Some science


P. V. Bruyns; C. Klak; P. Hanáček: A revised, phylogenetically-based concept of Ceropegia (Apocynaceae). South African Journal of Botany 112: 399-436. 2017

Well, well, well ….

This revision is quite a messy one, and I’m very unhappy with it.

I have to admit that I hoped for a revision so much, but I was suspecting a splitting of the genus Ceropegia into several smaller genera, however, that’s not what this revision has done.

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“Recent phylogenetic reconstructions in the Cerpegieae (Apocynaceae-Asclepiadoideae) show that the 357 species of highly succulent stapeliads and four lineages of the 141 species of Brachystelma R. Br. ex Sims are nested within the 219 species of Ceropegia L.”

Well, that’s right, but, in my opinion doesn’t mean that all of them should now be included in the genus Ceropegia!

The authors present a monophyletic genus Ceropegia, which, in my opinion, is a bit like calling all animals with a head and four legs a dog just because dogs have a head and four legs …. They furthermore present over 400 new combinations of names, [and I’m very, very sure that I’m right] that no one will ever use!

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So why not just splitting the genus Ceropegia?

The authors say that splitting is impractical because the new genera resulting from such a splitting would not be characterizable by external features. Well, that’s a weak reason, I think. In my opinion a splitting would just result in a [small] heap of new genus names for several plants formerly just called Ceropegia, certainly including all the African species. But now this is just an extreme heap of new species names which now are all included in the genus Ceropegia.

For example, Stapelia gigantea N. E. Br., probably a well-known plant, would now need to be called Ceropegia gigantea (N. E. Br.) Bruyns.

Hm, no, thanks.   😦

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References:

[1] P. V. Bruyns; C. Klak; P. Hanáček: A revised, phylogenetically-based concept of Ceropegia (Apocynaceae). South African Journal of Botany 112: 399-436. 2017

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Interactions with animals

It is well known that Ceropegia spp. are pollinated by small to very small flies from several families, so it is not really a surprise to find predatory invertebrates like spiders at the flowers or near the flowers.

One such example can be found on page 14 in P. G. Archer’s ‘Kenya Ceropegia Scrapbook’ from 1992, where a crab spider is photographed sitting very prominently close to a flower of a Ceropegia abyssinica Decne. ready for action.

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When Prof. J. Ollerton, who investigates pollinators and pollinator-plant-interactions in great detail, dissected flowers of ca. 50 years old herbarium specimens of Ceropegia nilotica Kotschy, he did not only found dried flies on occasion but discovered in one of the flowers two (unidentified) ants – caught in the act; one of them still had a part of a fly wing in its mouth parts, meaning it has been collected and preserved in the act of eating one of the probable pollinators!

Well, this is obviously still the only known case of ants eating flies inside a Ceropegia flower so far, I personally do not know of any other one.

But of course it leads to several questions:

Does that occur more often?
Does that occur all over Ceropegia’s range?
Which ant species are involved?

… and so on ….

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BTW: According to a very recent study, Ceropegia nilotica mostly attracts flies from the genus Desmometopa, so-called freeloader flies (family Milichiidae), and from the genus Forcipomyia, biting midges (family Ceratopogonidae). [2]

… more of that is coming soon ….

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References:

[1] Jeff Ollerton: Fly trapping in Ceropegia flowers – evidence of ant-predation on pollinators. Asklepios 77: 31-32. 1999
[2] Annemarie Heiduk; Irina Brake; Michael v. Tschirnhaus; Jean-Paul Haenni; Raymond Miller; John Hash; Samuel Prieto-Benítez; Andreas Jürgens; Steven D. Johnson; Stephan Schulz; Sigrid Liede-Schumann; Ulrich Meve; Stefan Dötterl: Floral scent and pollinators of Ceropegia trap flowers. Flora; puplished online: 1-Feb-2017

A new locality for Ceropegia oculata?

