An unexpected resident butterfly of the United Arab Emirates --the Arabian grizzled skipper Spialia mangana (Lepidoptera: Hesperiidae).
S. mangana is an uncommon and little known species having its principal range from south-west Arabia to East Africa (Yemen through Ethiopia and Somalia to Uganda and Kenya) with two localities reported from the Dhofar region of Oman (Larsen 1980, 1983, 1984a, 1984b and pers. comm.; Larsen & Larsen 1982). In December 2007, S. mangana was found in the mountains of Northern Oman as well, on the middle slopes of Jebel Kawr, an exotic limestone massif at the south-west corner of the Jebel Akhdar (Feulner 2007). The Jebel Kawr records were later supplemented by earlier unpublished observations by Tim Roberts (pers. comm.), made in late October 2006, from the nearby slopes of the Jebel Akhdar, above Wadi Ghul. All of the Northern Oman records were from similar elevations, ca. 1000-1400 metres.
They extended the known range of S. mangana, disjunctively, by some 725 kilometres, from central Dhofar to the Jebel Akhdar.
The new UAE record represents an additional range extension of ca. 225 kilometres. Because S. mangana is a sedentary (i.e., non-migratory) species (Larsen, pers. comm.), the new record is considered (as at Jebel Kawr and Jebdel Akhdar) to represent a relict population persisting from an era of more mesic (but probably still eremic) conditions.
The intervening Jebel Kawr and Jebel Akhdar reports make the UAE record somewhat less surprising, but no less significant from the standpoint of regional biogeography. The summit ridge of Jebel Qitab (Fig. 3) and neighbouring high ridges to the north-west, from elevations of ca. 600-1050 metres, collectively called the Olive Highlands (Feulner 2014), have previously been identified as a high elevation refuge for relict plant species within the Hajar Mountains of the UaE (Feulner 1997, 2014; AGEDI 2013). The presence of S. mangana provides faunal evidence to the same effect.
The authors had been attentive to skipper butterflies (Family Hesperiidae) in the UAE over the preceding year, but it was partly their recognition of the Jebel Qitab summit ridge as a biodiversity 'hotspot' that encouraged them to persist in their efforts to obtain a range of potentially diagnostic photographic views of the few skippers they observed there.
The butterflies were seen at midday on a sunny but relatively cool day. They remained in the area of the observers, generally within a radius of about 10-15 metres. They made periodic short sorties and were observed to feed on flowering Asphodelus tenuifolius and Viola cinerea (Fig. 1), two widespread annuals, but they returned regularly to alight in an open area of flat, silty and stony ground among boulders, either on the ground or on low but erect basal rosettes of Pallenia (formerly Asteriscus) hierochunticus. Typically they perched with their wings relatively wide open, but a photograph of the upper side alone would not necessarily permit a conclusive identification from among the five congeneric skippers found in the UAE and Northern Oman (Larsen & Larsen 1982; Gillett 1995; Feulner 2007).
The fact that they perched repeatedly and conspicuously within the same small, open area, suggests they were probably 'hilltopping', i.e., following the terrain to a topographic high point for the purpose of meeting and mating with other conspecifics. Larsen (pers. comm.) regards the behaviour described as typical of hilltopping for sexual purposes. Two other butterfly species were present in the vicinity at the same time - a single Common Swallowtail Papilio machaon and one or more Pea Blue Lampides boeticus. Both of those species are known for hilltopping (Larsen 1984b) and they were almost certainly also doing exactly that.
As in the case of Jebel Kawr, only a small number of individuals of S. mangana, perhaps only two or three, were seen at Jebel Qitab, and little more can be said directly from these observations about the ecology of S. mangana in the UAE or Northern Oman, except that the species appears to be found at medium to high elevations (ca. 1000-1400 metres) and is active through the fall and winter seasons, including late October, December and February.
