#mecoptera

Since 2020, it is unclear whether the Mecoptera form a single clade, or whether the Siphonaptera (“fleas”) should be included within that clade, so the traditional "Mecoptera" is paraphyletic. For the purposes of this tournament, so as to not leave some families “floating”, I have to include all “scorpionflies” under one umbrella, but the Nannochoristidae and Boreidae (“snow scorpionflies”) are not closely related to the rest of the Mecoptera, with either the Boreidae or Nannochoristidae possibly being more closely related to the Siphonaptera (“fleas”). If this leg of the tournament could have perhaps waited a few more years for confirmation I would have probably just thrown fleas in this poll but ¯\_(ツ)_/¯

As Permian insects, early Mecopterans may have played an important role in pollinating extinct species of gymnosperms before the evolution of other insect pollinators such as bees.

In a few areas, some species of scavenging scorpionfly are the first insects to arrive at a cadaver, making them useful in forensic entomology. These species may remain on a corpse for one or two days, which indicates to examiners that a body must be fresh.

Some research suggests the Nannochoristids are the only holometabolous insects to possess true compound eyes as larvae. All other eyed larvae have stemmata, which are structurally different from adult compound eyes with ommatidia. This is unusual, since most adult features are present as imaginal discs in larvae and not formed until pupation. The presence of compound eyes in Nannochoristid larvae suggests the timing of the development of adult features can be initiated earlier in development, which has important implications for insect evolutionary development.

Snow Scorpionflies (family Boreidae) (image 3) are wingless, boreal or high-altitude scorpionflies which are so named for being most active in the Winter, where they can be found in fields of snow. The body temperature, and therefore activity level, of these scorpionflies depend on their absorption of short-wave and long-wave radiation rather than surrounding air temperatures (by which they are completely unaffected). The boundary layer of snow that the insect occupies has very low thermal conductance, and so the insect loses its own heat very slowly here. This delicate balance between cold and heat means that the animal can easily be killed by heat when held in a human hand.

Notiothauma reedi (image 4) is the last living member of the family Eomeropidae, and is thus considered a “living fossil”. It is native to the Valdivian temperate rain forests of central Chile, and unique among scorpionflies for its flattened appearance. Like many other species of scorpionfly, N. reedi is an omnivorous scavenger, and has been found feeding on dead rabbits and chickens. It can be captured by leaving a trail of oatmeal. The larvae of this species has yet to be observed.

The Hangingflies (family Bittacidae) (image 2) are known for their elaborate mating rituals. Males capture prey insects, such as a caterpillar, bug, or fly. The male then attracts a female with a pheromone from vesicles on his abdomen, which he retracts once a female is nearby, and presents her with the prey. The female then judges his gift. The larger and more high-quality the gift, the higher the likelihood that she will stay and mate with him. If she decides to accept his gift, they will mate while the female hangs upside-down beneath him, eating the prey while mating. Follow BestAnimal for more… actually will there be more Bug Sex Facts? This might be the last one for a while. We’ll see if the fleas give us anything.

As seen in image 2, hangingflies are so called for their strange way of eating, bringing their meal to their mouth with their back feet while hanging upside-down.

As mentioned above, the name “scorpionfly” comes from the anatomy of the males in the family Panorpidae (image 1). Male Panorpids have long “tails” which superficially look similar to that of a scorpion’s stinger. However, this is not a stinger, and Panorpid scorpionflies can not sting. This is the male scorpionfly’s genitalia. The tail is displayed to female scorpionflies, like a peacock’s tail, sometimes accompanied with a nuptial gift.

The Meadow Scorpionfly (Panorpa vulgaris), has become a model insect for testing theories of sexual selection as its mating system has been noted to be similar to that of humans in some aspects. Studies show that both sexes of the species display mating preferences for direct (nuptial gifts) and indirect benefits (genetic benefits) to increase reproductive success. The production of nuptial gifts (salivary secretion or carrion) during copulation in males and high nutritional condition in females are indicators of "good foraging genes", an indirect benefit that individuals look for in their partners. These genetic benefits can increase fitness in offspring and improve their foraging ability. Okay now I’m done with Bug Sex Facts for real for real.

Adult Panorpid scorpionflies are known to sometimes steal prey from spiders, deftly dodging the webbing and taking wrapped insects right out of webs. Braver scorpionflies are even known to use their tails to knock the spiders aside if the spider attempts to stop them.

Like the Panorpidae, the Earwigflies (Meropeidae) are so named for the forceps-shaped genitalia of the males. Only three living species from this family have been discovered so far, and they are rarely encountered. The biology of these species is essentially unknown, and their larvae have never been seen. They are considered “living fossils”, with the oldest known species dating back to the Middle Jurassic.