Distribuição temporal do ermitão Clibanarius vittatus (Anomura, Diogenidae) no litoral do Paraná

Abstract

ABSTRACT. Temporal distribution of the hermit crab Clibanarius vittatus (Anomura, Diogenidae) from Paraná State coast, Brazil. A study on the temporal fluctuation of the population structure of the hermit crab Clibanarius vittatus (Bosc, 1802) was carried out at Baixio Mirim tideflat, Guaratuba Bay, Paraná State, southern Brazil (25°52'S, 48°36'W). Clibanarius vittatus is a species widely studied, but studies of population biology of these hermit crabs in different regions are scarce. Samplings were done in the intertidal zone, monthly, from April/2005 to March/2006. A total of 1187 hermit crabs were obtained, among which, 949 males, 22 intersexes, 204 nonovigerous females and 12 ovigerous females. The cephalothoracic shield length (CSL) was measured and grouped in 10 size classes. Males were distributed in 10 CSL classes while intersexes and females occurred only in six size classes. Males predominated in every month and in the whole population. All demographic categories were present all year round, except intersexes and ovigerous females. These were uncommon and occurred from late spring until autumn and in august/2005. The reproduction was considered seasonal-continuous, with higher intensity in the warmer months. The observed sex ratio in this population, that was different from other ones, corroborates the theory of migration for this species. The present research constitutes the first record of reproductive period of C. vittatus population occurring in warm subtropical shallow waters. KEYWORDS.Intertidal hermit crabs, reproductive period, intersexes, sex ratio, size classes. RESUMO. Um estudo sobre a flutuação temporal da estrutura populacional do ermitão PALAVRAS-CHAVE.Ermitões da zona entremarés, período reprodutivo, intersexos, razão de sexos, classes de tamanho.

Spatiotemporal distribution and population structure of Clibanariussymmetricus(Randall, 1840) (Crustacea, Diogenidae) in an Amazon estuary

“…Mantelatto et al (2010) also recorded continuous reproduction in a population in tropical northeastern Brazil, which indicates that this may be the typical pattern for C. symmetricus in tropical and equatorial regions. In subtropical regions, however, seasonal breeding is the norm (Turra and Leite, 2000;Sampaio et al, 2009;Sant' Anna et al, 2009;Mantelatto et al, 2010). This indicates that the breeding pattern of these hermit crabs varies by latitude, as observed by van de Kerk et al (2016), who concluded that the reproductive strategies of a species, such as its breeding frequency, may vary along a latitudinal gradient.…”

“…The relative rarity of intersex individuals (5.57%) appears to be a common feature of C. symmetricus populations throughout its geographic range. Turra and Leite (2000) found that 5%-7% of a population in a subtropical region was intersex, and even lower frequencies have been recorded in other tropical and subtropical areas, with Sant' Anna et al (2009) recording a frequency of 2.5%, Sampaio et al (2009) recording one of 1.9%, and Mantelatto et al (2010) only 0.3%.…”

“…Populations studies provide important insights into the distribution of a species and the adaptive mechanisms that determine this distribution, as well as the abundance of the organism (Mantelatto et al, 2010). However, in the specific case of C. symmetricus, population studies have been restricted mainly to the subtropical coast of southern Brazil (e.g., Sampaio et al, 2009;Sant' Anna et al, 2009;Mantelatto et al, 2010), and no ecological data are available from the equatorial region.…”

“…Seasonal breeding has been recorded in subtropical populations, for example (Turra and Leite, 2000;Sant' Anna et al, 2009;Mantelatto et al, 2010), whereas continuous reproduction has been reported from tropical South America (Mantelatto et al, 2010), with more intense reproductive activity being recorded in warmer months (Sant' Anna et al, 2009). The species is sexually dimorphic, with males being larger than females (Turra and Leite, 2000;Sampaio et al, 2009;Sant' Anna et al, 2009;Mantelatto et al, 2010), and while most populations have a biased sex ratio, there is no systematic pattern with the bias favoring either the males or the females in different populations (Negreiros-Fransozo et al, 1991;Turra and Leite, 2000;Sant' Anna et al, 2009;Mantelatto et al, 2010).…”

Carcinofauna bêntica estuarina de dois manguezais da costa amazônica maranhense, Brasil

“…As larvas de C. vittatus não toleram baixas salinidades e por esse motivo as fêmeas ovígeras migram para regiões mais estáveis e com maior teor de salinidade (Sampaio et al, 2009). Por outro lado, em indivíduos adultos a tolerância a variações desse parâmetro ambiental gira em torno de 10 a 38, onde esses organismos são normalmente encontrados em estuários, associados ao fundo de lama e areia (Almeida et al, 2010).…”