Three-spined stickleback
| Three-spined Stickleback | ||||||||||||||
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 photo: Ron Offermans | ||||||||||||||
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| Binomial name | ||||||||||||||
| Gasterosteus aculeatus |
The three-spined stickleback, Gasterosteus aculeatus, is native to much of northern Europe, northern Asia and North America. It has been introduced into parts of southern and central Europe.
Three subspecies are currently recognised.
- Gasterosteus aculeatus aculeatus is found in most of the species range, and is the subspecies most strictly termed the three-spined stickleback; its common name in England is the tiddler.
- G. a. williamsoni, the unarmored threespine stickleback, is found only in North America; its recognised range is southern California, though there are isolated reports of it occurring in British Columbia and Mexico;
- G. a. santaeannae, the Santa Ana stickleback, is also restricted to North America.
In spring, males defend territories where they build nests on the bottom of the pond or other body of water; the sequence of territorial, courtship and mating behaviours was described in detail by Niko Tinbergen in a landmark early study in ethology. Territorial males develop a red chest colouration, and Tinbergen showed that the red colour acted as a simple sign stimulus, releasing aggression in other males and the first steps in the courtship sequence from gravid females. Only the males care for the eggs they are fertilised.
Sticklebacks are easily maintained in the aquarium, and are not currently considered to be endangered. They are popular subjects for laboratory research.
The three-spined stickleback was featured on a 14-franc postage stamp issued by Belgium in 1990.