Quantum Bayesian Networks

November 18, 2014

Houston, Tranquility Base here, the Dragonfly has landed

Filed under: Uncategorized — rrtucci @ 9:18 pm
Houston, Tranquility Base here, the Dragonfly has landed. (image based on NASA photo from here)

Houston, Tranquility Base here, the Dragonfly has landed.
(image based on NASA photo from here)

Pacific Spiketail Dragonfly (Photo from here

Pacific Spiketail Dragonfly (Photo from here)

The new Artiste logo reminds me of a dragonfly. Like many people, I’ve been fascinated by dragonflies since I was a child. Here are some interesting facts about dragonflies (taken from references at the end of this blog post):

Dragonflies and damselflies are often called the “jewels of the pond”.

Damselflies rest with their wings closed like butterflies. Dragonflies, on the other hand, keep each wing pair at opposite sides of their thorax when at rest.

Flight
Dragonflies are among the fastest flying insects. (which, however, is not that fast). In general, large dragonflies like the hawkers have a maximum speed of 10–15 meters/sec (22–34 mph) with average cruising speed of about 4.5 meters/sec (10 mph).

Dragonflies can fly in all 6 directions: front, right, left, up, down and backwards. They can fly upside down, and can change direction quickly. They can hover for as long as a minute.

Each of their 4 wings has a separate muscle and can be maneuvered independently.

They can eat and mate in midair without need to alight.

Food Chain
They have a voracious appetite, especially for mosquitoes. They will use a person or other mammal (e.g., horses or cows) as bait. They will hover right above their bait, and when the bait attracts a mosquito, they will pounce on it.

Besides mosquitoes, they eat other small insects like flies, bees, ants, wasps, and very rarely butterflies.

Though dragonflies are predators, they themselves are subject to being preyed upon by birds, lizards, frogs, spiders, fish, water bugs, and even other large dragonflies.

Life cycle
From egg to underwater gilled larva (called a naiad or nymph) to adult flying stage. Larval stage may last anywhere from 2 months to 5 years depending on species. Adult flying stage can last anywhere from a few weeks to 6 months depending on species.

Bite
Adult dragonflies do not normally bite or sting humans. They don’t have a stinger at the end of their tails; they use that to lay eggs. If you trap one in your hands without crushing it, it will try to bite you with its mouth, but it will fail to break your skin. Nymphs, however, are capable of delivering a painful but harmless bite.

Hunting Effectiveness
African lions capture prey about 25% of the time
Sharks about 50% of time
Dragonflies about 95% of time.

A dragonfly comes equipped with very sophisticated target acquisition and Kalman filtering capabilities. It is able to focus on a single target prey amid a cloud of similarly fluttering insects. It is able to make very subtle mid-course corrections to intersect that moving target.

Senses
They have a nearly full (4pi) field of vision. Each eye has about 30,000 facets. But they can’t hear at all and they can’t smell very well either.

Evolution
Their order is Odonata, which means “toothed ones” — because of their noticeably serrated mandibles. Infraorder Anisoptera (from the Greek for “uneven wings”)

They first arose in the Carboniferous period, about 300 E6 years ago. For comparison, the Earth is 4.5 E9 years old, and the six animal classes are this old:

  1. Invertebrates- 600 E6 years
  2. Fishes – 510 E6 years
  3. Amphibians – 370 E6 years
  4. Reptiles – 315 E6 years
  5. Mammals – 200 E6 years but exploded 65 E6 years ago after great extinction
  6. Birds – 150 E6 years

Migration
Some dragonfly species migrate long distances each year, a still mysterious phenomenon not unlike the celebrated flight of the monarch butterfly. Recent studies have shown that green darner dragonflies migrate in sizable swarms each fall and spring between the northern United States and southern Mexico, while the globe skimmer dragonfly lives up to its name: it has been tracked crossing between India and Africa, a round trip, multigenerational pilgrimage that may exceed 10,000 miles.

References

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2 Comments »

  1. Cathars and Templars knew of dragonflies a loooong time ago!
    Beware of the Stone…

    http://terraumbra13.blogspot.gr/2012/10/the-otherworld-shooting-diary-part-two.html

    Comment by Elangel Exterminador — November 22, 2014 @ 12:35 pm

  2. Angel, we’ll be a good dragon, not an evil one.

    Comment by rrtucci — November 22, 2014 @ 2:31 pm


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