High-temperature responses of Myzus persicae and its parasitoid Aphidius gifuensis in relation to heat level, duration and developmental stage.

BACKGROUND: Understanding how parasitoids respond to temperature is crucial for improving biological control strategies under the context of global warming. This study examined the suitability of Myzus persicae and its parasitoid Aphidius gifuensis to varying temperature conditions, as well as the stage-specific response of A. gifuensis to high temperatures. RESULTS: High temperatures had a significant impact on the both M. persicae and A. gifuensis. When exposed to 36°C, M. persicae developed more slowly and produced smaller adults compared to control, regardless of the duration of exposure (2, 4 or 6 h); additionally, the survival rate of M. persicae nymphs sharply decreased under these conditions. Exposure to 36°C for 4 h negatively impacted the development of A. gifuensis. Female parasitoids exposed to 32°C developed into smaller adults, whereas males exposed to all three temperature levels were smaller compared to control group. Female parasitoids exposed to high temperatures, regardless of the specific heat level and duration, exhibited reduced longevity and decreased fecundity. None of the parasitoids exposed to 36°C for 6 h daily developed into adults. Heat treated during early developmental stages (2 and 4 days old) had a greater influence on parasitoid development, whereas heat treatment at 4 and 6 days old had a more significant impact on its fecundity. CONCLUSION: High temperatures not only directly affected the performance of A. gifuensis, but also exerted indirect effects by influencing the quality of the host aphids M. persicae. The deleterious effects of high temperature on larvae can persist into the adult stage, affecting the longevity and reproduction of adults. These findings are important for the utilization of A. gifuensis in the control of M. persicae in warming environments. © 2024 Society of Chemical Industry.

Discovery of Colpodella spp. in ticks (Hyalomma dromedarii) infesting camels in southern Egypt.

In Egypt, tick-borne diseases pose a significant threat to human and animal health, and the threat to dromedaries (Camelus dromedarius), the country's dominant camelid species, is of particular concern. These animals are frequently infested with ticks, and may thus develop tick-borne diseases or become reservoirs of tick-borne pathogens. However, there is a paucity of data on tick infestation in Egyptian camels, especially in the south of the country. Accordingly, we aimed to determine the prevalence of tick infestation in southern Egyptian camel populations (in Luxor and Aswan governorates), and identify the hemoprotozoan parasites carried by camel-infesting ticks. Camels were checked for ticks during veterinary examination at quarantine and household checks, and ticks were collected from infested camels for species identification using morphological examination and PCR analyses. Tick and hemoprotozoan species were identified using Basic Local Alignment Search Tool analysis with subsequent confirmation in phylogenetic analyses. All camel-infesting ticks belonged to the species Hyalomma dromedarii, and were clustered with ticks of this species previously found in Egypt in a phylogenetic tree based on the 16S rRNA gene. Molecular analysis targeting the 18S rRNA gene revealed the presence of hitherto undetected hemoprotozoan parasites, Colpodella spp., in 30/297 (10.1 %) camel-infesting ticks. In phylogenetic analysis, these Colpodella spp. were highly homologous (94-98.6 %) with Colpodella spp. previously deposited in GenBank with accession numbers OQ540590Q, MH208621, and GQ411073, which relate to Colpodella spp. previously detected from Haemaphysalis longicornis, Rhipicephalus haemaphysaloides, and humans in China. PCR analyses with spherical body protein-4 (SBP-4) gene-specific primers revealed Babesia bovis in 16/297 (5 %) of camel-infesting ticks, however, Babesia bigemina and Theileria annulata were not detected. Here, we report the first detection of Colpodella spp. in H. dromedarii in Egypt. Further epidemiological studies are needed to assess the risk to camels and humans, and the transmission dynamics. Based on the high tick infestation rates in Egyptian camels and the identification of previously unreported protozoan hemoparasites in ticks, we consider that the dromedary should be subject to surveillance as a sentinel species for tick-borne diseases in Egypt. Our findings underline the need for surveillance and collecting data on lesser known pathogens circulating in camel-infesting ticks, as part of a public health strategy for dealing with tick-borne diseases in Egypt.

