Do dietary stresses affect the immune system of Periplaneta americana (Blattaria: Blattidae)? / Estresses alimentares afetam o sistema immune de Periplaneta americana (Blattaria: Blattidae)?

Abstract Stresses can be caused by multiple biotic and abiotic factors and their effects can affect both the biology and the immune system of insects. American cockroach - Periplaneta americana (Linnaeus, 1758) (Blattaria: Blattidae) -besides being an excellent model species, has great medical importance because it can act as a mechanical vector of several pathogens. This study aimed to evaluate the influence of starvation, dehydration and both stresses on weight, and total and differential haemocyte count in P. americana adults. Each specimen was isolated in glass flasks containing or not food and/or water. They were weighed periodically. Another group received water for 24 h after the end of stress period. In the immunologic bioassay, we counted their haemocytes after the final weighing. All stresses reduced the insect weight, especially when the stresses were combined. Females of the control group gained weight and males had it unaltered. Different stress conditions and time did not influence on total haemocyte count. Insects without food and water had the proportion of prohaemocytes increased and plasmatocytes decreased. This study can serve as a basis of further studies of bioecology, behaviour and the ability of resisting insecticides, besides serving as a model to studies in other insect species.

Resumo Os estresses podem ser causados por múltiplos fatores bióticos e abióticos e seus efeitos podem afetar tanto a biologia como o sistema imune dos insetos. A barata-americana - Periplaneta americana (Linnaeus, 1758) (Blattaria: Blattidae) - além de ser uma excelente espécie modelo, tem grande importância médica, pois pode atuar como vetor mecânico de diversos patógenos. O objetivo desse estudo foi avaliar a influência da inanição, desidratação e ambos os estresses sobre o peso e o número total e diferencial de hemócitos em adultos de P. americana. Cada espécime foi isolado em frascos de vidro contendo ou não alimento e/ou água. Eles foram pesados periodicamente. Outro grupo recebeu água por 24 h após o término do período de estresse. Nos ensaios imunológicos, foram contados os seus hemócitos após a última pesagem. Todos os estresses reduziram o peso dos insetos, especialmente quando os estresses foram combinados. As fêmeas do grupo controle ganharam peso e os machos tiveram seu peso inalterado. As diferentes condições de estresse e tempo não influenciaram no número total de hemócitos. Os insetos sem alimento e água tiveram a proporção de pró-hemócitos aumentada e a de plasmatócitos reduzida. Esse estudo pode servir como base para estudos posteriores de bioecologia, comportamento e da habilidade de resistir aos inseticidas químicos, além de servir como modelo para estudos em outras espécies de insetos.

Dynamics of haemocytes from Pseudosuccinea columella circulating infected by Fasciola hepatica / Dinâmica de hemócitos circulantes de Pseudosuccinea columella infectados por Fasciola hepatica

Abstract The lymnaeids are important in the epidemiology of Fasciola hepatica, a neglected and endemic zoonosis. The interaction between the internal defense system of Pseudosuccinea columella and F. hepatica has been little studied. In the present study the effect of infection by F. hepatica on P. columella circulating haemocytes was investigated. Changes in the average number of total circulating haemocytes have been observed at 30 minutes post-infection and 1, 7, 10, 14, 21, 28 and 50 days post-infection (dpi). Miracidia were observed head-foot and mantle at 30 minutes post-infection. Miracidia/Sporocysts in the mantle skirt 1 dpi, and fully formed sporocysts were observed in the head-foot at 7 dpi. Rediae became evident at 10 dpi and were located between the haemocoel and the muscles from 14 dpi; 50 dpi, the rediae in the digestive gland contained cercariae. The statistical analysis of the total haemocytes of P. columella infected by F. hepatica showed significant differences on the 30 minutes post-infection and 1, 14, 21, and 28 dpi in comparison to uninfected molluscs (0 dpi). Therefore, the interference observed on the internal defence system of P. columella may have direct association with the development of F. hepatica.

