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fred first's List: dragonflies

    • Adults are also fearsome predators that have even been known to take down a hummingbird. Their hunting prowess is due in no small part to large eyes, resilient and maneuverable wings, spiky legs that form a snagging net and a powerful, muscular thorax serving both the wings and the legs. Adult dragonflies capture exclusively live prey and almost always while they are on the wing. Flying insects are located visually and smaller prey is caught directly by the mouth. Larger insects are snared in a basket that the dragonfly forms with its legs, transferring the food to its mouth after it has been secured. Prey is either eaten on the wing or from a perch. The hard parts of beetles and wings of butterflies, moths, damselflies and other larger insects are discarded and may be found below a favored perch by the observant naturalist. If you can approach close enough to a chewing dragonfly you will be able to hear them “crunch, crunch” on the exoskeleton of their “McBug” sandwich.
    • It is easy to see why the wasps congregate on the aphids' mating flights, but one might wonder why a large dragonfly weighing several grams would bother to feed on tiny aphids weighing less than one thousandth of a gram. In most other seasons, dragonflies focus on larger insects (mosquitoes, moths, butterflies, flies, ants, bees, and the like), but in the fall, aphids are filled with the sugars, fats, and proteins the dragonflies use as fuel to migrate south (darners and gliders) and reproduce (meadowhawks). Since autumn aphids are both slow fliers and found in huge numbers, they are readily captured, and the dragonflies merely have to fly lazily through the swarms to capture large numbers of prey, somewhat like a human eating handfuls of sweetened sunflower kernels from a jar.
      • Food chain: kestrels eat dragonflies eat aphids eat plants

    • They made the print and television news in early August, when green darners, appearing in huge swarms, were hailed as saviors from the flood plain mosquitoes that had just emerged in cosmic numbers. These impressive sights only happen when the ecological “planets” are aligned just right, and they may not recur for years.
    • Another population of green darners is home-grown, and their watches are not synchronized with those of the migrants. Naiads of the resident green darners spend the winter under the ice, feeding in slow motion on small critters in the frigid water. They emerge in early summer, replacing the dying adults of the migrating population, and they lay their eggs by mid summer.

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    • he migration is by far the longest known insect migration, dwarfing the 7,000km journey of monarch butterflies. Millions of dragonflies make the epic migration every year, which spans from India to the Maldives, the Seychelles, Mozambique, Uganda and back again.


      Perhaps the only thing more amazing than the migration is that it has somehow dodged scientific discovery until now.

    • All in all, the epic adventure spans a total of 14,000-18,000 kilometers, and the journey appears to follow the rains, from the monsoon season in India to the rainy season in eastern and southern Africa. The swarm of dragonflies complete a total of 4 generations by the time the entire migration is completed. Furthermore, the trip is mirrored by the migratory paths of a number of insect-eating bird species, which scientists now know must feed on the dragonflies as they travel.
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