Ultrastructure of the ovary of Dermatobia hominis (Diptera: cuterebridae). I. Development during the 3rd larval instar

The ultrastructure and distribution of gonial and somatic cells in the ovary of Dermatobia hominis was studied during the 3rd larval instar. In larvae weighing between 400 and 500 mg, the ovary is partially divided into basal and apical regions by oblong somatic cells that penetrate from the periphery; these cells show ovoid nucleus and cytoplasm full of microtubules. In both regions, gonial cells with regular outlines, large nucleus and low electron-density cytoplasm are scattered among the interstitial somatic cells. These later cells have small nucleus and electrodense cytoplasm. Clear somatic cells with small nucleus and cytoplasm of very low electron-density are restrict to the apical region of the gonad. Degenerating interstitial somatic cells are seen in the basal portion close to the ovary peduncle. During all this larval period the morphological features of the ovary remain almost the same. At the end of the period there is a gradual deposition of glycogen in the cytoplasm of the somatic cells, increase in the number and density of their mitochondria plus nuclear modification as membrane wrinkling and chromatin condensation in masses.

Germ line Cysts and the Formation of the Germinal Epithelium During the Female Gonadal Morphogenesis in Cyprinus Carpio (Teleostei: Ostariophysi: Cypriniformes)

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

Cytodifferentiation during the spermatogenesis of the hermaphrodite caridea Exhippolysmata oplophoroides

Among the decapods, the caridean Exhippolysmata oplophoroides has been described as a simultaneous protandric hermaphrodite, seeing that it presents a male initial stage followed by a hermaphrodite one in which it can function as male and as female. This work had the aims of characterizing the microscopical morphology of the male portion of the ovotestes gonads from E. oplophoroides, at the different development stages, identifying each cell from the germ lines during spermatogenesis, as well as describing the ultramorphology of spermatozoans in the terminal region of the vasa deferentia. Shrimps were collected in Ubatuba, north coast of São Paulo, and their male gonads and the ampoule were removed, fixed and processed according to histological routine and for scanning electron microscopy. The testicular portion is divided in lobes, inside which cells at the same stage of the spermatogenic cycle are observed, with prevalence of spermatogonia and spermatocytes at stages I, II and V of gonad development, whereas spermatids and spermatozoans are found at stages III and IV, respectively. Ultramorphology of the terminal portion of the vasa deferentia exhibits mature aflagellated spike-shaped spermatozoans, encased in secretion and between membrane foldings that will constitute the spermatophores. Despite presenting reproductive characteristics common to other decapods. E. oplophoroides shows spermatozoans as well as spermatophore with typical morphology, which is important for its identification and taxonomy. Further, this species showed polysaccharide secretions where the spermatozoa are immerse as far as the testicular portion, which could have a roe in their transport and nutrition as well as spermatophore constitution and/or fixation; differently, other caridean species begin spermatophore formation during the passage of the gametes through the vasa deferentia. (C) 2010 Elsevier Ltd. All rights reserved.

Influence of a cage farming on the population of the fish species Apareiodon affinis (Steindachner, 1879) in the Chavantes reservoir, Paranapanema River SP/PR, Brazil

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

MORPHOLOGICAL EVIDENCE FOR PROTANDRIC SIMULTANEOUS HERMAPHRODITISM IN THE CARIDEAN EXHIPPOLYSMATA OPLOPHOROIDES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Population and reproductive biology of the crab Uca burgersi (Crustacea : Ocypodidae) in three subtropical mangrove forests

Population and reproductive biology were studied in three populations of the crab Uca burgersi Holthuis, 1967, in the Indaia, Cavalo and Ubatumirim mangrove forests (Ubatuba, São Paulo State, Brazil). Crabs were collected during low tide (August 2001 through July 2002), by digging the sediment, with a standard capture effort (two persons for 30 min.). Carapace width was measured, and gonad developmental stage was recorded from all specimens. U. burgersi was most abundant in the Cavalo mangrove, where the largest mate was found. Juvenile crabs were found year-round at all three sites. However, the ratio of ovigerous females was very low, even null in the Cavalo mangrove. The gonad development rate indicated that U. burgersi was reproducing continuously, but more intensively during spring and summer, with recruitment occurring in winter. The synchrony between the populational and reproductive biology in the three areas showed that local features were not the limiting factors. It is suggested that this species is a habitat generalist.

Ecological distribution and reproductive period of the hermit crab Loxopagurus loxochelis (Anomura, Diogenidae) on the northern coast of São Paulo State, Brazil

The present study aimed to determine the ecological distribution of Loxopagurus loxochelis as a function of selected environmental factors, as well as its reproductive period based on the combined analysis of the presence of ovigerous females and the development of the gonad. The collections were carried out monthly from January to December 2000 in the region of Ubatuba (SP), using a fishing boat equipped with two double rig nets, in isobaths of 5, 10, 15, 20, 25, 30, 35 and 40 m, at which depths samples of sediment and water were collected. The cephalothoracic shield length and sex of the animals were determined; the abdomen was dissected to verify gonad development stages. A total of 334 individuals was obtained ( 196 males, 48 ovigerous females and 90 non-ovigerous females) with sizes varying from 3.0 to 8.6 mm (5.7 +/- 1.0 mm). A greater abundance of L. loxochelis (95.2%) was observed at depths of 20 and 25 m. These sites mainly revealed a substratum stable with a very fine sand fraction, which facilitates the habit of embedding shown by this hermit. With regard to gonadal analysis, it was possible to classify four gonad development stages for each sex: immature, rudimentary, developing and developed. It was observed that in the winter months about 71% of the females had gonads either developing or developed and 67% were ovigerous. Therefore, the winter period can be considered the peak of reproduction for this species, characterizing a typical seasonal-continuous reproduction.