Parasitoid-host interaction behaviors in relation to host stages in the Tamarixia triozae (Hymenoptera: Eulophidae)-Bactericera cockerelli (Hemiptera: Triozidae) system.

Females of host-feeding parasitic wasps often partition hosts of different stages for feeding and parasitization, but the underlying behavioral mechanisms are largely unknown, making it difficult to evaluate parasitoid-host interactions and their effects on biological control success. Tamarixia triozae (Burks) is an ectoparasitoid of tomato-potato psyllid Bactericera cockerelli (Sulc), which utilizes nymphs and kills them both by parasitization and host feeding. In this study, we exposed female wasps to 1st- to 5th-instar psyllid nymphs simultaneously and made 13-h continuous video recording of parasitoid-host interactions. We then quantified host stage-dependent handling time for feeding and oviposition and behaviors of parasitoid attacks and host defenses from encountering to successful feeding and oviposition. Female wasps were more likely to encounter and evaluate older hosts. However, the encounter and evaluation did not necessarily result in the success of feeding and oviposition. Our findings suggest that (i) T. triozae continues to assess the host using its ovipositor after the evaluation phase, (ii) females prefer the mid-aged hosts for feeding piercing and feeding and the later instars for oviposition probing and oviposition, (iii) the combination of stage-specific host nutrition value, integument thickness and defense behavior determines the success of feeding attacks, and (iv) the optimal host resource for parasitoid offspring fitness defines host stage selection for oviposition. This study contributes to our understanding of parasitoid-host interactions and mechanisms behind host stage selections.

Effects of thiamethoxam on physiological and molecular responses to potato plant (Solanum tuberosum), green peach aphid (Myzus persicae), and parasitoid (Aphidius gifuensis).

BACKGROUND: To improve integrated pest management (IPM) performance it is essential to assess pesticide side effects on host plants, insect pests, and natural enemies. The green peach aphid (Myzus persicae Sulzer) is a major insect pest that attacks various crops. Aphidius gifuensis is an essential natural enemy of M. persicae that has been applied effectively in controlling M. persicae. Thiamethoxam is a neonicotinoid pesticide widely used against insect pests. RESULTS: The current study showed the effect of thiamethoxam against Solanum tuberosum, M. persicae, and A. gefiuensis and the physiological and molecular response of the plants, aphids, and parasitoids after thiamethoxam application. Thiamethoxam affected the physical parameters of S. tuberosum and generated a variety of sublethal effects on M. persicae and A. gefiuensis, including nymph development time, adult longevity, and fertility. Our results showed that different thiamethoxam concentrations [0.1, 0.5, and 0.9 µm active ingredient (a.i.)/L] on different time durations (2, 6, and 10 days) increased the antioxidant enzyme activities SOD, POD, and CAT of S. tuberosum, M. persicae, and A. gefiuensis significantly compared with the control. Our results also showed that different thiamethoxam concentrations (0.1, 0.5, and 0.9 µm a.i./L) on different time durations (2, 6, and 10 days) increased the expression of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), acetylcholinesterase (AChE), carboxylesterase (CarE) and glutathione-S-transferase (GST) genes of S. tuberosum, M. persicae, and A. gefiuensis compared with the control. CONCLUSION: Our findings reveal that using thiamethoxam at suitable concentrations and time durations for host plants and natural enemies may enhance natural control through the conservation of natural enemies by overcoming any fitness disadvantages. © 2024 Society of Chemical Industry.

Nematodes (Mermithidae) parasitizing grasshoppers (Orthoptera: Acrididae) in the Pampean region, Argentina / Nematóides (Mermithidae) parasitando gafanhotos (Orthoptera: Acrididae) nos Pampas região, a Argentina

Abstract This work provides the results of a survey of entomonematodes parasites of grasshoppers in grasslands of the Pampean Region, Argentina. Nymphs of Staurorhectus longicornis Giglio-Tos, Laplatacris dispar Rhen, 1939, Dichroplus elongatus Giglio-Tos, 1894 and Metaleptea brevicornis (L.) (Orthoptera: Acrididae) were collected. Mermithidae was the only family registered with seven species: Agamermis decaudata Cobb, Steiner and Christie, 1923, Amphimermis bonaerensis Miralles and Camino, 1983, Amphimermis dichroplusi Camino and Lange, 1997, Amphimermis ronderosi Camino and Lange, 1997, Hexamermis coclhearius Stock and Camino, 1992, Hexamermis ovistriata Stock and Camino, 1992, and Longimermis acridophila Camino and Stock, 1989. The values of parasitism ranged between 1-12%, and intensity not overcome the number of 5.0 nematodes per larva. The nematodes observed showed specificity, not registering the same species of parasite in more than one host species. The Pampean region constituted an area with high diversity of mermithids where new species could be consider as bioregulator agents of this troublesome insect pests in agricultural areas of Argentina.