Resumo Os limnaeideos são importantes na epidemiologia de Fasciola hepatica, uma zoonose negligenciada e endêmica. A interação entre o sistema interno de defesa de Pseudosuccinea columella e F. hepatica tem sido pouco estudada. No presente estudo, investigou-se o efeito da infecção por F. hepatica nos hemócitos circulantes de P. columella. Alterações no número médio de hemócitos circulantes foram observadas aos 30 minutos e 1, 7, 10, 14, 21, 28 e 50 dias após a infecção (dpi). Miracídios foram observados na região cefalopodal e manto aos 30 minutos após a infecção. Miracídio/esporocistos foram observados no colar do manto ao 1 dpi, e esporocistos totalmente formados na região cefalopodal aos 7 dpi. Rédias tornam-se evidentes aos 10 dpi entre a hemocele e músculos a partir de 14 dpi; e rédias com cercárias próximas a glândula digestiva aos 50 dpi. A análise estatística dos hemócitos totais de P. columella infectados por F. hepatica demonstrou diferenças significativas nos 30 minutos pós-infecção e 1, 14, 21 e 28 dpi em comparação aos moluscos não infectados (0 dpi). Portanto, a interferência observada no sistema de defesa interna de P. columella pode ter associação direta com o desenvolvimento de F. hepatica.

Estudio de componentes hemolinfáticos de Rhodnius prolixus y Triatoma maculata alimentados con diferentes fuentes sanguíneas / Study of hemolymphatic components of Rhodnius prolixus and Triatoma maculata fed on different blood sources

RESUMEN Introducción: Tradicionalmente, Rhodnius prolixus ha sido considerado el principal vector, mientras que Triatoma maculata resulta ser un vector secundario de Trypanosoma cruzi en el medio rural venezolano. En este trabajo se provee información de interés acerca de los componentes bioquímicos y del sistema inmune, humoral y celular, de la hemolinfa de R. prolixus y T. maculata alimentados sobre gallina y rata. Metodología: los insectos provenían de una colonia del laboratorio, mantenida a una temperatura de 27-29ºC, 50% de humedad relativa y ocho horas luz/día. Se analizó la hemolinfa de adultos alimentados sobre gallina y rata. Se observaron los hemocitos mediante microscopía óptica y electrónica de transmisión. Resultados: los parámetros bioquímicos de glucosa, lípidos y proteínas fueron afectados de forma distinta en R. prolixus y T. maculata según la fuente alimenticia. T. maculata presentó mayores niveles de actividad lítica de lisozima. Se observaron cuatro poblaciones de hemocitos (prohemocitos, plasmatocitos, granulocitos y oenocitos), cuyas características y medidas están acorde a lo reportado por otros autores sobre la subfamilia Triatominae. T. maculata presentó mayor número de prohemocitos y oenocitos que R. prolixus. Conclusiones: En su hemolinfa, R. prolixus y T. maculata son afectados distintamente en los componentes bioquímicos (glucosa, lípidos y proteínas) e inmunes, tanto humorales (lizosima) como celulares (prohemocitos, oenocitos), según sean alimentados sobre gallina y rata. Esto pone de manifiesto de la alimentación sobre uno de los componentes de la competencia vectorial, como lo es el sistema inmune propio de la hemolinfa de los insectos.

ABSTRACT Introduction: Traditionally, Rhodnius prolixus has been considered the main vector, while Triatoma maculata remains to be a secondary vector of Trypanosoma cruzi in the Venezuelan rural habitat. In this work, interesting information about the biochemical and immune (humoral and cellular) aspects of the hemolymph of R. prolixus and T. maculate, feeding on hen and rat, are presented. Methodology: Hemolymph was extracted from adult insects, maintained at 2729 °C with 50% of relative humidity and 8/16 (Light/Dark) hours, and fed on hen and rat. Hemocytes were observed by optical and transmission electron microscopy. Results: Biochemical parameters (glucose, lipids and proteins) varied in both species according to the food source. T. maculata presented higher levels of lysozyme lytic activity. Four hemocytes populations were observed by optical and transmission electron microscopy (prohemocytes, plasmocytes, granulocytes and oenocytes), exhibiting characteristics and measurements in accordance with previous literature related to the Triatominae subfamily. T maculata presented more prohemocytes and oenocytes than R. prolixus. Conclusions: On their hemolymph, R. prolixus and T. maculata are distinctly affected in their biochemical (glucose, lipids and proteins) and immune components, both humoral (lysozyme) and cellular (prohemocytes, oenocytes), depending on whether they were fed on hens or rats. Our results show that the food source affects the immune system of triatomines, and subsequently, their vectorial capacity may be compromised as well.

Do dietary stresses affect the immune system of Periplaneta americana (Blattaria: Blattidae)?

