Oocyte maturation in the sloth's giant tick Amblyomma varium (Acari: Ixodidae) in an ecological context.

The sloth's giant tick Amblyomma varium Koch, which is a neotropical species that inhabits tropical rainforests, is the largest tick reported to date. The adult stage of this tick parasitizes mammals from the families Bradypodidae and Magalonychidae (Xenarthra) nearly exclusively. This study aimed to describe morphological and histological features of the reproductive system and the oocyte maturation process of this tick species. The ovary of A. varium is a long single tubular organ that is horseshoe-shaped, winding and arranged in the posterior part of the body. Two oviducts are connected to the ovary on each side; these thicken at certain region forming the uterus (common oviduct), followed by a muscular connecting tube, vagina and genital aperture. A large number of oocytes at different stages of development are attached to the ovary wall by the pedicel, as they reach maturity they are released into the ovary lumen and from there to the genital aperture. These oocytes develop simultaneously and asynchronically along the ovary. Amblyomma varium oocytes were classified into five development stages (i.e., I-V), and specific characteristics were observed; the processes of yolk and chorion deposition begin early in oocytes stage II, and oocytes V exhibit a very thick chorion and eggs of a large size. These characteristics are likely adaptations that enhance the survival and the reproductive success of this extremely host-specific tick, which is limited to a particular environment.

[Selection of isolates of entomopathogenic fungus Beauveria bassiana (Ascomycetes: Clavicipitaceae) for control of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)]. / Seleção de isolados do fungo entomopatogênico Beauveria bassiana (Ascomycetes: Clavicipitaceae) para o controle de Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

This study was carried out to select isolates of the entomopathogenic fungus Beauveria bassiana with pathogenic potential to control the Rhipicephalus (Boophilus) microplus tick. The effectiveness of thirty isolates was first tested at a concentration of 5 x 108 conidia.mL(-1). Of these, eight were evaluated (IBCB01, IBCB02, IBCB07, IBCB17, IBCB21, IBCB74, IBCB149, IBCB165) and showed an effectiveness between 90 and 99%; thirteen (IBCB03, IBCB14, IBCB16, IBCB24, IBCB95, IBCB97, IBCB102, IBCB141, IBCB146, IBCB147, IBCB150, IBCB154, IBCB157) between 80 and 89,5%; six (IBCB47, IBCB75, IBCB84, IBCB145, IBCB161, IBCB164) between 70 and 79%, and only two (IBCB13 and IBCB143) had lower pathogenicity (70% or below). In the second step of the study, the five more effective strains in the first phase of the experiment (IBCB01, IBCB07, IBCB21, IBCB66, IBCB165) were analyzed comparatively. Based on in vitro results, it can be concluded that IBCB66 and IBCB21 are the isolates with higher potential for field control of R. (B.) microplus. IBCB01, IBCB07, IBCB21, IBCB66 e IBCB165 isolates were submitted to a conidial production test using a rice-based substrate. The best mass production of the entomopathogenic fungus was obtained with the IBCB66 strain.

[Determination of LC 90 and LT 90 of IBCB66 Beauveria bassiana (Ascomycetes: Clavicipitaceae) isolate for Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) control]. / Determinação da CL90 e TL90 do isolado IBCB66 de BEauveria bassiana (Ascomycetes: Clavicipitaceae) para o controle de Rhipicephalus (Boophilus) microplus (ACari: Ixodidae).

The objective of this research was to evaluate the pathogenicity and the virulence of the IBCB66 isolate of Beauveria bassiana on infected larvae of Rhipicephalus (Boophilus) microplus. The IBCB66 fungus strain was used as standard isolates of B. bassiana against R. (B.) microplus larvae. The larval bioassay tests using the IBCB66 isolate were carried out to determine the (Lethal Concentration) LC50, LC90, (Lethal Time) LT50 and LT90. The IBCB66 fungus strain was tested at six different concentrations (5x10(6), 10(7), 5x10(7), 10(8), 5x10(8) and 10(9) conidia.mL(-1)) to determine the percentage of larval mortality. In addition, a Probit analysis was also performed. Total larval mortality was observed eighteen days after the beginning of the test in the group treated with 5x10(9) conidia.mL(1). The LC50 and LC90 were 3x10(7) and 5x10(8) respectively and the LT50 and LT90 were 10 and 16 days.

