Abstract In this work, we report for the first time the occurrence of the parasitoid wasp Brachymeria amenocles (Walker, 1846) (Hymenoptera: Chalcididae) associated with the larvae of the flesh fly, Peckia (Peckia) chrysostoma (Wiedemann, 1830) (Diptera: Sarcophagidae), in Brazil. This parasitoid species was collected together with the species Brachymeria podagrica (Fabricius, 1787), in the municipality of Rio de Janeiro, geographically located in the Southeast region of Brazil, in larvae of the same host species reared in the same attraction substrate, behaving as solitary parasitoids. A trap containing putrefying sardine was exposed for 48 h, in the upper part of a house, located in Vila Isabel, an urban area. The larvae collected were reared in the laboratory without control of environmental conditions. A total of three adult parasitoid wasps of the species B. podagrica, and nine adult parasitoid wasps of the species B. amenocles emerged from 12 host pupae, resulting in a prevalence of parasitoidism of 4.8% and 14.5%, respectively. Developing parasitoids at the pupal phase were observed in another 34 host pupae dissected.

ABSTRACT Plants represent a huge source of substances, with pharmacological potential. Brazil has a diversity of agricultural insect pests and an urgent need for safer methods of insect control. Dysdercus peruvianus (Guerin-Meneville, 1831), Pyrrhocoridae, is an economically important species of the Order Hemiptera and a pest of cotton (Gossypium hirsutum L., Malvaceae). Secondary metabolites in stems of Clusia hilariana Schltdl., Clusiaceae, such as terpenes and benzophenones, have been reported to be insecticidal. The present study investigated the effects of semi-purified fractions of hexane crude extracts from male C. hilariana stems on development of D. peruvianus. Biological parameters at different stages of development including body malformations, range of molting period and toxicity were evaluated. Most insects died and failed to develop due to attachment of their exuviae to the abdomen. Deformations of wings and defective tarsi also occurred. The secondary metabolites from semi-purified fractions of C. hilariana caused mortality, interference in molting and metamorphosis, and body deformations, probably by interacting with the neuroendocrine system. The results demonstrate the potential of C. hilariana extracts as an alternative for the control of the phytophagous insect D. peruvianus and for the development of environmentally safe and biodegradable bio insecticides.

Abstract: As a part of our continuing search for insect and arthropod development regulators from Brazilian restinga vegetation of the Rio de Janeiro State, crude extracts, purified fractions and essential oils were submitted to screening tests seeking for biological activities on the development of the insects Rhodnius prolixus, Dysdercus peruvianus, Oncopeltus fasciatus and Rhipicephalus (Boophilus) microplus. Up to now, 102 secondary metabolites have been detected in the fractions, among them monoterpenes, sesquiterpenes and two triterpenes which were obtained from the species, Eugenia sulcata, Pilocarpus spicatus, Manilkara subsericea, Myrciaria floribunda and Zanthoxylum caribaeum. These secondary plant metabolites are considered of interest for the use of studies related to arthropod endocrinology, vector-parasite interaction system, and population control of vector insect and agricultural pest. The observed biological activities were surprisingly high, involving increased mortality, molting and metamorphosis inhibition, paralysis, corporeal deformities, apparition of permanent nymphs, of adultoids and juvenoids, partial or total inhibition of oviposition and egg hatching. These compounds are now being studied further to determine if they may or may not be useful in controlling insect populations and/or interfere with the life cycle and vector transmission of parasites to animal and human populations.

ABSTRACT The effects of the hexanic extracts of the fruits and flowers of Clusia fluminensis Planch. & Triana, Clusiaceae, as well as their main constituents, the triterpene lanosterol and the benzophenone clusianone, were evaluated on hemipterans Dysdercus peruvianus and Oncopeltus fasciatus. The topical treatments of insects with the hexanic extracts significantly affected the survival of O. fasciatus, but not that of D. peruvianus. Concomitantly, extracts delayed the development of both hemipterans. Moreover, isolated lanosterol significantly reduced both the survival and development of O. fasciatus and D. peruvianus, while clusianone only reduce the survival of D. peruvianus and marginally inhibited the development of both insects. The results show the specific activity of lanosterol and clusianone against the two evaluated insect species and indicate the potential of compounds derived from C. fluminensis for the development of specific biopesticides for the control of agricultural pests. Subsequent work will examine the mode of action of lanosterol and clusianone isolates from C. fluminensis.

