New records of calyptrate dipterans (Fanniidae, Muscidae and Sarcophagidae) associated with the decomposition of domestic pigs in Brazil.

The calyptrate dipterans are the most important decomposers of human cadavers. Knowledge of their species and distribution are of great importance to forensic entomology, especially because of the enormous diversity in Brazil. Carcasses of domestic pigs (Sus scrofa, L) were the experimental models used to attract calyptrates of forensic interest during the winters of 2006 and 2007 and the summers of 2006 and 2008. A total of 24,423 specimens from 44 species were collected (19 Muscidae, 2 Fanniidae and 23 Sarcophagidae), three of which were new records of occurrence and 20 of which were new forensic records for the state of Rio de Janeiro. Fourteen of these species were newly identified as forensically important in Brazil.

New records of calyptrate dipterans (Fanniidae, Muscidae and Sarcophagidae) associated with the decomposition of domestic pigs in Brazil

The calyptrate dipterans are the most important decomposers of human cadavers. Knowledge of their species and distribution are of great importance to forensic entomology, especially because of the enormous diversity in Brazil. Carcasses of domestic pigs (Sus scrofa, L) were the experimental models used to attract calyptrates of forensic interest during the winters of 2006 and 2007 and the summers of 2006 and 2008. A total of 24,423 specimens from 44 species were collected (19 Muscidae, 2 Fanniidae and 23 Sarcophagidae), three of which were new records of occurrence and 20 of which were new forensic records for the state of Rio de Janeiro. Fourteen of these species were newly identified as forensically important in Brazil.

Morfologia e duração dos ínstares larvais de Chrysomya putoria (Wiedemann) (Diptera, Calliphoridae), em laboratório / Morphology and duration of larval instars of Chrysomya putoria (Wiedemann) (Diptera, Calliphoridae), in laboratory

Este trabalho visou descrever a morfologia e o tempo de desenvolvimento das larvas de Chrysomya putoria, um importante díptero para saúde pública e medicina legal. As amostras foram coletadas a cada duas horas e, a partir da 56ª hora, as coletas foram realizadas com intervalos de 12 horas até o abandono das larvas maduras do meio de criação. As larvas de C. putoria apresentaram um tempo total de desenvolvimento de 92 horas quando mantidas a 27 °C com comprimento médio de 13,42 mm e características morfológicas peculiares que as diferenciam das outras espécies exóticas e autóctones do Brasil. O esqueleto cefalofaringeano das larvas de terceiro ínstar é robusto e esclerotizado; o gancho labial é completamente pigmentado e curvo, a parte posterior é mais larga que a anterior, mostrando-se levemente pontiagudo. Estas larvas não possuem esclerito oral acessório e o corno dorsal e o ventral apresentam áreas menos pigmentadas. Nota-se uma região não pigmentada em continuação aos cornos, destacando-se no tamanho na região do corno ventral com uma incisão média bem demarcada. Apresentam de 10 a 11 ramificações no espiráculo anterior, peritrema incompleto e presença do botão espiracular, a partir do segundo ínstar.

The objective of this work was to describe the morphology and the developmental time of Chrysomya putoria larvae, a fly of public health and forensic importance. The samples were collected at 2 hr intervals, during the first 56 hr and at 12 hr intervals thereafter, until all mature larvae had abandoned the diet. The total developmental time for Chrysomya putoria larvae at 27 °C was 92 hr, with a mean length of 13.42 mm. The larvae presented unique morphological characteristics which differentiated them from other exotic and autochthonous species found in Brazil. The cephalopharyngeal skeleton of the third instar larvae is robust and sclerotized; the mouth hook is completely pigmented and curved; the posterior end is wider than the anterior, being slightly pointed. The accessory oral sclerit is absent and the dorsal and ventral horns have areas with less pigmentation. It is possible to visualize an area with no pigmentation adjacent to the horns, outstanding in size near the ventral corn with a well delimited medial incision. The anterior spiracles presented 10 to 11 ramifications, open peritrema and the presence of a spiracular bud from the second instar on.

