although in smaller numbers (<20%). The CO2 did not affect the hatching of larvae. The larvae could survive after hatching in 0.9% NaCl for 2 and 4 days at 37 degrees C and 25 degrees C, respectively. The present investigation gives a different information that human pinworm ova can hatch into larvae with or without exposure to acid digestive enzyme or alkaline solutions.

The effect of abiotic factors on the hatching of Moina micrura Kurz, 1874 (Crustacea: Cladocera) ephippial eggs

The roles of some abiotic factors in controlling the hatching rates of Moina micrura ephippial eggs were investigated. Determination of optimum hatching conditions would be important in developing the use of this species as a food for fish larvae in aquaculture. Ephippia were exposed to different treatments in the laboratory, and monitored for hatching over a period of seven days. Optimum hatching conditions were: pH 5-9, temperature 25ºC, photoperiod eight or more hours light per day and light intensity equal to or greater than 850 lux. Differences in water ionic concentrations (from deionized water to 880 mg.L-1 of selected salts) had no effect

Efecto del alimento sobre algunos aspectos reproductivos de la trucha arcoiris, Oncorhynchus mykiss, en un criadero venezolano / Food effects on some reproductive aspects of rainbow trout, Oncorhynchus mykiss, in a Venezuelan fish farm

Samples of rainbow trout, Oncorhynchus mykiss, were fed with three different dried diets, labeled D1, D2 and D3, the first ones were expanded and the last one pelleted type food. Their protein content ranged from 36 to 42, and only D1 diet presented a pigment in its composition. The gonodasomatic index (GSI) as well as the gonadial development showed a different behavior in males and females for all the samples tested. A continuous sperm production was observed in males fish, while in female fish the GSI showed a tendency to increase through the whole study, and they showed a reproductive rest period on july 92. Fish relative fecundity and egg diameter were similar in all cases. The gonodial maduration age was shorter for the female that were fed with D1 and D2, while the 50 of the trout population that got D3 had a gonodial maduration period two months longer. For all trouts tested the fertility was low with a maximum value of 49. The hatchery from the tested trouts with D2 intakes had a mortality value of 62. Meanwhile, those with D1 and D3 intakes showed mortality values of 36 and 43 respectively.