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First UAE and Arabian records of Chilades pandava, the Cycad Cupid butterfly, an introduced oriental species (Lepidoptera: Lycaenidae) hosted by the ornamental sago plant Cycas revoluta.

Introduction

During the Arabian summer of 2014, "mating frenzies" of a Lycaenid butterfly resembling the native Small Cupid Chilades parrhasius were observed on three occasions at sites in urban and suburban Dubai by the authors, all individuals associated with the Dubai Natural History Group (DNHG) (Fig. 1). In each case, the butterflies were mating on ornamental cycad plants.

HM was the first to notice this phenomenon, which she saw on 9th June at her apartment gardens in Jumeirah, opposite Jumeirah Beach Park, and she called attention to it in the DNHG's monthly newsletter, Gazelle (Meyer & Feulner 2014). She wrote, "I had the good fortune to see many butterflies in a frenzy to mate and some females were also laying eggs on [one of several potted] cycad plant[s]. They seemed to mate for ages and I observed one couple stuck together for 1.5 hours at least, while a lot of other males tried to interfere."

The butterfly in question was identified in the Gazelle account as the Small Cupid Chilades parrhasius, a common species in diverse environments in the UAE, but also a highly variable species and one which, in the wild, is active throughout the summer. C. parrhasius ranges from dry parts of India and Sri Lanka across southern Afghanistan and Iran to eastern and southern Arabia (Larsen & Larsen 1982, Larsen 1983). Larsen (1983) remarked on its variability in both size and markings, and left open the possibility that C. parrhasius might yet be found to comprise multiple species.

Subsequently, on 6th August, in the course of a DNHG survey of the wildlife at Dubai's Madinat Jumeirah resort, GRF and BR observed a similar mating frenzy at one of a row of five cycads at a landscaped plot along a golf cart path (Fig. 2). This was especially noteworthy because, with just two exceptions, these were the only butterflies seen flying on a muggy morning in the resort's environment of largely introduced plant species.

After seeing the report in Gazelle, TC remarked to GRF that she, too, had noticed mating frenzies of "Small Cupids" on several occasions during the summer, around potted cycads on the grounds of her apartment complex, the Jumeirah Beach Residence (JBR). In previous years she had noticed and photographed only smaller numbers of similar butterflies, feeding on several species of introduced ornamental flowers. TC's area of JBR, the Murjan area, also has a number of established cycads in some of its flower beds, which are much larger than the ones in the planters and have been there for at least the past three years. Due to ease of access, however, she has closely monitored only the potted cycads. Like HM, TC found the butterflies copulating while perched on the cycad fronds and budding leaves. She also found eggs glued to fronds, mainly on the central ribs near the base of fronds at the centre of the cycad, near where new foliage would emerge.

The cycad plant involved in each of the above instances appears to be Cycas revoluta, a native of Japan (Marler et al. 2012) that is now widespread as an agricultural and ornamental species, marketed as "sago", "sago palm" or "King Sago". In each case as well, the plant was undergoing a vegetative "flush", sending up new ribs from the centre of the plant, each flanked by the buds of new leaflets (see Figs. 2, 5). [NB: Although sago plants are often called "sago palms", they belong to the cycads, a primitive gymnosperm plant lineage dating back to the Jurassic (Wikipedia, "Cycad".) They are unrelated to true palms, which are a specialised group of angiosperms, i.e., flowering plants. Sago and most other ornamental cycads belong to the largest subgroup of cycads, the family Cycadaceae, a monogeneric family consisting of ca. 100 species, all classified in genus Cycas (Marler et al. 2012, Wikipedia, "Cycadaceae").] Another Gazelle reader was lepidopterist Torben Larsen, the author of numerous professional and popular works on the butterflies of Arabia, the Levant, West Africa and elsewhere. He immediately appreciated the real significance of HM's observations and wrote to comment that what the DNHG authors had treated as C. parrhasius "seems, in fact, to be Chilades pandava, which has extended its Asian range as shown in [Fric et al. (2014), a first report from Egypt]. It[s larvae] feed exclusively in cycads."

The appearance and behaviour of the butterfly, and the circumstances of its occurrence, leave no doubt that Larsen's inference is correct and that C. pandava has reached Dubai. Moreover, there can be little doubt that it will also be found at other landscaped sites in Dubai, and perhaps at other sites in the UAE and elsewhere in Arabia, where ornamental cycads are present. Confirming that prediction, as this report was being finalised in late October 2014, BR noticed several healthy landscaped cycads on a broad sidewalk outside his place of employment in Dubai's Media City. He immediately went out to investigate and found a handful of C. pandava there, plus evidence that they were breeding, undaunted by the movement of vehicles at an adjacent pick-up and drop-off ramp. However, the introduction of C. pandava in Dubai may be fairly recent. TC's photos from JBR in 2012 and 2013 do not appear to show C. pandava, but only C. parrhasius, on plants other than cycads. Two DNHG members involved in commercial landscaping were consulted, and were not aware of any recent problems or complaints involving damage to ornamental cycads.