Dinâmica populacional e parasitismo de Himenópteros parasitóides de Chrysomya megacephala (Fabricius) (Diptera, Calliphoridae), no Rio de Janeiro, RJ / Population dynamics and parasitism of hymenopterans parasitoids of Chrysomya megacephala (Fabricius) (Diptera, Calliphoridae), in Rio de Janeiro city, Brazil

Este estudo foi realizado no período de agosto de 1999 a julho de 2000 com o objetivo de conhecer os parasitóides de Chrysomya megacephala (Fabricius, 1794) (Diptera, Calliphoridae) e avaliar sua dinâmica populacional no Instituto Oswaldo Cruz (IOC/ FIOCRUZ) e Jardim Zoológico, na cidade do Rio de Janeiro, RJ. As coletas foram realizadas semanalmente através da exposição de larvas de terceiro instar da mosca e seu substrato de criação, carne bovina moída em putrefação. Foram identificadas três espécies de himenópteros parasitóides: Tachinaephagus zealandicus Ashmead, 1904 (Encyrtidae), Pachycrepoideus vindemiae (Rondani, 1875) (Pteromalidae) and Nasonia vitripennis (Walker, 1836) (Pteromalidae). Nos dois locais, T. zealandicus foi a espécie com maior taxa de parasitismo de C. megacephala, seguida por P. vindemiae e N. vitripennis. A população de parasitóides diminuiu drasticamente no verão (temperatura média = 28ºC; precipitação = 6,5 mm).O pico populacional desses insetos foi verificado no final do outono e durante todo o inverno. No Jardim Zoológico, o lixo acumulado no local de coleta exerceu forte influência na dinâmica populacional dos himenópteros parasitóides identificados nesse estudo e o pico populacional de parasitismo foi verificado em junho e julho de 2000.

Ocorrência de multiparasitismo em larvas de terceiro ínstar e pupas de Chrysomya megacephala (Fabricius) em condições de campo / Occurrence of multiparasitism in third instar larvae and pupae of Chrysomya megacephala (Fabricius) in field conditions

Durante experimento de pesquisa envolvendo o parasitismo de larvas de terceiro ínstar e pupas de Chrysomya megacephala (Fabricius, 1794) em dois locais da cidade do Rio de Janeiro, RJ, observou-se a ocorrência de multiparasitismo em 1,83 por cento das pupas expostas no Instituto Oswaldo Cruz (IOC) e em 2,16 por cento expostas no Jardim Zoológico (ZOO). O experimento foi conduzido semanalmente de agosto de 1999 a julho de 2000. Em ambos os locais, houve a co-ocorrência de duas espécies por pupa e os parasitóides encontrados foram os himenópteros Tachinaephagus zealandicus Ashmead, 1904, Pachycrepoideus vindemiae (Rondani, 1875) e Nasonia vitripennis (Walker, 1836). 72,73 por cento do multiparasitismo ocorreu no ZOO em julho de 2000. Em condições de multiparasitismo, T. zealandicus e P. vindemiae mantiveram seu hábito gregário e solitário, respectivamente, mas N. vitripennis foi encontrado solitário em algumas pupas.

Ecology of Anopheline (Diptera, Culicidae), malaria vectors around the Serra da Mesa Reservoir, State of Goiás, Brazil: 1 - Frequency and climatic factors

Foram estudados aspectos da ecologia de anofelinos (Diptera, Culicidae) em áreas da Usina Hidrelétrica de Serra da Mesa, Estado de Goiás, Brasil. Foram analisados a incidência das populações de anofelinos e os fatores climáticos. Foram realizadas capturas bimestrais, em isca humana e armadilha Shannon, ao longo de 36 meses consecutivos (janeiro de 1997 a dezembro de 1999). Capturamos um total de 5.205 anofelinos adultos, pertencentes a cinco espécies. Anopheles darlingi foi o anofelino mais freqüente (61,4 por cento), seguido de An. albitarsis s.l. (35,4 por cento), An. triannulatus (2,5 por cento), An. oswaldoi (0,4 por cento) e An. evansae (0,2 por cento). O nível da água e a vegetação às margens do reservatório foram determinantes para a freqüência das espécies de anofelinos. Os fatores climáticos tiveram influência secundária. A estabilidade do reservatório, o aumento na freqüência do An. darlingi e a chegada de garimpeiros foram responsáveis pelos casos de malária diagnosticados.

