ARTICLE Taxonomy of black scavenger flies (Diptera: Sepsidae) from Luzon, Philippines Socrates D. Letana Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines ourteen species of black scavenger flies in four gene- (Ozerov 2005, Ozerov 2010, Iwasa 2008, Iwasa et al. 2008, Ang ra are treated taxonomically in this paper. Five spe- and Meier 2010). This discovery is largely from the Afrotropical cies belonging to the subfamily Sepsinae are record- region, also with the highest generic endemicity, with some rep- ed for the first time in the Philippines, namely: Sep- resentatives in the Neotropics, Oriental and Australasian regions. sis sepsi Ozerov, Dicranosepsis dudai Ozerov, Di- There are about 78 species and two endemic genera from the Fcranosepsis transita Ozerov, Dicranosepsis sauteri Ozerov, and Oriental region (5.4% generic endemism) (Ozerov 2005). Iwasa Dicranosepsis pseudotibialis Ozerov. A new Philippine island mainly contributed to the discovery and description of the Asian distribution record of Australosepsis niveipennis (Becker) is also and Oriental species (Iwasa 1980, Iwasa 1981, Iwasa 1982, noted. Taxonomic keys for the genera and species are presented. Iwasa 1984a, Iwasa 1984b, Iwasa 1985, Iwasa 1986, Iwasa 1995, Iwasa 1999, Iwasa 2001, Iwasa 2007, Iwasa 2008). INTRODUCTION The taxonomic literature and knowledge regarding the Phil- In the most recent world catalogue of Sepsidae (Ozerov ippine black scavenger flies are very limited. The early works of 2005), there are about 37 genera with 312 described species of Duda (1926a,b) and Zuska (1977b) included Philippine materi- black scavenger flies worldwide. Twelve genera are distributed als. Later, Baltazar’s inventory of Philippine insects (Baltazar in the Oriental region and six of these are from the Philippines. 1990) paved the way for gathering pertinent information about Previously, Baltazar (1990) listed 12 species in five genera of this group and there are four species added since then in the sepsid flies from the Philippines. In his catalogue, Ozerov (2005) world catalogue (Ozerov 2005). Taxonomic keys in the generic accounted for 14 species in six genera, adding Toxopoda viduata and species levels, literature citation, general description, distri- and three more species of Dicranosepsis. Iwasa (2008) described bution and illustrations are included in this study. and added Toxopoda angulata as a Philippine endemic. The Sep- sidae of the Philippines have been poorly investigated and rec- This work is limited to the collections made in Luzon, Phil- ords are scattered. This study includes 14 species, five of which ippines (Camarines Norte: Daet; Laguna: Mt. Makiling, Univer- are reported for the first time. sity of the Philippines (UP) Los Banos (UPLB), International Rice Research Institute (IRRI), UP Land Grant; Pangasinan: From 2000 to 2010, approximately an average of six sepsid Sison; Quezon: Alabat island; and Zambales) covering a variety fly species per year are being discovered and are new to science of ecosystems, such as ricefields, pasture and grazing land, resi- dential area, coastal area, dipterocarp forest, and bordering *Corresponding author mossy forest. Email Address: [email protected] Submitted: March 31, 2013 Accepted: April 11, 2014 KEYWORDS Published: May 10, 2014 Philippine Sepsidae, black scavenger flies, ant-mimicking flies, Guest Editor: Victor P. Gapud Dicranosepsis, Sepsis, Australosepsis, Meroplius 155 Philippine Science Letters Vol. 7 | No. 1 | 2014 The Sepsidae had received little attention due to their minute lected live female specimens were kept alive and fed sugarwater size and association with filth and disgusting habitat. Larvae and solutions for rearing. As for the armature of specimens with clus- adults of this group are exclusively saprophagous with most spe- tered legs, the femoro-tibial joint was temporarily softened with cies associated with mammal feces (Meier 1996, Pont and Meier a drop of xylene and the tibia gently teased away from the femur 2002). with a fine pin. All specimens are currently in the author’s col- lection. The black scavenger flies are considered an important group of flies in the decomposition of pasture dung. There are species Method of Identification associated with both cow and human excrements (Meier 1996). This group of flies is believed to be of some public health con- The adults were identified using a light stereomicroscope up cern due to potential harm as vectors of pathogens and their to 40x magnification and good light quality to detect some of the synanthropic association (Pont and Meier 2002). They are even subtleties of bristling and pruinosity against the black back- reported to be attracted to perishable foods, or foods prepared for ground