Die Wehrdrüsen der Altraupe von Attacus crameri C. Felder in von Frauenfeld, 1861 von Ambon, Indonesien (Lepidoptera: Saturniidae)

"Larvae of Attacus crameri C. FELDER in von Frauenfeld, 1861 (Lepidoptera: Saturniidae) were collected by the author on the island of Ambon, Moluccas, Indonesia. A. crameri is a rare species of the genus Attacus LINNAEUS 1767 of the tribe Attacini BLANCHARD, 1840. This species is distributed on the islands of Ambon and Seram, central Moluccas. The distribution on further islands in the Moluccas, which is recorded in literature needs confirmation. For the first time being the function of defensive glands was examined at fresh outdoor (wild) larvae of this species. A few 5th instar larvae were collected on the island of Ambon during the trade winds in July 2017. That means that the larvae (and the author) encountered heavy rain 24 hours daily. 5th instar larvae were not immediately examined regarding defensive glands because no equipment has been available to carry out the examination and documentation. The larvae were taken to West Java were they immediately molted from 5th to 6th larval instar. Three larvae were kept indoors and three larvae outdoors, both groups on Ligustrum ovalifolium HASSK. (Oleaceae). After two days all outdoor larvae were found being attacked by very tiny ants (Formicidae) and dead. We have to point out that this ant species is certainly not a primary enemy of A. crameri larvae because the ants probably do not occur in the wild but in residential areas only. The 6th instar larvae were examined regarding defensive glands. It was found that the defensive glands were already activated during transport indicated by black residues of the secretion at the defensive gland complexes at the 9th and 10th (anal plate) abdominal segments. Contrary to previous observations, cf. L. H. & U. Paukstadt (1997), two further defensive glands / gland complexes were found being present at the 6th instar larvae. Those are at the caudal end of the anal plate. During manipulation of the reduced scoli no droplets emerged from the glands but its surface became “wet”. This might indicates that a small quantity of secretion most probably emerged. On the other hands, after transportation the surface of the aftmost reduced scoli has been found with black residues of the secretion as at other reduced scoli of the 9th and 10th abdominal segments of the larva. As in A. lorquinii C. & R. FELDER, 1861 and other species of the genus Attacus a well developed eighth row of scoli is present ventrolaterally at the thoracic and the 1st and 2nd abdominal segments which is almost missing in A. caesar MAASSEN, 1873 and much reduced in A. erebus FRUHSTORFER, 1904 and A. selayarensis NAUMANN & PEIGLER, 2012. A further observation has been made on the coloration of scoli different from a previous description. The bases of some dorsal and subdorsal scoli are pale violet colored at the 5th instar larvae and the bases of the dorsal and subdorsal scoli are pale orange colored at the 6th instar larvae. The 5th and the 6th instar larvae and details of the defensive glands are illustrated in color."