Tiger beetles, subfamily Cicindelinae, are the fourth richest
fauna in the world. There are 203 species on the island of Madagascar alone, as
of 2003, when the Natural History of
Madagascar was published, so there may be even more species known today.
The most remarkable statistic about these beetles, however, is that only two of
those 203 species are non-endemic. The other 201 are entirely and gloriously
all Madagascar’s creations. New Zealand and New Caledonia, for comparison, host
14 species and 16 species, respectively. Indonesia, India and Brazil host
comparable numbers of species but lower levels of endemism.
Three-quarters of Madagacar’s tiger beetles subfamily
consist of two genera, Pogonostoma and Physodeutera. Beetles in both are
typically forest-dwelling, while Pogonostoma spp. are tree-dwelling to point of
being arboreal as lemurs. Larvae burrow under the periderm of woody branches
over which adults spiral to and fro in ceaseless pursuit of prey. The larvae of
Physodeutera spp. in contrast, are more elusive, possibly beneath the ground surface.
Adult Physodeutera also inhabit more reachable regions, often dappled forest
trails or mossy stepping stones crossing streams. We might encounter quite a
few in the northeast, the region of greatest species richness, where 92 species
are known.
But I wouldn’t count on catching one without practice. They’re may not seem all that fast to us, at about 5 mph. However, if the racetrack were leveled and
a tiger beetle (typically 4.75-25 mm long) were to be regrown with a human’s
size, you would have to run something on the order of 480 miles per hour to
keep up…that’s approximately 2/3 the speed of sound!
Source: F. Cassola, Coleoptera: Cicindelidae – Tiger Beetles,
S. M. Goodman, J. P. Benstead, The Natural History of Madagascar (2003), 669.
(-Emma)
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