Abstract Stresses can be caused by multiple biotic and abiotic factors and their effects can affect both the biology and the immune system of insects. American cockroach Periplaneta americana (Linnaeus, 1758) (Blattaria: Blattidae) besides being an excellent model species, has great medical importance because it can act as a mechanical vector of several pathogens. This study aimed to evaluate the influence of starvation, dehydration and both stresses on weight, and total and differential haemocyte count in P. americana adults. Each specimen was isolated in glass flasks containing or not food and/or water. They were weighed periodically. Another group received water for 24 h after the end of stress period. In the immunologic bioassay, we counted their haemocytes after the final weighing. All stresses reduced the insect weight, especially when the stresses were combined. Females of the control group gained weight and males had it unaltered. Different stress conditions and time did not influence on total haemocyte count. Insects without food and water had the proportion of prohaemocytes increased and plasmatocytes decreased. This study can serve as a basis of further studies of bioecology, behaviour and the ability of resisting insecticides, besides serving as a model to studies in other insect species.

Resumo Os estresses podem ser causados por múltiplos fatores bióticos e abióticos e seus efeitos podem afetar tanto a biologia como o sistema imune dos insetos. A barata-americana Periplaneta americana (Linnaeus, 1758) (Blattaria: Blattidae) além de ser uma excelente espécie modelo, tem grande importância médica, pois pode atuar como vetor mecânico de diversos patógenos. O objetivo desse estudo foi avaliar a influência da inanição, desidratação e ambos os estresses sobre o peso e o número total e diferencial de hemócitos em adultos de P. americana. Cada espécime foi isolado em frascos de vidro contendo ou não alimento e/ou água. Eles foram pesados periodicamente. Outro grupo recebeu água por 24 h após o término do período de estresse. Nos ensaios imunológicos, foram contados os seus hemócitos após a última pesagem. Todos os estresses reduziram o peso dos insetos, especialmente quando os estresses foram combinados. As fêmeas do grupo controle ganharam peso e os machos tiveram seu peso inalterado. As diferentes condições de estresse e tempo não influenciaram no número total de hemócitos. Os insetos sem alimento e água tiveram a proporção de pró-hemócitos aumentada e a de plasmatócitos reduzida. Esse estudo pode servir como base para estudos posteriores de bioecologia, comportamento e da habilidade de resistir aos inseticidas químicos, além de servir como modelo para estudos em outras espécies de insetos.

Caracterização hemocitária de uma linhagem resistente de Biomphalaria straminea (Dunker, 1848) exposta a schistosoma mansoni sambon, 1907 / Haemocyte characterization of a resistant lineage of biomphalaria straminea (Dunker, 1848) exposed to schistosoma mansoni sambon, 1907

A esquistossomose mansônica ainda constitui um grave problema de saúde pública no Brasil e, portanto, o conhecimento dos diversos aspectos da interação Schistosoma mansoni-Biomphalaria, são pertinentes e relevantes como subsídios à medidas de controle e prevenção desta parasitose. Estudos in vitro têm mostrado que a suscetibilidade dos hospedeiros intermediários de S. mansoni, Biomphalaria straminea e Biomphalaria glabrata está relacionado à presença de lectinas. Importante transmissor da Esquistossomose no Brasil, B. straminea apresenta baixos índices de infecção em condições experimentais. Apesar disto, existem poucos estudos a respeito das características morfológicas e do comportamento in vitro dos hemócitos deste molusco frente à infecção por S. mansoni. Com o objetivo de caracterizar a resposta hemocitária de B. straminea (cepa Souza-PB) expostas a miracídios de S. mansoni, os moluscos foram expostos em massa e expostos individualmente a cinco miracídios. Exemplares de B. glabrata foram utilizadas como controle positivo. A hemolinfa foi coletada, corada em Azul de Tripan e os hemócitos foram contados em câmara de Neubauer. Alguns hemócitos foram colocados em placa de cultura para observação da interação das células com os parasitos e outros foram submetidos à marcação por lectinas fluoresceinadas de Griffonia simplicifolia e Lens culinaris conjugadas a FITC. As imagens foram obtidas e gravadas através de microscópio AxioObserver e câmera McR5 Zeiss. Os moluscos expostos em massa foram sacrificados logo após a penetração inicial do parasito (0 minuto), 24, 48, 72 horas e 30 dias após exposição (dpe)...