These photos were taken by  N.S. Dungriyal, the field director of the Satpura Tiger Reserve, they show a plant that I would identify as Ceropegia oculata Hook..

The flowers are quite similar to nearly identical to a special form of the species, that had been described in 2005 as a distinct variety: Ceropegia oculata var. satpudensis Punekar, S. D. Jagtap & Deokule, this has now been reduced to synonymy with the nominate race.

If my identification turns out to be correct, then this find would probably represent a new locality for this species, since it obviously is known only from Maharashtra so far – as far as I know.

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c.oculata.nsd

c.oculata.nsd1

Photos: N.S. Dungriyal; by courtesy of N.S. Dungriyal

Parasites and parasitism

Of course the leaves of Ceropegia are consumed by different kinds of insects, yet there appear not to be much information of such cases, but an example is given in O. A. Leistner’s “Flora of Southern Africa”, 1980.:

“It is difficult to get complete specimens with seed, flowers and leaves, as the last are usually stung by some fly and drop off when the maggots hatch.”

(source: H. R. Brownlee in 1935 while studying Ceropegia plant material) [1]

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The fruit fly species Dacus apoxanthus Bezzi (family Tephritidae) is known to parasitize the flower buds of Ceropegia ampliata E. Mey., resulting in the flower buds becoming translucent, and in the flowers wilting thereafter. [2]

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I hope that there will be more studies to come.

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References:

[1] O. A. Leistner: Flora of Southern Africa 27(4). Botanical Research Institute, Dept. of Agricultural Technical Services 1980
[2] Gareth Coombs; Anthony P. Dold; Craig I. Peter: Generealized fly-pollination in Ceropegia ampliata (Apocynaceae – Asclepiadoideae): teh role of trapping hairs in pollen export and receipt. Plant Systematics and Evolution 296(1): 137-148. 2011

Moving closer towards a result regarding kinship relations within the several ‘Ceropegia’ lineages.

It appears that there may actually be as much as 13 distinct, more or less closely related genera involved in forming the artificial genus Ceropegia, see here.:

The genera Brachystelma Sims and Ceropegia L. of the Ceropegieae (Apocynaceae-Asclepiadoideae) consist of ±320 species of geophytes and slender climbers with a tendency to stem-succulence in Ceropegia. They occur in and around the semi-arid, mainly tropical parts of the Old World. For 146 species (around half of the total) from most of the geographic range of the genera, we analysed data from two nuclear and five plastid regions. The evolution of Ceropegia is very complex, with at least 13 mostly well-supported lineages, one of which is sister to the ±350 species of stapeliads. Species of Brachystelma have evolved at least four times, with most of them nested within two separate major lineages. So, neither Brachystelma nor Ceropegia is monophyletic. We recover a broad trend, in two separate major lineages, from slender climbers to small, geophytic herbs. Several clades are recovered in which all species possess an underground tuber. Small, erect, non-climbing, geophytic species of Ceropegia with a tuber are nested among species of Brachystelma. Consequently, the distinctive tubular flowers used to define Ceropegia do not reflect relationships. This re-iterates the great floral plasticity in the Ceropegieae, already established for the stapeliads. Both major lineages exhibit a trend from tubular flowers with faint, often fruity odours, pollinated by very small Dipteran flies, to flatter flowers often with a bad odour, pollinated by larger flies. Most of the diversity in Brachystelma and Ceropegia is recent and arose within the last 3my against a background of increased aridification or extreme climatic variability during the Pliocene. In the ingroup, diversity is highest in Southern Africa, followed by Tropical East Africa and other arid parts of Africa, the Arabian Peninsula and India. Many disjunctions are revealed and these are best explained by recent, long distance dispersal. In Africa, the diversity arises from the presence of many different lineages over wide areas but there is also evidence of closely related species growing together with different pollinators.

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source:

– P. V. Bruyns; C. Klak; P. Hanáček: Recent radiation of Brachystelma and Ceropegia (Apocynaceae) across the Old World against a background of climatic change. Molecular Phylogenetics and Evolution 90: 49-66. 2015

Which are the next relatives of the two isolated Canary Islands Ceropegia species?

