Josia gigantea (Druce)

Miller, James S, 2009, Generic Revision Of The Dioptinae (Lepidoptera: Noctuoidea: Notodontidae) Part 2: Josiini, Bulletin of the American Museum of Natural History 2009 (321), pp. 675-1022 : 822

Josia gigantea (Druce) Plates 32, 39O [EX]

Josiomorpha gigantea Druce, 1885a: 150 .

TYPE LOCALITY: Costa Rica, Irazu, 600– 700 ft.

TYPE: Syntype ³, leg. H. Rogers ( BMNH).

DISCUSSION: This taxon, originally described by Druce (1885a) in the arctiid genus Josiomorpha , is represented in most museum collections, but never in great numbers. As the name implies, it is the largest Josia species. However, its size is now challenged by the newly described J. neblina (pl. 33; see below). In the field, J. gigantea occurs in disturbed habitats along road embankments and stream banks. Whereas adults, always elusive, are rarely encountered, the larvae (pl. 39O) can be common. My own collecting experience with J. gigantea is instructive regarding the patchy, yet seemingly stable nature of many josiine populations. In all cases the moths are inextricably tied to their Passiflora hosts.

One day in March 1991, while collecting in Costa Rica, I happened upon a female of J. gigantea flying near the banks of the Río Poasito, a small stream that flows from the summit of Volcán Poas. Even at that early date, I had learned that when an adult is found, host plants and larvae must be nearby. My search quickly revealed a large patch of Passiflora sexflora , its leaves covered with J. gigantea larvae in all instars. During a more recent collecting trip (January 2007), I revisited precisely the same locality. A small house was under construction, but 16 years later the site otherwise looked the same. Again, but with the added help of Jorge Corrales, dozens of J. gigantea larvae were discovered, this time on two Passiflora species — P. sexflora and P. apetala (table 6). Both plant species were growing intermixed along the stream bank. Adults of J. gigantea were not observed.

This anecdote illustrates an important aspect of dioptine biology: throughout the subfamily, few species exist whose adults would be characterized as common in the field. On the other hand, when the location of a moth’s host plant becomes known, larvae can predictably be found in large numbers.

A specimen in the Alonso and Rafael Turrent Collection (Mexico City), collected in Chiapas, represents the northernmost record for J. gigantea . The sister species of J. gigantea is J. neblina , sp. nov., from Cerro Neblina in southern Venezuela (fig. 304). These two taxa are roughly the same size and exhibit similar body coloring, but differ in genitalia morphology. The two species show surprisingly disjunct distributions.

DISTRIBUTION: Colombia (BMNH, OUMNH) ; Panama (AMNH, BMNH, FNHM, USNM, ZMC, ZMH); Costa Rica (AMNH, BMNH, CMNH, INBio, EME, LACM, USNM, ZMH); El Salvador (PMNH); Guatemala (AMNH, CMNH, LACM, MNHN, USNM); Mexico (ARTC).

DISSECTED: ³, Panama, Chiriquí, Wm. Schaus Collection, USNM (genitalia slide no. JSM-1373 ) ; ♀, Guatemala, Volcán Sta. Maria, Schaus & Barnes coll., USNM (genitalia slide no. JSM-1374 ) .