![Geological Survey of Canada Geological Survey of Canada](/web/20061103025845im_/http://www.gsc.nrcan.gc.ca/esst_images/gsc_e.jpeg) Natural Resources Canada > Earth Sciences Sector > Geological Survey of Canada > Past lives: Chronicles of Canadian Paleontology
Past lives: Chronicles of Canadian Paleontology Fossil termite excrement
Fossil wood is so drab that few paleontologists bother to examine it
closely. However, a non-descript chunk of wood from the West Coast
includes something quite special -- cryptic evidence of the most ancient
social behavior.
![Concretion with fossil wood 20 cm across with termite borings packed with termite fecal pellets. Upper Cretaceous of Hornby Island. Vancouver Island Paleontological Museum Collections. (Photo by BDEC (c).) Concretion with fossil wood 20 cm across with termite borings packed with termite fecal pellets. Upper Cretaceous of Hornby Island. Vancouver Island Paleontological Museum Collections. (Photo by BDEC (c).)](/web/20061103025845im_/http://www.gsc.nrcan.gc.ca/paleochron/images/termite1.jpg) Concretion with fossil wood 20 cm across with termite borings packed with termite fecal pellets. Upper Cretaceous of Hornby Island. Vancouver Island Paleontological Museum Collections.
(Photo by BDEC (c).) |
Collishaw Point on Hornby Island in the Strait of Georgia is a
favourite haunt of fossil collectors who come to search for the attractive
Upper Cretaceous ammonites that occur in concretions at this site. A 10 cm
diameter chunk of fossil driftwood includes cryptic fossils of some
importance. A polished section of this wood reveals that it is riddled by
unfilled holes about a centimetre across -- borings in the form of
interconnected tunnels. Many of these holes are packed with six-sided
millimetre-sized black pellets. These holes are galleries excavated by
wood-boring insects and the black pellets could only be their fecal
material -- frass to entomologists -- excrement backfilled into vacant
galleries.
Many insects bore into wood -- beetles, termites, bees, ants, weevils,
wasps and moths; but the order Isoptera (termites) is the only group that
excavates galleries to make nests in the centre of wood. Termites are rare
as fossils and termite nests in wood are almost unknown as fossils. The
fossil log discovered on Hornby Island contains the oldest termite nest
anywhere on earth -- well dated as 70 million years old.
Termites are considered a menace now because they eat wood. Cellulose,
however, cannot be digested directly by termites. Recent wood-eating
termites live in close symbiosis with protozoans which break down the
cellulose into digestible carbohydrates in a fermentation chamber in the
termite's gut. The Hornby nest and the fossil frass now provide strong
circumstantial evidence that this termite-protozoan symbiosis dates, at
least, from the Late Cretaceous.
Every living species of termite comprises separate castes -- queens,
winged sexual forms, sterile workers and sterile soldiers -- each
performing specific tasks in constructing and maintaining the nest and in
ensuring the viability of the colony. So, although the Hornby fossils
yield no direct evidence of the presence of different castes of termites
in the Late Cretaceous, they must have existed then because a termite nest
could only be built and maintained by the coordinated activity of
different castes of one species -- diminutive evidence of perhaps the most
ancient social behaviour discovered to date.
The termites that excavated the nest in that undistinguished log from
Hornby Island shared their Cretaceous world with ammonites, dinosaurs,
elasmosaurs, mosasaurs, ichthyosaurs and pterosaurs. These and many other
animal groups perished in a cataclysmic mass extinction 65 million years
ago. The termites, unperturbed in their sealed nests, carried on.
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