Resumo Este trabalho apresenta os resultados de uma pesquisa entomonematode parasitando gafanhotos em pastagens da região pampeana, Argentina. Ninfas de Staurorhectus longicornis Giglio-Tos, Laplatacris dispar Rhen de 1939, Dichroplus elongatus Giglio-Tos, 1894 e Metaleptea brevicornis (L.) (Orthoptera: Acrididae) foram coletados. Mermithidae era a única família registrado com sete espécies: Agamermis decaudata Cobb, Steiner and Christie, 1923, Amphimermis bonaerensis Miralles and Camino, 1983, Amphimermis dichroplusi Camino and Lange, 1997, Amphimermis ronderosi Camino and Lange, 1997, Hexamermis coclhearius Stock and Camino, 1992, Hexamermis ovistriata Stock and Camino, 1992, e Longimermis acridophila Camino and imagem, de 1989. Os valores de parasitismo variou entre 1-12%, e intensidade não superar o número de 5,0 nematóides por larva. Os nemátodos observados demonstraram especificidade, não registar as mesmas espécies de parasita em mais do que uma espécie de hospedeiro. A região pampeana constituída uma área com alta diversidade de mermithids onde novas espécies poderiam ser consideradas como agentes bio-reguladores deste incômodos insetos pragas em áreas agrícolas da Argentina.

Prevalencia de triatominos infectados con Trypanosoma cruzi en el litoral de la ciudad de Arica / Prevalence of triatomines infected with Trypanosoma cruzi in the coast of Arica city

It has been observed throughout America that when eradicating or diminishing the population of the domestic vector of Chagas disease, the wild vectors adquires more epidemiological importance. For this reason the objective of this investigation was to determine if the wild vectors from the coast of Arica City are infected with Trypanosoma cruzi. The study was made in 52 triatomines captured from the coast of Arica city, during a period of 3 months since October until December 2004. Then, it was applied PCR method on these triatomines to find T. cruzi. The investigation showed that Mepraia gajardoi was infected with T. cruzi with a Trypano/triatomine index of 19.2 percent, similar to the infection level found for Mepraia spinolai in other investigations.

Se ha observado a lo largo de América que en la medida que se erradica o disminuye la población de los vectores domésticos de la enfermedad de Chagas, los vectores silvestres van cobrando mayor importancia epidemiológica. Por este motivo, el objetivo de esta investigación fue determinar si los vectores silvestres del litoral de la ciudad de Arica se encuentran infectados con Trypanosoma cruzi. El estudio se realizó en un total de 52 triatominos capturados en el litoral de la ciudad de Arica, entre Octubre y Diciembre del a+/-o 2004. utilizando la técnica de la Reacción en Cadena de la Polimerasa (PCR) para la búsqueda de T. cruzi. La investigación mostró que Mepraia gajardoi se encontraba infectado con T. cruzi presentando un índice Trypano/ triatomino de 19,2 por ciento, similar a lo observado en Mepraia spinolai en otras investigaciones.

