"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift

September 7, 2012

Antricola marginatus

People usually associate bats with the image of vampires and blood feeding, even though most bats are not blood drinkers. However, bats are themselves host to all manners of blood-feeding parasites. Today, we are looking one such blood sucker - Antricola marginatus - a tick with a caring, maternal side that people don't usually associate with the word "parasite" (though we have featured a few parasites on this blog which go out of their ways to give their offspring with the best possible start to life).

Image from Figure 1 of the paper
While collecting ticks in a cave which is home to nine species of bats (if you are wondering, none of those bats are vampires) in the Yucatan, Mexico, a trio of researchers came across eight female A. marginatus that were covered in massive broods of little baby tick. Each of the female ticks carried between a hundred to four hundred nymphs on their backs. Those little nymphs are very attached to their mother - when the researchers tried to brush some nymphs off, they quickly scramble back onto mother's back at their own volition.

Over the course of its evolution, A. marginatus has almost completely given up its vampiric life-style of drinking bat blood in favour of... something less glamourous - eating bat droppings. However, they still go through a stage in their life as nymphs when they retain their taste for blood. So how are the nymphs suppose to disperse to a suitable host when their mothers are scrambling around and munching on bat poop? The researchers suggested that A. marginatus facilitates her babies by making regular visits to roosting bats, where the nymphs can disembark and drink all they want.

Indeed, when they brush a nymph-ladened mother tick onto a rabbit's ear, the nymphs quickly jump off and started gorging themselves on blood. However, after three days of chugging down rabbit blood, they died - this is not surprising because as I have discussed in a previous post, blood-feeding parasite can be remarkably picky about their hosts, and for some parasites even a slight host species difference can result in deterioration in survival, let alone the large difference between bats and rabbits. So it was no surprises that those nymphs dropped dead after a few days of imbibing rabbit blood. Back in their natural environment of the bat cave, the next warm-bodied mammal A. marginatus would have off-loaded her nymphs on to would have been roosting bat.

Maternal care has been reported for other arachnids like spiders and scorpions, but not ticks. It is unknown just how unique A. marginatus is among ticks with its maternal behaviours, or if there are many other caring, motherly ticks out there which are just waiting to be discovered.

Reference:
Labruna MB, Nava S, Guzmán-Cornejo C, Venzal JM. (2012) Maternal Care in the Soft Tick Antricola marginatus. Journal of Parasitology 98: 876-877

8 comments:

  1. That picture almost came close to triggering my Trypophobia. It's not so bad when I see it enlarged (obviously because then it ceases to resemble a cluster of holes; although I've now horrified myself by mentioning the latter *facepalm*).

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  2. Niroot, I didn't realise Trypophobia was a thing - thanks for enlightening me.

    Well, I guess this post *is* about a tick, not to mention one which carries hundred of little ticks on her back - it's bound to trigger sensation ranging from itching to horror in some people - Trypophobia or not.

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    1. It wasn't until recently that I learned it even had a name. I also thought I was probably alone (or at least among the exceedingly few) who experienced it, but it turns out to be less uncommon than I thought.

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  3. The possible "reactions" are interesting, cool, funny, and yuck. But I need a box labeled "adorable."

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  4. You know what Danna, I'm feeling rather whimsical - so I've added an "adorable" box just for lulz

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  5. I don't have the faintest clue why holes would be scary. But I can understand why ticks would be. Anaplamaphobia, babasiaphobia, and spirochaetophobia are legitimate psychological conditions.

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