Schistosomiasis still remain as an important parasitic disease under the public health point of view.Thus, studies that involve the interaction between Schistosoma mansoni-Biomphalaria are pertinentand useful to the disease prevention and control. In vitro studies have shown that the susceptibility ofBiomphalaria straminea and Biomphalaria glabrata, intermediate hosts of Schistosoma mansoni, isrelated to the presence of lectins. As an important carrier of schistosomiasis in Brazil, B. stramineapresents low infection rates under laboratory conditions. Despite of that, there are few studiesregarding the morphological features and in vitro behavior of this mollusc's haemocytes challenged byS. mansoni miracidia. For this purpose, we analyzed the haemocyte response of B. straminea (Sousa– PB strain) challenged by the parasite, so the molluscs were put under mass exposure and individualexposure to five miracidia. B. glabrata molluscs were used as positive controls. The molluscs had theirhaemolymph drawn, the haemocytes were stained in Trypan Blue and counted in Neubauer chamber.Some haemocytes were put into cell culture plates in order to observe the interaction between thecells and the parasites and other cells were stained by FITC conjugated lectins from Griffoniasimplicifolia and Lens culinaris. The images and films were made at the microscope AxioObserver withMcR5 camera from Zeiss. The mass exposed molluscs were killed at 0 minutes (first penetration of themiracidia), 24, 48, 72 hours and 30 days after exposure (dae)...

Comparison of hemocytes of V-instar nymphs of Rhodniusprolixus (Stål) and Rhodnius robustus (Larousse 1927), before and after molting / Comparación de los hemocitos de las ninfas de V instar de Rhodnius prolixus (Stål) and Rhodnius robustus, antes y después de la muda (Larousse 1927)

Background. The immune response of insects involves humoral factors and cellular elements known as hemocytes. There are different reports that explore the response of hemocytes to infections, but the effect that molting has on this response has not been explored so far. We hypothesized that there would be a change in the percentage of hemocytes as a response to the molting process. Objective. The aim of this work was to compare the hemogram (CBC), the formula, and the differential count of hemocytes in IV instar before molting and in V instar nymphs 24 hours after molting in two species: Rhodnius prolixus and Rhodnius robustus. Materials and methods. We assayed different staining methodologies including Giemsa, Alcian Blue pH 2.0, Alcian Blue pH 2.6, Gomori substrate, PAS (Schiff), Sudan Black and Papanicolau with positive controls for each one. In the Gomori staining, we observed lysosomes in the granulocytes and plasmatocytes, but the differentiation was better detected using Giemsa staining. Results. There were no statistically significant differences between the two species studied in plasmatocytes (p=0,053) or even in granulocytes (p=0,5). However, differences were significant in the prohemocytes (p=0,001) during the molting process in both Rhodnius prolixus and Rhodnius robustus. Conclusions. Significant differences in prohemocytes between nymphs of IV and V instar were detected. No significant differences in the amount of cells were observed between the two species and the two stages. These findings may be explained due to their role as precursor cell of prohemocytes.

Antecedentes. La respuesta inmune de los insectos involucra factores humorales y elementos celulares llamados hemocitos. Existen varios trabajos explorando la respuesta de los hemocitos frente a infecciones, pero no como respuesta al proceso de muda. Objetivo. Comparar el hemograma: la fórmula y el recuento diferencial de hemocitos de Rhodnius prolixus y Rhodnius robustus en ninfas de IV estadio antes de la muda y ninfas de V estadio 24 horas después de la muda. Materiales y métodos. Se ensayaron las coloraciones Giemsa, Alcian Blue pH 2.0, Alcian Blue pH 2.6, sustrato Gomori, PAS (Schiff), Sudán Negro, Papanicolau, con controles positivos para cada una. Con la coloración de Gomori se observaron lisosomas en los granulocitos y en plasmatocitos, pero la diferenciación se logró mejor con la coloración de Giemsa. Resultados. Los plasmatocitos fueron más abundantes en las ninfas de IV estadio de Rhodnius robustus y en las de V estadio de las dos especies, pero en las ninfas de V estadio de R. prolixus, el recuento de prohemocitos fue mayor; para los oenocitoides, esferulocitos y adipohemocitos el recuento no alcanzó al 1 %. En las dos especies no se encontraron diferencias estadísticamente significativas en plasmatocitos (p=0,05319), ni en granulocitos (p=0,5), entre las ninfas de IV y V estadio, pero fue significativa en prohemocitos (p=0,001). Conclusiones. Se detectaron diferencias significativas en prohemocitos entre las ninfas de IV y V estadio. No hubo un aumento significativo en el conteo de células en los diferentes estadios.

