Darkling Beetle
25% of all known species1 are types of beetles. This preponderance of taxa led J.B.S. Haldane to say, “If one could conclude as to the nature of the Creator from a study of creation, it would appear that God has an inordinate fondness for stars and beetles.” There are over 20,000 beetle species in Family Tenebrionidae. I am not certain that this is in fact a darkling, but it seems to match the taxon.
This beetle turned up in my house a week ago. It was about 8mm long and its black, pitted carapace flashed iridescent green in the sunlight, making for a neat picture. My wife asked about the pitting on its shell, and I told her the dimples helped it travel farther when flying, like a golfball. Telling outrageous whoppers like that is nearly half the fun of running this site!
1 My wife saw this and asked if I had forgotten “…of insect” after species. Nope. 25% of all known species of anything are beetles.
Slowly getting the site back onto an even keel. It's nice to get back into the old posting rhythm.
Arrkhal said,
October 16, 2007 @ 1:16 pm
25% would have to not include bacteria or other microorganisms. There’s a bit over 1.56 million known species of mostly macroscopic life (350,000 of which are beetles, and 950,000 insects total). But the highest estimate I’ve seen for bacteria is up to 1 billion species, while the estimated number of beetle species (known and unknown) is a measly 5 to 8 million.
Which is why a lot of Leviticus is about diseases of the skin, rather than beetles.
David Brady said,
October 16, 2007 @ 2:08 pm
Arrkhal: very cool, I didn’t know that. I dug up some stats on the taxa, and yeah, it looks like the 25% is limited to “described species”. If we include an estimate of “between 5 and 50 million species” out there, that’s only a twentieth of the billion or so estimated bacteria.
It’s always fun to make bold, broad statements about science because there will inevitably be some people who say “Well, that depends on the definition of….”
I got the 25% figure from a quotation wiki, justifying Haldane’s remark. It is possible that the figure was circa 1950 (as was the quote). And it may also be that Haldane simply observed a preponderance of beetle species while the 25% figure came from a layperson’s review of the taxa.
I’d love to look more into that. Do you have a link?
Thanks!
SamWibatt said,
October 16, 2007 @ 3:56 pm
Oooh! Nice shot of the texture!
Arrkhal said,
October 17, 2007 @ 10:05 am
Let’s see. To start with, there’s good ol’ Wikipedia:
http://en.wikipedia.org/wiki/Species#Numbers_of_species
As you can see, most of those species listed are macroscopic. I don’t even see a “bacteria” category in the first part. The 5-10 million species estimate, if you check the citation, is based on an article was referring to _only the oceans_. And to badly misquote a marine biologist whose name I forget, “if we knew as little about land animals as we do about sea animals, we wouldn’t know elephants exist.”
According to the abstract for this paper (http://www.ingentaconnect.com/content/klu/anto/1998/00000073/00000001/00152911), there “may be” over a billion species of bacteria. That’s one of the highest estimates I’ve seen, but given that scientists find things like several thousand different species in 1 gram of soil or 1 milliliter of seawater, I can believe it.
Let’s see, this link (http://whyfiles.org/shorties/count_bact.html) estimates 5e30 individual prokaryotes on planet earth. Astronomers estimate there are at least 7e22 stars in the observable universe (http://en.wikipedia.org/wiki/Star#Distribution). So bacteria on earth alone have stars in this part of the universe beat by several orders of magnitude, looks like. Though it depends on what % of the universe we are capable of observing.
However, the Milky Way galaxy has 4e11 stars at the highest estimate, and is one of the largest galaxies in the local cluster. Even if we assume that the Milky Way is an average sized galaxy, there would only need to be one earth-like planet for every 1.25e19 galaxies, for bacteria to equal the number of stars.
Thor said,
October 17, 2007 @ 11:06 pm
I’m thinking that water droplets tend to roll off of coarsely textured surfaces more easily (instead of sticking), but as to why you would need something like that, I have no idea.
Sarah Thaler said,
October 18, 2007 @ 1:49 pm
yep, it’s a darkling. I have 2 at home. I have been trying to get a colony going, starting with the larvae but only 2 hatchlings have made it and they aren’t mating. thanks for the pic
David Brady said,
October 18, 2007 @ 2:46 pm
Thor: Dunno… it seems to me that at that scale, capillary action would be pretty high and it would actually cause the water to stick even more than normal. Having thought about this, my current best theory is that the ridges and dimples may serve the same function as corrugation in cardboard: it stiffens the material by artificially extending it into a 3rd dimension.
Sarah: Wow, cool! How long have you been doing this? Do you have any pictures? Send them in and I’d be happy to put them up on the site. And thank you for posting this–I now feel much less weird for trying to breed spiders and praying mantises in my office!