The larval foodplant of S. mangana remains unknown (Larsen, pers. comm.), but the presence of S. mangana only in the botanical refuge of the Olive Highlands suggests the possibility that its distribution maybe controlled, at least in part, by the presence of a preferred foodplant among the dozen or so species that are locally restricted to the Olive Highlands. Those include the following species (Feulner 2014):
Abutilon fruticosum (Malvaceae) Convolvulus acanthocladus (Convolvulaceae) Desmidorchis flavus (Asclepiadaceae) Ehretia obtusifolia (Boraginaceae) Ephedra pachyclada (Ephedraceae) Fagonia schimperi (Zygophyllaceae) Grewia tenax (Tiliaceae) Melhania muricata (Sterculiaceae) Monsonia cf. heliotropioides (Geraniaceae) Olea europaea (Oleaceae) Pennisetum orientale (Poaceae) Phagnalon schweinfurthii (Asteraceae)
Other Grizzled Skippers (Spialia spp.) found in Arabia are known to be polyphagous on various low Malvaceae (mallow family) and Sterculiaceae (cacao family), and to a lesser degree Tiliaceae (linden family), although they may also use other plants (Walker & Pittaway 1987; Kehimkar 2008; Larsen pers. comm.).
In the case of S. mangana at Jebel Qitab, circumstantial evidence points most strongly towards Melhania muricata (Fig. 4), which is also present at the Jebel Kawr site (Feulner 2007). M. muricata is a known foodplant of the Zebra Grizzled Skipper S. zebra, which ranges from East Africa through Southern Arabia to Baluchistan and the Punjab (Larsen & Larsen 1982; Larsen 1983). It is also the UAE's only representative of the Sterculiaceae and is reasonably common along the Jebel Qitab summit ridge. However, the list of Olive Highlands local endemics also includes a medium-sized Malvaceae, Abutilon fruticosum, and a large Tiliaceae, Grewia tenax, both of which can be found on the slopes and/or summit cliffs of Jebel Qitab.
Larsen (pers. comm.) advises that the larvae of S. mangana, like other Spialia larvae, probably shelter in little envelopes made from the leaves of the foodplant and would not be easily seen, except by using the envelopes as a proxy.
It is difficult to test more rigorously the hypothesis that the distribution of S. mangana is controlled by the distribution of M. muricata, since both the butterfly and the plant are rare and have been found only at relatively remote locations. It is not clear that any records of M. muricata exist from the Hajar Mountains between the Jebel Akhdar and the Olive Highlands. Thus, in addition to favouring higher elevations, M. muricata may also be limited by geology, avoiding the ultrabasic rocks (harzburgite) of the Semail nappe (a/k/a the Oman ophiolite), which comprise most of the mountainous area between the existing records. But that area is also extremely rugged and very poorly explored at higher elevations (900 to 1500+ metres), so the plant could simply have been overlooked.
Jebel Rais, in Oman, is an isolated promontory of carbonate sediments within that intervening area of ultrabasic rock (rising to 1800+ metres above uppermost Wadi Hawasina) and for that reason was the subject of a botanical reconnaissance in by the senior author (GRF) in December 2005. M. muricata was not recorded at Jebel Rais, although several other Olive Highlands local endemics were found there: Convolvulus acanthocladus, Ephedra pachyclada, Fagonia schimperi and Olea europaea. Of those four species, three are otherwise unrecorded in the intervening area, but O. europaea is the most common tree species at higher elevations within the ophiolite mountains, from Jebel Hatta in the UAE south to the Jebel Akhdar.
A second species of Sterculiaceae, M. phillipsae, has been recorded from Northern Oman (Ghazanfar 1992; Jongbloed 2003); it appears to be equally uncommon. The senior author (GRF) has encountered it at only a single locality, at ca. 1200-1300 metres on the upper slopes of Jebel Muqayleet, a gabbro massif like Jebel Qitab (i.e., basic, not ultrabasic rock), some 15-20 kilometres south of Wadi Jizzi. Neither M. muricata nor M. phillipsae has yet been recorded from the several outlying carbonate (limestone and dolomite) ridges along the mountain front from AlAin/Buraimi to the north, i.e., Jebel Hafit, Jebel Ghaweel and Jebel Sumayni, each of which reaches 1100-1200 metres.
