Diatraea saccharalis ( Fabricius, 1794 )

Diatraea saccharalis ( Fabricius, 1794) View in CoL

Figs 6 View Figs 1-8 , 41 View Figs 40, 41 , 54 View Figs 51-55

Phalaena saccharalis Fabricius, 1794: 238 . Type locality: “America meridionalis”.

Diatraea saccharalis (Fabricius) View in CoL : Roque-Albelo & Landry, 2018.

Material examined: 2 ♀ from Ecuador, Galápagos . – San Cristóbal: El Chino , z[ona]. agricola, [S]00.9096927, W089.4458128 (genitalia preparation BL 1585); MHNG-ENTO-85752 , La Toma , ca. 5.6 km East El Progreso, 299 m elev. S00°55.356’, W89°31.089’. Deposited in CDRS and MHNG GoogleMaps .

Diagnosis: In the Galápagos Islands this rather large Crambinae known from two females (wingspan 26-30 mm) cannot be mistaken with other species, but males are generally smaller and the wingspan recorded for the species by Dyar & Heinrich (1927) is 18-39 mm. The moths ( Fig. 6 View Figs 1-8 ) harbour brownish forewings thinly striated with dark brown, with two diffuse dark brown oblique lines running from the dorsum at mid length to the apex (more strongly marked in male specimens), and with marginal dark brown spots between veins. Other Diatraea species occur on continental South America and can only be reliably identified by examination of the genitalia (see Solis & Metz, 2016). The male genitalia of D. saccharalis ( Fig. 41 View Figs 40, 41 ) are similar to those of D. albicrinella Box, 1931 , D. impersonatella ( Walker, 1863) , and D. tabernella Dyar, 1911 , and can be separated based on the following features: lateral lobe of tegumen evenly rounded, basal costal lobe of valva well-marked, globular, protruding at a 90° angle with valva, covered with tiny spines, and juxta arms tapered apically, not pointed. Female genitalia ( Fig. 54 View Figs 51-55 ) share features characteristic of the D. saccharalis group: sternite VIII with broad transverse “pocket” mostly concealing the ostium bursae; lamella antevaginalis composed of a pair of hardened, posteriorly projecting extensions that may cover the genital opening or surround it laterally; cuticle laterad of lamella postvaginalis wrinkled and/or densely setose, contrasting strikingly with a smooth and glabrous medial area ( Solis & Metz, 2016). From other species of the D. saccharalis group, it can be separated by the posteriorly projecting triangular extensions of the lamella antevaginalis, the lateral, wrinkled and/ or densely setose cuticle of the lamella postvaginalis not reaching the posterior margin of sternite VIII, the lamella postvaginalis with a distinct pair of elevated transverse ridges posterad, and the glabrous and pear-shaped corpus bursae slightly longer than large ( Solis & Metz, 2016). Unambiguous segregation between D. albicrinella and D. impersonatella is possible with the examination of female genitalia only.

Biology: Diatraea saccharalis is a well-known pest of sugar cane ( Saccharum officinarum L.) and has been reported feeding on 26 different Poaceae species ( Robinson et al., 2010). Sugar cane has been introduced on the Galápagos for sugar production and spread in the wild. Guézou et al. (2010) record it from all inhabited islands of the Galápagos, except Baltra, and 25.6% overall of the localities visited.

Distribution: Diatraea saccharalis is widely distributed in the tropical and subtropical Americas, from Florida, USA, southwards to Argentina ( GBIF, 2021). In the Galápagos so far, it has been found only on San Cristóbal.

Remarks: One of the Galápagos specimens was collected at light in February while the other was collected manually in May on a young shoot of corn (“cogollo maiz”).