of the sepsid integument. storage, which may induce the growth of bacteria and fungi (Gagné 1987). A single-female rearing technique was employed in associ- ating collected live female sepsid flies. Males are more easily This group of flies has been a subject of studies in mating identified because of their strong dimorphic characters especially behaviors, e.g., courtship involving leg displays, female recep- in their forelegs: tubercles, number of setae, setulae, spines, spi- tivity as related to ovarian status, precopulatory guarding, and nules, and osmeterium, and their shape. Head and thoracic chae- copulation posture in understanding male foreleg morphology totaxy and wing venation are important characters in sorting to (Eberhard 2001, Eberhard 2002, Ingram et al. 2008, Puniamoor- genera and species. Female sepsids are difficult to pin down to thy et al. 2008). Breeding substrates of Sepsidae are very varied, species since outstanding leg characters and genitalic features ranging from bird and mammal droppings, vertebrate carrion, are very rare and difficult as most taxonomic keys and descrip- decaying vegetation, slime molds, dead insects or snails, to de- tions deal with male specimens. Some illustrations were used caying brown algae. There are reports of swarming of this group along with photographs of observed specimens in identifying the of flies as a hibernation phenomenon (Pont 1987) that may have collection. been the result of mass emergence (Meier 1996). The species treated in this work were identified with the aid The minute black scavenger flies (or ant-mimicking flies or of pertinent taxonomic literature. ensign flies) have been used in forensic investigations and crime scene interpretations such as determining the time of death or the The terminology follows that used by McAlpine (1981). season wherein other groups of flies could not have been present Abbreviations used in the descriptions are as follows: Head: oc, (Benecke 2001). ocellar setae; or, upper fronto-orbital setae; vti, inner vertical setae. Thorax: dc, dorsocentral setae; m, mesopleural setae; npl, METHODOLOGY notopleural setae; sa, supra-alar setae; pa, postalar setae; pprn, postpronotal setae; sc, scutellar setae. Wings: bm, basal medial Collection and Preservation cell. Length of body and length of wing were measured. Adult black scavenger flies were collected by sweeping and RESULTS AND DISCUSSION hand-netting over substrates where adults are gathering for feed- ing, mating or oviposition. Dung baits from cow, carabao, goats, Family SEPSIDAE Walker, 1883 horse and pig were used in collecting the specimens placed in various habitats such as ricefields, pasture and grazing land, for- Sepsidae Walker, 1833: 245. Type-genus: Sepsis Fallén, 1810, ested area, coastal and along rivers or natural water sources. Pre- by present designation. vious or relatively old excrements in the different localities were also used in collecting the sepsids. Cow dung was used in rear- Taxonomy ing some collected female sepsids from the field. Newly collect- ed adults were killed in 70-95% ethyl alcohol in separate vials The Sepsidae constitute a small family of acalyptrate flies in with screw caps. They were sorted and stored in smaller vials the Sciomyzoidea. They are distributed in all known zoogeo- and/or tubes with 95% ethyl alcohol for future molecular work graphic regions. Melander and Spuler (1917) separated Sepsidae and slide preparation. Specimens were provided with labels and and Piophilidae and recognized them as different families along codes using lead pencils. with misplaced genera. The early classification scheme of the Sepsidae was summarized by Duda (1926a,b), but Hennig Specimens were kept in 90-95% ethyl alcohol in vials. The (1937), according to Meier (1996), completed the taxonomic ornamentation of the male forelegs and genitalia are highly spe- task by including Orygma luctuosum in Sepsidae; it was previ- cies-specific and are easily seen in alcohol materials. The col- ously classified in the Coelopidae by using the female genitalic Vol. 7 | No. 1 | 2014 Philippine Science Letters 156 features. Steyskal (1987) modified Duda’s (1926a,b) and Zus- one pair of dorsocentral; lower margin of face projecting; ka’s (1977b) systems probably only to reflect loosely phyloge- middle femora of male bent in middle....Toxopoda Macquart netic relationships, unlike the strict and explicitly phylogenetic intention of Hennig (1949) (see, also, Meier 1996). Body usually shining, at least on parts of pleura; microsetae present, and often macrosetae on abdomen...........................3 Two subfamilies, Orygmatinae and Sepsinae, are recognized in this study. The subfamily Orygmatinae contains only one Hol- 3. A pair of strong