Triatomíneos rupestres infectados por Trypanosomatidae, coletados em Quaraí, Rio Grande do Sul, 2003 / Rupestrian triatomines infected by Trypanosomatidae, collected in Quaraí, Rio Grande do Sul, 2003

Foram capturados triatomíneos rupestres em seis localidades do município de Quaraí-RS, com o intuito de verificar o índice de infeccão por Trypanosomatidae, bem como o animal reservatório. A captura ocorreu no ambiente silvestre, sendo coletados 453 exemplares, os quais foram identificados e separados por estádio ninfal. Coletaram-se 421 (92,9 por cento) exemplares de Triatoma rubrovaria, 26 (5,7 por cento) de Triatoma circummaculata e 6 (1,3 por cento) de Panstrongylus tupynambai. Dentre as três espécies coletadas, somente Triatoma rubrovaria mostrou-se positivo para Trypanosomatidae, num total de 13 (4,2 por cento) exemplares. Após a inoculacão em camundongos e meio de cultura LIT, isolaram-se cinco cepas de Trypanosoma cruzi. Dos triatomíneos infectados com Trypanosomatidae, 4 (30,8 por cento) tiveram a reacão de precipitina não reagente para os anti-soros testados, 4 (30,8 por cento) positivos para anti-soro de roedor, 4 (30,8 por cento) para anti-soro de cabra e 1 (7,7 por cento) para anti-soro de porco e humano.

DNA evidence of Trypanosoma cruzi in the Chilean wild vector Mepraia spinolai (Hemiptera: Reduviidae)

Molecular evidence showed 46.2 percent of Trypanosoma cruzi infection in Mepraia spinolai insects from North-Central Chile, which is significantly higher than previous reports of up to 26 percent by microscopic observation. Our results show similar infection levels among nymphal stages, ranging from 38.3 to 54.1 percent, indicating that younger nymphs could be as important as older ones in parasite transmission. A cautionary note must be stressed to indicate the potential role of M. spinolai in transmitting T. cruzi in country areas due to the high infection level detected by molecular analysis.

Estudio comparativo de la sensibilidad y mortalidad de las ninfas III y IV de triatoma infestans usadas en el xenodiagnóstico de pacientes chagásicos crónicos / Comparative study on sensivity and mortality of triatoma infestans nymphs III and IV used in the xenodiagnosis of chronic chagasic patients

Triatoma infestans nymphs have shown a good sensitivity for detecting trypanosoma cruzi in the bood stream of infected hosts when are used in the xenodiagnosis (XD). This method, with its natural limitations, using seven nymphs III of T. infestans, has been routinely utilized with a satisfactory yield. With the aim of an eventual improving of the yield of XD (with 7 nymphs), two series of 54 XD boxes each, containing a total of 378 nymphs III and 378 nymphs IV respectively, were applied one of each during three consecutive days to nine chronic chagasic patients. Each of the nymphs was weighted before an after the application of the boxes, and the intestinal content of them was examined 30, 60 and 90 days later. The main comparative results obtained with nymphs III and IV of T. infestans were: blood ingestion 40 versus 107 mg (2,7 higher), positivity of insects 35,8 percent versus 50,6 percent (15,8 percent higher), positivity of XD boxes (7 nymphs each) 46,3 percent versus 55,6 percent (9,3 percent higher), and mortality rates 28,6 percent versus 12,2 percent (16,4 percent lower). All these results demonstrate that nymphs IV of T. infestans, because their higher capacity of ingesting blood and higher tolerance to examination manipulations, are more suitable for been used in XD

Encontro de Panstrongylus megistus em ecótopo artificial: domiciliação ou mera visitação? / The finding of Panstrongylus megistus in an artificial ecotope: taking up residence or merely visiting?

No combate à doença de Chagas no Brasil, foi utilizado como primeira medida o controle químico, erradicando o Triatoma infestans, o mais importante vetor, tal combate vem favorecendo o aparecimento de vetores secundários, como Triatoma sordida and Panstrongylus megistus, espécies que podem eventualmente ser encontradas no domicílio, como os triatomíneos provenientes de Bernardino de Campos e Sete Barras por nós examinados que foram encontrados no domicílio e positivos para o T. cruzi, sugerindo que, apesar da doença de Chagas estar controlada no Estado de São Paulo, existe a necessidade de aprimorar os conhecimentos sobre o comportamento destes vetores para que mudanças nas medidas de controle sejam introduzidas.

As a first measure of Chagas' disease control in Brazil with chemical elimination of the most important vector of the disease, Triatoma infestans was removed. Attention is now being paid to Triatoma sordida and Panstrongylus megistus. That species can eventually be found inside houses, as happened with the specimens we examined from Bernardino de Campos and Sete Barras, all of them infected by Trypanosoma cruzi. These data suggest that a better knowledge about the behavior that species is needed to introduce changes in the control measures.

