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Photo 1
Photo 2
Photo 3
The Madagascan Giant
Hissing-Cockroach
Literature citations relating to the photos and others:
Yoder, J. A. and N. C. Grojean. (1997) Group influence on water
conservation in the giant Madagascar hissing-cockroach, Gromphadorhina
portentosa (Dictyoptera: Blaberidae). Physiological Entomology 22:79-82.
Yoder, J. A. (1996) The Madagascar hissing-cockroach mite
(Gromphadorholaelaps schaeferi): First observations of its larva and
ptyalophagy in the Acari. International Journal of Acarology 22:141-148.
Yoder, J. A. and J. C. Barcelona. (1995) Food and water resources used by
the Madagascar hissing-cockroach mite, Gromphadorholaelaps schaferi.
Experimental and Applied Acarology 19:259-273.
Yoder, J. A. (1997) Exterminator-mites (Acari: Dermanyssidae) on the giant
Madagascar hissing-cockroach. International Journal of Acarology
23:233-236.
Here's a brief summary of the papers:
Group influence on water conservation in the giant Madagascar hissing-cockroach...
This paper demonstrates that cockroaches form clusters as a way to conserve water; water loss rates are reduced nearly two-fold for cockroaches in a group of 6. The cockroaches are maximized for water retention (large body size= small surface area to volume ratio) plus the group effect helps them to conserve water. This is perhaps best demonstrated by the fact that an adult female cockroach can survive in absolute dryness (0% relative humidity) without food and liquid water for at least a month. The 'group effect' is what enables the cockroach to survive during the long tropical dry season of Madagascar. It also suggests that the hissing-cockroaches are social insects, with a social structure.
On the MITE papers here's the scoop:
The mites are NOT parasitic, rather they feed on cockroach saliva-- this is the first known spittle-feeding mites. In turn, these mites are predatory and provide an extermination service for the cockroach. Keep in mind that these cockroaches live in litter on the floor of the tropical rain forest and they are slow moving- the cockroaches are very easy targets for ectoparasitic invaders. The hissing-cockroach mites keep these parasites off the cockroach. This is a case of true mutualism- both organisms benefit by the existence of the other. These mites remain on the cockroach througout its life, they remain even while the cockroach sheds its skin (moults). An additional tidbit of information is that the mites hang out in places on the cockroach's body that are highly specific for feeding (in between the cockroach's legs where cockroach saliva accumulates, and at the sides of the cockroach's body around the cockroach's spiracles (breathing holes)- mites that are around the spiracles, at the sides of the cockroach's body, are drinking water vapor lost from cockroach respiration; it is interesting that these mites take up water lost from the cockroach. Another important feature of the mites is that their life history pattern and genetic system are totally geared for their life on the cockroach.
Thanks to Jay Yoder for writing the above summaries, as the journal could not allow the published abstracts to be reproduced on-line.
Emma Craib, elementary school art teacher in Manchester, CT USA. My art web site has cool things to do ...check out the WADDELL School link in the navigation bar if you like origami.