Evaluation of a larval development assay for the detection of anthelmintic resistance in Ostertagia circumcincta

Two experiments were carried out to evaluate a larval development assay for the detection of anthelmintic resistance in O. circumcincta. In Experiment I, the dose responses to levamisole (LEV), thiabendazole (TBZ) and ivermectin (IVM) of 8 isolates of O. circumcincta were measured 34 days after infection (DAI). Four of these isolates were shown to be resistant to 1 or more anthelmintics. With 2 exceptions, all isolates considered to be resistant had higher LD50 values than the susceptible isolates for that anthelmintic. One exception was isolate RM8, which was considered to be resistant to all 3 anthelmintics based on faecal egg count reduction tests in goats, but the LD50 value for LEV did not differ from that for the susceptible isolates. The other exception was an isolate considered to be susceptible to TBZ which had a relatively high LD50 value. In an unrelated trial that was prompted by this finding, this isolate was confirmed to be benzimidazole-resistant. Isolate RM8 and an isolate susceptible to all 3 anthelmintics (SK2) were used in the second experiment, which was conducted to monitor changes in the LD50 values of LEV, TBZ and IVM over time following a single infection of 35 000 infective larvae in young sheep. Faecal samples were collected weekly from 24 to 115 DAI. With all 3 anthelmintics, the LD50 values increased with time to a peak around 50-60 DAI, and then declined to levels similar to those observed soon after patency. This trend was consistent for both isolates. The highest mean LD50 values for isolates SK2 for IVM and TBZ and RM8 for IVM and RM8, respectively, were 1.7 and 1.8 times, and 2.2 and 2.9 times higher than the initial mean LD50 values. There was a clear distinction in LD50 values between isolates at each sampling day for both IVM and TBZ. However, as a consequence of the changes in LD50 values with time, the peak LD50 values of IVM for isolate SK2 were higher than the minimum LD50 values of isolate RM8. As there was no apparent difference in LEV efficacy between these 2 isolates, the data were pooled. The highest mean LD50 value was 2.3 times higher than the initial LD50 value. (C) 1997 Australian Society for Parasitology.

Larval stages of Pyromaia tuberculata (Lockington, 1877) (Decapoda, Majidae, Inachinae) reared in the laboratory

The larval development of Pyromaia tuberculata (Lockington, 1877) is described from specimens reared in the laboratory. Larvae were obtained from ovigerous females collected by trawl in Ubatuba, São Paulo state, Brazil. Rearing was carried out at 24 +/- 1 degrees C in 35 parts per thousand S. The larvae pass through two zoeal stages before moulting to the megalopa. A comparison is made with previously studied majid species occurring in the southern and southeastern regions of Brazil.

Electrophoretical studies of proteins of the hypopharyngeal glands and of the larval food of Melipona quadrifasciata anthidioides Lep (Hymenoptera, Meliponinae)

The electrophoretical protein patterns of hypopharyngeal glands, larval food of Melipona, and royal jelly of Apis were compared.Since protein patterns of hypopharyngeal glands from newly emerged workers, brood cell provisioners and foragers are similar to freshly deposited larval food, the identical protein bands probably represent actual gland secretion. This suggests that, as in Apis, the glands secrete proteins to the larval food, and maintain this ability throughout life, although at slightly different intensities, according to the activity of the bees.The similarity on the electrophoretic profiles of the major larval food protein in Apis and Melipona is an interesting finding because of its probable evolutionary significance.

Feeding ecology of a selective folivore, the thin-spined porcupine (Chaetomys subspinosus) in the Atlantic forest

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative larval morphology of eight species of Hypsiboas Wagler (Amphibia, Anura, Hylidae) from Argentina and Uruguay, with a review of the larvae of this genus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morphological changes in the salivary glands of Amblyomma cajennense females (Acari : Ixodidae) in different feeding stages on rabbits at first infestation

This study examined salivary glands of unfed, partially engorged, and engorged females of the tick Amblyomma cajennense on rabbits at first infestation using histological and histochemical techniques. In type I acini, no significant changes were observed among the three feeding conditions. In type II acini of unfed females, c1, c2, and c4 cells were described for the first time in this species. In a comparison among the three feeding conditions, an increase in this acinus was observed, due to the increase in secretion in c1, c2, and c4 cells and the appearance of c3 cells. In engorged females, some cells were still active. Type III acini presented cells d, e, and f containing secretion in unfed females. In partially engorged females, these cells were devoid of secretion. In engorged females, type III acini exhibited a reduced lumen. After engorgement, all acini underwent a degenerative process, as observed in females after two to five days post-engorgement.