Metaciclogênese do Trypanosoma cruzi como parâmetro de interação do parasita com o triatomíneo vetor / The metacyclogenesis of Trypanosoma cruzi as a parameter of parasite interaction with the triatomid vector

Triatoma infestans infectados por três amostras do Trypanosoma cruzi permitiram observar: 1) variabilidade numérica de metacíclicos obtidos de cada amostra após diferentes períodos de infecção; 2) diferenças na perda da infecção de acordo com a amostra infectante e 3) a relação entre o número de parasitas ingeridos e metacíclicos obtidos posteriormente.

Infection of Triatoma infestans with three different strains of Trypanosoma cruzi permited to observe: 1) numerical variability of metacyclics obtained after different times; 2) the differences of loss of infection according to each strain; 3) the relationship between ingested parasites and later obtained metacyclics.

Xenodiagnóstico na doença de Chagas crônica: I - Sensibilidade de Panstrongylus megistus e Triatoma infestans / Xenodiagnosis in chronic Chagas' disease: I - Sensibility of Panstrongylus megistus and Triatoma infestans

From January 1986 to February 1994, 563 xenodiagnosis (XD) were applied in 563 chronic chagasic patients from different areas of Brazil; 292 were women and 271 were men between 6 and 89 years (average: 41.4 +/- 14.7 years). To each XD 40 nymphs on the 4th stage were used: 20 from Panstrongylus megistus (Pm) and 20 from Triatoma infestans (Ti) in fast, during at least 14 days. The exam in each nymph was made 45 days after being applied on the patient, by observation in optical microscopy of the drugs and/or the grinded from the digestive tube. The results are: a) 205 (36.4 per cent) positive XD, including 85 (15.1 per cent) due only nymphs of Pm, 44 (7.8 per cent) Ti and 76 (13.5 per cent) Pm and Ti; b) positively in 4.9 per cent of the nymphs from Pm and in 3.0 per cent of the Ti nymphs examined. These results' analysis showed that the Pm nymphs were more sensitive that Ti's ones to the infection by Trypanosoma cruzi, increasing considerably the xenopositivity, independently from birthplace, sex or age of the patients. These results point out that to increase the efficacy of XD in chronic Chagas' disease, the exam must have more than a species of triatomine with different sensibilities to the T. cruzi infection, and in case of using one species on XD, Pm must substitute Ti.

Parâmetros biológicos do estágio ninfal de Amblyomma cajennense (Fabricius, 1787) (Acari: lxodidae) em coelhos / Biological parameters of the nymphal stage of Amblyomma cajennense (Fabricius, 1787) (Acari: lxodidae) in rabbits

Com o objetivo de se obterem maiores informações sobre parâmetros relativos à fase ninfal do Amblyomma cajennense, foram realizadas 28 infestações com ninfas de 1 a 12 dias de idade em 20 coelhos de ambos os sexos e com pelagem uniforme nas cores branca ou preta. A fase não parasitária foi acompanhada sob condições controladas de laboratório (temperatura de 27°, umidade relativa do ar superior a 70% e 12 h de fotofase). Foram utilizadas 21.182 neoninfas, recolhendo-se 11.319 metaninfas, resultando em uma eficiência de infestação de 53,44%. O período de ingurgitamento ninfal oscilou entre 3 e 5 dias com uma maior quantidade de ninfas levando 5 dias para completar o ingurgitamento. O tempo transcorrido entre o desprendimento da metaninfa e o término da ecdise ninfa/adulto oscilou entre 13 e 14 dias, com média de 13,43 ± 0,50 dias. Esse período não sofreu influência do sexo nem da cor da pelagem do coelho utilizado para ingurgitamento ninfal. Do total de metaninfas recolhidas, 95% realizaram ecdise completa, obtendo-se cerca de 10.700 adultos jovens, machos e fêmeas na proporção de 1:1.