[Compatibility of Beauveria bassiana (Ascomycetes: Clavicipitaceae) with chemicals acaricides used in the control of cattle tick]. / Compatibilidade de isolados de Beauveria bassiana (Ascomycetes: Clavicipitaceae) com carrapaticidas químicos utilizados no controle do carrapato dos bovinos.

The purpose of the present study was to assess compatibility between IBCB66 and IBCB21 isolates of Beauveria bassiana and acaricides: Flumethrin+Coumaphos, Deltamethrin, Dichlorvos+Cypermethrin, Dichlorvos+Chlorpyrifos, Cypermethrin High Cis, Dichlorvos+Cypermethrin High Cis, Cypermethrin and Amitraz, utilized on the control of Rhipicephalus (Boophilus) microplus in our country. The effect of commercial products on the isolates was assayed according to observation of vegetative growth, conidia production, and viability of strains of B. bassiana fungus. With concerning about IBCB66 isolate, products Deltamethrin, Cypermethrin High Cis and Amitraz were compatible, not affecting the entomopathogen development. Product Cypermethrin was toxic, and products Flumethrin+Coumaphos, Dichlorvos+Cypermethrin, Dichlorvos+Chlorpyrifos and Dichlorvos+Cypermethrin High Cis were very toxic. In regard to IBCB21 isolate, products Flumethrin+Coumaphos, Dichlorvos+Cypermethrin, Dichlorvos+Chlorpyrifos, Cypermethrin High Cis, Dichlorvos+Cypermethrin High Cis and Cypermethrin were very toxic and product Amitraz was toxic. From the acaricides evaluated, product Deltamethrin was the single agent that did not produce toxic effect on the entomopathogen.

Thermal requirements of Dermanyssus gallinae (De Geer, 1778) (Acari: Dermanyssidae).

The thermal requirements for development of Dermanyssus gallinae were studied under laboratory conditions at 15, 20, 25, 30 and 35 degrees C, a 12h photoperiod and 60-85% RH. The thermal requirements for D. gallinae were as follows. Preoviposition: base temperature 3.4 degrees C, thermal constant (k) 562.85 degree-hours, determination coefficient (R(2)) 0.59, regression equation: Y= -0.006035 + 0.001777x. Egg: base temperature 10.60 degrees C, thermal constant (k) 689.65 degree-hours, determination coefficient (R(2)) 0.94, regression equation: Y= -0.015367 + 0.001450x. Larva: base temperature 9.82 degrees C, thermal constant (k) 464.91 degree-hours, determination coefficient (R(2)) 0.87, regression equation: Y= -0.021123 + 0.002151x. Protonymph: base temperature 10.17 degrees C, thermal constant (k) 504.49 degree-hours, determination coefficient (R(2)) 0.90, regression equation: Y= -0.020152 + 0.001982x. Deutonymph: base temperature 11.80 degrees C, thermal constant (k) 501.11 degree-hours, determination coefficient (R(2)) 0.99, regression equation: Y= -0.023555 + 0.001996x. The results obtained showed that 15 to 42 generations of Dermanyssus gallinae may occur during the year in the State of São Paulo, as estimated based on isotherm charts. Dermanyssus gallinae may develop continually in the State of São Paulo, with a population decrease in the winter. There were differences between the developmental stages of D. gallinae in relation to thermal requirements.

[Abundance and seasonality of Diptera (Insecta) in a poultry house in the northeast region of the state of São Paulo, Brazil]. / Abundância e sazonalidade de Dípteros (Insecta) em granja aviária da região nordeste do Estado de São Paulo, Brasil.

