Megalographa Lafontaine, 1991

Lafontaine, J. Donald & Sullivan, J. Bolling, 2009, A review of the genus Megalographa Lafontaine and Poole (Lepidoptera: Noctuidae: Plusiinae) with the description of a new species from Costa Rica, Insecta Mundi 2009 (77), pp. 1-10 : 1-2

Megalographa Lafontaine and Poole

Megalographa Lafontaine and Poole 1991: 94 . Type species. Plusia biloba Stephens , selected by Lafontaine and Poole (1991) because it is widely distributed.

Diagnosis. Megalographa was established to accommodate those New World plusiines with a bilobed silver stigma in the forewing. This stigma, which looks like two large joined adjacent hemispheres, is characteristic of all but one of the known species, although in three species the spots may be partially or completely separated. Although the genus ranges throughout the Americas (largely because M. biloba is a migratory species) most species are found in the southern half of South America, particularly in the Andes. Lafontaine and Poole (1991) were aware of an undescribed species from the mountains of Costa Rica which we describe below.

Megalographa is best characterized by genital characters. In the male genitalia the valve is relatively short and broad; the clavus at the base of the sacculus is a short process (longer in M. biloba ); the vesica is short, 1.0–1.5X as long as the aedeagus and with a subbasal pouch and an apical pouch in four species and a distinctive canoe-shaped cornutus at the apex in four species. In the female genitalia the corpus bursae is long, slender, J-shaped, usually with a mesial twist; the corpus bursae usually is 2–4X as long as the ductus bursae but is 6X as long in M. talamanca .

The larva of the well known and wide ranging M. biloba is distinct among plusiines because the segments are covered dorsally with a fine pelage of moderately long white hairlike spines which become coarse, conical spinules ventrally. Male and female genitalia are typical of other New World plusiines which historically have been arranged in genera largely on the basis of their forewing patterns, particularly the stigma.

Phylogeny. Lafontaine and Poole (1991) suggested that based on genitalic characters, Megalographa could be closely related to Lophoplusia Zimmerman , a genus restricted to Hawaii, because both genera share the peculiar canoe-shaped cornutus at the apex of the vesica ( Figure 14 ). DNA sequence analyses of the CO1 locus indicates that Megalographa is most closely related to Anagrapha McDunnough and Syngrapha Hübner (5–6% different) ( Hebert et al. 2003; Ratnasingham and Hebert 2007), although CO1 from Lophoplusia have not been sampled. The genera Megalographa , Anagrapha , Syngrapha , Autographa Hübner occupy a distinct phylogenetic branch within the New World plusiines (genera sequenced are: Abrostola Ochsenheimer , Allagrapha Franclemont , Anagrapha , Argyrogramma Hübner , Autographa , Chrysanympha Grote , Diachrysia Hübner , Enigmogramma Lafontaine and Poole, Eosphoropteryx Dyar , Exyra Grote , Euchalcia Hübner , Plusia Ochsenheimer , Polychrysia Hübner , Pseudeva Hampson , Syngrapha and Trichoplusia McDunnough ). Within the clade containing Megalographa , Autographa is the sister group to the other three genera and Megalographa is the sister group to Syngrapha with Anagrapha nested within Syngrapha (pers. observation).

Discussion. Megalographa would seem to be a genus of South American origin which spread northward via the species M. biloba , a well known migrant. The undescribed species in Costa Rica and the genus Lophoplusia may have originated from periodic migrations of a biloba -like ancestor.

Figures

Figure 9–14. Male genitalia of Megalographa spp. and Lophoplusia sp. 9) M. monoxyla, Cochabamba, Incachaca, Bolivia. 10) M. agualaniata, Venezuela. 11) M. bonaerensis, Curitiba, 920 m, Paraná, Brazil. 12) M. biloba, Verdugo, California. 13) M. talamanca, Reserva los Nimbulos, 3150 m, Cerro de la Muerte, San José, Costa Rica. 14) Lophoplusia sp., Kauai, Hawaii.