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Past twilight the canyon lights up with tiny creatures we call Dismalites. These "glowworms" require a select habitat to survive and are unique to only a few places on Earth. Dismals Canyon is one of only a few places outside New Zealand where they are known to exist.
Guided night tours are available throughout most of the year.
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Dismalite
Night Tours:
Fridays and Saturdays at 8:30 pm
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Colloquially known as Dismalites, they are the larvae stage in the life of an insect called the fungus gnat "Arachnocampa luminosa" that emits a bright blue-green light to attract food, in the form of other flying insects.
It requires a select habitat to survive: humidity to prevent it from drying out; hanging surfaces to allow it to send down sticky feeding lines to trap the food; an adequate food supply of insects brought in on the river flowing through the canyon; a still atmosphere to prevent lines from tangling and darkness to allow it to show a light.
Dismals Canyon provides the perfect habitat for these unique insects to survive.
When looking up at the moss covered canyon walls it's hard to tell where the Dismalites stop and the stars begin.
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Magnified view of Dismalite
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Life Cycle
Four stages are involved in the life cycle of the glowworm; the egg changes to larvae, then to pupae, and finally to the adult fly (which lays more eggs). The entire cycle takes 10-11 months to complete, most of which is spent in the larvae stage.
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1) Eggs
The eggs are laid by the adult, and hatch into larvae about three weeks later. They are creamy-brown balls, less than a millimeter across, and are sticky enough to hang onto walls, overhangs and cave ceilings.
2) Larvae
The larvae is the most familiar form of the fungus gnat. Starting a few millimeters long, it slowly grows to the shape and size of a matchstick - after which it is ready to grow into a pupae. The larvae stage is usually 6-9 months, depending on the availability of food. However, the glowworm can survive for long periods without eating. Because the other stages don't feed, the larvae must store enough energy to nourish the later stages of the life cycle (and the eggs of the next generation if it is a female). The glowworm displays a bright blue-green light throughout the larval stage to attract its food.
3) Pupae
The pupae stage is like the cocoon stage of a moth's life, as the simple body of the larvae is changed into the complex adult. The larvae first rearranges its sticky threads into a circular protecting barrier, then hangs in the middle of the circle and encases itself in a pupae "skin". A little less than two weeks later it emerges as an adult gnat.
4) Adults
The adult fungus gnat wriggles out of the pupae skin and spends its first few hours drying, until it is able to fly. It has no mouth, cannot feed, and therefore lives only a few days. During this time mating takes place. Soon after mating the female starts laying her eggs, usually in several clumps of 40-50. As they are laid one at a time, the egg-laying can take a whole day, after which the female dies.
Feeding
The larvae is the only stage of the life cycle at which the species eats - as an adult it has no mouth. To feed, the glowworm hangs down dozens of sticky threads which are used to trap any insects which fly towards the light. When an insect is caught in the threads, the glowworm senses the vibrations and hauls in its victim - at the same time chemicals in the thread paralyze the insect. When the thread has been pulled up the glowworm bites the insect and kills it, then either sucks out the juices or eats the entire body.
Glowworm prey include midges, mayflies and caddis flies. In caves these insects breed on the mud banks beside streams, or fly in accidentally. Adult glowworms are occasionally caught and eaten as well.
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If you plan on taking the Dismalite Night Tour, you will want to bring a flashlight (preferably one with a red filter).
About Red Light and Night Vision:
While taking a Dismalite Night Tour, you may see thousands of Dismalites, but most are very dim and may be hard to see at first. This is due to the human eye's inability to adapt very quickly to the dark.
While taking the night tour, most people (if not all) should have a flashlight in order to see while walking through the canyon. When everyone stops to look at the Dismalites, everyone should turn off their lights. Otherwise, it's hard to see most of the Dismalites.
Although portable illumination is necessary, the white light from a regular flashlight is detrimental to your night vision. Especially if someone points a flashlight in your face (even if for a brief moment).
We recommend using a red filter on your flashlight (or something to mask out most of the light). The use of a red filter (or simply, a red light), enables you to have better night vision when you turn off your light. . . . Keep reading for a better explanation of why we recommend the use of a red filter.
The human eye has two types of sensors — rods and cones. Cones provide the best visual acuity (focus and fine detail), but require good illumination. By contrast, rods are very sensitive at low lighting levels, and hence provide a person's night vision. However the rods which impart night vision take up to 30 minutes to adapt fully to the dark (think about how long it takes for your eyes to adapt when you enter a dimly-lit restaurant or dark theater). Just a brief exposure to a bright light can "bleach out" the rods and wipe out a person's night vision for many minutes. Rods are insensitive to red light though. So by using a red filter on your flashlight, you can provide enough illumination to be able to walk through the canyon during the tour without compromising your (or anyone else's) night vision. |
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