Genus Metadelphax Wagner, 1963
Distribution: New World, except M. propinqua is Pantropical
Type species (in original combination): Delphax propinqua Fieber, 1866.
Five currently recognized species worldwide as follows:
Metadelphax argentinensis (Muir, 1929) - Argentina, Bolivia, Brazil, Chile, Columbia, Paraguay, Peru, Venezuela.
Metadelphax dentata Gonzon and Bartlett, 2008 - Costa Rica, Ecuador, Nicaragua, Panama, Venezuela.
Metadelphax pero (Fennah 1971) - Cayman Islands, Cuba
Metadelphax propinqua (Fieber, 1866) - Cosmopolitan (found everywhere), especially in tropics and warm temperate regions; from Argentina to Canada, South Africa to Europe and central Asia.
Metadelphax wetmorei (Muir and Giffard, 1924) - USA: Florida, Georgia, Louisiana, North Carolina.
Metadelphax propinqua is reported on about 15 grass species, including sugarcane (Saccharum officinarum L), barley (Hordeum vulgare L.), Bermuda grass (Cynodon dactylon (L.) Pers.), maize (Zea mays L.), and rice (Oryza sativa L). Metadelphax propinqua reaches high population levels on Bermuda grass..
Metadelphax argentinensis is reported from Oats (Avena sativa L.), barley (Hordeum vulgare L.), sorghum (Sorghum bicolor (L.) Moench), rye (Secale cereale L.), beet (Beta vulgaris var. cicla (L.) Koch, tomato (Solanum lycopersicum L.), pepper (Capiscum L.), and maize (Zea mays L.).
The other three species have no reported hosts.
Metadelphax propinqua is known to transmit Cynodon chlorotic streak nucleorhabdovirus (CCSV) in corn and bermudagrass, Maize rough dwarf virus (also here) (MRDV), Barley yellow striate mosaic cytorhabdovirus (also here) (BYSMV).
Metadelphax argentinensis has been taken on corn and other crops in Argentina, but its economic impact is unclear.
Metadelphax is very similar to Toya in most respects. They are both medium-sized and usually straw-colored. Most species have darker markings alongside the carinae of the face. The genera and species are best separated by features of the male genitalia. Females (without males) usually can not be identified to species.
Metadelphax argentinensis is a relatively common species of temperate South America. Additional images from Gonzon and Bartlett (2008) are here:
Metadelphax dentata is a recently described South and Central American species that had been confused with M. wetmorei. Additional images from Gonzon and Bartlett (2008) are here:
Metadelphax pero (these photos are of the holotype)
This is a rarely encountered species. Other than the type specimen from the Caymen islands, it has been reported from Cuba. Additional images of the type specimen are here.
Metadelphax propinqua is a very common species, often found at lights or sweeping. Short-winged forms are also common. This species is variable in form and has been incorrectly described as a new species may times, Additional images from Gonzon and Bartlett (2008) are here.
Metadelphax wetmorei is an uncommon species of the southeastern United States (possibly Mexico). Additional images from Gonzon and Bartlett (2008) are here.
Molecular resourcesMolecular resources for Metadelphax appear quite limited. BOLD does not list any available barcodes for Metadelphax (or Toya). As of this writing, a Genbank search in the taxonomy browser does not list any sequences for Metadelphax (or Toya propinqua, the name for Metadelphax propinqua until recently. Urban et al. (2010) sequenced 4 genes for Metadelphax propinqua (18s, 28s, CO1, WG).
Select references on biology and life history of Metadelphax propinqua
Buntin, G. D. 1988. Species composition and phenology of leafhoppers (Homoptera: Cicadellidae) and planthoppers (Homoptera: Delphacidae) in bermudagrass forage. Journal of Economic Entomology 81(1): 201-207.
de Remes-Lenicov, A.M. M., E. G. Virla, and G. Varela. 1997. Description of preimaginal stages of Toya propinqua (Fieber) and notes on its behavior under laboratory conditions. Neotropica (La Plata) 43(109-110): 85-91.
Raatikainen, M., T. Raatikainen, and A. Vasarainen. 1994. Effect of feeding by Metadelphax propinqua (Fieber) (Homoptera, Delphacidae) on barley. Agricultural Science in Finland 3: 513-517.
Raatikainen, M. and A. Vasarainen. 1990. Biology of Metadelphax propinqua (Fieber) (Homoptera: Delphacidae). Entomologica Fennica 1(3): 145-149.
Wilson, B. H., S. Phillips, and H. M. Harris. 1973. Species and seasonal occurrence of leafhoppers and planthoppers in a ‘Coastal’ bermudagrass pasture in the Macon Ridge area of Louisiana. Journal of Economic Entomology 66: 1346-1347.
Metadelphax argentinensis in Argentina:de Remes-Lenicov, A.M.M. and E. G. Virla. 1999.Delfácidos asociados al cultivo de maíz en la República Argentina (Insecta – Homoptera – Delphacidae). Revista de la Facultad de Agronomía (La Plata) 104(1): 1-15.
Important taxonomic resources for Metadelphax species:
Gonzon, A. T. and C. R. Bartlett. 2008[dated 2007]. Systematics of Hadropygos n. g., Metadelphax Wagner and New World Toya Distant (Hemiptera: Delphacidae). Transactions of the American Entomological Society 133(3/4): 205-277.