Microhimenópteros parasitóides de Chrysomya megacephala / Microhimenopteran parasitoids of Chrysomya megacephala found in Brazil

O objetivo do estudo foi levantar os principais parasitóides de Chrysomya megacephala, na cidade do Rio de Janeiro, RJ, devido a importância dessa mosca como vetor de patógenos para o ambiente urbano. As coletas foram realizadas semanalmente, no período de agosto de 1999 a julho de 2000, por meio da exposiçäo de larvas e pupas da mosca em carne putrefata. Foram identificadas três espécies de microhimenópteros no local: Tachinaephagus zealandicus (Encyrtidae), Pachycrepoideus vindemiae (Pteromalidae) e Nasonia vitripennis (Pteromalidae), cujos testes posteriores poderäo mostrar seu potencial para utilizaçäo em futuros programas de controle.

Ecologia de mosquitos (Diptera, Culicidae) em áreas do Parque Nacional do Iguaçu, Brasil: 1 ­ Distribuição por hábitat / Mosquito (Diptera, Culicidae) ecology in the Iguaçu National Park, Brazil: 1 ­ Habitat distribution

Estabelecemos a influência exercida pela cobertura vegetal de quatro diferentes biótopos em áreas do Parque Nacional do Iguaçu (PNI) sobre a fauna local de mosquitos. Realizaram-se capturas bimestrais, em isca humana e armadilha Shannon, em três diferentes períodos do dia, em ambiente silvestre e domiciliar, durante 24 meses consecutivos. Dentre os 20.273 espécimes de fêmeas adultas capturadas, pertencentes a 44 espécies, Ochlerotatus serratus (10,3 por cento), Haemagogus leucocelaenus (9,7 por cento), Mansonia titillans (9,6 por cento) e Chagasia fajardoi (8,8 por cento) foram predominantes. Anopheles cruzii, Runchomyia theobaldi, Wyeomyia aporonoma e Wy. confusa ocorreram exclusivamente em áreas com vegetação bem preservada e densa configuraçäo. Culex nigripalpus, Oc. pennai, Oc. serratus, Sabethes purpureus e Sa. albiprivus foram capturados nos três biótopos essencialmente silvestres. Na mata no entorno da represa foram capturadas principalmente An. albitarsis s.l., An. galvaoi, An. evansae, An. fluminensis, Coquillettidia venezuelensis, Cq. juxtamansonia, Wy. quasilongirostris e Onirion personatum. As espécies que apresentaram maiores incidências na área sob açäo antrópica foram Ch. fajardoi, Cq. fasciolata, Cq. nitens e Ma. titillans

Evaluation of the impact of Bacillus thuringiensis serovar israelensis and Temephos, used for the control of Simulium (Chirostilbia) pertinax Kollar, 1832 (Diptera, Simuliidae) on the associated entomofauna, Paraty, state of Rio de Janeiro, Brazil

The study was set up to evaluate the impact of two commercial larvicide formulations, Bacillus thuringiensis serovar israelensis base (Bti) at 15 ppm/1 min and temephos at 0.03 ppm of active ingredient, used to control Simulium pertinax populations, on associated non-target entomofauna occupying the same breeding sites. The experiments were carried out on the Pedra Branca and Muricana rivers, on the slopes of Serra do Mar massif, municipality of Paraty, state of Rio de Janeiro, Brazil. Bti was applied to the river Pedra Branca and temephosto theriver Muricana. On both rivers, treatment and control sections were labeled as such, each one with two observation posts: slow moving water and fast water regions respectively. Artificial substrata was used to evaluate the abundance of associated entomofauna. Attached immature stages of arthropods were removed from both of its surfaces fortnightly. Were collected, from the two rivers, 28 477 specimens of the entomofauna associated with S. pertinax. The families Hydropsychidae, Chironomidae, Bactidae, Simuliidae, Blephariceridae and Megapodagrionidae were represented. These was an impact of temephos on the entomofauna associated with S. pertinax only in Simuliidae and Chironomidae, and to Bti only in Simuliidae. However, the reduction in their numbers was not statistically significant

Dípteros muscóides como vetores mecânicos de ovos de helmintos em jardim zoológico, Brasil / Muscoid dipterans as helminth eggs mechanical vectors at the zoological garden, Brazil

