Angelo Pires do Prado

Resistance of Musca domestica L. populations to cyromazine (insect growth regulator) in Brazil

Five field populations of Musca domestica L. collected in poultry farms were bioassayed in order to detect possible resistance to the larvicide cyromazine in Brazil. The concentrations used were 0, 0.5, 0.1, 0.2, 0.4, 1, 2, 4 and 8 ppm. Three populations (Petrópolis, RJ, Montes Claros, MG and Promissão, SP) were resistant, while the other two populations (Ibiuna, SP and Monte Mor, SP) were more susceptible than the reference pathern used by the World Health Organization. The presence of three resistant house fly populations to cyromazine in Brazilian poultry farms strongly suggests that the operational aspects of larvicide use are important for the resistance development. Cyromazine is applied as a feed-through, both in Brazil and in the USA, where resistance has already been documented. However, in Denmark, where it was approved only as a topical manure spray, no case of resistance has yet been detected.

Influence of Temperature on Development Time and Longevity of Tachinaephagus zealandicus (Hymenoptera: Encyrtidae), and Effects of Nutrition and Emergence Order on Longevity

Abstract Tachinaephagus zealandicus Ashmead is a gregarious endoparasitoid that attacks third instars of muscoid flies in the Southern Hemisphere. The purpose of the current study was to evaluate the influence of six constant temperatures (16, 18, 20, 22, 25, and 27°C) on development time, the influence of emergence order on longevity, and the effects of temperature and food treatment on longevity. Emergence success was greatest at 22°C for both males and females; significantly fewer (24.1–30.4%) parasitoids emerged at 16 and 25°C compared with 22°C. Development time ranged from 24.0 to 56.9 d for both sexes. No emergence was observed at 27°C. Early-emerging parasitoids had greater longevity than parasitoids that emerged later from the same cohorts. The longevity of females given honey and water decreased with increasing temperature, and those reared at 16°C lived about three times longer than those kept at 27°C. Females given honey and water had similar longevities at 16–20°C, and females that were given only water lived for only 4.8–7.6 d at all temperatures. Females lived significantly longer overall than males at all temperatures except 16°C, but differences due to sex were small compared with the effects of temperature and nutrition. Further investigations will be necessary to determine the climatic zones in which T. zealandicus is most likely to be an effective biological control agent of muscoid flies.

House dust mites in Brazil - an annotated bibliography

House dust mites have been reported to be the most important allergen in human dwellings. Several articles had already shown the presence of different mite species at homes in Brazil, being Pyroglyphidae, Glycyphagidae and Cheyletidae the most important families found. This paper is an annotated bibliography that will lead to a better knowledge of house dust mite fauna in Brazil.

Development of Dermanyssus gallinae (Acari: Dermanyssidae) at different temperatures

The development, viability, and life cycle parameters of Dermanyssus gallinae at five different temperatures (15, 20, 25, 30 and 35 degrees C), and at relative humidity 70-85% were evaluated. Life cycle duration was 690.75 h (28 days) at 15 degrees C, 263.12h (11 days) at 20 degrees C, 164.63 h (7 days) at 25 degrees C, 140.69 h (6 days) at 30 degrees C and 172.04 h (7 days) at 35 degrees C. The optimal development temperature for D. gallinae was 30 degrees C, with the greatest survival in all stages and the shortest development time. High mortality at 35 degrees C indicated that this temperature had adverse effects on development of D. gallinae, and that in field conditions D. gallinae populations may decrease or even disappear due to the negative impact of high temperature on development. There were no significant differences in the pre-oviposition period among the four temperatures 20-35 degrees C, indicating that temperature did not affect this part of the life cycle.

Recognition of competitive asymmetries reduces the severity of fighting in male Idarnes fig wasps

Intense sexual selection leading to male fighting in fig wasps is extensively documented and has evolved independently in several lineages of nonpollinating and pollinating fig wasps. We studied wingless males of nonpollinating Idarnes fig wasps, and observed assessment display and defensive behaviour (mating inside the female galls and sheltering within empty galls) during the mating period, in opposition to reported indications that such behaviour does not play an important role in the avoidance of fatal combats in fig wasps. Compared to males of other species with similar morphology and future reproductive opportunities, males of these species generally showed lower scores of physical injuries due to aggressive confrontations. Our results are consistent with models of asymmetric contest competition, and suggest that defensive behaviour and particular internal features of figs may increase the importance of the recognition of competitive asymmetries in reducing the severity of fighting in closed systems.

Dinâmica sazonal de carrapatos (Acari: Ixodidae) na mata ciliar de uma área endêmica para febre maculosa na região de Campinas, São Paulo, Brasil

Spotted fever is recognized worldwide as a reemerging public health problem. In Campinas region, state of Sao Paulo, the transmission area has expanded and the number of positive cases has increased in the lastest years. In these region most cases are usually related to the increased number of capybaras, which are one of the main primary hosts for the tick Amblyomma cajennense. The main objective of this study was to determine the seasonal dynamic of larvaes, nymphs and adults of Amblyomma species in a gallery forest. From November 2000 to October 2002 free-living ticks were collected using carbon dioxid traps. Larvae of Amblyomma spp were abundant during almost all months. Nymphs of Amblyomma spp occurred during the whole year and were more abundants from July to December. Adults of A.cajennense were more abundants during the spring-summer months. Adults of A. dubitatum showed higher populational peaks from August to February.