In an attempt to obtain more information on the parameters of the nymphal phase of Amblyomma cajennense, 28 infestations were conducted with 1 to 12 day nymphs in 20 rabbits of both sexes and uniform white or black calor. Non-parasitic phase was followed under controlled laboratory conditions (27°C temperatura, 70% relative air humidity, and 12 hr photophase exposition). 21,182 neonymphs were used, out of which 11,319 metanymphs were collected, which accounted for and infestation efficiency of 53.44%. The period of nymphal ingurgitation ranged from 3 to 5 days, with a higher number of nymphs taking 5 days to complete ingurgitation. The time lapsed between metanymph loosening and completion of the ecdisis nymph/adult ranged from 13 to 14 days, with an average of 13.43 ± 0.50 days. This period was not influenced neither by sex nor by hair colar of rabbit used for nymphal ingurgitation. Out of the total of collected metanymphs, 95% had complete ecdisis, being obtained approximately 10,700 young adults, male and female, on a 1:1 rate.

Positividad del xenodiagnóstico según edad en personas con serología positiva para enfermedad de Chagas / Positive xenodiagnosis according to age in people with seropositive Chagas's disease

An analytical study of positive xerodiagnosis (XD), according age distribution, in people with a positive indirect hemagglutination test (IHAT) for Chagas's disease has been carried out. A total of 1,137 IHAT for Chagas's disease positive persons were submitted to two wooden XD boxes containing 7 triatoma infestans nymphs III each. The positivity in percentage of XD in the different age groups was: 0-9 year old (60,8), 10-19 (35,8), 20-29 (31,5), 30-39 (28,7), 40-49 (30,0), 50-59 (34,3) and ò 60 (43,3). The 60,8 positivy of XD in children under 10 years of age is possibly due to the rather recent trypanosoma cruzi infection in this age group and to diverse inmunological mechanisms, which decrease with the age increasing

Prevalência, índices de infecçäo e hábitos alimentares de triatomíneos capturados em uma área de vigilância epidemiológica / The prevalence, infection indices and feeding habits of the Triatominas captured in an area epidemiological surveillance

Em continuaçäo a estudo anterior, relativo à prevalência por Trypanosoma cruzi dos triatomíneos capturados na regiäo administrativa de Campinas, SP, os autores apresentam dados do período de 1982-1986, acrescentando informaçöes sobre respastos sangüíneos realizados por 7.785 exemplares. Para tanto, foram utilizados os anti-soros: ave, marsupial, roedor e humano, através dos quais constataram o ecletismo alimentar de Panstrongylus megistus, espécie predominante na regiäo, cujas formas aladas säo encontradas com freqüência, infectadas por T. cruzi, nas casas habitadas. Desses, 14,78 por cento reagiram frente ao anti-soro humano. Com Rhodnius neglectus foi observada situaçäo assemelhada, mas com números menos expressivos. Em relaçäo ao Triatoma sordida, näo foi constatada infecçäo natural e tampouco sinais de ingestäo de sangue humano. Foi constatado acentuado aumento de T. arthurneivai nas casas, fruto da provável modificaçäo ocorrida no ambiente natural. No de t. arthuneivai nas casas, frutos da provável modificaçäo ocorrida no ambiente natural. No período, foi encontrado Microtiatoma borbai, detectado pela primeira vez no Estado de Säo Paulo. Ressaltam também a importância da "investigaçäo de foco" nas áreas em fase de vigilância

Tentativas de criacao de triatomineos em laboratorio por meio de alimentacao "in vitro" / Attempts for cultivation of triatominae in laboratory through \"in vitro\" feeding

Para simplificar a criacao de triatomineos em laboratorio, necessaria, por exemplo, a execucao do xenodiagnostico e em estudos de carater biologico, foi tentada alimentacao "in vitro", mediante emprego de sangue, citratado ou desfibrinado, de galinhas abatidas em matadouro avicola. Para avaliacao da eficacia desse proposito, observacoes de duas naturezas, com Triatoma infestans, tiveram lugar, atraves das seguintes medidas; a) analise do encadeamento de estadios nifais sucessivos e da exequibilidade de satisfatorios acasalamentos, oviposicao fertil e adequada reproducao; b) apreciacao da infectividade e da viabilidade do Trypanosoma cruzi nos insetos. Como conclusao, ficou evidente que, a despeito da facilitacao operacional, o intuito nao conduziu ao exito desejado, ja que o procedimento classico, usado como controle, mostrou-se sempre superior.