The larvae are another fascinating aspect of these insects. Depending on their behaviour and microhabitats, anisopteran larvae are typically recognised into four broad categories: claspers; sprawlers; hiders; and burrowers. Aeshinids larvae are generally claspers as they cling onto submerged vegetation or twigs. They are elongated with large prominent compound eyes. The shape and position of those eyes can be used to identify aeshnids larvae to genus. Anax species larvae have large forward facing oval-shaped eyes. They are very aggressive, excellent hunters. Apparently they can also change their colouration with each successive moult to suit their surroundings for better camouflage. I think this emerald green Anax larva is particularly eye-catching.
The labium is unique to odonates. It is basically an extensible organ with hook and pincers to ensnare prey. It is like an energy storage mechanism which can be released with speedy accuracy. Sight and labium co-ordination required by a larva to capture prey is undoubtedly precision of the highest order.
Pictures and videos taken at: Bukit Timah Nature Reserve, April 2009 (Anax guttatus); ex-situ, April 2009 (Anax larva).
References:
Corbet, P. S. & S. J. Brooks, 2008. Dragonflies. Harper Collins Publishers, London, UK.
Norma-Rashid, Y., L. F. Cheong, H. K. Lua & D. H. Murphy, 2008. The dragonflies (Odonata) of Singapore: Current status records and collections of the Raffles Museum of Biodiversity Research. Raffles Museum of Biodiversity Research, Singapore. 24 pp. Uploaded 07 Nov 2008 [http://rmbr.nus.edu.sg/raffles_museum_pub/Dragonfly_of_Singapore.pdf]
Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.
Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia
7 comments:
Thanks for this article. Here in the southeastern US we have an anax called the Common Green Darner it looks almost just like this guy. In another week or two I'll be able to find the larva emerging out of my pond.
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