Tuesday, May 06, 2008

Rhapsodizing further on insects

Elaborating further on Rhapsody in iridescent blue: A quartet from "The Theater of Insects," in this weblog network's preferred variation on the theme of synesthesia:

I. The Theater of Insects Revisited

Images from Jo Whaley, The Theater of Insects, © 2000-2007. Left to right: 19: Coleoptera, 17: Meganuera.
Jo Whaley's visual tour de force, The Theater of Insects, is heavy on butterflies and moths, on the order Lepidoptera. As these images demonstrate, though, Ms. Whaley does not altogether neglect the extremes of the insect world. She pays homage to Coleoptera, the most diverse extant order of insects, and to Meganuera monyi, perhaps the largest insect ever. A member of the order Protodonata, Meganuera closely resembles and is related to modern dragonflies (Anisoptera) and damselflies (Zygoptera).

Ms. Whaley, to my knowledge, hasn't trained her considerable talent on Hymenoptera, typified by the three big taxa of strikingly eusocial insects: bees, wasps, and ants. We'll just have to wait for her book.

II. A Musical Interlude

Herewith three versions of George Gershwin, Rhapsody in Blue (1924):

A. The original 1924 recording of Rhapsody in Blue (parts 1 and 2)

George Gershwin

B. An upbeat, one-file version, courtesy of Imeem.com
C. Leonard Bernstein plays Rhapsody in Blue in 1976 (parts 1 and 2)

III. A Modest Scientific Observation

What precisely should we make of Meganuera monyi, the Carboniferous giant portrayed at the top of this post? Gigantism, in insects and other organisms, may depend on atmospheric conditions. See Gauthier Chapelle & Lloyd S. Peck, Polar gigantism dictated by oxygen availability, 399 Nature 114-15 (May 1999) (doi:10.1038/20099):
Benthic amphipod crustaceanThe tendency of some animals to be larger at higher latitudes ('polar gigantism') has not been explained, although it has often been attributed to low temperature and metabolism. Investigation of gigantism requires widely distributed taxa with extensive species representation at many well-studied sites. We have analysed length data for 1,853 species of benthic amphipod crustaceans from 12 sites worldwide, from polar to tropical and marine (continental shelf) to freshwater environments. We find that maximum potential size (MPS) is limited by oxygen availability.
This study's specific discussion of insect gigantism offers further insight into the vulnerability of giant species to changes in global temperatures and/or oxygen levels, as well as the heightened vulnerability of such species' to extinction over geological time:
Oxygen supply may also have led to insect gigantism in the Carboniferous period, because atmospheric oxygen was 30-35% . . . . The demise of these insects when oxygen content fell indicates that large species may be susceptible to such change. Giant amphipods may therefore be among the first species to disappear if global temperatures are increased or global oxygen levels decline. Being close to the critical MPS limit may be seen as a specialization that makes giant species more prone to extinction over geological time.
Haast's eagle and moaCouple this environmentally driven evolutionary constraint with the tendency of megafauna to be K-strategists — which is to say that they have long lifespans, low death rates, slow reproductive rates, and few or no natural predators (at least against adults) — and you have a recipe for extermination through human exploitation. So it was when humanity began to colonize the earth. Imagine how much more lethal our species will become as climate change compounds the sixth great extinction spasm of the Phanerozoic Eon.


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