The Escapologist (Horse-hair worm, Gordian Worm, Nematomorpha)

Gordian Worms are found all over the world, in still water such as puddles, ditches, ponds and quiet areas in streams. Sometimes they get into domestic water supplies, such as toilets or bowls of water. They are usually found after rains, their sudden appearance leading to stories to explain their presence. Some communities believe that a 'rain of worms' has occurred, others that horsehairs have 'come to life' after falling into a pond or stream. Since they often appear in animal watering troughs and their appearance is not unlike that of horsehair, although they are thicker, it is not difficult to see how this explanation came about. This also led to other common names, such as 'Horsehair Worms' and 'Horsehair Snakes'.
Adult Gordian Worms are free-living in water, but the juveniles are parasitic in land-dwelling insects and spiders. Because these hosts are not found in water, the larvae must reach them by a two-step process. The adult Gordian Worms attach long egg-strings to waterweeds and other debris in water. From these eggs, tiny larvae hatch and sink to the bottom, but can only survive for a short time unless they find a host. Many animals, such as fish, snails and small crustaceans, get infected.
The Gordian worm larvae are thought to bore into the first host's tissues by means of an armature of spines on the proboscis (feeding structure, 'nose'). The larvae then form cysts (protective shells on their outer surfaces) in the body, but usually do not proceed further through their life cycle within these aquatic hosts. Many insects, however, have an aquatic, worm-like, larval stage (for example mosquito and dragonfly larvae), and if these animals are infected, then the Gordian cysts can be carried from the water when the insect larvae metamorphose into flying insects. When these insects are eaten by other invertebrates, such as grasshoppers, crickets, mantids, beetles, cockroaches and spiders, the Gordian Worm cysts can then break open and the larvae penetrate the gut of the new terrestrial host. Sometimes these hosts can be infected directly when they visit water, or live close to it.
A larva lives in the body cavity of its host, secreting digestive enzymes through its skin to gradually absorb the host's body contents. It grows and sheds its larval structures, such as the hooks and stylets of the proboscis, and gradually changes its skin to that of an adult. Larval development takes a number of weeks, or even months, during which time the contents of the host's abdomen are completely consumed and the larva completely fills the cavity. It then breaks out when the host is near water, and takes up a free-living existence until its sex organs mature. The worms don't feed at all in the adult phase of their life cycle, so they die when the stored foods in their bodies are depleted.
The one pictured is about 30cm long and about 2mm wide and was found in a bucket of water beside its dead host in the Yarra Valley, Victoria..

- See more at: australianmuseum.net.au/gordian-worms#sthash.2D3mvL4T.dpuf

Taken on: December 27, 2015

Tags:

Worm

Hoddles Creek

Insect

Marine Life « less

Sets appears in: • Down by the creek

Camera: Fujifilm FinePix S100FS, f/3.3, 1/140 sec, 14mm, ISO 400 (more info) (hide info)

Camera:	Fujifilm FinePix S100FS
Aperture:	f/3.3
Exposure Time:	0.007 sec (1/140)
Focal Length:	14mm
ISO:	400
Exposure Bias:	0 EV
Flash:	Off, Did not fire
Exposure Program:	Program AE
Exposure Mode:	Auto
Metering Mode:	Multi-segment
White Balance:	Auto
Color Space:	sRGB
Software:	Adobe Photoshop Elements 7.0 Windows
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