|Dead horse arum lily|
|Illustration from Louis van Houtte's Flore des serres et des jardins de l'Europe (1849)|
|Range of Helicodiceros muscivorus in Europe|
Helicodiceros muscivorus (dead horse arum lily) is an ornamental plant native to Corsica, Sardinia and the Balearic Islands. It is the only species in the genus Helicodiceros. Within the Araceae family the plant is part of the Aroideae subfamily, and although the origin of the common name its unknown, it can be concluded that is named after the plant's appearance of a carcass.
The flowers of Helicodiceros muscivorus smell like rotting meat, attracting carrion-seeking blowflies which act as pollinators. One of a rare group of thermogenic plants, the dead horse arum can raise its temperature by thermogenesis. This helps to lure flies into the plant to contact its pollen. Up to today the plant still is researched for the way the plant is able to produce its own heat without being necessarily dependent of ambient temperature.
The inflorescences of the arum lilies is a three part spadix which resembles the anal area of a dead mammal. In between there is a hairy spathe such as a ‘tail’ running long down into the chamber of the flower which bands with the fertile male and female florets. The appendix and the male florets are thermogenic, but both have a different temporal pattern. It's exits of the female florets is hindered by spine and filament which serve to trap the blowflies once inside. Its male florets exhibit independence from the ambient temperatures as it has been found through research that heat production depends on the time of the day rather than ambient temperatures. Also, uncoupling protein was found in both of the thermogenic male florets and appendix. There is 1178 nucleotides in length in the dead-horse arum mRNA excluding the poly-A tail and its believed to have a protein of 304 amino acids. It also possesses three mitochondrial carrier signature domains, six membrane spanning domains, and one nucleotide binding domain to be known as well by its characteristics of the unknown uncoupling protein. Potato and Rice have been compared to the plant at times due to its typical features of the uncoupling protein. Uncoupling protein plays a big role into the production of energy to become heat.
The dead-horse arum manipulates the heat to release an odor that lures the flies to the structure of the appendix of the flower to begin pollination. This odor is a strong putrid smell, its composition has a similarity to a real carcass which flies are not able to differ from a real carcass. Blowflies find the horrific smell and possible the fleshy colored hairy inflorescence of the plant irresistible and retracts in large numbers into the plant. It has been found in research that the thermogeny has a direct effect on the pollinators, by altering their behavior. Although male florets of the dead-horse arum exhibit some independence from ambient temperature the pattern has shown that heat production depends on time of the day. Pollination occurs in to two days. During a research it was recorded it's highest temperatures of the plant to have increase by noon on day 1. The appendix temperature was 12.4C higher than ambient temperature. During day 1, the eight plants flowering, scored the behavior of a total 881 fly visits. Thermogeny has been linked to be produced by the uncoupling protein that has been found on the plant. This type of protein does not complete the process to ATP synthesis, instead it allows electrons to flow through, into the mitochondria without creating ATP. Thus, the result of creating a lot more energy which causes that extra energy to dissipate into heat.
The dead-horse arum has a two-day process for pollination. The individual flowers is able to receive pollen for 1 day only and usually that day its male parts are not mature. Although the next day the male is able to produce pollen, the female shrivels up and can not receive it. Thus the solution is its Thermogeny. When ready to pollinate the plant produces its own heat and generate a rotten smell like rotting flesh. This smell attracts the blowflies into the chamber of the plant for pollination. Once the flies inside; they are trapped in the chamber by spines that are blocking the exit path. The flies carrying pollen from previous visits to other flowers including others as same as them, cover the female floret with that pollen; as they try to find a place where to lay their eggs. The flies remained trapped overnight, and the spines remain erect; until the male florets at the entrance of the chamber start producing pollen and the female florets are no longer receptive, upon which the spines wilt and the flies are able to leave. Just as the flies leave they have to pass through the male florets and again are coated with pollen.
- Kew World Checklist of Selected Plant Families
- H. muscivorus at International Plant Names Index
- D. crinitus at Lemaire, Charles. Flore des serres et des jardins de l’Europe (1849)[dead link]
- S. Castroviejo et al. (eds.) (2008). Flora Iberica 18: 1-420. Real Jardín Botánico, CSIC, Madrid.
- Altervista Flora Italiana, Gigaro mangiamosche, Helicodiceros muscivorus (L. Fil.) Engler
- A. M. Angioy, M. C. Stensmyr, I. Urru, M. Puliafito, I. Collu & B. S. Hansson (2004). "Function of the heater: the dead horse arum revisited". Proceedings of the Royal Society B: Biological Sciences 271 (Suppl. 3): S13–S15. doi:10.1098/rsbl.2003.0111. PMC 1809992. PMID 15101405.
- Stensmyr, Marcus C., et al. “Pollination: Rotting Smell of Dead- Horse Arum Florets.” Nature 420.6916 (2002): 625-6.ProQuest.Web.29 Oct. 2014. http://0search.proquest.com.library2.pima.edu/biologyjournals/docview/204482339/294A9FD32A0B44A6PQ/1?accountid=13194.
- R, S., Seymour, M., Gibernau., and S.A Pirintsos. (2009), Thermogenesis of three species of Arum from Crete. Plant, Cell & Environment, 32:1467-1476.doi: 10.1111/j.1365-3040.2009.02015.x. Http://onlinelibrary.wiley.com/do/10.1111/j.1365-3040.2009.02015.x/full
- Angioy, A. M., Stensmyr, M. C., Urru, I., Puliafito, M., Collu, I., and Hansson, B.S., Function of the heater; The dead horse arum revisited. 7 February 2004 doi:101098/rsbl.2003.0111Proc.R.Soc.Lond.B 7 February 2004 vol.271.n0.Suppl 3 S13-S15.Http://rspb.royalsocietypublishing.org/content/271/Suppl_3/S13.short
- Ito, K., Yukie, A. Johnston, S. D., Seymour, R.S., Ubiquitous expression of a gene encoding for uncoupling protein isolated from the thermogenic inflorescence of the dead horse arum Helicodiceros muscivorus. J. Exp. Bot. (2003) 54(384): 1113-1114.doi: 10.1093/jxb/erg 115. http://jxb.oxfordjournals.org/content/54/384/1114.short
- R. S., Seymour, M., Gibernau., K. Ito. Thermogenesis and respiration of inflorescences of the dead horse arum Helicodiceros muscivorus, a pseudo-thermorgulatory aroid associated with fly pollination.11 Dec 2003.DOI:10.1111/j.1365-2435.2003.00802.x. Http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2435.2003.00802.x/full
- Media related to Helicodiceros muscivorus at Wikimedia Commons
- Araceum: Helicodiceros muscivorus page
- International Aroid Soiety: Helicodiceros muscivorus photo
- Pacific Bulb Society: Helicodiceros muscivorus
Dead Horse Arum (with pictures and video) on www.realmonstrosities.com