Immunopathological features developing in the mosquito midgut after feeding on anopheles gambiae mucin-1 / interleukin-12 cDNA immunized mice / Desarrollo de características inmunopatológicas en el intestino medio del mosquito después de alimentarse de ratones inmunizados con mucina-1 / interleucina-12 ADNc de anopheles gambiae

The mosquito midgut is the organ into which the blood meal passes and in which, within a peritrophic membrane secreted by the epithelium, the blood is retained during digestion and absorption. The mosquito midgut is lined with an actin filled microvilli that are exposed to the harsh environment of the gut lumen such as food particle abrasion, digestive hydrolases and attack by pathogens and parasites that are taken in by the blood meal. These microvilli are protected them these effects by the peritrophic matrix, the glycocalyx and the mucin proteins that line their epithelial surfaces. Immunization of BALB/c mice with AgMUC1/IL-12 cDNA has been shown to kill mosquitoes when fed on these mice. Mucin is one of the proteins produced in the mosquito midgut after a blood meal. The fine structure of the mosquito midgut epithelium interacting with immune factors such as antibodies or immune cells is of special significance for interpreting early events in the interaction between the mosquito midgut lining and the specific immune components present in the blood of AgMUC1/IL-12 cDNA immunized BALB/c mice. Following bright light microscopy, scanning electron and transmission electron microscopic observations of the features seen in mosquito midgut sections from An. gambiae mosquitoes fed on BALB/c mice immunized with AgMUC1/IL-12 cDNA, the most likely immune mechanisms responsible for mosquito killing could be cell mediated, most likely antibody dependent cellular cytotoxicity. Both necrotic and apoptotic processes that could be the cause of mosquito death were seen to take place in the cells lining the midgut epithelium.

El intestino medio es el órgano al cual pasa la sangre consumida por el mosquito y donde, mediante una membrana peritrófica secretada por el epitelio, esta sangre es mantenida durante la digestión y absorción. El intestino del mosquito está revestido por microvellosidades llenas de actina que son expuestas a las complejas condiciones en torno a la luz intestinal, tales como la abrasión producida por partículas de alimentos, hidrolasas digestivas y el ataque de patógenos y parásitos que son tomados en la sangre consumida. Estas microvellosidades se protegen de estos efectos mediante la matriz peritrófica, el glicocálix y las proteínas de mucina que revisten las superficies epiteliales. La inmunización con AgMUC1/IL-12 ADNc en ratones BALB/c ha demostrado ser útil para matar los mosquitos cuando se alimentan de estos ratones. La mucina es una de las proteínas producidas en el intestino medio del mosquito después de consumir sangre. La fina estructura del epitelio del intestino interactúa con factores inmunes tales como anticuerpos o células inmunes es de especial importancia para interpretar los eventos tempranos en la interacción entre el revestimiento del intestino medio y los componentes inmunológicos específicos presentes en la sangre de ratones BALB/c inmunizados con AgMUC1/IL-12 cDNA. Después de observar mediante microscopías de luz, electrónica de barrido y de transmisión las características de secciones del intestino medio del mosquito Anopheles gambiae alimentado de ratones BALB/c inmunizados con AgMUC1/IL-12 cDNA, mecanismos inmunes mediados por citotoxicidad celular dependiente de anticuerpos (ADCC) podrían ser los responsables de matar a los mosquitos. Los procesos necróticos y apoptóticos que pueden ser la causa de la muerte del mosquito tienen lugar en las células que recubren el epitelio del intestino medio.

Defense response of susceptible and resistant Biomphalaria alexandrina snails against Schistosoma mansoni infection

In Egypt, Biomphalaria alexandrina is the intermediate host for Schistosoma mansoni. The fates of Schistosoma miracidia in the snails varies between different species of Biomphalaria. The internal defense system is one of the factors that influence the susceptibility pattern of the snails. The interaction between Biomphalaria snails and S. mansoni needs to be identified for each species, and even between the members of the same species with different degrees of susceptibility. In the present study, the first generation of susceptible and resistant parents of B. alexandrina was examined histologically at the 30th day post exposure. The study includes the characterization of the immune response, as expressed by tissue reactions, of susceptible and resistant B. alexandrina snails against S. mansoni. It was also designed to determine the impact of the resistance increase in parent snails, on the mechanisms of interaction of their offspring against infection. The results showed that the infection rate of the offspring from the susceptible parents was 92%. No susceptible offspring was produced from the resistant parents. When the parents were of equal number of susceptible and resistant snails, they gave an offspring with an infection rate of 20%. Susceptible snails that had susceptible parents showed a higher degree of susceptibility than those that had both susceptible and resistant parents. A common feature of the resistant snails was the absence of any viable parasites. The tissue reactions of the resistant snails having only resistant parents occurred at the site of miracidial penetration. In resistant snails for which susceptible ones were included in their parents, the reactions occurred in the deep tissues. These results characterized the immune response of B. alexandrina snails against Schistosoma infection which was found to occur by two different mechanisms. One type of defense occurs in highly resistant snails, and employs direct miracidial destruction soon after parasite penetration. The other type occurs in less resistant snails where a delayed resistance development occurs after the dissemination of the sporocysts in the snail tissues. It seems that B. alexandrina snails respond more or less similar to B. glabrata. The results also proved that the immune response of the internal defense system increased with increasing the number of the inherited resistant genes.

