1. CDFA Home
  2. Plant Health
  3. PPD
  4. Entomology
  5. Scenopinidae
Entomology Banner

Plant Pest Diagnostics Center - Entomology Laboratory

Research Programs - Insecta: Diptera Asiloidea: Scenopinidae

Window Flies of the World (Diptera: Scenopinidae)

Metatrichia bulbosa

Drs. Shaun Winterton & Steve Gaimari

Welcome to the Window-fly website. The study of scenopinid evolution and biodiversity is an important part of the Diptera research programs of Steve Gaimari and Shaun Winterton, who both work on Asiloidea and 'Therevoid'-clade systematics. The current project is supported by an NSF grant to both of them (DEB-0614213). Scenopinidae are a poorly studied group of flies that show a tremendous wealth of unexplored morphological and biological diversity. This site is still under construction, but already contains an extensive bibliogrpahy of Scenopinidae literature, a checklist of world species, and a dichotomous key to genera. Shortly, a full catalogue of the family will be finished, and interactive Lucid3 keys, fact sheets and image galleries will be placed on this site. Please check back frequently for updates.

Scenopinidae, the window-flies, are a cosmopolitan group of flies with adults that are typically small and dark with a body size rarely greater than 5.0 mm. While found in a variety of habitats, by far the greatest diversity of this group is in arid regions, where the dry sandy soils provide a suitable habitat for the larvae. As larvae, scenopinids are elongate, fossorial predators of arthropods in friable soils and leaf litter, although larvae have also been reared from, or suspected of breeding in, habitats as diverse as galleries of wood-boring insects, birds nests, mammal nest holes, termite mounds, bat guano, beehives and stored products (Kelsey 1969, Rahman et al. 1981, Yucel 1988, Gnaspini 1989, Yao & Lo 1992, Dobson 1999). A single case of human urogenital myasis is recorded for a larva of Scenopinus Latreille (Thompson et al. 1970), but this appears to be exceptional.

Some adult scenopinids apparently do not to feed (e.g. Belosta Hardy), but many are nectar and honeydew feeders and are often collected by sweeping flowers and foliage (Kelsey 1975a, 1987). Adults of some species (e.g. Scenopinus spp.) are often collected on windows inside human dwellings due to their predation as larvae on pests associated with human activities; hence leading to their common name as window-flies (Kelsey 1969, Kelsey 1981a,b,c, Cole 1923, Melander 1950).

Scenopinidae are placed in the superfamily Asiloidea, and had long been accepted as the sister group to the stiletto-flies (Therevidae) based on secondary segmentation of the larval abdomen (Woodley 1989). Using morphological evidence, Sinclair et al. (1994) and Yeates (1994, 2002) showed that Scenopinidae and Therevidae are closely related to Apsilocephalidae, a hypothesis supported by 28S ribosomal and elongation factor-1 alpha (EF1-a) sequence data (Yang et al. 2000, Wiegmann et al. 2003) Using 28S rDNA Yeates et al. (2003) placed the newly described family Ocoidae as sister to Scenopinidae and Therevidae. While the monophyly of the 'therevoid' clade is relatively well supported in their analysis, the relationships between the four individual families are not. Unfortunately the larvae of both Apsilocephalidae and Ocoidae are unknown, so we cannot determine whether they too have secondarily segmented abdomens. Moreover, several authors have suggested that the lack of clear synapomorphies supporting the Therevidae may be indicative of Therevidae being paraphyletic with respect to Scenopinidae (Woodley 1989, Yeates 1992, Yeates & Wiegmann 1999).

Scenopinidae are placed in the superfamily Asiloidea, and had long been accepted as the sister group to the stiletto-flies (Therevidae) based on secondary segmentation of the larval abdomen (Woodley 1989). Using morphological evidence, Sinclair et al. (1994) and Yeates (1994, 2002) showed that Scenopinidae and Therevidae are closely related to Apsilocephalidae, a hypothesis supported by 28S ribosomal and elongation factor-1 alpha (EF1-a) sequence data (Yang et al. 2000, Wiegmann et al. 2003) Using 28S rDNA Yeates et al. (2003) placed the newly described family Ocoidae as sister to Scenopinidae and Therevidae. While the monophyly of the 'therevoid' clade is relatively well supported in their analysis, the relationships between the four individual families are not. Unfortunately the larvae of both Apsilocephalidae and Ocoidae are unknown, so we cannot determine whether they too have secondarily segmented abdomens. Moreover, several authors have suggested that the lack of clear synapomorphies supporting the Therevidae may be indicative of Therevidae being paraphyletic with respect to Scenopinidae (Woodley 1989, Yeates 1992, Yeates & Wiegmann 1999).