As is the case for many plant and animal species, there is no agreed common name in English for C. pandava. In its native India and Southeast Asia, it has generally been called the Plains Cupid (Kehimkar 2008, Marler et al. 2012, Singh 2011). Other authors, mainly working in the Western Pacific (where there is no other "Cupid"), have also called it the Cycad Blue (LaRosa 2008, Fric et al. 2014, Wu et al. 2009, 2010, Moore online). We have suggested the alternative of Cycad Cupid, to emphasise not only its preferred larval foodplant but also its close resemblance and kinship to the sympatric Small Cupid C. parrhasius, recognised in the Indian English vernacular. We believe that choice has advantages for lay butterfly enthusiasts, but of course it is always desirable to encourage use of the scientific nomenclature, Chilades pandava, to avoid possible confusion. The Latin epithet pandava (pronounced PAN-da-va) is an Indian classical reference; it is the name given to five brothers, sons of Pandu and warriors who prevailed in the internecine Battle of Kurukshetra recounted in the Mahabharata, a Hindu epic.

Discussion

What are the implications of the introduction of C. pandava to the UAE? C. pandava has proven to be a successful coloniser, using both native and ornamental cycads. Within the past fifteen years it has spread from its native India and Southeast Asia to various other regions including temperate East Asia (Korea and Japan) (Wu et al. 2009, 2010), islands of the western Pacific (Guam and Rota) (La Rosa 2008), islands in the Indian Ocean (Mauritius, Reunion and Madagascar) (Wu et al. 2009, 2010), and Mediterranean North Africa (the Nile delta) (Fric et al. 2014).

In areas where it is not native, C.pandava is considered a serious invasive pest of indigenous Cycas species (La Rosa 2008, Marler et al. 2012), many of which are on the IUCN Red List (Wikipedia, "Cycadaceae"). These include threatened endemic species in Guam (LaRosa 2008, Moore) and Taiwan (Tavou et al., in prep.). Even where C. pandava is native, the introduction of non-native horticultural cycads has been blamed for an increase in butterfly predation on native cycads (Wu et al. 2010). (NB: A second and equally important pest of ornamental and native cycads in Southeast Asia and the Western Pacific is the Asian cycad scale insect Autocapsis yasumatsui (LaRosa 2008, Marler et al. 2012, Moore online). The scale insect is considered the more important of the two in the Western Pacific (LaRosa 2008, Moore online).)

There are no native cycads in the UAE, or in Arabia, so C. pandava has almost certainly arrived with ornamental plants, most likely C. revoluta. Its record of establishment elsewhere suggests that it is unlikely to disappear from the UAE unless the larval host plants themselves are eliminated, which seems improbable given current fashion in real estate development and landscaping. Tony Pittaway, co-author of the venerable Insects of Eastern Arabia, describes the expansion of C. pandava in urban China: "This has become a very common butterfly in the concrete jungles of eastern China, where it feeds on the ornamental potted cycads which seem to adorn the front entrances of almost every large building, especially hotels, restaurants, government centres, hospitals etc." (A.R. Pittaway, pers. comm.)

C. revoluta has been shown to be one of the most susceptible cycad species to damage by C. pandava, which lays its eggs in the soft, expanding tissue of the leaf buds and new leaves, which are eaten by its caterpillar larvae (Marler et al. 2012). Different cycad species produce new leaves on different schedules and some species produce new leaves throughout the year (Marler et al. 2012). These vegetative flushes, when new fronds are produced, attract C. pandava adults to mate and oviposit. C. revoluta is known to have relatively prolonged vegetative flushes (Tavou et al., in prep.). Thus there exists the potential for C. pandava to become a "pest" species in the UAE as well, although not in natural environments. Moreover, although its primary foodplant is invariably given as Cycas spp., alternative foodplants have been mentioned for C. pandava, including other common landscaping species found in the UAE, e.g. Acacia spp. and Albizzia lebbeck (Kehimkar 2008, Tiple et al. 2009) as well as cultivated varieties of gram and beans (Fabaceae) and other Mimosaceae (Kehimkar 2008).

