Most humans–and I include quite a few entomologists in that category–love to hate roaches. This is a sad thing, because the vast majority of roaches never set foot (feet?) in a kitchen. The few species that tap-dance around in your sugar bowl are just a tiny piece of a huge spectrum of amazing roachy biodiversity in the world.
Over 99% of all roach species are innocent soil and forest dwellers, and are important for ecosystem functioning. Some of them can leap like grasshoppers. Some of them can run 4 times faster than a cheetah (well, in terms of body lengths traveled per second, anyway.) The group of insects with the highest frequency of parental care? Roaches. One estimate puts roaches at 24% of all arthropod biomass in tree canopies, and 43% of arthropod biomass in alluvial forests. There are a LOT of roaches in the world, and you’ve never seen or heard of most of them. H. E. Evans may have said it best:
“The study of roaches may lack the aesthetic values of bird-watching and the glamour of space flight, but nonetheless it would seem to be one of the more worthwhile of human activities.” [Life on a Little Known Planet]
This week a new paper came out that highlights the importance of roaches to an animal we have kinder feelings about:
Unusual macrocyclic lactone sex pheromone of Parcoblatta lata, a primary food source of the endangered red-cockaded woodpecker. Eliyahu et. al PNAS Dec. 19 2011
The red-cockaded woodpecker is an adorable little bird that lives in old pine forests. Historically their range covered much of the eastern US, but these days they are down to remnant populations in the southern US, and they’ve been listed as an endangered species since 1970.
Red-cockaded woodpeckers need large stands of old growth long-leaf pine to survive–they are unique because they nest in living trees, not dead trees. And here is where roaches come into the story–69.4% of the food given to nestlings is wood roaches.
Logging has reduced the number of old pines, resulting in a major loss of habitat for the birds. Artificial nesting cavities have been drilled in trees in hopes of getting more birds to breed. Deciding where to drill a nesting cavity means assessing just how many roaches are in an area, and if there are enough roaches around to support a brood of hungry baby birds.
The majority of wood roaches are secretive and nocturnal, so finding them and counting them is not an easy thing. They live underground, under bark, and generally hide in places you can’t see. It’s not only humans that have trouble finding the roaches–this also makes it tough for the roaches to find each other for mating.
Like many other insects, they’ve solved this problem with chemical signals called pheromones. Pheromones are “chemicals emitted by living organisms to send messages to individuals of the same species.” By making a species-specific blend of chemicals and releasing it into the air, insects can communicate over great distances.
With sex pheromones, the message is usually from the female, and has the content “I’m here and ready to get it on, big boy!” Male antennae are exquisitely sensitive to even single molecules of a female sex pheromone. Because of that sensitivity, you can use male antennae as a type of pheromone detector. (Watch an animation of what happens neurologically in an antenna when pheromone hits a receptor, via UC Davis.)
You can hook up a male antenna to electrodes and actually measure just how much the neurons depolarize in response to a specific compound. This is electroantennography, or EAG. In really fancy EAGs, you can run an unknown compound through a gas chromatograph (GC) and an EAG simultaneously. With the help of these expensive machines, you can extract the pheromone gland from a female, get information about the structure of the chemicals from the GC, and figure out just which chemicals are the ones that attract the males with the EAG. The graph at the right is what that looks like.
It’s fairly clear when you find the right molecule–the male antenna produces a big spike like the one you see for compound #1.
(Side note: I actually did a fair amount of EAGs in my earlier research, and I have to say I’ve never felt more like Dr. Frankenstein in my entire life. You basically decapitate an insect and then stick all sorts of electrodes on their brain and antennae, and hook it up to a lot of really, really fancy instrumentation. I kept having to stifle the “Bwa ha ha ha ha ha” that wanted to bubble up, and found myself rubbing my hands together in glee a lot.)
There are many insects for which humans have figured out how to synthesize artificial pheromones and use them as a type of buggy birth control. In this case, knowing what the pheromone is for this wood roach gives humans a simple way to assess how many roaches are in an area under consideration for woodpecker habitat restoration.
You put the pheromone out near a sticky trap; male roaches come a running for some roachy lovin’, and then you count up how many of the unlucky suitors end up dead on a glue trap.
And now a surprise ending much more pleasurable than that experienced by the roaches on this trap: a holiday entomological carol written about this very research!
This carol actually includes some details I left out, like the species name of the roach (Parcoblatta latta); the researcher whose lab this work was done in (Coby Schal); and the use of nuclear-magnetic resonance (NMR) to determine the specific chemical structures. Enjoy!
(to the tune of “Walking in a Winter Wonderland”)
Roaches stink, are you smellin’?
Pheromones, they’re a-tellin’.
So succulent-sweet, what woodpeckers eat.
Parcoblatta lata wonderland.
Dr. Schal took a reading.
Found the compounds for breeding
By using some gas as roaches chased ass.
Parcoblatta lata wonderland.
Nuclear magnetic resonating
Let him know what turned a suitor on.
Then he synthesized a mix for baiting
And watched the males all falling for the con.
Now his sexy solution
Tells about evolution:
Viagra for some, for others it’s dumb.
Parcoblatta lata wonderland.
