Tuesday, 19 May 2015

Might of the Ant Mite

"A mite makes the seas roar" Richard Feynman (1988) so reads the opening lines of Macromite’s Blog which is really mind-boggling considering the amount of information that has been compiled on this blog on these more so obscure subject!

Mites have not been a group I love especially because I have been prone to mite attacks every time I came out of the forests of the Mhadei in Goa which is part of the Western Ghats. I have never given them much of a thought except on few occasions. The first time I came across them was on the body of an electrocuted Indian flying-fox (Pteropus giganteus) which we had tried to preserve in my early days as a graduate student of Zoology. I was so excited about the prospects of performing taxidermy on the winged mammal that I almost overlooked the small creatures scampering around the dead flying-fox’s body, but once I did get a look at them, it took me more than fifteen minutes to actually pull out an individual from the flying-fox’s body. It was one mean looking individual. Back then, I did not show much interest and ended up mounting the specimen on a card point, leaving it in a specimen box which eventually got lost thanks to renovation activities of my erstwhile institution. 

Probable specimen of Cyclopodia horsfieldi from Pteropus giganteus (Lateral View)

Probable specimen of Cyclopodia horsfieldi from Pteropus giganteus (Dorsal View)

Years from then though, I was lucky to catch a glimpse of them on the subjects I love the most “ANTS”. I was aware of parasitism in ants and had been under the notion that ectoparasites usually affect big sized ant species and that perception went for a toss when I saw what I saw. 

Just before pulling the curtains on my stint at Pondicherry University, I was attending a dinner party at my friend’s place when I happened to see 20 medium sized ants milling around a crack on the floor tiles. A closer examination revealed they were queens of the invasive Monomorium pharaonis (Linnaeus, 1758). This species of Monomorium live as populous polygynous (a typical ant colony has just one queen but there are species where a colony may have many queens living together and such colonies are called polygynous) colonies which can survive on almost anything as a resource. This generalist behavior of theirs has made them quite successful and they according to me were someone who could never be subjected to any misery, but what I saw that day changed this perspective off mine. 

Affected Monomorium pharaonis queens and workers

A closer observation revealed small bumps covering the entire body of the queens. The workers too had these bumps all over their body. The colony appeared to be shifting but they were disoriented and unorganized. The workers seemed to be moving around in circles while the queens just lay there doing nothing. Occasionally a queen would start jerking violently but it lasted only a few seconds. The entire scene was dramatic and unlike anything I had ever seen previously.
All I could do was take a few pictures that day and move on from there with the threat of becoming an anti social-gathering individual looming on my head. 

Affected Monomorium pharaonis queens and workers

Close up showing mites attached through out the body of the queens. Also seen mites infecting the entire body of the worker at the bottom left.

Later I did try to search for instances of observation on mite parasitism on Monomorium pharaonis but I kept meeting dead ends. A paper titled “The diversity and host specificity of mites associated with ants:the roles of ecological and life history traits of ant hosts” by K. U. Campbell, H. Klompen and T. O. Crist in Insectes Sociaux gives a list of 151 mite species identified from 43 species of ants from Ohio but there is no mention of the Monomorium pharaonis. It seems that either there is nothing much on this in the public domain or my “googling” skills are very poor. Both ways this observation is very interesting and warrants some PhD student’s in-depth attention. Is anyone willing to take that offer?