Comparative studies on the growth and reproductive performances of Rhodnius prolixus reared on different blood sources

Host blood source was found to affect both the development and the reproductive performance of Rhodnius prolixus. The insects were reared on citrated human, rabbit, chicken, sheep and horse blood sources, through a membrane feeder, during an entire life cycle, from eggs to adults. Development and reproduction in terms of the number of unfed insects, number of moulting, mortality intermoulting period, number of egg/female, conversion of blood into egg (mg meal/egg) and percentage of hatch as effective physiological parameters were investigated. Our results showed that human or rabbit blood meals were more nutritionally efficient than the other blood samples used because (i) the insects developed faster, presented low mortality and about 80% of them reached the adult stage; and (ii) females oviposited an average of at least 100% more eggs. The inefficiency of chicken and horse blood sources as diets for R. prolixus was manifested in (i) a decrease of the amount of ingested blood and (ii) only a reasonable nutritional quality. The inadequacy of sheep blood was observed by a mortality extremely high, poor moulting response and drastic reduction in egg production

Short and long-term effects of azadirachtin A on development and egg production of Rhodnius prolixus

Azadirachtin A was given through a blood meal to 4th-instar larvae and to adult females of Rhodnius prolixus. Development (ecdysis) and egg production were inhibited in a dose-dependent manner. Long-term experiments with subsequent four feedings on azadirachtin-free blood were performed with 4th-instar larvae and with adult females. Only in the low-dose azadirachtin larval groups (0.01 and 0.1 microng/ml of blood), development was partially restored; after a single 1.0 microng/ml treatment about 50% of the treated larvae were still alive 120 days later without any adult emergence. Similarly fed females had a dose-dependent lower survival and egg deposition rate. The results are discussed in relation to the mode of azadirachtin A action

Efficacy of ivermectin against the bloodsucking insect, Rhodnius prolixus (hemiptera, triatominae)

A alimentaçäo de ninfas e adultos de Rhodnius prolixus em camundongos tratados previamente com ivermectin (0,2 mg/kg peso corporal, via subcutânea) resultou em alta mortalidade dos insetos. Este efeito foi mais drástico em ninfas de 1§ e 2§ estádios. Foi observado que as ninfas de 3§ estádio alimentadas 24-48 horas após o tratamento dos camundongos demonstraram uma mortalidade maior do que os insetos alimentados 72 horas após o tratamento. Os insetos de 3§ estádio sobreviventes aos tratamentos apresentaram uma inibiçäo total das mudas. Fêmeas adultas alimentadas em camundongos 24 horas após o tratamento com invermectin demonstraram uma considerável reduçäo na produçäo de ovos. Este efeito näo foi revertido por uma posterior alimentaçäo em camundongos normais. Foi sugerido que dose subletal de ivermectin poderia interferir no controle neuro-endócrino do desenvolvimento e reproduçäo do inseto