OBJETIVO: Verificar as espécies de dípteros muscóides capazes de veicular ovos e larvas de helmintos e avaliar o potencial de contaminaçäo dos dípteros capturados. MÉTODOS: A pesquisa foi realizada em dois pontos distintos do Jardim Zoológico da cidade do Rio de Janeiro, RJ, no período de maio de 1996 a abril de 1998. As capturas dos dípteros foram realizadas semanalmente com armadilhas contendo peixe em putrefaçäo, que permaneceram expostas durante uma hora nos dois pontos: local 1- próximo à lixeira do zoológico e o local 2- perto do recinto do hipopótamo e das aves de rapina. Foram capturadas 41.080 moscas, sendo a espécie Chrysomya megacephala mais representativa com 69,34 por cento, seguida de Chrysomya albiceps 11,22 por cento, Musca domestica 7,15 por cento, Chrysomya putoria 4,52 por cento, Fannia sp. 3,12 por cento, Ophyra sp. 2,53 por cento e Atherigona orientalis 2,08 por cento. As moscas capturadas tiveram a superfície dos corpos lavadas com água destilada e os tubos digestivos dissecados. RESULTADOS: Das espécies estudadas, C. megacephala e M. domestica apresentaram maior quantidade de ovos de helmintos na superfície do corpo e no conteúdo intestinal. Ovos de Ascaridoidea e Trichinelloidea prevaleceram no conteúdo intestinal de C. megacephala. Dos ovos de helmintos encontrados na superfície do corpo e no conteúdo intestinal foram identificados: Ascaris sp., Toxascaris sp., Toxocara sp., Trichuris sp., Capillaria sp., Oxiurídeos, Triconstrogilídeos e Acantocephala. Também foram encontradas larvas de helmintos na superfície do corpo dos dípteros. Houve diferenças significativas (nível de 5 por cento, pelo teste F) entre os diferentes pontos de capturas em relaçäo ao número de ovos de helmintos encontrados nos dípteros. CONCLUSOES: As fezes dos animais do jardim zoológico, encontradas freqüentemente nos abrigos e lixeiras, contribuíram para a proliferaçäo dos dípteros muscóides, que assumem importante papel na veiculaçäo de ovos de helmintos, principalmente pelo contato direto do corpo do díptero com o alimento dos animais

Ecology of mosquitoes (Diptera: Culicidae) in areas of Serra do Mar State Park, State of Säo Paulo, Brazil. III - Daily biting rhythms and lunar cycle influence

The ecology of mosquito species (Diptera: Culicidae) was studied in areas of the Serra do Mar State Park, State of Sao Paulo, Brazil. The influence of the lunar cycle and the daily biting rhythms of mosquito populations were analyzed. Systematized biweekly human bait collections were made in a silvatic environment for 24 consecutive months (January 1991 to December 1992). A total of 20,591 specimens of adult mosquitoes belonging to 55 species were collected from 545 catches. Sabethini species were captured exclusively during daylight periods, with the exception of Trichoprosopon digitatum, while members of Anophelinae predominated during nocturnal hours. Members of the subfamily Culicinae that were collected primary during nocturnal periods included Culex nigripalpus, Coquillettidia chrysonotum and Cq. venezuelensis while daytime catches included Psorophora ferox and Ps. albipes. Others members of culicines mosquitoes that were collected during both day and night included: Aedes serratus, Ae. scapularis and Ae. fulvus. Lunar cycles did not appear to influence the daily biting rhythms of most mosquito species in the area, but larger numbers of mosquitoes were collected during the new moon. Ae. scapularis were captured mainly during the full moon

Ecology of mosquitoes (Diptera: Culicidae) in areas of Serra do Mar State Park, State of São Paulo, Brazil. I - Monthly frequency and climatic factors

The ecology of mosquitoes were studied (Diptera: Culicidae) in areas of Serra do Mar State Park, State of São Paulo, Brazil. Systematized monthly human bait collections were made three times a day, for periods of 2 or 3 h each, in sylvatic and rural areas for 24 consecutive months (January 1991 to December 1992). A total of 24,943 specimens of adult mosquitoes belonging to 57 species were collected during 622 collective periods. Coquillettidia chrysonotum was the most frequent collected mosquito (45.8 per cent) followed by Aedes serratus (6.8 per cent), Cq. venezuelensis (6.5 per cent), Psorophora ferox (5.2) and Ps. albipes (3.1 per cent). The monthly averages of temperature and relative humidity were inserted in the ten-year average limits of maximum and minimum of the previous ten-years. Rainfall accompanied the curve of the ten-year averages. Those climatic factors were influential in the incidence of some species; temperature: Anopheles cruzii, An. mediopunctatus, Ae. scapularis, Ae. fulvus, Cq. chrysonotum, Cq. venezuelensis, Runchomyia reversa, Wyeomyia dyari, Wy. confusa, Wy. shannoni, Wy. theobaldi and Limatus flavisetosus; relative humidity: Ae. serratus, Ae. scapularis, Cq. venezuelensis and Ru. reversa; rainfall: An. cruzii, Ae. scapularis, Ae. fulvus, Cq. venezuelensis Ru. reversa, Wy. theobaldi and Li. flavisetosus.