Morphometric study of the ghost crab Ocypode quadrata (Fabricius, 1887) (brachyura, ocypodidae) from Ubatuba, São Paulo, Brazil

A morphometric study of the ghost crab Ocypode quadrata from Ubatuba, São Paulo, Brazil, focusing on the relationships between carapace width and carapace length, abdomen width, gonopod length and propodus length and height of the major cheliped is presented. An allometric positive growth was found for most of the analyzed relationships; however, important changes in the gonopod and abdomen were observed at the size at which sexual maturity is attained. Morphological (external) sexual maturity for both sexes is achieved at a smaller size than that at which gonad maturity is reached. Concerning heterochely, 53.3% of the analyzed specimens exhibited a longer propodus length in the right cheliped.

Reproductive cycle and recruitment period of Ocypode quadrata (Decapoda, Ocypodidae) at a sandy beach in southeastern Brazil

The reproductive cycle and recruitment period of a ghost crab population from Ubatuba, São Paulo, Brazil were investigated by means of examining the developmental stages of gonads of breeding crabs and the ingress of young recruits to the studied population. Monthly collections over a one-year period were carried out during nocturnal low-tide periods at Vermelha beach. The morphology of the abdomen and pleopods was used for sex determination. All captured crabs were measured for carapace width and dissected for the determination of the development stage of the gonads. A total of 582 specimens was captured: 271 males, 241 females, and 70 juveniles. Size ranged from 8.5 to 37.5 mm for males, from 9.5 to 39.2 mm for females, and from 5.8 to 12 mm for early juveniles. Median size of males and females did not differ statistically. The frequency of ovigerous females was markedly low. The onset of sexual maturity in females is achieved at around 23 mm of carapace width. Mature females with advanced gonad stages were not recorded from May to September. Recruitment of young was highest during summer, but the presence of early and late juvenile specimens throughout the year indicates that continuous recruitment is taking place in the studied population.

Reproduction of the speckled swimming crab Arenaeus cribrarius (Brachyura : portunidae) on the Brazilian coast near 23 degrees 30 ' S

The reproductive biology of Arenaeus cribrarius from Ubatuba, São Paulo State, Brazil, was studied. Swimming crabs were sampled monthly for two years with otter trawls in two bays. A total of 941 males and 1,012 females were examined. Mating took place mainly in autumn involving postmolt females and intermolt males. At that time, gonad regression was verified in adult males, due to spermatophore transfer, and the molting of adult females. Ovigerous females or females with mature gonads were present year-round but more frequently captured during spring and summer. We found that 19, of all adult females were premolt, which indicated the occurrence of another mature instar and thus the absence of a well-defined terminal molt after puberty. Intermolt males were captured throughout the whole study period.

Breeding season of the hermit crab petrochirus diogenes (anomura : diogenidae) in the north coast of São Paulo state, Brazil

Petrochirus diogenes, one of the largest hermit crabs in the western Atlantic, was studied in the north coast of the State of São Paulo, Brazil, to determine its breeding season through the analysis of gonad development at a macroscopic level. The analysis of 999 crabs collected from 1995 to 1999, based on four categories of gonad development, showed that males present gonads in the advanced stage during all seasons, and although females present developed ovaries all year as well, the peak incidence is in the summer. The peak of recruitment occurs in the winter.

Sexual maturity of Eurytium limosum (say 1818) from a subtropical mangrove in Brazil

The size at onset of maturity of Eurytium limosum from a subtropical mangrove in Brazil was investigated. In this species, sexual maturity for males can be indicated by the allometric growth and gonopod length. For females, the morphological sexual maturity can only be externally verified through the relative quantity of setae along the abdominal margins and pleopods. Internally, gonad development was also examined. The size at which half of the population is physiologically mature was 11.6 mm of CW for females and 12.3 mm of CW for males. The values for the morphological and physiological maturity are very similar, indicating that the development of the secondary sexual characters is synchronized with the achievement of the physiological maturity for E. limosum.

Population biology of the burrowing crab Neohelice granulata, (Crustacea: Decapoda: Varunidae) from a tropical mangrove in Brazil

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

Reproductive cycle and ovarian development of the marine ornamental shrimp Stenopus hispidus in captivity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of cytotoxic effects of fipronil on ovaries of semi-engorged Rhipicephalus sanguineus (Latreille, 1806) (Acari : Ixodidae) tick female

The ovary of the Rhipicephalus sanguineus dog tick female is structurally formed by oocytes in five different stages of development (from I to V) and attached to the gonad by the pedicel. The present study evaluated possible toxic effects of the acaricide fipronil (Frontline (R)) on ovaries of semi-engorged ticks. Sixty partially fed females of R. sanguineus tick were distributed into four groups of 15 specimens each: I - non-treated; II, III and IV - treated with 1, 5 and 10 ppm of fipronil, respectively. The acaricide induced structural changes in the oocytes of individuals of the different treated groups ranging from the presence of a few small vacuoles to cellular death. In conclusion, germinative cells of semi-engorged R. sanguineus tick female are affected by different concentrations of fipronil leading to the reduction of tick fertility. (c) 2008 Elsevier Ltd. All rights reserved.