Catching the fleeting scenes of many splendored life with a camera.
'Look closely. The beautiful may be small' — Kant

28 September 2012

Dung beetles and Other Things on a Sandy Beach

Dung beetles are beetles that feed partly or exclusively on faeces, that is, they are nature's garbage collectors. All these species belong to the super family Scarabaeoidea. This roller beetle in particular is also referred to as the scarab beetle, and as most species of Scarabaeinae (often dubbed true dung beetles), it feeds exclusively on faeces. Apart from being important at providing ecosystem services, it's also an example of nature's feat of engineering — I'm referring to its wings. It's fascinating the way this amazing creature unfurls its transparent foldaway wings and takes off like a chopper, or folds its wings after landing along the veins, and then carefully tucks them under the elytra (a shell-like protection).

Roller dung beetle digging a burrow. (© 2012 LightColourShade. All rights reserved)

Roller dung beetles on the sand. (© 2012 LightColourShade. All rights reserved)

The following two pictures illustrate the concept of "presence" in a way. A seagull dropped its feather,

Seagull feather stuck into the sand casting shadow
(© 2012 LightColourShade. All rights reserved)

...passed here and left its footprints on the sand. I always find such marks comforting, to me it means the world still stands. When I go to the beach I always try to pick a spot with lots of seagulls' footprints, somehow such places feel cosier and safer.

Seagull footprints on the sand dumes. (© 2012 LightColourShade. All rights reserved)

Pelagia noctiluca, is a jellyfish in the family Pelagiidae (multicellular eukaryote, in the phylum Cnidaria). As its name suggests — in Latin, Pelagia means "of the sea", nocti stands for night and luca means light — Pelagia noctiluca has the ability to bioluminesce, or produce light, that is, to glow in the dark, which it does in the form of flashes when the medusa is stimulated by turbulence created by a ship’s motion or by waves. This flashing is of relatively short duration and gradually fades.

This species of jellyfish commonly known as the mauve stinger in Europe, amongst many other common names, is widely distributed in all warm and temperate waters of the world's oceans, including the Mediterranean Sea, Red Sea and Atlantic Ocean. It's also found in the Pacific Ocean, with sightings in warm waters off Hawaii, southern California and Mexico, as well as other Pacific locations. This is typically an offshore species, although sometimes it's washed near the coastlines and may be stranded in great numbers on beaches. The colour varies worldwide, and in addition to pink or mauve, it is sometimes shades of golden yellow to tan.

I remember once bumping into a whole family of purple-spotted beauties while swimming in the sea. I rushed out of the water at the speed that would put Michael Phelps to shame.

Mauve stinger (Pelagia noctiluca) on the sand
(© 2012 LightColourShade. All rights reserved)

Velella is a genus of free-floating hydrozoans that live on the surface of the open ocean. They occur worldwide, and are commonly known by the names by-the-wind sailor, purple sail, little sail, or simply Velella. Currently the only known and identified species is the Velella velella.
These small cnidarians are part of a specialised ocean surface community that includes the cnidarian siphonophore known as the Portuguese Man o' War. Specialized predatory gastropod molluscs prey on the cnidarians. The predators include nudibranchs (sea slugs) in the genus Glaucus and purple snails in the genus Janthina.

Each apparent Velella animal is in fact a hydroid colony, and most are less than about 7 cm long. They are usually deep blue in colour, but their most obvious feature is a small stiff sail that catches the wind and propels them over the surface of the sea. Under certain wind conditions, they may be stranded by the thousand on beaches.

Amazing isn't it? I wonder how they reproduce, or start to form a colony, or which member(s) of the colony the sail belongs to.

Like other Cnidaria, Velella are carnivorous. They catch their prey, generally plankton, by means of tentacles that hang down in the water and bear cnidocysts (also called nematocysts). Though the toxins in their nematocysts are effective against their prey, Velella are harmless to humans, because either their nematocysts are unable to pierce our skin, or perhaps because humans do not react to the toxins encapsulated in their nematocysts. Nevertheless, it is wise to avoiding touching one's face or eyes after handling Velella, or better yet, don't handle it at all.

Velella (by the wind sailor). (by-nc-nd)

Velella (purple sail). (by-nc-nd)

2 comments:

  1. A really entertaining and enlightening post! I especially liked your stuff on Dung Beetles. It reminds me of an occasion from my childhood (in India) which involved a particular Dung Beetle that was flying around in my room, and how it took a pan with an enormous pile of books on top to keep it contained til morning. Truly creatures of amazing strength!

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    Replies
    1. Thanks, glad you liked it. I had a similar case a couple of years ago -- a family of bats honoured us by making their nest outside our window and as a result flew by mistake into the bedroom several times. I usually managed to flush them out successfully, but on one occasion, the bat squeezed into the slot under our bedroom ceiling lamp and wouldn't come out, so I left it there overnight. Next morning we found it hanging upside down on the curtain, I still regret I didn't have a camera at hand at that moment.

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