Ecology of mosquitoes (Diptera: Culicidae) in areas of Serra do Mar State Park, State of São Paulo, Brazil. II - Habitat distribution

The mosquito (Diptera: Culicidae) ecology was studied in areas of Serra do Mar State Park, State of São Paulo, Brazil. Systematized biweekly human bait collections were made three times a day, for periods of 2 or 3 h each, in sylvatic and rural areas for 24 consecutive months (January 1991 to December 1992). A total of 24,943 adult mosquitoes belonging to 57 species were collected during 622 collective periods. Aedes scapularis, Coquillettidia chrysonotum, Cq. venezuelensis, Wyeomyia dyari, Wy. longirostris, Wy. theobaldi and Wy. palmata were more frequently collected at swampy and at flooded areas. Anopheles mediopunctatus, Culex nigripalpus, Ae. serratus, Ae. fulvus, Psorophora ferox, Ps. albipes and the Sabethini in general, were captured almost exclusively in forested areas. An. cruzii, An. oswaldoi and An. fluminensis were captured more frequently in a residence area. However, Cx. quinquefasciatus was the only one truly eusynanthropic. An. cruzii and Ae. scapularis were captured feeding on blood inside and around the residence, indicating that both species, malaria and arbovirus vectors respectively, may be involved in the transmission of these such diseases in rural areas.

Prevalencia de anofelinos (Diptera: Culicidae) no crepusculo vespertino em areas da usina hidreletrica de Itaipu, no municipio de Guaira, Estado do Parana, Brasil / Prevalence of anophelines (Diptera: Culicidae) during sunset in areas of the Itaipu hydroelectric usine in Guaira county, State of Parana, Brazil

Systematic collections of anophelines were conducted from November 1994 to August 1995 from 18:00 to 20:00 hr using Shannon traps and human-bait along the lake margin which forms the Itaipu hydroelectric reservoir, State of Parana, Brazil. Species prevalence was studied at 15 min intervals. Anopheles albitarsis sensu latu and An. galvaoi, were the most frequently collected mosquitoes. All Anopheles species populations peaked between 18:45 and 19:30 hr. The observations illustrate the existence of a haematophagic activity cycle during the early evening hours: exogenous stimulus (the beginning of sunset) - Shannon trap (light attraction) - human bait (haematophagy) - rest and digestion - exogenous stimulus - Shanon trap or surrounding vegetation. The grater abundance of An. albitarsis collected in human-bait and Shannon trap suggests it may be a potencial malaria vector in the region.

Morphological aspects of the larval instars of Chrysomya albiceps (Diptera, Calliphoridae) reared in the laboratory

In order to study the morphology of young Chrysomya albiceps forms, newly hatched larvae were collected at 2 hr intervals, during the first 56 hr; after this time the collection was made at 12 hr intervals. For identification and drawing, larvae were placed between a slide and a coverslip. The cephalopharyngeal skeletons along with the first and last segments were cut off for observation of their structures and spiracles. The larvae present microspines, which are distributed randomly throughout the 12 segments of the body surface; the cenphalopharyngeal skeleton varies in shape and extent of sclerotization according to larval instar; the second and third instars have relatively long processes (tubercles) on the dorsal, lateral and ventral surfaces, with microspine circles on the terminal portion.

The effect of different proportions of males and females over the Chrysomya albiceps (Wiedemann 1819) (Diptera, Calliphoridae) boitic potential and longevity under laboratory conditions

Chrysomya albiceps specimens were derived from colonies kept under laboratory conditions. The oviposition period, total number of eggs-mass and the weight of the eggs-mass (average/female) presented significant differences between colonies regarding the sexual ratio of 1 male/1 female (situation I), when compared to the other ratios (1 male/3 female, situation II), (1 male/5 female, situation III), (3 male/1 female, situation IV) and (5 male/1 female, situation V). It was ascertained that the increase in the proportion of females, resulted in higher weight and greater number of ovipositions and lenghtening of the period of oviposition, leads to a decrease in their lifespan.

