Epibiosis and molting in two species of Callinectes (Decapoda: Portunidae) from Brazil

The external infestation of Callinectes ornatus Ordway, 1863 and Callinectes danae Smith, 1869, in particular cirripeds, was studied for two consecutive years in the Ubatuba Bay (SP) (23 degrees 26' S and 45 degrees 02' W). Bryozoans, polychaetes and cirripeds were found on both swimming crab species, but cirripeds were the most abundant and frequent. The number of infested swimming crabs increased proportionally to carapace size, but not surpassing 30 %, suggesting an absence of terminal anecdysis in both species. The establishment of the pernicious organisms on their hosts is influenced by other factors, such as their habit of burying themselves in sediments. The correlation between molting activity in adult specimens of both sexes and the low incidence of epizoonts suggest that C. ornatus and C. danae may be molting after maturity.

Exotic species of freshwater decapod crustaceans in the state of São Paulo, Brazil: records and possible causes of their introduction

Based on recent surveys of the freshwater decapod fauna, distributional data of five exotic species of freshwater decapod crustaceans for the hydrographic basins of the state of São Paulo are presented, as part of a large initiative for a comprehensive survey of the state's biodiversity (BIOTA-FAPESP Program). These species are the North American crayfish Procambarus clarkii (Girard) (Cambaridae), the crab Dilocarcinus pagei Stimpson (Trichodactylidae) from the Amazon and Paraguay/lower Parana River Basins, and the palaemonid shrimps Macrobrachium rosenbergii (De Man), from the Indo-Pacific region, Macrobrachium amazonicum (Heller) and Macrobrachium jelskii (Miers), both from the Orinoco, Amazon and the Paraguay/lower Parana River Basins. Possible modes by which their introduction might have occurred are commented upon and potential consequences are discussed.

Hepatozoon canis infection of wild carnivores in Brazil

Hepatozoon canis was diagnosed in a crab-eating fox (Cerdocyon thous) found on a highway in the region of Botucatu, São Paulo, Brazil, after being hit by a car. The fox had bilateral fractures of the olecranon, which was corrected by osteosynthesis. Hematologic findings included a neutrophilia, eosinophilia, monocytosis and mild anemia. In the Leishman-stained blood film, gametocytes of Hepatozoon canis in neutrophils were identified measuring 9.1+/-0.54x5.3+/-0.46 mu m. (C) 1997 Elsevier B.V. B.V.

Fecundity in Portunus spinimanus Latreille, 1819 (Crustacea, Brachyura, Portunidae) from Ubatuba, São Paulo, Brazil.

The object of this work was to study the conditions of embryo development and egg production in Portunus spinimanus Latreille, 1819 at Ubatuba region of Brazil. The number of eggs laid by 21 females in a range of size was determined. Eggs at 3 differ ent stages of embryonic development were measured P. spinimanus fecundity varied between 188,065 and 682,992, with an average of 429,676 +/- 157,203, for animals with a carapace width ranging from 56.2 to 86.6 mm. Between the initial and final stages of development there was an increase of 55.1% in egg diameter. The relatively high fecundity of P. spinimanus may be a strategy of the species faced with a high mortality rate in the larval phase; however this hypothesis should be tested.

Distribution of Neohelice granulata (Dana 1851) in its northernmost latitudinal occurrence in a tropical mangrove forest, Brazil (Crustacea, Decapoda, Brachyura, Grapsoidea, Varunidae).

Neohelice granulata ecological distribution was evaluated in its northernmost latitudinal occurrence in a Brazilian tropical mangrove (23[degree]13'4" S, 44[degree]42'47" W). Samples were collected in three sites along the main river in the mangrove. Crabs were manually captured by two people, 15 min each, at low tide periods. The sex of the animals was assessed and carapace width measured. The size-frequency distribution was determined in each site. Environmental factors (salinity, temperature, organic matter and sediment texture) were analyzed, compared among sites and related to crab abundance and size in each site. Crab abundance decreased with the distance from the sea. Juvenile crabs were more frequent next to the sea, whereas larger and ovigerous ones were mainly found in the most distant site. Crab size was proportional to the organic matter percentage in the sediment. N. granulata spatial distribution varies along the river course, which is probably related to the most productive areas that have more nutrients available; this may also occur in order to prevent intraspecific competition.