Modern production systems accommodate broody hens in high densities, leading to the accumulation of excrement under the cages. This substrate is excellent for the development of sinantropic flies. Thus, the accomplishment of surveys in these places becomes essential, in order to plan better strategies of control. The present work aimed at studying the entomofauna and the seasonality of the species of dipterous present in the Crisdan poultry house located in the Municipality of São João da Boa Vista, the State of São Paulo, Brazil. In the period of January of 2001 to December of 2002, 1,012,595 flies were captured using the "jug-trap". The species were identified: Drosophila repleta (Wollaston, 1858), Musca domestica (Linnaeus, 1758), Ophyra spp., Hermetria illucens (Linnaeus, 1758), Fannia canicularis (Linnaeus, 1761), Chrysomya megacephala (Fabricius, 1794), and Sepsidae. More frequently D. repleta and M. domestica had added 99.47% of the dipterous. Increased rainfall and the collection months influenced the sampling of dipterous (P<0.05). Drosophila repleta was the most abundant species, representing 91% of all captured flies. However, this diptera did not develop at the surveyed site since immatures were not captured therein.

[Associated arthropodes in the laying hen excrement]. / Artrópodes associados ao excremento de aves poedeiras.

A research about arthropode fauna in laying hen excrement was carried out in a poultry house in the State of São Paulo, from January 2001 to December 2002. The objective was to verify the frequency of Diptera and Coleoptera collected by Berlese funil and flutuation methods, and to show correlation between the collect methods and sazonality possible in the currents seasons. A total of 29,499 insects were collected from seventy five collects, being 16,702 Diptera (six families) and 12,797 Coleoptera (four families). Some arthropodes presented direct relation with the collect method, the seasons of the years and the rainfall precipitation, with significant increase in the number of insects collected in certain periods of the year.

First record of Megaselia scalaris (Loew) (Diptera: Phoridae) infesting laboratory colonies of Triatoma brasiliensis Neiva (Hemiptera: Reduviidae).

Megaselia scalaris (Loew) is a cosmopolitan and synanthropic scuttle fly, eclectic in its feeding habits and acts as detritivore, parasite, facultative parasite, and parasitoid. Here we report for the first time M. scalaris infesting laboratory colonies of Triatoma brasiliensis Neiva, the most important Chagas disease vector in semiarid areas of Brazil. M. scalaris larvae were found feeding inside bugs; pupae were found in the esophagus and intestinal regions of T. brasiliensis through dissection. Other relevant information about this finding is also described in this note, including some preventive measures to avoid laboratory colonies infestations.

[Synanthropic flies (Diptera: Cyclorrapha) and their microhymenoptera parasitoids (Insecta: Hymenoptera) at Monte Mor poultry production system, São Paulo, Brazil]. / Moscas sinantrópicas (Diptera: Cyclorrapha) e seus parasitóides microhimenópteros (Insecta: Hymenoptera) num plantel avícola de Monte Mor, São Paulo, Brasil.

A survey of synanthropic flies and their microhymenopteran parasitoids was conducted at the Capuavinha poultry farm, municipality of Monte Mor, State of São Paulo, Brazil, from 1991 to 1992. Bird manure samples were collected biweekly for examined and selected by the following methods: flotation in water, dissected pupae, and sentinel pupae. The species of flies more abundant were: Chrysomya putoria (Wiedeman) (41.2% - Calliphoridae), Muscidae: Muscina stabulans( Fallén) (27.3%), Musca domestica Linnaeus (23.9%), Fannia pusio (Stein) (5.3% - Fanniidae) e Sepsidae (2.3%). The pupal parasitoids were: Tachinaephagus zealandicus (Ashmead) (72.4% - Encyrtidae), Pteromalídeos: Spalangia gemina Boucek (9.2%), S. cameroni (Perkins) (7.3%), S. endius (Walker) (3.7%), Muscidifurax raptoroides (Kogan e Legner) (1.5%), Pachycrepoideus vindemiae (Rondani) (0.8%), Nasonia vitripennis Walker (0.06%). Trichopria sp. Nixon (Diapriídeo 5.5%) detected only in C. putoria pupae (t=-1,5269; P <0,1296). Some significant mean values were obtained for parasitoids in the collected hosts (t = 0.9540; Pr <0.0001), proportion of collected pupae and parasitoids with respect to the collecting site (F = 60.85; Pr <0.0001; F = 358.35; P <0.0001) and for the host species and parasitoid species (F = 2.58; Pr <0.0001; F = 9. 48; P <0.0001). The dissected host species was significant for proportion dissected pupae (F = 1.57; Pr <0.2053). These results concerning the insect fauna can be of help for an appropriate management of this poultry farm in terms of the control of synanthropic flies.