The fly emerges

September 15, 2014 • 1:24 pm

by Matthew Cobb

This brief macro video from Ammonite Films shows a fly emerging from its pupa. Some of you might find it NSFL, but I think it’s pretty cool. Put it on full screen and freak out your housemates/partners/officemates.

Things to note 1: The fly emerges from a circular hole at the end of the pupal case – this is the defining feature of the Cyclorrhapha, a group of flies that does just this. This “unranked” taxonomic term is apparently out of favour (especially at Wikipedia), and is more or less synonymous with “Muscamorpha”, but I’m no taxonomist and am happy to use it. Anyone with expert knowledge/opinions on the matter, please chip in (and explain!) below.

Things to note 2: More importantly, you can see the effort that the fly goes to in order to extricate itself from the case. There is an awful lot of squeezing and pushing that goes on, enabled by the fact that its cuticle is extremely soft. After emerging and literally blowing itself up as it goes, the fly will scuttle off to find somewhere dry and safe to inflate its wings and harden up its cuticle. [JAC: I’ve watched this many times with Drosophila flies and I never get tired of it.]

Things to note 3: Those movements the fly makes as it emerges are redolent of the movement shown by the maggot before it pupates, with waves of contractions.

Things to note 4: The video doesn’t show how exactly how the maggot turns into the fly inside the pupa. The reason for this is contained in those three most important words in science: we don’t know.

16 thoughts on “The fly emerges

  1. Things to note 4: The video doesn’t show how exactly how the maggot turns into the fly inside the pupa. The reason for this is contained in those three most important words in science: we don’t know.

    Tomorrow I swallow a camera capsule to inspect my small intestines. Does a really small camera exist so they could do an endoscopy in the pupa?

  2. Beautiful. Such noble and splendid creatures. *sniff*.

    One thing the readers might like to know: the larvae of this family of flies (and several other related fly families) pupate inside the larval cuticle. So you see the magnificent maggot turn brown and oblong. The cuticle has separated from the soft tissues inside, and hardens and turns dark brown. The pupa is inside that. Other insects molt the larval cuticle, revealing the pupa with its cuticle.

    The adult fly has an inflatable sac inside its head, which balloons out to help push its way out of the older cuticle. Flies that do this have a distinct upside-down horseshoe suture on their face, which is where this sac comes out. You can see this suture here.

  3. Spectacular!

    Complete metamorphosis–one of the most mind-blowing phenomena in nature. Which is totally overlooked or not seen as anything particularly special by most people.

  4. You missed one very important word in the final sentence:

    “The reason for this is contained in those three most important words in science: we don’t know.”

    Yet

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