Apr 15 2010

Going my way? Blood sucking hitch-hikers!

Published by under parasitism and tagged: , ,

I came across this photo taken by Horace Tan while blog-surfing recently and at first glance mistook the bright red object for the butterfly’s eye. Upon closer inspection of both the photo and the site itself, I realized that it is in actual fact, a mite!

‘What in the name of ecology is a mite doing ‘impersonating’ the butterfly’s eye?’ you might ask?

Truth is, this brightly-coloured mite clings onto the butterfly and feeds on its blood! At the same time, the mite uses the butterfly as a private transport, dropping off when it is full from feeding. Phoresy, a dispersal method, is where an organism attaches itself to another for merely transportation only (Encyclopaedia Britannica Online, 2010). However, in this case, since the mite is mainly feeding on the butterfly’s blood, this is more of parasitism coupled with phoresy.

Mites, from the subclass Acari, are one of Nature’s most successful and diverse groups of invertebrate, with over 45,000 species documented (David Evans Walter et al, 1996).  They can cause allergic diseases in humans and among them, the House dust mite, Dermatophagoides pteronyssinus, is one of the most common mites to cause allergic reactions (Teoh, 1977). This particular mite in the photo is suspected to be Trombidium breei from the family Trombidiidae (Ben Bolet, 2009). Interestingly, it is unclear why the mites are mostly observed attached to the butterfly’s head or eye instead of the thorax.

Bright red Trombidium mite (from Ben Bolet, 2009)

Bright red Trombidium mite (from Ben Bolet, 2009)

Even though these mites feed on the butterfly’s blood, the amount taken is apparently so little that it appears to be harmless to the host butterfly! Studies have shown that these mites do not in any way affect the butterfly in its flying or behavior; those with mites behave the same as those without (Conradt et al, 2002). This relationship also does not shorten the butterfly’s lifespan or reproductive capabilities, thus the butterflies do not seem to mind it one bit. Talk about having a free lunch!

References

1. Second Source Link: Conradt, L., S.A. Corbet, T. J. Roper & E.J. Bodsworth, 2002. Parasitism by the mite Trombidium breei on four U.K. butterfly species. Ecological Entomology, 27 (6): 651-659.

2. “Parasitic Mites on Butterflies” by Khew SK. Butterflies of Singapore, 21 October 2009. URL: http://butterflycircle.blogspot.com/2009/10/parasitic-mites-on-butterflies.html (accessed on 7 April 2010)

3. “Trombidium, Dicrocheles mites and their Lepidoptera hosts” by Ben Bolet. Ben The Butterfly Guy, 23 October 2009. URL: http://benthebutterflyguy.blogspot.com/2009/10/trombidiums-dicrocheles-mites-and-their.html (accessed on 7 April 2010)

4. “Phoresy.” by Encyclopaedia Britannica Online, 2010. URL: http://www.britannica.com/EBchecked/topic/457351/phoresy (accessed 8 April 2010)

5. “Acari” by David Ethans Walter, Gerald Krantz, and Evert Lindquist. Tree of Life web project, 13 December 1996. URL: http://tolweb.org/Acari/2554 (accessed on 10 April 2010)

6. Teoh, P.C., W.C. Tan, C.J. Oon, K.F. Lui, 1977. Prick skin tests in bronchial asthma and their correlation with the specific serum lgE levels. Singapore Medical Journal, 18 (4): 228-231.

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