Oogenesis in Chrysomya putoria (Wiedemann) (Diptera : Calliphoridae)

Abstract The development of the ovarian follicles of Chrysomya putoria (Diptera : Calliphoridae) during the 1 st gonadal cycle is described in 10 stages and compared with that of other blow flies. The descriptions are based on histological sections, Feulgen-stained whole-mounts, and fresh preparations of the ovaries. The separation into stages was based mainly on the shape of the follicle, the relative proportion occupied by the oocyte and nurse chamber within the follicle and the morphology of the follicular epithelium. Stage I occurs at emergence and stage X is the mature follicle. Polytene chromosomes were only seen in the nucleus of the nurse cells in stage II. Contrary to that usually described, females were found carrying 2 batches of mature follicles (stage X) in their ovarioles. The size of the follicle increased markedly up to stage VIII. After this, the length continued to increase a little, but the width and volume decreased up to stage X. The female reproductive system is also described.

Comparison of house dust mites found on different mattress surfaces

BACKGROUND House dust mites have been considered the most important source of allergens for humans. These allergens have been encountered at different indoor sites, mainly on mattresses and pillows. OBJECTIVE To evaluate the number and different specimens of mites on Brazilian bunk-bed mattresses. METHODS Dust samples were collected once using a standardized method on the upper mattress surface (US) and lower mattress surface (LS) (bed frame also included in the latter) of 58 mattresses. RESULTS The total number of mite bodies on the LS was 3.5-fold higher than on the US, with a mean concentration of 932 mites per gram of fine dust (mites/g) on the US (range, 0-3,375 mites/g) and 3,254 mites/g on the LS (range, 125-14,500 mites/g) (P < .001). Additionally, the number of house dust mite bodies on the LS was 2.4 higher than on the US (P < .001); the mean concentration was 750 mites/g on the US (range, 0-2,875 mites/g) and 1,816 mites/g on the LS (range, 0-10,875 mites/g). Approximately 91% (n = 52) of the US and all LS dust samples had more than the limit of 100 mites/g. The most frequent family was Pyroglyphidae in both mattress surfaces, with Dermatophagoides pteronyssinus the most important species found. Storage mites, including Glycyphagidae (P < .001), Acaridae (P < .001), and other families (P < .001), also showed significant differences in the number of mites between both sample counts. CONCLUSIONS This study shows a significant difference in US and LS mite counts, with higher counts on the LS. Mite allergen avoidance should include the LS and bed frame as potential targets.

Trichopria sp. (Hymenoptera: Diapriidae) attacking pupae of Chrysomya putoria (Wiedemann) (Diptera: Calliphoridae) in a poultry facility

This work was carried out in a poultry house (Granja Capuavinha), Monte Mor, State of Sao Paulo, from February 1991 to April 1992 with the purpose of studying the synanthropic flies and their parasitoids. The pupae were extrated from manure using a water-flotation method. Berlese-Tullgrens funnel was used to extract parasitoids and fly larvae. Each pupa was kept in a small transparent glass vial for 35 days until the emergence of the fly or parasitoid. After this period, the pupae that did not yield adult flies or parasitoids were dissected. The following species of fly were collected: Chrysomya putoria (Wiedeman), Muscina stabulans (Fallen), Musca domestica L., Fannia pusio (Stein). In addition several species of Sepsidae were also collected. The following species of parasitoids that emerged from fly pupae were collected: Spalangia gemina (Boucek), S. cameroni (Perkins), Muscidifurax raptoroides Kogan & Legner, Pachycrepoideus vindemiae (Rondani), Nasonia vitripennis (Walker) and Trichopria sp. (Diapriidae). Tachinaephagus zealandicus (Ashmead) (Encyrtidae) a larval pupal parasitoid also ocurred. This is the first report of Trichopria sp., a gregarious parasitoid, attacking pupae of C. putoria. About 13% of parasitoids did not eclode successfuly from the parasitoid pupae which may indicate a recent association between Trichopria sp. and C. putoria in Brazil.

Effect of local mate competition on fig wasp sex ratios

In fig wasps, mating takes place among the offspring of one or a few foundress mothers inside the fig from which mated females disperse to found new broods. Under these conditions, related males will compete with each other for mating and several studies have shown female bias in brood sex ratios as a response to Local Mate Competition (LMC). Studying Pegoscapus tonduzi which pollinates Ficus citrifolia in Brazil, we analysed the effect of LMC (number of foundresses) on the sex ratio of the offspring of pollinating wasps. The relationship between the foundress number and brood sex ratio qualitatively followed the theory, however the empirical sex ratio was more female biased than expected from theoretical values. The model for an optimal sex ratio considers that each foundress wasp contributes the same number of eggs to be bred and that the violation of this assumption may explain the lack of adjustment in relation to the theory.