Sterphus aurifrons Shannon, 1926

Barahona-Segovia, Rodrigo M., Riera, Pamela, Pañinao-Monsálvez, Laura, Guzmán, Vicente Valdés & Henríquez-Piskulich, Patricia, 2021, Updating the knowledge of the flower flies (Diptera: Syrphidae) from Chile: Illustrated catalog, extinction risk and biological notes, Zootaxa 4959 (1), pp. 1-178 : 79

Sterphus aurifrons Shannon, 1926

Figs 113–114

Sterphus aurifrons Shannon, 1926: 46

Type locality and data. “ Juan Fernández , Chile ” (T, ♂, BMNH) .

Material examined. Valparaíso: 1♂, Mirador Selkirk , 30.XII.1992, Leg. Marshall & González ( IEUMCE) ; 1♂, 1♀, Jardines CONAF, 24.I.2003, Leg. A. Sandoval ( SAG) ; 1♂, Juan Bautista, Masatierra , 04.VII.2004, Leg. A. Sandoval ( SAG) ; 1♂, Masatierra , 05.II.1952, Leg. Kuschel ( IEUMCE) ; 16♂, 15♀, Plazoleta El Yunque , 1.II.1973, Leg. L.E. Peña ( CNC) ; 2♀, Robinson Crusoe , 18.IV.2016, Leg. H. González ( CSP) ; 1♀, Robinson Crusoe , 05.II.1952, Leg. Kuschel ( MZUC) .

References. Shannon, 1926: 46 (desc.); Shannon & Aubertin, 1933: 156 (desc.); Stuardo, 1946: 127 (cat.); Fluke, 1955: 42 (key & desc.); Fluke, 1957: 107 (cat.); Etcheverry, 1963: 79 (cat.); Thompson, 1973: 204 (key & desc.); Thompson et al., 1976: 116 (cat.); Hippa & Thompson, 1994: 494 (key); Zumbado & Thompson, 1997: 87 (key).

World distribution. Chile.

Chileand distribution. Only recorded from Robinson Crusoe, Juan Fernández Islands ( Fig. 117 ).

Altitudinal range. This species inhabits native forests in ravines and clifttops between 100 and 600 m. a.s.l.

Biology and notes. Sterphus aurifrons is associated with native vegetation of the Robinson Crusoe in Juan Fernández Islands. This species was assessed in the local red list of threatened species of the Environmental Ministry of Chile under IUCN criteria (CR B1abiii + 2abiii) (www.mma.gob.cl/clasificacionespecies), and was cataloged as threatened due to deforestation and invasive species such as goats Capra hircus (Linnaeus) , austral thrushes Turdus falcklandii magellanicus (King) and coatis Nasua nasua (Linnaeus) . These species affect S. aurifrons in different ways. Goats invade the forests and trample leaf litter and dead wood where larvae probably develop. The coati is a generalist predator that searches the forest floors for invertebrates to feed on and climbs trees in search of other prey. Thrushes are omnivorous introduced birds that attack insects in semi-urban areas (CONAF, pers. comm.). Etcheverry (1963) recorded the species in Angol, however, it be a labeling error because all other specimens collected are from the Robinson Crusoe Island.

Conservation status. CR under B1ab (iii) + 2ab (iii); AOO = 12 km 2; EOO = 12 km 2 and one locality (or subpopulation).

Figures

FIGURE 117. Distribution map of Sterphus aurifrons Shannon, 1926 (blue circles); Sterphus coeruleus (Rondani, 1863) (red circles), and Sterphus plagiatus (Wiedemann, 1830) (yellow circles) in Chile.

FIGURES 113–116. Sterphus aurifrons Shannon, 1926: (113) resting in a dead wood, Juan Fernández Island (photo by Cristian Pardo) and (114) resting in Rhaphithamnus venustus (Phil.) B.L. Rob., Juan Fernández Island (photo by Hernán González). Sterphus coeruleus (Rondani, 1863): (115) resting in a leave, Los Lagos (photo by Luis Candia) and (116) dorsal view (photo by Matías Barceló). Scale bars = 1 mm.