Contribution to the knowledge of Actias groenendaeli ROEPKE, 1954 from the Lesser Sunda Islands, Indonesia with descriptions of two new subspecies (Lepidoptera: Saturniidae)

Abstract

Two new subspecies of the genus Actias LEACH in Leach & Nodder, 1815 (Lepidoptera: Saturniidae) are described from the Lesser Sunda Islands, Indonesia and Timor Leste (= East Timor): Actias groenendaeli tirnorensis subsp. nov. from the island of Timor and Actias groenendaeli sumbawaensis subsp. nov. from the island of Sumbawa. Etymology: both subspecies are named after the collecting sites, the island of Timor and the island of Sumbawa respectively. A. groenendaeli ROEPKE, 1954 is a taxon of the maenas-group (sensu Nassig 1994) and distributed on the Lesser Sunda Islands of Indonesia (Nusa Tenggara Barat Province and Nusa Tenggara Timur Province) and Timor Leste (= East Timor). A singleton from the island of Wetar, Moluccas off the northern coast of Timor was reported by Brechlin (pers. comm.), cf. Paukstadt, U. & Paukstadt, L. H. (1998, 2001a, 2003). Its status needs to be investigated after more material is available. The record of groenendaeli for the island of Lombok by Paukstadt, U. & Paukstadt, L. H. (2001a) was based on a lapsus, cf. Paukstadt, U. & Paukstadt, L. H. (2003). The island of Sulawesi is occupied by Actias Isis (SONTHONNAX, 1899 ("1897")), the Greater Sunda Islands (Bali, Java, and Borneo) by Actias maenas diana MAASSEN in Maassen (& Weymer), 1872, and Sumatra by Actias maenas saja VAN EECKE, 1913, cf. Paukstadt, U. & Paukstadt, L. H. (2000) and Paukstadt, L. H. & Paukstadt, U. (2000b). A. maenas diana was reported from the Malay Peninsula, cf. Paukstadt, U. & Paukstadt, L. H. (2004 and 2005), but further investigation on the status is considered needed. A. philippinica philippinica NAESSIG & TREADAWAY, 1997 and A. philippinica bulbosa NAESSIG & TREADAWAY, 1997 are distributed in the Philippines. The Andaman Islands are occupied by the endemic A. ignescens MOORE, 1877. The nominotypical subspecies of maenas ranges widely on the Asian Continent. The border between the nominotypical subspecies and diana may be the Isthmus of Kra in the northern part of the Malay Peninsula. A confirmation of this hypothesis through analysis of DNA barcodes is in progress. Thus far not much is known about groenendaeli, in particular the ecology and the biology of the subspecies remain mostly unknown. A. groenendaeli was actually described from the island of Flores as a subspecies of Actias maenas DOUBLEDAY, 1847 but elevated to species rank by Paukstadt, U. & Paukstadt, L. H. (1992). The unknown -[male] adult of groenendaeli (Flores) was described and figured by Paukstadt, U. & Paukstadt, L. H. (1992). The population from Timor was reared and the preimaginal instars were described and figured, cf. Paukstadt, U. & Paukstadt, L. H. (1993 and 1995) and Peigler & Wang (1996). The only host plant on which cocoons of groenendaeli groenendaeli were found in the wild has been Timonius sericeus K. SCH, (recte Timonius sericeus (DESF.) K. Sarum. = Timonius timon (SPRENG.) MERR.), Rubiaceae (vernacular names are "kuro-kuro" and "timo" on the island of Timor), cf. Paukstadt, U. & Paukstadt, L. H. (1993). Another taxon of the maenas-group (sensu Naessig 1994) in the Indonesian Archipelago is A. isis (SONTHONNAX, 1899 ("1897")) from Sulawesi. The life-history of isis was described, illustrated, and compared with groenendaeli by Paukstadt, L. H. & Paukstadt, U. (2000a). The life-history of maenas diana (Bali) was described, illustrated and compared with those of isis (Sulawesi) and groenendaeli (Timor) by Paukstadt, U. & Paukstadt, L. H. (2000) and Paukstadt, L. H. & Paukstadt, U. (2000b). In the same work the [male] antennal structures of isis (Sulawesi), philippinica (Mindoro), maenas (Myanmar), and groenendaeli (Flores) were compared and found distinct. A