En Egipto, Biomphalaria alexandrina es el huésped intermediario de Schistosoma mansoni. La supervivencia de los miracidios de Schistosoma en los caracoles varía entre las especies de Biomphalaria. El sistema de defensa interno es uno de los factores que influyen en el patrón de susceptibilidad de los caracoles. La interacción entre los caracoles Biomphalaria y S. mansoni requiere ser identificada para cada especie e incluso, entre los miembros de la misma especie con diferente grado de susceptibilidad. En el presente estudio, la primera generación de padres susceptibles y resistentes de B. alejandrina fue examinada histológicamente al día 30, después de la exposición. El trabajo fue realizado tanto para caracterizar la respuesta inmune, según las reacciones de los tejidos, de los caracoles susceptibles y resistentes de B. alejandrina contra S. mansoni. También, el estudio se diseñó para determinar el impacto en el aumento de la resistencia en los caracoles padres, en los mecanismos de interacción de sus crías contra la infección. Los resultados mostraron que la tasa de infección para las crías, de padres susceptibles, fue del 92%. No se originaron crías susceptibles de los padres resistentes. Cuando los padres incluían un número igual de caracoles susceptibles y resistentes, dieron como resultado crías con una tasa de infección del 20%. Los caracoles susceptibles que tuvieron padres susceptibles mostraron un mayor grado de susceptibilidad que los que tenían tanto padres sensibles como resistentes. Una característica común de los caracoles resistentes fue la ausencia de parásitos viables. Las reacciones en los tejidos de los caracoles resistentes de sólo padres resistentes ocurrió en el sitio de penetración del miracidio. En los caracoles resistentes, para los que variedades susceptibles fueron incluídas entre sus padres, las reacciones se produjeron en tejidos profundos. Los resultados caracterizaron la respuesta inmune de los caracoles B. alexandrina contra la infección por Schistosoma, que ocurre por dos mecanismos diferentes. El primer tipo de defensa la cual se produce en los caracoles con alta resistencia, utiliza la destrucción directa del miracidio poco después de la penetración de los parásitos. El segundo tipo se produce en los caracoles menos resistentes, en el cual se después de la difusión de los esporocistos en los tejidos del caracol. Parece que los caracoles B. alexandrina responden de una manera más o menos similar a B. glabrata. Los resultados también demostraron que la respuesta inmune del sistema de defensa interna aumentó cuando en el número de genes de resistencia heredados es mayor.

Hemocyte types and total and differential counts in unparasitized and parasitized Anastrepha obliqua (Diptera, Tephritidae) larvae

The hemocyte types, in addition to total and differential hemocyte counts were studied in parasitized and unparasitized Anastrepha obliqua larvae at the beginning and at the end of the third instar. In both developmental phases, in parasitized and unparasitized larvae, prohemocytes, plasmatocytes, granulocytes, adipohemocytes, spherulocytes and oenocytoids cells were observed. Mitotic figures indicate prohemocytes as stem cells. Prohemocytes, plasmatocytes and granulocytes are the most numerous cells in the hemolymph of A. obliqua. Difference in the total number of hemocytes was observed between unparasitized and parasitized larvae at the end of the third instar, but not at the beginning.

Os tipos de hemócitos e as contagens total e diferencial foram estudados em larvas parasitadas e não parasitadas de Anastrepha obliqua pertencentes ao início e ao final da terceira fase. Em ambas as fases do desenvolvimento, tanto em larvas parasitadas quanto nas não parasitadas, foram observados pró-hemócitos, plasmatócitos, granulócitos, adipo-hemócitos, esferulócitos e oenocitóides. A presença de divisões mitóticas indica os pró-hemócitos como células-tronco. Pró-hemócitos, plasmatócitos e granulócitos são as células mais numerosas na hemolinfa de A. obliqua. Foi observada diferença no número total de hemócitos entre larvas parasitadas e não parasitadas apenas no final da terceira fase.