Twenty-four extant genera of Scenopinidae are presently recognised; (Table 1) containing more than 420 described species worldwide (Kelsey 1973b, Yeates 1992, Nagatomi et al. 1994). Kelsey (1969 to 1989) contributed significantly to our present knowledge of Scenopinidae taxonomy, describing numerous new species and genera from all major biogeographical regions. Unfortunately, this work was not based on rigorous cladistic methodology, so the predictive value of Kelsey's work is limited. The genus and tribal level relationships of the Scenopinidae are not known and discovering these is the next step in furthering our understanding of the group. To date, only Yeates (1992) and Nagatomi et al. (1994) have examined the Scenopinidae in a phylogenetic context. In a cladistic analysis of 25 adult morphological characters, Yeates (1992) justified the inclusion of Prorates, Caenotus, Alloxytropus and Caenotoides in Scenopinidae and erected the first robust subfamilial classification of the family. Three subfamilies are now recognized, the basal Caenotinae (containing Caenotus), the Proratinae (containing Prorates, Alloxytropus, Caenotoides, Jackhallia Nagatomi & Lui and Acaenotus Nagatomi & Yanagida) and the Scenopininae (containing all other scenopinid genera). Unfortunately, Yeates (1992) did not examine scenopinine relationships and included only two genera from the subfamily in the analysis. Nagatomi et al. (1994) subsequently examined the Proratinae (inclusive of Caenotus), describing two new genera (Acaenotus and Jackhallia) and proposing several competing hypotheses of generic relationships within the subfamily. Such contradictory proposals by Nagatomi et al. (1994) has not generally lead to better understanding of proratine relationships, but did provide important detailed morphological studies of the group. Recently Winterton & Metz (2005) described an entirely new genus of scenopinid from Namibia (i.e. Cyrtosathe Winterton & Metz) that exhibits characteristics from all three subfamilies. Cyrtosathe is presently placed as incertae sedis within Scenopinidae until a complete phylogenetic analysis and detailed reappraisal of the classification can be undertaken to place this new taxon. Just when we thought that the relationships of Scenopinidae subfamilies had started to become clearer, the discovery of this enigmatic new genus has forced us to reevaluate our basic definitions of the subfamilies themselves. Moreover, the phylogenetic relationships of the bulk of Scenopinidae, i.e. those genera placed in the Scenopininae and representing over 85% of the species diversity of the family, are still unknown and remain a significant challenge. Clearly, the relationships of the 'basal' scenopinid subfamilies (Caenotinae and Proratinae) with respect to the Scenopininae, along with scenopinine relationships, need to be tested fully with more extensive exemplar sampling from all groups. These are central questions for my research on these flies.

Preliminary scenopinid phylogeny
A preliminary phylogeny for the family is presented in this image based on the combined morphological and molecular (COI, CAD, 16S) data.

Family: SCENOPINIDAE

    Caenotus Cole 1923a: 14

    • hospes Melander 1950: 149, Nearctic
    • inornatus Cole 1923a: 16, Nearctic
    • mexicanus Nagatomi & Yanagida 1994: 159, Nearctic
    • minutus Cole 1923a: 15, Nearctic
    • tanyrhynchus Metz 2003 : 4, Nearctic
Pest Hotline: 1-800-491-1899

Entomology Sub-Menu

Entomology Home State Collection of Arthropods Publications

Plant Pest Diagnostics Center

Home Botany Entomology Nematology Plant Pathology Seed Botany

CDFA Collections

California State Collection of Arthropods CDFA Herbarium CDFA Plant Pathogen Collections CDFA Seed Herbarium CDFA Nematode Collection

General Info/Links

Job Openings Pacific Coast Entomological Society National Museum of Natural History - Entomology List of journals without page charges Price list for submitting Service Samples Insect & Invertebrate Pest Sheets National Plant Diagnostics Network (NPDN) Western Plant Diagnostics Network (WPDN)

Contact Us

Plant Pest Diagnostics Center & Entomology Laboratory
3294 Meadowview Road
Sacramento, CA 95832
Phone: 916-262-1100
Fax: (916) 262-1190