TC has inspected the potted sago plants at JBR for eggs and larvae and has found both, but only a few young, reddish-purple larvae (Fig. 3), not later instars, which are said to be greenish and may sometimes be tended by any of several species of ants (Moore, online). At all stages, the larvae feed only on the soft tissue of younger leaves (Wu et al. 2010, Marler et al. 2012, Moore, online), causing aesthetic damage; dense populations can cause complete defoliation (Figs. 2, 4), killing the plant (Moore, online). From her observations, TC queries whether some factor, possibly an avian or other predator, may be "controlling" this new butterfly at JBR at the later instar stage. HM's initial report made the point that the mating frenzy she witnessed was attended by many of the insectivorous Red-Vented Bulbul Pycnonotus cafer, a common garden bird in Dubai, trying to catch the butterflies, but she also noted that the birds appeared to be attacking the false eye spots on the hindwings of the butterfly, presumably mistaking these for the insect's head, with the result that the targets were able to avoid mortal damage.

Establishment of C. pandava in the UAE and Arabia would not be unprecedented. Another small Lycaenid butterfly, the Western Pygmy Blue Brephidium exilis, a native of arid south-western North America, has established itself in the Arabian Gulf region, from Northern Oman to Kuwait, apparently over the past 25 years (see, e.g., Pittaway et al. 2006). In the UaE, B. exilis thrives primarily on low, spreading, succulent Sesuvium spp. (Aizooaceae), widely used as a landscaping element. B. exilis has also been found in association with other Aizooaceae (Otto 2014) and other halophytes, but almost always in anthropogenic or perianthropic environments.

Only a single individual of B. exilis has been recorded in the UAE from an indisputably natural environment, the wadi bed of a third order tributary of Wadi Zikt, within Wadi Wurayah National Park, in the mountains of Fujairah emirate on the East Coast of the UAE (G.R. Feulner and J. Judas, unpublished observation). That individual was flying with several Grass Jewel butterflies Chilades trochylus (syn. Freyeria trochylus) feeding on flowering Lavandula subnuda and Convolvulus virgatus. As there were none of its customary succulent or halophyte associates in the area, it had almost certainly lost its way. Thus even the relative success of B. exilis highlights the rigours of the UAE environment: despite more than four and a half decades of introductions of large numbers of exotic plants, and to a lesser extent animals, no animals and only one species of plant (the mesquite tree Prosopis juliflora) can be said to have proved to be "invasive" in natural habitats in the UAE.

GRF and BR returned to Madinat Jumeirah on 19th October 2014 to review the situation of C. pandava there. They found modest numbers of C. pandava perched on cycads at each of a number of locations where cycads were planted, and several females were ovipositing. Moreover, C. pandava was the only butterfly that they saw, and it could be found not only on the cycads and immediately adjacent plants, but in hedges and cultivated beds up to 10-15 metres away. Even very small cycads in a planted area seemed able to attract these butterflies. In one instance, they observed two C. pandava in a treed courtyard where no cycads could be seen.

It was also possible to observe the egg-laying process (Fig. 5) and the tiny white eggs, disk-shaped and ornamented, but with depressed centres on one surface (Fig. 6). Many eggs could be found on the stunted and drying remains of moribund flushes (Figs. 5, 6). The reason for the failure of the new growth is speculative, but there was abundant evidence of aesthetic damage to new cycad leaflets (Fig. 4).

It has long been recognised that landscaped sites in Dubai - resorts, parks, golf courses, etc. - however attractive they may be to the human eye, are typically greatly impoverished in butterflies and most other invertebrate species, compared to natural environments. This has generally been attributed to a combination of (i) a robust regime of pesticide application and (ii) a biota primarily consisting of exotic plants, with which native invertebrate species are unfamiliar. The success of C. pandava may be evidence that the role of unfamiliar plant species is greater than the role of pesticides in discouraging the presence of native species at these artificial sites, since the cycads at Madinat Jumeirah are not exempt from the pesticide regime that applies to landscaped areas generally.

Identifying characteristics

"Pest" or otherwise, it should prove instructive to monitor the status of the newly recognised Cycad Cupid C. pandava within the UAE, and elsewhere within the Arabian Gulf region. What should observers look for in order to be able to distinguish it from the familiar and common Small Cupid C. parrhasius in the field or garden?

Available descriptions and images indicate that one of the most objective characteristics is the presence in C. pandava of a line of four dark spots arranged in a circumferential arc near the base of the under side of the hindwing (Figs. 1 and 7), versus only three such spots in C. parrhasius (Fig. 8) (Kehimkar 2008). Use of this criterion depends on a good view of the hindwing, because the two inferior spots may be inconspicuous and, in both species, the lowest spot is at the basal or inner margin of the hindwing where it may be difficult to see due to posture or wear. But if it can be seen, the third spot immediately below the second that is sufficient to confirm C. pandava; this is the spot that is "missing" in C. parrhasius. In technical terms, it is a sub-basal spot in space 1c (Fig. 9).

