Blattella germanica ecdysis

Short Life of an 'Albino' Cockroach

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Photos by Joe Kunkel as part of independent research as an undergraduate, 1964. This research contributed to his first published paper (Kunkel, 1966). Here we see a V instar Blattella germanica larva molting into a VI instar nymphal female.


During ecdysis (the shedding of an arthropod's old cuticle) a cockroach's new cuticle is creamy white. This has resulted in many claims by novices of having discovered an albino cockroach. But the hour long ecdysial process ends with the tanning (darkening and hardening) of the new cuticle and, sadly, the 'extinction' of the 'albino' cockroach.

B.germanica ready to molt

Blattella germanica ecdysis + 0 min. (with reflection in mirror).
The pronotal cuticle has just split under the hydrostatic pressure of swallowed air!


B.germanica

Ecdysis + 1 min.
The larva continues to swallow air to expand out of the old cuticle.


B.germanica

Ecdysis + 3 min.
The legs and antennae are being drawn out of their old cuticular sheaths.


B.germanica

Ecdysis + 8 min.
The legs and antennae are for the first time free. Inflation continues.


B.germanica

Ecdysis + 10 min.
The newly molted larva reaches its new maximum size. It provisionally hardens itself at this size.


B.germanica

Ecdysis + 17.5 min.
The deflation process is underway. The larva regurgitates the swallowed air and becomes flatter.


B.germanica

Ecdysis + 19.5 min.
Now almost deflated.


B.germanica

Ecdysis + 35.5 min.
Now quite flat, the larva will procede to harden and visibly darken this cuticle starting at 1 hour after the initial split of its pronotal cuticle. In four hours it will be as dark as it will get and can start eating to fill in the newly provided room with growing tissue.


B.germanica

Ecdysis + 11 hrs.
Now over night the VI nymphal female is darkened as much as it will and has not as yet started eating to fill in the new tissue space.


This hardened and darkened VI instar female can be stored at 15°C for up to a month and then started on its metamorphic molt to an adult frmale by placing it at 30°C with food (Kunkel, 1966).

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Page maintained by Joe Kunkel, joe@bio.umass.edu. Copyright(c) 1996. Created: 96/07/18 Updated: 96/07/20