Notes on the feeding habits of the skate Rioraja agassizi (Chondrichthyes, Rajidae) off southeastern Brazil

Feeding habits of the skate Rioraja agassizi were analyzed in southeastern Brazil from samples obtained along Silo Paulo coast. A total of 258 specimens were examined, ranging between 96 and 532 mm total length. About 57.85% were females and 42.15% were males, resulting in a 1:1.37 sex-ratio to females. From 223 stomachs collected (94 males and 129 females) empty stomachs represented only 1.4%. Nine prey categories were identified: Polychaeta, Copepoda, Cumacea, Isopoda, Gammaridea, Dendrobranchiata, Brachyura, Teleostei, and one non-animal category (non-identifiable items). Crustaceans were the most important item, indicating that the species has a carcinophagic preference. The presence of fish was just verified in juveniles and some adult individuals, with predominance in summer. Sex, maturity stage and seasonality did not influence the feeding habits of the species.

Biological aspects of Orius insidiosus (Say) feeding on eggs of Plutella xylostella (Linnaeus) and Anagasta kuehniella (Zeller).

The objective of this work was to evaluate the biology of Orius insidiosus fed on eggs of Plutella xylostella and Anagasta kuehniella. The eggs used were obtained from the Laboratorio de Biologia e Criacao de Insetos, Departamento de Fitossanidade, FCAV/UNESP. The experiment was carried out with a total of 50 12-to-24-hour-old O. insidiosus nymphs, 1 per Petri dish (50 replications). P. xylostella or A. kuehniella eggs were places into each Petri dish daily, along with a small cotton pad moistened with distilled water. The evaluations were carried out daily. The adults were separated in couples, and placed in Petri dishes. The following biological aspects were evaluated: duration, survival rate and consumption of the nymph instars and of the nymph period; longevity of males and females; consumption per day and adult longevity; eggs per day; female fecundity; egg viability; embryonic period; preoviposition period, oviposition period, post-oviposition period. The fertility life table parameters were also evaluated. The predator O. insidiosus did not present significant differences for its biological characteristics, when feeding on P. xylostella and A. kuehniella eggs, however it showed improved fertility life table parameters when fedo n eggs of P. xylostella, suggesting the possibility of using these eggs in the mass rearing of this insect.

Effects of broiler breeder genetic, diet type, and feeding program on maternal antibody transfer and development of lymphoid tissues in chicken progeny

Maternal antibody (MatAb) transfer is important for early chicken survivability. Diet composition and the amount of feed given to breeder pullets during rearing may affect the development of immunity and the transfer of MatAb to progeny, and could affect progeny performance and resistance to disease. The effects of broiler breeder nutrition and feeding management practices were evaluated for the transfer of MatAb to progeny and for spleen and bursa development at hatching in 2 genetic strains (A and B). In this experiment, the levels of MatAb against Newcastle disease virus were assessed by enzyme-linked immunosorbent assays in serum samples taken of pedigreed chicken progeny from hatching to 13 d of age. Chickens were fed corn-and wheat-based diets, as were their parents. The breeder feeding program and diet type altered the Newcastle disease virus MatAb found in progeny at hatching and affected how long these antibodies were maintained in circulation. Bursal follicle size at hatching was influenced by an interaction among all factors evaluated. Percentage of white pulp in the spleen was affected mainly by genetic strain and diet type, but responses varied according to the breeder feeding program. It was concluded that breeder feeding programs influence MatAb transfer and half-life, and may also affect the early development of lymphoid tissues.