Amerila mulleri ( Häuser & Boppré, 1997 )

Przybyłowicz, Łukasz, Maicher, Vincent, László, Gyula M., Sáfián, Szabolcs & Tropek, Robert, 2019, Amerila (Lepidoptera: Erebidae: Arctiinae) of Cameroon with morphological remarks on male and female genitalia, Zootaxa 4674 (2), pp. 283-295 : 289-291

Amerila mulleri ( Häuser & Boppré, 1997) (Figs 9–11, 20–21, 27)

Material (30 specimens). 1♀ Mount Cameroon (SW slope), 25.xi.2016 , Crater Lake (1500 m a.s.l.), N 4.1443°, E 9.0717°, lgt. V. Maicher, Sz. Sáfián, Š. Janeček, R. Tropek ; 1♀ as above but 27.xi.2016; 1♂, 1♀ as above but 24.xi.2014, Elephant camp (1850 m a.s.l.), N 4.1453°, E 9.0870° ; 1♀ as above but 20.iv.2017, lgt. V. Maicher, P. Potocký, S. Delabye; 2♀♀ as above but 6.xi.2016, Mann’s Spring (2200 m a.s.l.), N 4.1428°, E 9.1226°, lgt. V. Maicher, Sz. Sáfián, Š. Janeček, R. Tropek ; 2♂♂ 7♀♀ as above but 7.xi.2016; 1♀ as above but 8.xi.2016; 2♂♂ 2♀♀ as above but 9.xi.2016; 1♀ as above but 11.xi.2016; 1♂ as above but 18.iv.2017, lgt. V. Maicher, P. Potocký, S. Delabye; 1♀ as above but 19.iv.2017; 1♂ Mapanja sector; 14.x.2017 , Mapanja camp (1800 m a.s.l.), N 4.1191°, E 9.1284°, lgt. V. Maicher, S. Delabye ; 1♂ as above but 23.x.2017; 1♂ as above but 29.x.2017; 2♂♂ 1♀ as above but 26.x.2017 (all above attracted by light).

Distribution

The species range is probably underestimated due to the small number of available records. The species has earlier been recorded in several Eastern and Southern African localities. The northwesternmost locality is Ituri-Nioka near Albert Lake (northeast Democratic Republic of Congo). The new localities in Cameroon indicate that the species’ distribution in tropical Africa is substantially wider than was known before (by approximately 2300 km to the west). As several males and females were collected on Mount Cameroon over the four years of our sampling, there are no doubts about the existence of a stable population of A. mulleri . On Mount Cameroon it was collected from 1450 m a.s.l. up to the timberline, occurring mainly in the montane forest ( Fig. 1 ).

Male genitalia (Figs 20–21)

Morphology of one of the studied males (Fig. 20) shows some differences compared with the drawings published by Häuser & Boppré (1997), especially concerning the aedeagus structure. The aedeagus (Fig. 21) is at most two times longer than its width while the drawing suggests it is much longer. These differences reflect the weak sclerotization of the aedeagus typical for this species and are artificially produced during the mounting of the permanent genital slide. The aedeagus is delicate and prone to artificial distortion caused by the cover slip. The vesica bears medially a small plate-like sclerotization, as written in the original description of species but invisible on the illustration ( Häuser & Boppré 1997).

Female genitalia (Fig. 27)

Papillae anales subsquare, terminally covered with sparse setae, bearing a pair of indistinctive membranous protu- berances ventrally, anteriorly from oviduct; anterior apophyses moderate length, thick, slightly sinuose; apophyses posteriores narrower, almost three times as long as the anterior apophyses; dorsal and ventral pheromone glands re- duced; sternum VIII moderately sclerotized in the form of a pair of small, flat, subsquare protrusions; ostium bursae wide, membranous; ductus bursae much shorter than corpus bursae, membranous with a distinct dilation at 1/3 of its length; corpus bursae oval, membranous, moderately plicate, without any trace of sclerotizations; ductus seminalis originating at the anterolateral portion of the corpus bursae, with very wide, gradually tapering opening.

Remarks

The morphological description of male provided in Häuser & Boppré (1997) requires some corrections based on the examined specimens. The information claiming forewing veins to be dark is misleading and can be misinter- preted by readers. In fact, the veins of older specimens usually look dark, because the scales are worn off; but the scales of younger specimens could be removed also accidentally during their spreading in the laboratory. Actually, the dark coloration comes from the chitin sclerotization of veins. Such a trait, although easily visible in the lighter species, should not be treated as diagnostic feature. In fact, the entire wing of the undisturbed specimens is always covered by white scales (Fig. 9-10). We did not examine the types of A. mulleri , however, we are convinced that this character is artificial based on the comparison of many specimens representing both sexes of A. mulleri . Similar “dark veins” can be seen in some other taxa referred in Häuser & Boppré (1997), A. bubo (Walker, 1855) and A. nigrivenosa (Grünberg, 1910) . In fact, none of these have diagnostically darker veins caused by any dark (blackish) scales.

Another mistake concerns the number of dark dots on tegula referred to regarding most species in Häuser & Boppré (1997). The authors recognized only the anterior and posterior dots, omitting the additional, often prominent dot located in many species basoventrally between the ventral margin of patagium and the base of forewing. Taking this into consideration, A. mulleri possesses two well defined black dots on tegula: basoventral and anterior. This observation is also based on our examination of numerous specimens representing various Amerila species.

The relatively high number of available females in our material (17 specimens) allowed revealing of a so far unknown phenotypic variation in the coloration of abdominal tergites. The typical and commonest form was entirely white (Fig. 10), while part of the specimens (three in our material) differed by a pinkish suffusion in the distal half of abdomen (Fig. 11). These forms do not differ in their genitalia morphology.

Figures

FIGURE 1. Elevational distribution of Amerila species on Mount Cameroon. The three elevational zones, with their transitions, are visualized by different colors. The weighted mean elevation of individual species (black dot), together with their lowest and highest records, are visualized. After species names, numbers of collected specimens are stated.