According to a new scientific paper (see below), which also contains some new phylogenetic trees, the next relatives of Ceropegia dichotoma and Ceropegia fusca from the Canary Islands are three species from Asia, resp. Australia, namely Ceropegia cumingiana, Ceropegia intermedia and Ceropegia pubescens.

According to the paper, the Canary Islands were colonised by the genus Ceropegia only once.

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The phylogenetic trees furthermore show – again – that the genus Ceropegia as such does not exist, but is either a much larger genus, including all of the Brachystelma species and some of the stapeliad species (or perhaps even all of them), or it must be split into several smaller genera (that is what I would prefer), with the name Ceropegia remaining for Ceropegia candelabrum (the species that was first described under that genus name) and its relatives.

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… by the way: the paper is naming my website as a source for pictures. 😛

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source:

– Ambroise Valentin: Phylogenetic position of Ceropegia dichotoma and Ceropegia fusca and their biogeographical origin. Uppsala Universitet 2014

Natural enemies

Most, if not all species of the genus Ceropegia contain larger or smaller amounts of the alkaloid Ceropegin, and thus are probably not specifically taken by mammals as food, however, giraffes have been observed in the Niger to occasionally eat shoots of Ceropegia aristolochioides. [5]

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On the other hand, however, several species of Ceropegia are very important food plants for the caterpillars of some butterfly species from the Brush-footed Butterfly family (Nymphalidae).

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danaus.genutia.raupe.fm.li

danaus.genutia.fm.li

above:

The caterpillars of the Common Tiger (Danaus genutia (Cramer)) from India feed on Ceropegia elegans, Ceropegia intermedia, Ceropegia lawii, Ceropegia manoharii, Ceropegia oculata, and Ceropegia thwaitesii. [1][6][9]

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parantica.aglea.raupe.fm.li

parantica.aglea.fm.li

above:

The caterpillars of the Glassy Tiger (Parantica aglea (Stoll)) have been recorded from the Andaman Islands to feed on Ceropegia andamanica, and from India on Ceropegia bulbosa, Ceropegia hirsuta, Ceropegia lawii, and Ceropegia oculata. [2][6][9][10]

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parantica.taprobana.fm.li

above:

The caterpillars of the Ceylon Tiger (Parantica taprobana (Felder & Felder)) from Sri Lanka are thought to feed on Ceropegia thwaitesii, however, this is still to be proven. [8]

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euploea.core.raupe.fm.li

euploea.core.fm.li

above:

The caterpillars of the Common Crow (Euploea core (Cramer)) in Australia – which, by the way, is a collective species, consisting of at least five distinct species – are known to feed on Ceropegia cumingiana. [4]

Depictions from: ‘F. Moore: Lepidoptera Indica. London 1890-1913’

http://www.biodiversitylibrary.org

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danaus.chrysippus.raupe.kn

danaus.chrysippus.kn

above:

The caterpillars of the African Monarch (Danaus chrysippus L.), a species that is distributed over Africa and parts of Asia, are known to feed on several species of Ceropegia in Africa, and at least on Ceropegia bulbosa in India. [2]

The same species was formerly a straggler to the Canary Islands but is now a resident, its larvae were recorded on the islands first on the introduced asclepioid species Orbea variegata (L.) Haw. in 2010. [7]

This species is now known to feed on the endemic Ceropegia species as well (see photograph, which, by the way, was taken in 2008 (!)).

