Dinâmica populacional do caranguejo Austinixa aidae (Brachyura, Pinnotheridae): simbionte de Callichirus major (Thalassinidea, Callianassidae) no Atlântico sudoeste

The Pinnotheridae family is one of the most diverse and complex groups of brachyuran crabs, many of them symbionts of a wide variety of invertebrates. The present study describes the population dynamics of the pea crab Austinixa aidae (Righi, 1967), a symbiont associated with the burrows of the ghost shrimp Callichirus major (Say, 1818). Individuals (n = 588) were collected bimonthly from May, 2005 to September, 2006 along a sandy beach in the southwestern Atlantic, state of São Paulo, Brazil. Our data indicated that the population demography of A. aidae was characterized by a bimodal size-frequency distribution (between 2.0 and 4.0 mm and between 8.0 and 9.0 mm CW) that remained similar throughout the study period. Sex ratio does not differ significantly from 1:1 (p > 0.05), which confirms the pattern observed in other symbiontic pinnotherids. Density values (1.72 ± 1.34 ind. • ap.-1) are in agreement with those found for other species of the genus. The mean symbiosis incidence (75.6%) was one of the highest among species of the Pinnotheridae family, but it was the lowest among the three studied species of the genus. Recruitment pattern was annual, beginning in May and peaking in July, in both years, after the peak of ovigerous females in the population (from March to May). Our findings describe ecological and biological aspects of A. aidae similar to those of other species of this genus, even from different geographic localities.Pinnotheridae constitui um dos mais diversos e complexos grupos de caranguejos, sendo muitos deles simbiontes de uma grande variedade de invertebrados. O presente estudo descreve a dinâmica populacional do caranguejo pinoterídeo Austinixa aidae (Righi, 1967), um simbionte que vive associado às galerias do "corrupto" Callichirus major (Say, 1818). Os exemplares (n = 588) foram coletados a cada dois meses entre maio de 2005 e setembro de 2006, em uma praia arenosa no litoral de São Paulo, Brasil. Nossos resultados indicaram que a população de A. aidae foi caracterizada por uma distribuição bimodal em classes de tamanho (entre 2,0 e 4,0 mm (CC: comprimento da carapaça) e entre 8,0 e 9,0 mm (CC)), padrão constante ao longo do período de estudo. A razão sexual não diferiu significativamente de 1:1 (p > 0,05), confirmando o padrão observado para outros pinoterídeos simbiontes. Os valores de densidade desta espécie (1,72 ± 1,34 indivíduos por toca) estão de acordo com os estabelecidos para o gênero. A incidência média (75,6%) está entre as mais altas das espécies de Pinnotheridae, entretanto é a menor dentre as três espécies do gênero já estudadas. O padrão de recrutamento foi anual (tendo início em maio e atingindo maior proporção em julho, nos dois anos de estudo), e foi registrado após os picos de ocorrência de fêmeas ovígeras na população (de março a maio). Nossos resultados confirmam que A. aidae possui padrões ecológicos e biológicos similares aos desenvolvidos pelas espécies do gênero, mesmo em diferentes localidades

Avaliação dos camarões atiídeos (Decapoda: Atyidae).

Introdução. Distribuição geográfica. Habitat e ecologia. Biologia geral. Ameaças. Ações de conservação. Pesquisas necessárias. Bibliografia. Espécies avaliadas no processo conduzido pelo ICMBio.bitstream/item/165868/1/CNPASA-2016-cap5.pd

Population structure of the deep sea hermit-crab Catapaguroides microps (Paguroidea, Anomura) in the Campos Basin, RJ, Brazil

The population of Catapaguroides microps A. Milne-Edwards and Bouvier, 1892 in the Campos Basin was studied with an emphasis on its composition in the Northern and Southern parts of the Basin, the different gender sizes, sex ratio, and size class distribution. Specimens were collected under the "Program for the Environmental Characterization of the deep waters of the Campos Basin" ("Programa de Caracterização Ambiental das Águas Profundas da Bacia de Campos") in February and August 2003. A total of 339 hermit crabs were analyzed. Individual abundance was higher in the North. C. microps shows sexual dimorphism for body size, the males being larger than the females. The sex ratio is skewed in the female's favor (1:0.7), as shown by previous studies on shallow-water populations.A população de Catapaguroides microps A. Milne-Edwards and Bouvier, 1892 da foi analisada com foco na abundância de indivíduos, diferença de tamanho entre machos e fêmeas, razão sexual e distribuição dos indivíduos nas classes de tamanho, ao norte e ao sul da Bacia de Campos. As amostras foram coletadas pelo Programa de Caracterização Ambiental da Bacia de Campos em fevereiro e agosto de 2003. O total de indivíduos analizados foi de 339. A abundância foi maior no norte da Bacia de Campos. Catapaguroides microps mostrou dimorfismo sexual no tamanho do corpo, sendo os machos maiores que as fêmeas. A razão sexual favorece as fêmeas (1:0,7), de forma similar a outros estudos efetuados com populações de águas rasas

Feeding spectra and activity of the freshwater crab Trichodactylus kensleyi (Decapoda: Brachyura: Trichodactylidae) at La Plata basin

Background: In inland water systems, it is important to characterize the trophic links in order to identify the ‘trophic species’ and, from the studies of functional diversity, understand the dynamics of matter and energy in these environments. The aim of this study is to analyze the natural diet of Trichodactylus kensleyi of subtropical rainforest streams and corroborate the temporal variation in the trophic activity during day hours. Results: A total of 15 major taxonomic groups were recognized in gut contents. The index of relative importance identified the following main prey items in decreasing order of importance: vegetal remains, oligochaetes, chironomid larvae, and algae. A significant difference was found in the amount of full stomachs during day hours showing a less trophic activity at midday and afternoon. The index of relative importance values evidenced the consumption of different prey according to day moments. Results of the gut content indicate that T. kensleyi is an omnivorous crab like other trichodactylid species. Opportunistic behavior is revealed by the ingestion of organisms abundant in streams such as oligochaetes and chironomid larvae. The consumption of allochthonous plant debris shows the importance of this crab as shredder in subtropical streams. However, the effective assimilation of plant matter is yet unknown in trichodactylid crabs. Conclusions: This research provides knowledge that complements previous studies about trophic relationships of trichodactylid crabs and supported the importance of T. kensleyi in the transference of energy and matter from benthic community and riparian sources to superior trophic levels using both macro- and microfauna.Fil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: de Azevedo Carvalho, Debora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

The reproductive performance of the Red-Algae shrimp Leander paulensis (Ortmann, 1897) (Decapoda, Palaemonidae) and the effect of post-spawning female weight gain on weight-dependent parameters

AbstractDecapod species have evolved with a variety of reproductive strategies. In this study reproductive features of the palaemonid shrimp Leander paulensiswere investigated. Individuals were collected in the coastal region of Ubatuba, São Paulo, Brazil. In all, 46 ovigerous females were examined in terms of the following reproductive traits: fecundity, reproductive output, brood loss and egg volume. Leander paulensis produces a large number of small eggs with an average fecundity of 635 ± 246 eggs. Egg volume increased significantly from early (0.034 ± 0.008 mm3) to late development stage (0.05 ± 0.012 mm3). The reproductive output did not correlate with female size. The weight of females bearing stage 2 eggs was significantly higher than that of females carrying stage 1 eggs. We assume that the reason for this weight gain is the recovery of female reserves that have been depleted for egg production. Moreover, we emphasize that this weight gain must be considered when evaluating weight-dependent variables such as reproductive output or brood loss in relation to female weight. Otherwise, an overestimation of these variables might lead to inaccurate results