Aspectos bionômicos de Squamatoides trivittatus (Diptera, Sarcophagidae) sob condiçöes de laboratório / Bionomical aspects of the Squamatoides trivittatus (Diptera, Sarcophagidae) under laboratory conditions

Experiments with Squamatoides trivittatus were carried out in two different controlled temperatures (16ñ1§C/50-60 per cent RH and 27ñ1§C/70-80 per cent RH). The viability of larvae and pupae at 27§C was 89.82 per cent and 92.75 per cent respectively. Larvae did not develop at 16§C. Larval development lasted for 20ñ4hr, 16ñ8 hr and 60ñ7 hr for the first, second and third instars, respectively, completing a total of 96ñ6 hr. The mean pupal period lasted for 15.7ñ1.6 days. In longevity tables for the adults, life-expectancy for 50 per cent of the colony submitted to 16§C was of 1.78 weeks for males and 2,42 for females. At 27§C a life-expectancy of 1.15 weeks for males and 0.78 week for females was recorded. The average life-spans for males and females at 16§C were 3.5ñ2.0 and 3.8ñ2.6 weeks, respectively, and 1.9ñ1.2 weeks for both sexes. At 27ñC, the longevity recorded was of 2.1ñ1.3 weeks for males and 1.7ñ1.1 week for females.

Comportamento de dípteros muscóides frente a substratos de oviposiçäo, em laboratório, no Rio de Janeiro, RJ, Brasil

How adult females of calyptrate Diptera recognize the appopriate breeding substrate is a matter of controversy. Among holometabolic insects, the feeding opportunities of immature stages are generally determined by the adult female choice of an oviposition site. The ovipositional and larvipositional substrate preference for the synanthropic flies (Chrysomya megacephala, C. putoria, Phaenicia cuprina: Calliphoridae; Atherigona orientalis, Synthesiomyia nudiseta: Muscidae; Ravina belforti, Parasarcophaga ruficornis, Peckia chrysostoma: Sarcophagidae) is presented in this work. The substrate used for testing were the following: bovine minced meat, fish (sardine), bovine liver, shrimp, squid, human faeces and banana. Bovine minced meat was the ovipositional and larvipositional substrate preferred by seven species. Human faeces were preferred by R. belforti.

Biologia do Triatoma nitida Usinger, 1939 em laboratório (Hemiptera: Reduviidae)

Biology of Triatoma nitida Usinger, 1939 under Laboratory Conditions - Triatoma nitida is a wild species occurring in Mexico and Central America. In order to establish the length of its life cycle and transmission potential, the following parameters were observed: the incubation period, the interval between hatching, or moulting, and the first feeding; the number of blood meals and the time of development. The time-lapse before the bite, the length of feeding and the interval between the end of the blood meal and defecation, as well as the site of defecation were also analyzed. Average length of the egg incubation period was 18.2 days. Time interval between the food source offering and the bite was less than 4 min in 60//of the analyzed cases, except in the fifth instar, where only 38//of the insects began feeding in less than 5 min. The blood-sucking period was long and rising until the fifth instar, decreasing in adults, and ranging from 1 min to 2 and a half hours. Only 26//of the blood meals were followed by defecations within 20 min. The average length of the life cycle was 897.5 days.

Lethal effect of a bait for Rhodnius prolixus (Hemiptera: Reduviidae), the vector of Chagas' disease, containing hexachlorocyclohexane (HCH), under laboratory conditions

The lethal effect of a bait containing an aqueous hexachlorocyclohexane (HCH) suspension at the concentration of 1g/l and maintained at room temperature was studied in the laboratory over a period of 12 weeks. The suspension was placed in a latex bag hanging inside a 1000-ml beaker tightly covered with nylon netting, and left there with no changes for 85 days. Sixteen groups of R. prolixus bugs, consisting on average of 30 specimens each, were successively exposed to the bait and observed at different intervals for one week each. The mortality rate was 100% for all groups, except for the 16th, whose mortality rate was 96.7%. As the groups succeeded one another, mortality started to occur more rapidly and was more marked at the 6- and 24-h intervals. Later tests respectively started at 6:00 a.m. and 6:00 p.m. showed that diurnal and nocturnal periodicity in the offer of food had no effect on mortality. First- and 2nd- instar nymphs and adults male were more sensitive and 5th- instar nymphs were more resistant to the active principle of the bait