As emphasised in connection with the Jebel Kawr records, the discovery of S. mangana continues the progressive recognition in Northern Oman (and now in the UAE) of small populations of arid Afro-tropical butterfly species previously known in Arabia only from Yemen and Dhofar, e.g. Brown Playboy Deudorix antalus, African Cupid Euchrysops osiris (Gillett 1997) and Somali Cupid Euchrysops lois (Gillett 1999). Moreover, it seems that S. mangana, like E. lois, cannot be satisfactorily accounted for by the possibility of recent immigration in response to favourable conditions and/or human intervention, but must be considered a previously unrecognised relict species.
Abu Dhabi Global Environmental Data Initiative (AGEDI). 2013. Local, National Regional Biodiversity Rapid Assessment: Systematic Conservation Planning Assessments and Spatial Prioritizations - Supporting Technical Information for the United Arab Emirates. (See Table 3-3: UAE Habitat Classification Table; Table 3-7: Summary of mapped data provided by Gary Feulner; Fig. 3-4: Integrated Terrestrial and Marin Habit Map of the UAE; Fig. 3-5: Legend; Appendix C.5 UAE Priority Areas Map). Environment Agency - Abu Dhabi and Hyder Consulting.
http://www.agedi.ae/Pages/downloads/MU945 F11 2 01 UAE Supporting%20Tech%20Report.pdf (Accessed 1 June 2014)
Feulner, G.R. 1997. First observations of Olea cf. europaea and Ehretia obtusifolia in the UAE. Tribulus 7.1: 12-14.
Feulner, G.R. 2007. An unexpected resident butterfly of northern Oman: the Arabian Grizzled Skipper Spialia mangana. Tribulus 17: 99-101.
Feulner, G.R. 2011. The Flora of the Ru'us al-Jibal --the Mountains of the Musandam Peninsula: An Annotated Checklist and Selected Observations. Tribulus 19: 4-153.
Feulner, G.R. 2014. The Olive Highlands: a unique "island" of biodiversity within the Hajar Mountains of the United Arab Emirates. Tribulus 22: 9-34.
Ghazanfar, S.A. 1992. An Annotated Catalogue of the Vascular Plants of Oman. Scripta Botanica Belgica 2. National Botanic Garden of Belgium, Meise. 153 pp.
Gillett, M.P.T.G. 1995. An updated and annotated list of butterflies recorded from the UAE, the Musandam Peninsula and the Buraimi-Al Mahdah region of Oman. Tribulus 5.2:16-17.
Gillett, M.P.T.G. 1997. The butterflies of the United Arab Emirates and neighbouring areas of northern Oman - three newly recognised species and some other interesting records (Lepidoptera: Rhopalocera). Tribulus 7.1:15-18.
Gillett, M.P.T.G. 1999. Preliminary notes on some newly recorded butterflies from the UAE and adjacent parts of northern Oman (Lepidoptera: Rhopalocera). Tribulus 9.1:22-23.
Kehimkar, I. 2008. The Book of Indian Butterflies. Bombay Natural History Society / Oxford Univ. Press. 497 pp.
Larsen, T.B. 1980. Butterflies of Dhofar. In: The Scientific Results of the Oman Flora and Fauna Survey 1977 (Dhofar). Office of the Government Advisor for Conservation of the Environment. Jour. of Oman Studies Special Rept. No. 2: 153-186.
Larsen, T.B. and Larsen, K. 1982. Butterflies of Oman. John Bartholomew and Sons, Edinburgh. 80 pp. Available online at:
Larsen, T.B. 1983. 'Insects of Saudi Arabia Lepidoptera; Rhopalocera (A Monograph of the Butterflies of the Arabian Peninsula).' Fauna of Saudi Arabia 5:334-478.
Larsen, T.B. 1984a. The zoogeographical composition and distribution of the Arabian butterflies (Lepidoptera; Rhopalocera). Jour. Biogeography 11:119-158.
Larsen, T.B. 1984b. Butterflies of Saudi Arabia and its Neighbours. Stacey International, London. 160 pp.
[NB: Tribulus, the journal of the Emirates Natural History Group, Abu Dhabi, is available online at: http://www.enhg.org/trib/]
Gary R. Feulner
Chadbourne & Parke
P.O. Box 23927
Dubai, United Arab Emirates
Dubai, United Arab Emirates
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|Author:||Feulner, Gary R.; Roobas, Binish|
|Date:||Jan 1, 2014|
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