Entomological fauna from Reserva Biológica do Atol das Rocas, RN, Brazil: I. Morphospecies composition

Abstract

Atol das Rocas, the unique atoll in the South-western Atlantic, is located 144 nautical miles (266 Km) northeast from the city of Natal, NE Brazil and 80 nautical miles from Arquipélago de Fernando de Noronha, with geographic co-ordinates 3º51'S and 33º49"W. It's of volcanic origin and coralline formation. The reef is ellipsoid, its largest axis (E-W) is approximately 3.7 km long, and the shortest (N-S) is 2.5 km. Inside the lagoon, there are two islands: the Ilha do Farol and Ilha do Cemitério, which comprehend 7.2 Km 2 of emerged area. The Atol das Rocas lodges 143,000 birds, mainly by Sula dactilatra, S. leucogaster, Anous stolidus, A. minuta and Sterna fuscata. Due to their remote location, the islands remain largely undisturbed by the human activities. Aiming to a first characterization of the entomological diversity and the general trophic niches of atoll's entomofauna, three collects were made (1994, 1995 and 1996) utilizing several methods for a wide sample. One thousand six hundred and six insect specimens were collected belonging to eight orders: 1. Coleoptera -333 individuals of Dermestidae (Dermestes cadaverinus); Tenebrionidae (Phaleria testacea and morphospecies) and Curculionidae (one morphospecies); 2. Dermaptera -50 individuals of Carcinophoridae (Anisolabis maritima); 3. Diptera -281 individuals of Ephydridae (Scatella sp. and Hecamede sp.) and Hippoboscidae (one morphospecies); 4. Hymenoptera -45 individuals of Formicidae (Brachymyrmex sp.); 5. Lepidoptera -111 individuals of Microlepidoptera (one morphospecies); 6. Mallophaga -18 individuals in birds (two morphospecies); 7. Orthoptera -237 individuals of Acrididae (Schistocerca cancellata), Tridactylidae (one morphospecies) and Blattidae (three morphospecies); 8. Thysanoptera -531 individuals (one morphospecies). Also were collected 112 individuals of Arachnida. The taxa of the Order Araneae were represented by the families: 1. Miturgidae (Cheiracanthium inclusum); 2. Salticidae (two morphospecies) and 3. Segestriidae (Ariadna sp.); 4. Theridiidae (Achaearanea sp. and Latrodectus geometricus). For the Order Scorpionida, only samples of Buthidae (Isometrus maculatus) were collected. Through field observations, it was concluded the most insects are detritophagous and/ or necrophagous. It is suggested that which the dimension of ecological niches of the insects are a function of the droppings, trash and corpses of birds. A low diversity in the entomofauna of atoll, with its 25 morphospecies, was ascertained.Key words: Atol das Rocas, entomological fauna of islands, trophic niche. (1994, 1995, 1996)

Spider Diversity on the Oceanic Island of Fernando De Noronha, Brazil, and Implications for Species Conservation

“…Low diversity and heterogeneity of species composition was documented in a field survey at the Atoll das Rocas (Almeida et al 2000); in this unique atoll 266 km from the Brazilian coast that shares some characteristics with Fernando de Noronha islets, only four Araneae species were reported, one of them being C. inclusum , which was reported here.…”

Utilização de coleópteros na preparação de material osteológico

“…Os estágios larvares destes coleópteros são necrófagos 10,11 . Um estudo da fauna entomológica da reserva biológica do Atol das Rocas revelou que Dermestes cadaverinus, da família Dermestidae, ordem Coleoptera, em sua forma larvar e adulta, quando presentes em corpos de pássaros mortos, aceleravam o processo de decomposição 12 . Os dermestídeos, adultos e larvas, são saprófagos ou necrófagos, alimentam-se da matéria orgânica deixada por outros destruidores de carcaças de animais, músculos e tendões, que ficam presos aos ossos.…”