Molecular detection of Hepatozoon spp. in Brazilian and exotic wild carnivores

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

The fitness of the Brazilian damsel Stegastes fuscus is increased by sharing the territory with the dusky grouper Epinephelus marginatus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A Meta-Analysis of Predation Risk Effects on Pollinator Behaviour

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Assessment of Cerdocyon thous distribution in an agricultural mosaic, southeastern Brazil

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

Western blot analysis of tick antigens from a Rhipicephalus sanguineus unfed larval extract and identification of antigenic sites in tick sections using immunohistochemistry. A comparative study between resistant and susceptible host species

Most parasite-host relationships are characterized by the development of resistance by the host, thus limiting the number of parasites. However, some cases are very unusual. In the relationship of the domestic dog with the brown dog-tick Rhipicephalus sanguineus this does not occur, whereas guinea pigs develop efficient resistance. Sera from domestic dogs, crab-eating foxes and guinea pigs collected before and after infestation with R. sanguineus ticks, and after immunization with a whole tick adult or larval homogenate, were used in Western blot analysis to compare and identify potential important antigens from a tick larval homogenate. The same sera were tested in an indirect immunohistochemistry assay in an attempt to compare relevant antigenic sites on histological tick sections. The immunoblotting displayed antigens recognized only by the guinea pigs, as well as several shared antigens between host species, depending on the kind of immunization. Immunohistochemistry revealed probable antigenic sites on the cells and tissues of ticks, which varied depending on the kind of immunization (infestation or vaccination) and the animal species involved.

Influence of temperature on larval survival, development and respiration in Chasmagnathus granulata (Crustacea, Decapoda)

Larvae of an estuarine grapsid crab Chasmagnathus granulata Dana 1851, from temperate and subtropical regions of South America, were reared in seawater (32 ‰) at five different constant temperatures (12, 15, 18, 21, 24 °C). Complete larval development from hatching (Zoea I) to metamorphosis (Crab I) occurred in a range from 15 to 24 °C. Highest survival (60% to the first juvenile stage) was observed at 18°C, while all larvae reared at 12°C died before metamorphosis. The duration of development (D) decreased with increasing temperature (T). This relationship is described for all larval stages as a power function (linear regressions after logarithmic transformation of both D and T). The temperature-dependence of the instantaneous developmental rate (D-1) is compared among larval stages and temperatures using the Q10 coefficient (van't Hoff's equation). Through all four zoeal stages, this index tends to increase during development and to decrease with increasing T (comparing ranges 12-18, 15-21, 18-24 °C). In the Megalopa, low Q10 values were found in the range from 15 to 24 °C. In another series of experiments, larvae were reared at constant 18°C and their dry weight (W) and respiratory response to changes in T were measured in all successive stages during the intermoult period (stage C) of the moulting cycle. Both individual and weight-specific respiration (R, QO2) increased exponentially with increasing T. At each temperature, R increased significantly during growth and development through successive larval stages. No significantly different QO2 values were found in the first three zoeal stages, while a significant decrease with increasing W occurred in the Zoea IV and Megalopa. As in the temperature-dependence of D, the respiratory response to changes in temperature (Q10) depends on both the temperature range and the developmental stage, however, with different patterns. In the zoeal stages, the respiratory Q10 was minimum (1.7-2.2) at low temperatures (12-18 °C), but maximum (2.2-3.0) at 18-24 °C. The Megalopa, in contrast, showed a stronger metabolic response in the lower than in the upper temperature range (Q10 = 2.8 and 1.7, respectively). We interpret this pattern as an adaptation to a sequence of temperature conditions that should typically be encountered by C. granulata larvae during their ontogenetic migrations: hatching in and subsequent export from shallow estuarine lagoons, zoeal development in coastal marine waters, which are on average cooler, return in the Megalopa stage to warm lagoons. We thus propose that high metabolic sensitivity to changes in temperature may serve as a signal stimulating larval migration, so that the zoeae should tend to leave warm estuaries and lagoons, whereas the Megalopa should avoid remaining in the cooler marine waters and initiate its migration towards shallow coastal lagoons.