lengthy contribution on the variability of the [male] adults and the variability in the aedeagus of the [male] genitalia of groenendaeli was published by Paukstadt, U. & Paukstadt, L. H. (2001b). The unknown [female] adult of groenendaeli acutapex from the island of Sumba was described and illustrated dorsally and ventrally in color under the name of groenendaeli by Paukstadt, U. & Paukstadt, L. H. (2003). The [male] adult of the nominotypical groenendaeli was figured in color by Paukstadt, U. (2009). Further information on groenendaeli was not available or is unknown to the authors. Samples of groenendaeli from the islands of Flores, Timor, Sumba, and Sumbawa ex coll. Laela H. Paukstadt (Wilhelmshaven) were examined within the context of the global DNA barcoding campaign for the family Saturniidae (see http://www.lepbarcoding.org/saturniidae/index.php), an international collaborative effort carried out from the Biodiversity Institute of Ontario at the University of Guelph. The results of maximum parsimony (Fig. 36) and distance (Table 1) analyses of the generated DNA barcodes are perfectly congruent with the morphological differences reported below and reveal a consistant geographical structure of genetic differentiation. Genetic distances between populations of the four above listed islands are ranging from 2.2% (between the Sumba and Sumbawa islands' populations) to 4.6% (between the Timor and the Sumbawa islands' populations), interestingly matching the overall geographical distances between the populations as if following a westward path of colonization from Timor to Sumbawa. Whereas the genetic distances reported here have been regularly considered species-specific in other Lepidoptera barcoding studies (eg. in Decaens & Rougerie, 2008), we preferred the use of subspecific status for these island populations because of their obvious close affinities and their strictly allopatric distributions. The populations of the islands of Sumbawa (Western Lesser Sunda Islands) and Timor (Eastern Lesser Sunda Islands) are therefore described as new subspecies of groenendaeli (Flores): A. groenendaeli timorensis subsp. nov. (Timor) and A. groenendaeli sumbawaensis subsp. nov. (Sumbawa) are herewith described and illustrated in color. Furthermore, the subspecies acutapex KISHIDA, 2000 stat. rev., which was described from the island of Sumba, Eastern Lesser Sunda Islands, is herewith re-instated in subspecific rank. The populations of groenendaeli from Sumbawa, Flores, Sumba, and Timor are distinguishable by the shape of forewing apices, shape and coloration of wing ocelli and the morphology of the basal- and postmedianlines. The male genitalia structures of groenendaeli from above mentioned islands are clearly distinct mainly in the shapes of the uncus and juxta. Further distinguishing marks are in some structures of the valve, intensity of bristles and the tip of the aedeagus. The presence of four subspecies of groenendaeli for this region can be explained by the particular geographic situation of the Lesser Sunda Islands. The islands of the Lesser Sunda Islands (east of Bali) lie between the Sunda Shelf and the Sahul Shelf and were never connected with the mainland of Asia or Australia during the ice ages. Furthermore there never was any connection between the islands of the Lesser Sunda Islands during the ice ages. Therefore groenendaeli was isolated on this string of islands, as well as isis on Sulawesi for a much longer period of time than comparatively maenas on the remaining Greater Sunda Island. During the ice ages the islands of Java, Sumatra and Borneo were repeatedly connected to the Asian mainland and among themselves, enabling dispersal and gene flow within the maenas populations. Contrary to the situation on the Greater Sunda Islands, gene flow and dispersal were hardly possible from the region of the Lesser Sunda Islands.