Diptera research in Hawaii dates to the latter part of the 18th century when RCL Perkins was employed to survey the terrestrial biota of the Hawaiian Archipelago (Evenhuis 2007). Subsequent research by Sweezy, Bryan, Williams, Cresson, Wirth, Hardy and others greatly expanded the number of endemic species and refined our understanding of their relationships (reviewed in Zimmerman and Liebherr 2001). The senior author's laboratory has been collecting Hawaiian Diptera for the past 15 years in order to elucidate the patterns and processes involved in the impressive radiations seen in these lineages in the Hawaiian Islands. We have amassed a large amount of fine-scale distributional data and new island records for many species and this is the second in a series of papers on the taxonomy and distribution of endemic Hawaiian Diptera. The current paper reports four new island records from the genus Scatella (Diptera: Ephydridae) and provides a comprehensive catalog of the available material in the Bernice Pauahi Bishop Museum (BPBM), University of Hawaii at Manoa (UHM), and Essig Musuem of Entomology at UC Berkeley (EMEC).

Ephydridae, or the shore flies, is a cosmopolitan family of ecologically diverse acalyptrate Diptera, with 2000 species placed in five subfamilies (Mathis and Zatwarnicki 1995, Pape et al. 2011). Most ephydrids are aquatic or semi-aquatic, but some genera have adapted to harsh environments and can survive in high elevations, sulfurous hot springs, highly alkaline or saline lakes, and even in pools of crude petroleum (Evenhuis 2008, Foote 1995). Many ephydrids are beneficial and provide food for wildlife, such as migratory birds (Wirth et al. 1987). Others are agricultural pests, mining in the stems or leaves of watercress, rice, barley, and other irrigated cereals (Grigarick 1959). The majority of native Hawaiian ephydrids are placed in the cosmopolitan genus Scatella, a group containing a total of 135 species (Brown 2010). Scatella is widespread in the Pacific basin and it has been recorded from Hawaii, French Polynesia, Western Samoa, Australia, New Zealand, and Easter Island (http://hbs.bishopmuseum.org/aocat/aocathome.html). There are 17 Hawaiian species (Table 1), 15 of which are endemic (Nishida 2002). Scatella has a complex taxonomic history, particularly in Hawaii. Tenorio (1980) classified these taxa in three separate genera (Scatella, Neoscatella, and Apulvillus), but they have since been combined into the same genus. Ten species are found on multiple islands and only five (cinereifacies, kauaiensis, williamsi, wirthi, and femoralis) are single island endemics (Nishida 2002).

Literature and specimen review

Collection methods

Species distribution maps