Studies evaluated the effects of hexanic extracts from the fruits and flowers of Clusia fluminensis and the main component of the flower extract, a purified benzophenone (clusianone), against Aedes aegypti. The treatment of larvae with the crude fruit or flower extracts from C. fluminensis did not affect the survival of Ae. aegypti (50 mg/L), however, the flower extracts significantly delayed development of Ae. aegypti. In contrast, the clusianone (50 mg/L) isolate from the flower extract, representing 54.85% of this sample composition, showed a highly significant inhibition of survival, killing 93.3% of the larvae and completely blocking development of Ae. aegypti. The results showed, for the first time, high activity of clusianone against Ae. aegypti that both killed and inhibited mosquito development. Therefore, clusianone has potential for development as a biopesticide for controlling insect vectors of tropical diseases. Future work will elucidate the mode of action of clusianone isolated from C. fluminensis.

Essential oils are known for their insect control potential, which is mainly attributed to the presence of terpenes that interfere with hormonal and physiological processes of arthropods. The aim of the present study was to evaluate the effects of essential oil from the leaves of Eugenia sulcata Spring ex Mart., Myrtaceae, on the development of two species of agricultural pest insects, Dysdercus peruvianus and Oncopeltus fasciatus.Results showed that the essential oil induced mortality, and reduced numbers of adults. Topical treatment of Oncopeltus fasciatus using pure essential oil caused significant mortality rates (96.67%), while Dysdercus peruvianus had a higher tolerance, with 80% mortality at the end of the experiments. Results suggest that essential oil from the leaves of Eugenia sulcata may be used in agriculture for insect pest control.

Myrciaria floribunda (H. West ex Willd.) O. Berg, Myrtaceae, is popularly known as "camboim-amarelo" and was collected at Restinga de Jurubatiba (RJ, Brazil). Leaves from this species were submitted to hydrodistillation to extract its essential oil. Monoterpenes were the main compounds found (53.9%), and 1,8-cineole was the major constituent (38.4%). Studies were carried out to evaluate the effects of this essential oil on the development of two species of agricultural pests (Oncopeltus fasciatus and Dysdercus peruvianus). The essential oil was considered effective against D. peruvianus and O. fasciatus, causing mortality in both insects. The LD50 values (µg/insect) observed were 112.44 µg/insect (O. fasciatus) and 309.64 µg/insect (D. peruvianus) after one day of treatment, and 72.18 µg/insect (O. fasciatus) and 94.42 µg/insect (D. peruvianus) after 22 days of treatment. The present study reports for the first time the bioinsecticidal activity of essential oil of Myrciaria floribunda leaves, and provides important data regarding the use of essential oils in complementary programs for pest control.

Semiconductor nanoparticles, such as quantum dots (QDs), were used to carry out experiments in vivo and ex vivo with Trypanosoma cruzi. However, questions have been raised regarding the nanotoxicity of QDs in living cells, microorganisms, tissues and whole animals. The objective of this paper was to conduct a QD nanotoxicity study on living T. cruzi protozoa using analytical methods. This was accomplished using in vitro experiments to test the interference of the QDs on parasite development, morphology and viability. Our results show that after 72 h, a 200 μM cadmium telluride (CdTe) QD solution induced important morphological alterations in T. cruzi, such as DNA damage, plasma membrane blebbing and mitochondrial swelling. Flow cytometry assays showed no damage to the plasma membrane when incubated with 200 μM CdTe QDs for up to 72 h (propidium iodide cells), giving no evidence of classical necrosis. Parasites incubated with 2 μM CdTe QDs still proliferated after seven days. In summary, a low concentration of CdTe QDs (2 μM) is optimal for bioimaging, whereas a high concentration (200 μM CdTe) could be toxic to cells. Taken together, our data indicate that 2 μM QD can be used for the successful long-term study of the parasite-vector interaction in real time.

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.

The results presented in this paper clearly indicate that precocene and azadirachtin are effective inhibitors of moulting and reproduction in the hemipteran Rhodnius prolixus. The time of application is important and only applications of these substances early in the intermoulting period cause their effects in nymphs. The inhibition of moulting is fully reversed by ecdysone therapy. Precocene and azadirachtin also affected drastically the oogenesis and egg deposition in this insect. Precocene-induced sterilization is reversed by application of juvenile hormone III. However, this hormone is unable to reverse the effect of azadirachtin on reproduction. Ecdysteroid titers in nymphs and adult females are decreased by these treatments. In vitro analysis suggest that precocene and azadirachtin may act directly on the prothoracic glands and ovaries producing ecdysteroids. Based on these and other findings the possible mode of action of these compounds on the development and reproduction of Rhodnius prolixus is discussed.