Reproductive patterns of Aratus pisonii (Decapoda: Grapsidae) from an estuarine area of São Paulo Northern Coast, Brazil

This paper describes the frequency of occurrence and reproductive patterns of the tree mangrove crab Aratus pisonii. Monthly samples were taken from January 1993 to June 1994 in an estuarine mangrove from Ubatuba region, Brazil. A total of 1 078 animals, 489 males and 589 females (131 ovigerous females) were collected. Carapace width ranged from 4.2 to 25.9 mm. A summer reproductive peak followed by a recruitment juvenile pulse was verified. Females were more abundant than males in the intermediate size classes. The sex-ratio in several months was biased towards females, suggesting a poligynous population and migration of females to mangrove fringes at the time of incubation and spawning.

Comparação do peso dos quelípodos e crescimento em duas espécies de sirís do gênero Callinectes (Brachyura, Portunidae)

A comparison of the cheliped's weight in two species of the genus Callinectes was accomplished. The species C. danae e C. ornatus were collected by two otter trawl in Ubatuba bay (23°26' S and 45°02' W). The allometric constants obtained from the regression adjusted to a power function (Y = aXb) were analyzed. These species presented different allometry degrees for each sex considered. The relation PQ x PC presented positive allometry for sex of both species, but male presented higher positive allometry than female. C. danae presented higher positive allometry for chelipeds than C. ornatus. We suggest here that C. danae could be indicated to be submitted to grow out in ponds since it reaches higher size and bigger chelipeds. © 1998, Paraná Institute of Technology Publication.

Population biology of Callinectes ornatus Ordway, 1863 (Decapoda, Portunidae) from Ubatuba (SP), Brazil

Population structure and reproductive season of the portunid crab Callinectes ornatus were studied in animals collected from the Ubatuba bays, Sao Paulo, Brazil (23°20' to 23°35' S and 44°50' to 45°14' W). The samples were taken in three trawls performed every other month from January 1991 to May 1993. A total of 3,829 specimens of C. ornatus were obtained. Their size ranged from 9.3 to 84.6 mm (carapace width). Their median size based on their cephalothoracic width and their size frequency were determined as well. Their reproduction was continuous, with variable proportions of ovigerous females. The highest incidence of ovigerous females occurred in January 1991, 1992 and 1993 and March and November 1992. The oscillations of the environmental factors between the seasons are not so intense in subtropical regions, therefore allowing the continuity of the physiological process of growth and reproduction throughout the year.

Larval development of Epialtus bituperculatus H. Milne Edwards, 1834 (Crustacea: Decapoda: Brachyura: Majidae) with comments on majid larvae from the southwestern Atlantic

The larval development of the spider crab Epialtus bituberculatus H. Milne Edwards which lives on rocky shores with algae such as Sargassum and Hypeneia, is described. Larvae were obtained from ovigerous females collected in Ubatuba, State of São Paulo, Brazil. Rearing was carried out at 24 ± 1°C, with an average salinity of 35%. Larval development consists of two zoeal stages and one megalopa. Zoeal development was completed in 9.5 days. Analysis indicated that zoeae of E. bituberculatus are very similar to those of E. brasiliensis Dana and Acanthonyx scutiformis (Dana). Differences noted between these species pertain to the setation of the carapace, maxillule and second maxilliped. The main morphological features useful for identification are presented together with a summary of features that characterize larvae of majid subfamilies in Brazil. A key for the identification of southwestern Atlantic majid zoeae to the family level is provided.