Chironomidae (Diptera: Insecta) in oceanic islands:New records for the Azores and biogeographic notes

摘要

Oceanic islands freshwater systems are unique due to their volcanic origin, oceanic situation,catchment morphology and the presence of distinct freshwater communities when compared with continentalsystems. This study provides an update of Azorean chironomid fauna records, distribution data and includesbiogeographical comments, based on collections covering a range of freshwater habitats on several islandsover 2005 to 2008. Island species area-relationships or ISAR was performed as a descriptive model for speciesaccumulation patterns in each island in relation to their area. Six new chironimid species records are given forthe Azores archipelago: Orthocladiinae: Orthocladius (Eudactylocladius) fuscimanus (Kieffer, 1908), Pseudo-rthocladius (Pseudorthocladius) curtistylus (Goetghebuer, 1921), Synorthocladius semivirens (Kieffer, 1909),Parachaetocladius abnobaeus (Wulker, 1959); Chironominae: Chironomus (Chironomus) annularis (Meigen,1818), Parachironomus tenuicaudatus (Malloch, 1915). As a result, the Azorean chironomid fauna has in-creased from 38 to 44 species, spread across 33 genera. Most recorded chironomids are primarily of westernPalaearctic origin; Nearctic, Oriental and Neotropical regions are comparatively poorly represented. A check-list is provided, incorporating and updating previous records. Chirononidae distribution pattern among theislands is analyzed and island species area-relationship (ISAR) analyses, performed to provide a descriptivemodel for species accumulation patterns in each island, indicated a positive correlation between species rich-ness (number of species) and the area of the Azorean islands, supporting MacArthur and Wilson's equili-brium theory of island biogeography. Chironomidae could be promising for searching candidate bioindicatorsto answer the demand of Water Frame Directive.