Ocorrência de três espécies do gênero Bledius Leach, 1819 (Coleoptera, Staphylinidae, Oxytelinae) nas praias arenosas expostas do Paraná, Brasil.

Abstract

The upper portions of sandy beaches usually have a strip of debris deposited by the action of waves and tides known as "drift line" or "stranded wrack". This deposit is inhabited by amphipods Talitridae and insects, particularly beetles of the family Staphylinidae. For their sensitive to environmental variations, these beetles can be considered important bio-indicators of sandy beach ecosystem health. In the southern coast of Brazil three species of the genus Bledius Leach, 1819 were reported: Bledius bonariensis, B. fernandezi and B. hermani. The present work analyses the relationship between sandy beach sedimentological and morphodynamic characteristics and the occurrence pattern of Bledius species from data obtained on a preliminary survey on 12 sandy beaches of Paraná state. B. hermani was the most abundant and frequent species, present in ten of the 12 beaches studied. B. fernandezi showed a positive correlation with morphodynamics and sedimentological characteristics. Furthermore, B. hermani was dominant on beaches with coarse sand and more reflective to intermediate morphodynamic. B. bonariensis showed higher densities at beaches with dissipative characteristics near the mouth of Paranaguá Bay. The highest densities of Bledius were recorded on inhabited Superagüi beaches, located in a national park. This suggests that the group could be affected by human interference, particularly urbanization.

Distribuição Espacial Da Macrofauna Bêntica Da Praia Da Avenida – Ilhéus-Ba, Brasil

“…Estudos anteriores têm detectado a ocorrência de espécies de Coleoptera da família Staphylinidae nos níveis superiores dos sistemas de praias arenosas (SCHREINER & OZORIO, 2003;ROSA et al 2008;GANDARA-MARTINS et al 2010). A associação da maior participação de insetos com a maior abundância do isopoda Excirolana braziliensis nos níveis mais elevados, da região de entre marés de praias arenosas, também foi registrada por BRAZEIRO & DEFEO (1996), na Praia da Barra Del Chuy (Uruguai).…”

Distribuição espacial e temporal de espécies de Bledius (Coleoptera, Staphylinidae) em praias arenosas no sul do Brasil

“…Entretanto, no caso de B. hermani, a linha de detritos não demonstrou ser um fator determinante para sua ocorrência. Segundo Gandara-martins et al (2010), esta espécie apresenta maior plasticidade em relação ao tamanho do grão do sedimento e não ocorre em locais onde o lençol freático é mais superficial, mostrando sua maior tolerância e/ou preferência por locais com maior salinidade.…”

“…Recentemente, outras duas espécies, Bledius hermani Caron & Ribeiro-Costa, 2007e B. fernandezi Bernhauer, 1939, têm sido reportadas para a Região Sul (borzone et al, 1996;borzone & souza, 1997;caron & ribeirocosta, 2007;Gandara-martins et al, 2010). Estas três espécies foram encontradas em locais próximos à zona supralitoral de praias arenosas expostas (souza & Gianuca, 1995;borzone et al, 1996;borzone & souza, 1997;Gandara-martins et al, 2010). Gianuca (1987) reportou B. bonariensis e suas larvas no supralitoral da praia do Cassino, no Rio Grande do Sul.…”

First record of Bledius caribbeanus Blackwelder, 1943 (Coleoptera: Staphylinidae: Oxytelinae) from Brazil and distributional extension of B. hermani Caron and Ribeiro- Costa, 2007

“…However, after a recent revision of the species of Bledius recorded from sandy beaches of Brazilian coast, Caron and Ribeiro-Costa (2007) These two species, B. caribbenaus and B. hermani, are morphologically very similar and mainly differences are higher size, elytra entirely black and sternite VII with just two prominent setae in B. caribbeanus, whereas B. hermani has pale yellow elytra with a basal and usually subapical median brownish spot and sternite VII with eight prominent setae arranged in a transverse row near the apex (Caron and Ribeiro-Costa 2007). The former species had its distribution restricted to Caribbean Sea (Jamaica, Dominican Republic and Trinidad and Tobago) (Frank and Ahn 2011), whereas the latter had been recorded to Brazilian south coast (Rio Grande do Sul and Paraná) (Caron and Ribeiro-Costa 2007;Gandara-Martins et al 2010). These samplings represent the first record of B. caribbeanus in Brazil and extend the known geographic distribution of B. hermani in approximately 2,000 km northwards (Figure 1).…”

“…Along Brazilian coast, studies dealing with sandy beaches insects are scarce and were mainly carried out at south region (Gianuca 1997;Schreiner and Ozorio 2003;Caron and Ribeiro-Costa 2007;Rosa et al 2008;Gandara-Martins et al 2010). In this way, further studies addressing the composition of sandy beach insects will be needed to help us understand the real diversity as well the distributional pattern of Bledius species along Brazilian coast.…”