People say the lata’s a home-wrecker,
But the bugs are happy in the wood,
‘Til they’re chomped by red-cockaded pecker
Who wants a lata latté in the ‘hood.
Synthesized, it’s a winner.
“Go get laid, then be dinner!”
That pheromone blend helps avian friend.
Parcoblatta lata wonderland.
Parcoblatta lata wonderland.
Suggested additional reading:
- Cockroaches: Ecology, behavior, and natural history. 2007. William J. Bell, Louis Marcus Roth, Christine A. Nalepa. Johns Hopkins Press.
- More about the Red-cockaded Woodpecker (USFW)
Eliyahu, D., Nojima, S., Santangelo, R., Carpenter, S., Webster, F., Kiemle, D., Gemeno, C., Leal, W., & Schal, C. (2011). PNAS Plus: Unusual macrocyclic lactone sex pheromone of Parcoblatta lata, a primary food source of the endangered red-cockaded woodpecker Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1111748109
(this post appeared as a guest post at Scicurious)
“The Center for Biological Diversity announced its participation in the second annual Global Population Speak Out, a month-long effort to publicize the crisis of unsustainable human population growth. The Center is speaking out as part of its overpopulation campaign, which addresses the devastating impacts of overpopulation on endangered species.
As part of its actions for GPSO, the Center for Biological Diversity will distribute 100,000 free Endangered Species Condoms beginning on Valentine’s Day and has launched an educational Web site chronicling the devastating impact of human overpopulation on endangered species.”
I am a little puzzled by the “win a lifetime supply of endangered species condoms” contest. Lifetime of ….me, the human? The species on the condom?
And how do they calculate what a lifetime supply is, anyway? Is there an average daily condom usage statistic that you plug into (heh!) a formula of some sort? It probably uses your age as an adjusting denominator for the total amount. I’m just sayin’…..
Despite the painful Seuss-ian rhyme, I am very entertained by this. I would totally sign up to distribute the condoms if they could promise me they would all be beetle skins. So to speak.
Please suggest alternate slogans for other insectile prophylactics in the comments!
I have discussed the CITES treaty before, and also dealing in endangered species. A local Michigan man just ran afoul of both:
Kevin Rucinski of Roscommon County’s Gerrish Township was sentenced Thursday as part of an 18-month term of probation. The 49-year-old also was ordered to pay $5,000 in restitution and a $15,000 fine.
Rucinski pleaded guilty earlier this year to violating the Endangered Species Act. Authorities say he bought more than $15,000 worth of dried insects including butterflies on eBay, many from abroad.
As usual on news stories, the comments are quite cranky–mostly focusing around “why are cops doing this instead of finding real criminals?”
Well, why ARE they chasing a Michigan dentist, rather than a drug kingpin?
There are several answers to that question. CITES stands for Convention on International Trade in Endangered Species of Wild Fauna and Flora. As a signatory to CITES, the US has a responsibility to enforce it.
CITES bans the worldwide trade of species that are on the verge of extinction. It is important because many governments in areas of high biodiversity are not able to fully control collection and export of endangered species.
CITES acts to reduce the demand for endangered animals and plants by regulating their trade. Ideally, as more people realize that (for example) owning rhino horns is illegal, fewer rhinos will will be killed for their horns. This is not always the case, alas.
If our Michigan dentist had bought thousands of dollars worth of tiger skins, rhino horns, or clouded leopards, I think law enforcement action against him would be quite understandable. People look at this photo of a bird smuggler and immediately are outraged at the cruelty.
But…this Michigan dentist bought a lot of what, colloquially, are known as bugs. Which are seen as trivial in the public view, or worse, pest species. Hence, the cranky comments about this not being a “real” crime.
But insects are just as important, possibly more so, than vertebrate charismatic species. Insects are the little gears that make an ecosystem work. We don’t actually know, most of the time, what consequences total removal of an insect species from their native habitat will have. We can guess, based on experience, that it will be a bad thing.
This utilitarian argument for saving species is one that most people can understand, regardless of their knowledge of ecosystems and nutrient cycling.
There is also a second argument to be made: that insects have an intrinsic value, simply because they exist. In other words, when we see a paper that reports 50% of insect species living on an island have dissapeared, we should be saddened, even if there is no commercial value to those insects.
“Depending on what happens to human societies, we will spend the next few generations coming to terms with what we have lost,” said Dunn. “We won’t know most of what we have lost because it will have never been named. Some of the species we will have lost will have had important medicinal values. Some of them will have pollinated our crops. Some of them will have been strange creatures deserving explanation. Some will have been beautiful. Some will have had values that we are not yet capable of understanding.
“We live in a vast living museum that is being flooded and burned and ravaged. We know that we must save some of the art, but we don’t know anything about the art. So we grab the showiest things and hope they are important.”
Yeah. What he said.
Citation of the paper I mentioned:
Sodhi, N., Wilcove, D., Subaraj, R., Yong, D., Lee, T., Bernard, H., & Lim, S. (2009). Insect extinctions on a small denuded Bornean island Biodiversity and Conservation DOI: 10.1007/s10531-009-9585-7
Additional Info on Extinction and Importation:
- Rob Dunn’s page has many PDFs of his scholarly work on saving parasite species
- US Fish and Wildlife info on importing endangered species