Glowing Mushrooms and Fireflies

I've been neglecting you dear Zoology blog. I am very sorry and I am going to try and post on here at least once a week to keep on top of my extra reading. This evening I would like to talk to you about a very interesting subject I had a lecture on this week, bioluminescence. Many of us will have seen examples of bioluminescence (without knowing the fancy word for it) in fireflies and some people may also have seen glow worms. The majority of bioluminescence however is found in the oceans.

animals.nationalgeographic.com

As you would expect, it is very hard to see when you live in a deep sea habitat. The photo above is a Anglerfish which lives in very deep regions of the ocean and looks very much like a scary alien from a sci-fi movie! As you can see, the Anglerfish has a lure which has a light on the end. If you have ever seen Finding Nemo you will know that it uses this lure to attract smaller fish for it to eat. Dragonfish have a similar lure which goes underneath them rather than over their mouth. Dragonfish also have a light next to their eye which is a wavelength that only they can see. This is a pretty nifty way of being able to see both predators and prey without them seeing you.

tech.ca.msn.com

Bioluminescence is also helpful for marine organisms avoiding predators. The Hawaiian Bobtail Squid uses a bacterium (Vibrio fischeri) to create light which it reflects from its body in the same direction as the moonlight and therefore obscures its silhouette in the water and makes it difficult for predators to see them. The image above is the deep sea octopus (Stauroteuthis syrtensis) which is one of the very few bioluminescent octopuses. Strangely, it is the suckers on this octopus which light up and the function of this is not yet known but could be to either attract prey or for communication. The bioluminescence shown in ocean species is generally either blue or green as these are the colours that travel the furthest. In terrestrial organisms the colours can vary greatly.

animals.nationalgeographic.com

As I mentioned earlier, fireflies are a well known example of bioluminescence and are one of the few terrestrial examples. Since fireflies are usually seen as little glowing dots I thought I would give you a close up picture of one. Different species of firefly use different colours of light depending on the time of day they use their light and the ability of that particular species to see different colours. Many species emit red light but we only see yellow or green light due to our eyes. These organisms use their light to attract mates so they can reproduce, which is very different from the marine organisms we have already talked about.

Wikipedia

Finally I would like to talk to you about bioluminescent mushrooms. That's right, glowing mushrooms. The picture above shows a tropical fungus which is often found on decaying matter such as wood or leaves. When conditions, such as temperature and water content of the soil are right, these fungi glow. At night insects are attracted to the fungi and carry away spores which are then dropped somewhere nearby. This allows maximum growth of the spores due to the good conditions.

Bioluminescence is a very interesting subject that is still being researched. It is unknown why many organisms spend so much energy on producing light and studies are currently going on to help us discover more about this fascinating subject. The animals I have mentioned about are only a few of the many examples of this phenomenon and many are still being discovered.

References:

•  Deheyn, D.D., Latz, M.I., 2007, Bioluminescence characteristics of a tropical terrestrial fungus (Basidiomycetes), Luminescence, Voll 22, pp 462-467
• Dehingia, N., Baruah, D., Siam, C., Gohain Barua, A., Baruah, G.D., 2010, Purkinje effect and bioluminescence of fireflies, Current Science, Vol 99 (10), pp 1425-1429
• Johnsen, S., Balser, E.J., Widder, E.A., 1998, Light emitting suckers in an octopus, Nature, Vol 398, p113
• Nyholm, S.V., McFall-Ngai, M.J., 2004, The winnowing: establishing the squid-vibrio symbosis, Nature, Vol 2, pp 632-643