The converse is not true unfortunately. The absence of the third spot is not sufficient to confirm C. parrhasius. In a significant number of instances, both at JBR and at Madinat Jumeirah, we have seen and photographed butterflies which were evidently C. pandava - perching, mating and ovipositing on cycads - but in which neither of the two inferior sub-basal spots were visible (Fig. 5). In such cases field discrimination between C. pandava and C. parrhasius is extremely difficult in the absence of circumstantial evidence such as habitat and behaviour; mating on vegetating cycads can probably be taken as conclusive of C. pandava (Fig. 10).

With experience, a field determination can possibly also be based on a combination of qualitative factors, including size, colour and details of patterning. Dark veins on the upperside of the male's blue wings are said to be indicative of C. pandava (Kehimkar 2008, Singh 2011), although those veins may appear prominent in C. parrhasius as well. Images of the underside of C. pandava, taken as a whole, are brownhued, whereas images of the underside of C. parrhasius are mostly pale grey (compare Figs. 1, 5, 7 and 9-10 with Fig. 8), but ground colour is not an infallible guide; exceptions are known.

Larsen (pers. comm.) adds two further qualitative differences signaling C. pandava: (i) larger size and (ii) deeper blue upperside wing colour in the male (versus pale, greyish lavender in C. parrhasius). As to size, at Madinat Jumeirah, most of the several dozen C. pandava observed closely appeared to be at the large end of the size range for C. parrhasius; a few were larger, although not generally rivalling the size of the Pea Blue Lampides boeticus. Impressionistically, most of the larger specimens were thought to be females.

As to colour, a C. pandava male upper side is shown in Fig. 11. A C. pandava female upper side is shown in Fig. 12 and features a very broad but diffuse brown border on all four wings. This differs from what is shown for C. parrhasius in Larsen & Larsen 1982 (a modest brown border) and Larsen 1984 (a uniformly brown upperside, but with a paler interior).

It is possible that more detailed study will reveal additional consistent differences in the underside patterns of C. pandava and C. parrhasius, but if so, these are likely to be both subtle and complex. The recognised variability of C. parrhasius, noted by Larsen (1983), has been mentioned above. In the wild in its native India, C. pandava displays an exceptional diversity of dry season forms that are genetically determined but environmentally mediated, a phenomenon called seasonal polyphenism (Kunte & Tiple 2009, Tiple et al. 2009). The dry season forms are not seen in populations and subspecies from the wet Southeast Asian and Sri Lankan regions (Tiple et al. 2009). It remains to be seen to what extent such polyphenism may be found in C. pandava in the UAE, which subsists on plants growing in artificially maintained environments.

Acknowledgements

The authors wish to thank Torben Larsen for his continuing encouragement and advice to those of us attempting to better understand Arabian butterflies, and for his review of a draft of this paper. The authors, however, take full responsibility for the facts, interpretations and opinions expressed in the final paper.

References

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Tiple, A., Agashe, D., Khurad, A.M., and Kunte, K. 2009. Population dynamics and seasonal polyphenism of Chilades pandava butterfly (Lycaenidae) in central India. Current Science 97(12): 1774-1779.

Wikipedia. "Cycad" http://en.wikipedia.org/wiki/Cycad [Accessed 13 October 2014]. "Cycadaceae" http://en.wikipedia.org/wiki/Cycas [Accessed 13 October 2014].

Wu, L-W., Horn, Y.S., Lees, D.C. and Hsu, Y-F. 2010. Elucidating genetic signatures of native and introduced populations of the Cycad Blue, Chilades pandava, to Taiwan: a threat both to Sago Palm and to native Cycas populations worldwide. Biological Invasions 12: 2649-2669.

Wu, L-W., Lees, D.C. and Hsu, Y-F. 2009. Tracing the Origin of Chilades pandava (Lepidoptera, Lycaenidae) Found at Kinmen Island Using Mitochondrial COI and COII Genes. BioFormosa 44(2): 61-88.

Gary R. Feulner

Chadbourne & Parke

P.O. Box 23927

Dubai, United Arab Emirates

e-mail: grfeulner@gmail.com
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Author:Feulner, Gary R.; Roobas, Binish; Carlisle, Tamsin; Meyer, Helga
Publication:Tribulus
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Date:Jan 1, 2014
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