Photos: Klaus Nowak; by courtesy of Klaus Nowak

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References:

[1] Naresh Chaturvedi; Meena Haribal: New larval food plants for the Common Tiger Butterfly in India (Lepidoptera: Nymphalidae: Danainae). Tropical Lepidoptera 3(2): 158. 1992
[2] N. Patil; M. R. Almeida: Ceropegia bulbosa var. lushii (Grah.) Hook. f.: a new food plant for plain tiger butterfly Danaus chrysippus (Linn.). Journal of the Bombay Natural History Society 93(3): 600. 1996
[3] P. V. Sreekumar; K. Veenakumari; Mohanraj Prashanth: Ceropegia andamanica (Asclepiadaceae) a new ‘fly trap flower’ from the Andaman Islands, India. Blumea 43(1): 215-217. 1998
[4] R. L. Kitching; E. Scheermeyer; R. E. Jones; N. E. Pierce: Biology of Australian Butterflies. CSIRO Publishing, 1999
[5] I. Ciofolo; Y. Le Pendu: The Feeding Behaviour of Giraffe in Niger. Mammalia – International Journal of the Systematics, Biology and Ecology of Mammals. 66(2): 183–194. 2002
[6] Mamata Chandrakar; Sachin Palekar; Sangita Chandrakar: Butterfly fauna of Melghat Region, Maharashtra. Zoos’ Print Journal 22(7): 2762-2764. 2007
[7] T. van der Heyden: Orbea variegata (L.) Haworth, 1812 (Apocynaceae, Asclepiadoideae) als Futterpflanze der Larven von Danaus chrysippus (Linnaeus, 1758) auf den Kanarischen Inseln (Spanien) (Lepidoptera: Nymphalidae, Danainae). Shilap Revta. lepid., 38(149): 107-110. 2010
[8] George van der Poorten; Nancy van der Poorten: New and revised descriptions of the immature stages of some butterflies in Sri Lanka and their larval food plants (Lepidoptera: Nymphalidae). Part 1: Sub-family Danainae. The Journal of Research on the Lepidoptera 44: 1-16. 2011
[9] P. Sujanapal; P. M. Salim; N. Anil Kumar, N. Sasidharan: A new species of Ceropegia (Apocynaceae: Asclepiadoideae) from India with notes on rare and threatened Ceropegia in Nilgiris of Western Ghats. Journal of the Botanical Research Institute of Texas 7(1): 341-345. 2013
[10] M. Bhakare; H. Ogale: Larval host plants — Asclepiadaceae. In: K. Kunte, S. Kalesh & U. Kodandaramaiah (eds.). Butterflies of India, v. 2.00. Indian Foundation for Butterflies 2014

How many distinct genera are actually included in the genus Ceropegia?

More than one 😉 , see here.:

Ceropegia includes more than 200 species distributed in the Old World ranging from the Canary Islands to Australia. In India, there are about 50 species described on a morphological basis as belonging to Ceropegia, and most of them are endemic to the Western Ghats. To investigate evolutionary relationships among Indian Ceropegia taxa and their allies, a phylogenetic analysis was conducted to include 31 Indian taxa of Ceropegia and Brachystelma and their congeners from other geographical regions using nuclear ribosomal internal transcribed spacer (ITS) and three noncoding chloroplast DNA (cpDNA) sequences, including intergenic spacers trnT-L and trnL-F, and trnL intron. The Western Ghats Ceropegia species were found to be most closely related to Indian Brachystelma, with the two genera being placed sister to each other in the ITS phylogeny or with the Brachystelma clade nested within one of the two subclades of Indian Ceropegia in the cpDNA phylogeny. In contrast, Ceropegia species from other regions and African Brachystelma all formed separate clades basal to the Indian Ceropegia–Brachystelma clade. Thus, it can be concluded that the classical morphology-based delineation of the two genera needs revision to reflect their phylogenetic relationships, which are more in accordance with their geographical origin than with morphology.

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source:

– Siddharthan Surveswaran; Mayur Y. Kamble; Shrirang R. Yadav; Mei Sun: Molecular phylogeny of Ceropegia (Asclepiadoideae, Apocynaceae) from Indian Western Ghats. Plant Systematics and Evolution 281(1-4): 51-63. 2009

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In short, the genus Ceropegia is in fact not a single genus, and will probably be split into several distinct genera some day.