X-branded Moth

An addition to the X-men family~


Chalciope mygdon
Noctuidae, Catocalinae
Location: Shrub opp. Singapore Polytechnic

You Tick me off!

KB invited me to help out HS in his survey at Bukit Timah Hill today. It was a pretty challenging field trip, carrying ladders, climbing slopes etc. I was breathless by the end of the journey. Phew, what a nice workout though.

However, the more shocking discovery was when we were packing up to leave. That was when I sneaked a peep at my socks where I felt this persistent prickling throughout the trip. I noticed many tiny little dots on my socks and a closer inspection revealed that they were moving. That was when I shouted ticks!

The three of us immediately started to pull out our socks. Apparently I was the one who had the most ticks on me. If you looked closely and count, just this side of one feet already have 24 ticks! Luckily I had a pair of tweezers with me and plucked these blood suckers off one by one. Some were anchored so firmly on me that it drew blood when I forcefully removed them. But it was just a tiny bit of red.

Evidently, socks do not provide much protection since so many managed to crawl under it to my flesh... Think there must be about a hundred on my legs at that moment. Probably another hundred on my socks. Shivers...

Ticks belonged to the class of Arachnida, the eight-legged group of arthropods, same as the spiders. It is said that they attach themselves to a host using their mandibles and a feeding tube known as a hypostome, which happen to have backward pointing spikes like a rattan. No wonder it was hard to remove them.

I threw my bug covered socks into a ziplock and tried to take some photos using my raynox macro lens at home. Unfortunately, these pesky little buggers were already dead by then. But at least you can have a view of these nasty parasites. Still, I felt that it was an interesting experience, though I don't endeavour to have another encounter!

Anyway, don't worry. I probably picked up those ticks (or rather, they hunt me down) off trail. Another reason why you should stick to the route at Bukit Timah Hill.

Horseshoe crab and LAL (II)

In continuation from my first posting, this second one will cover about the discovery of horseshoe crab's blood and their eventual commercialisation.

Scientists have been studying the properties of blood clotting of the horseshoe crab more than a century ago. However, it was only during the 1950s when Fred Bang discovered in that blood from Limulus polyphemus clot when bacteria was present, even dead ones. Eventually, it was recognised that it was due to a mobile blood cell called ameobocyte.

These cells possess lots of granules which will release clotting factors and other antimicrobial molecules in response to external stimulus. Besides this, many agglutinins are also present in the blood stream to as an additional protection. This is probably the reason why these living fossils have managed to survive on Earth for millions of years.

It was eventually found out that endotoxins found on gram-negative bacteria causes the clotting in the horseshoe crab's blood. They managed to devise a method to isolate these chemicals by centrifuging the blood to separate the ameobocytes and placing them in water causing them to lyse or burst. The resulting liquid is known as LAL or Limulus Ameobocyte Lysate.

So sensitive and thus effective is the LAL in detecting endotoxins that the Food and Drug Administration (FDA) replaced this from the standard rabbit test. Unfortunately, at that time, the only way to obtain LAL was to harvest live horseshoe crabs and gave them a forced blood donation. They were then returned to the sea (if they managed to survive the process). But studies had shown that mortailty was low.


Another species of horseshoe, Tachypleus gigas found locally

A leap in scientific advancement but unfortunately, not much in terms of ethics. I guess most would prefer horseshoe crabs suffering instead of rabbits due to the "Bambi syndrome" (in simple terms, just being cute and cuddly) but it would not be if you see this picture. To me, it is no different from catching bears to extract their bile which is condemned by many.

Check out my other postings in this series:
Part I: Horseshoe crabs and Endotoxin
Part III: Horseshoe crabs and Factor C (to be updated)