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Cylindrococcus spiniferus
An amazing flower-like structure created by a scale insect on Allocasuarina stems. They look similar to the actual tree cones among which they are interspersed.
On Allocasuarina stems in a local nature reserve.
Likely female insects inside these. The scale insect uses chemistry to force the tree to grow this clever little flowery home for it. The details of the gall 'stem' are particularly fascinating. These only appear on Allocasuarina and not on Casuarina. Pics 1 and 4 show the gall and 2,3 show the tree cones for comparison. Evolution is mind boggling... I can imagine that small creatures which live in trees quickly find out that hiding under the bark or in a node is a good idea but to get from that point to this is really impressive. Go nature !!
Spotted on Dec 31, 2013
Submitted on Dec 31, 2013
5 Comments
Thanks very much for the input Lyn. Yet more fascinating gall info - they just keep on surprising .
The galls are induced on new vegetative growth (new branchlets) rather than cones, and they can grow on male and female plants (many Allocasuarina species have separate sexes, and cones are only on females). One of the identifying features of the host plant species is the number of scale-like leaves around the nodes of branchlets, and the galls make them easy to count - the number of bracts in each ring on the gall is the same as the number of tiny leaves around a branch node.
Galls are so very interesting. There's no reason they should be lovely, and yet so many of them are. A sense of whimsy, there, ingenuity. These mimic the plant, as if the chemicals injected by the insect kicked an ongoing process into a parallel track. Which, of course, they did. But galls often look completely alien to their hosts. Galls make me wonder, too ... thanks, Mark, great photos.
Yes I assume that's what they do. I think it would be interesting to look at how evenly they spread themselves onto a stem also. This particular tree seemed to have them regularly spaced with the real cones. I guess that would be just as much a part of the mimicry attempt. I'll check my other pics for spacing.
Nice series Mark. Eriococcidae are fascinating. Do you think they locate and stimulate a cone bud? This was always my assumption. I like pic#2 showing both structures.