Bugs

Answer to the Monday Mystery

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Cimex lectularius, the common bedbug, getting a taste of me.

 

What were those grapelike globules? All ten points go to Guillaume D for his guess of a bed bug’s compound eye. Guillaume accumulated enough points earlier in the month to lock in a win for February. Congrats, Guillaume, email me for your loot!

The SEM image in the mystery post was taken from the CDC public domain image library, a great source of open images for blogging and teaching.

 

The Jurassic History of Assassin Bugs

A chronogram of the assassin bugs derived from 5 molecular markers. Adapted from Hwang & Weirauch (2012) figure 4.

If you’re into assassin bugs- and really, who isn’t- you should check out this recent paper by Hwang & Weirauch:

The evolution of blood-feeding may thus have occurred once or twice independently among predatory assassin bugs. All prey specialists evolved from generalist ancestors, with multiple evolutionary origins of termite and ant specializations. A bark-associated life style on tree trunks is ancestral for most of the lineages of Higher Reduviidae; living on foliage has evolved at least six times independently. Reduviidae originated in the Middle Jurassic (178 Ma), but significant lineage diversification only began in the Late Cretaceous (97 Ma).

Assassin bugs are fascinating predatory insects found all over the world, and this paper is the first modern effort to synthesize this group’s life history with phylogeny. This sort of big-picture evolutionary research is increasingly common, so if you’re new to biology it’s well worth learning how to interpret studies like these.

Phymata sp. ambush bug (Reduviidae: Phymatinae)

source: Hwang WS, Weirauch C (2012) Evolutionary History of Assassin Bugs (Insecta: Hemiptera: Reduviidae): Insights from Divergence Dating and Ancestral State Reconstruction. PLoS ONE 7(9): e45523. doi:10.1371/journal.pone.0045523

Answer to the Monday Night Mystery

Euschistus sp. stink bug (Pentatomidae) - Urbana, Illinois

5 points to Morgan Jackson for getting Order & Family (-1 for missing the genus, though!); 4 points for Matt Bertone for the correct genus; 1 point to Mark Fox for brazenly attempting a species guess, and one point for ABM for the tongue depressor comment.

We’re all on alert for the dreaded marmorated stink bug that has plagued the east coast in recent years and and has been sighted in our area. But there are some non-pesty native look-alikes, and Euschistus is one of them. The groove on the tibia I showed in Monday’s post is diagnostic for this genus.

Rose aphids

A splash of color for your Thursday evening:

Macrosiphum rosae - rose aphids, on a yellow rose in Tucson Arizona

The rose aphid, Macrosiphum rosae, dates its taxonomic heritage right to the opening of modern nomenclature. It was described by Linneaus himself in the 1758 volume Systema Naturae.

Of course, the aphids don’t pay much attention. They’re just happy to tap into rose phloem.

***update: Cameron Brumley informs me these may actually be Rhodobium porosum, another rose-feeding aphid. Am checking into it.


photo details:
Canon MP-E 65mm 1-5x macro lens on a Canon EOS 20D
ISO 100, f/13, 1/200 sec
diffuse twin flash

The Bloodsucking Conenose

Triatoma sanguisuga, the eastern bloodsucking conenose

In Paraguay, where I lived for a time in the 1990s, one insect is feared more than any other: the Vinchuca, or bloodsucking conenose.

The bug itself isn’t the problem. It’s the pathogen it transmits while feeding. Trypanosoma cruzi is a horrific slow-acting protozoan that chews at the muscle fibers of your internal organs. It takes its time, though. 15 years later, your heart up and stops. Or more gruesome your bowels dialate, loosing their ability to move business along. Fecal matter piles up unvoided in the intestines and you perish bloated, painfully, with blood poisoning. This awful disease is called Chagas. It affects millions of people in rural Latin America.

I would frequently search for Triatoma in the cracks of the walls of my little Paraguayan campo house in the hopes of keeping my risk at a minimum. I never found any, thankfully, though I did see them in my area. This memory has burned itself deeply enough in my consciousness that I still respond viscerally to Triatoma, even a different species on a different continent.

The individual photographed above came to a blacklight at BugShot a couple weeks ago. Triatoma sanguisuga, the eastern bloodsucking conenose, is a strikingly colored bug. I jumped a little when seeing it.

Our native bugs have a key difference preventing Chagas outbreaks on our continent: they don’t defecate in the bite wound while feeding, which is how the trypanosome gets from the insect to the mammalian host. We’re safe because our bugs crap discretely. I guess that’s good. For us. Though I can’t help but feel our South American friends got a raw deal just because their local bugs have runny bowels.

What’s a Bug?

An issue that invariably surfaces when entomologists interact with non-entomologists is the “bug problem“.

I don’t mean pest infestation troubles. Rather, I mean that entomologists use a different definition of the word “bug” than the general English-speaking populace, with confusing results.

To most people, a “bug” is any small crawly animal. Like a spider, or a centipede, or maybe a chihuahua. To an entomologist, a “bug” is specifically a member of a particular lineage of insects, the Hemiptera. A cockroach is not a Hemipteran, so it can’t be bug. Neither is a beetle, or a spider.

I bring this up because of a comment over at Jerry Coyne’s blog:

In ordinary usage, “bug” applies not just to insects but to arthropods of all kinds, including lobsters and crawfish.

If the argument is that the technical meaning came first, and only later did the word come into popular usage, I don’t think that’s the case. According to Wiktionary, “bug” derives from “bugge” meaning “beetle”, at least a century before Linnaeus.

I suppose on some level scientists are entitled to assign narrow technical meaning to common words. But if such assignments needlessly defy common sense (as in the assertion that cockroaches are not bugs), doesn’t that tend to undermine public trust in science?

(Gregory Kusnick)

Is my restricted use of “bug” against common sense?

Well, no. It’s the most natural thing ever. For me, and for other entomologists. That entomologists narrowly circumscribe the word isn’t a problem per se. Rather, it is indicative of the fact that we buggy folks in our little buggy subculture have a different notion of what is and isn’t common sense. This is trivially true of any specialized field. I’m pretty sure a quantum physicist holds ideas as “common sense” that are simply loony.

Common sense is objectively meaningless, anyway. The better issue is whether “bug” should be considered a technical term.

And I unequivocally think it should not. “Bug” is a common name. What’s more, it is a common name for both the lay public and for insect specialists. That it refers to different organisms in the two cultural contexts does not change the fact that it is vernacular in both spheres.

Common names are particular to individual cultures and local contexts. That is their point. The beauty of common names is their fluidity. They are dynamic, ever-changing, adaptable. Vocabularies arise to suit people’s needs. Entomologists find a narrow meaning for Bug useful. Non-entomologists don’t. And that is fine.

What’s spectacularly unnecessary about the bug debate is that we’ve already got a standardized international entomological lexicon. Researchers the world over, speaking hundreds of different native tongues, all use the technical term “Hemiptera” to refer to the same group of insects. Scientific nomenclature- though perhaps unappreciated-  is one of the triumphs of the Enlightenment. I can arrive in any country, find a local entomologist, ask for a hemipteran, and I’d know what to expect.

So I don’t have a problem with people loosely throwing about the term “bug”. That’s what it’s for, after all. If there’s a need to be technical, well, we’ve got Hemiptera.

Household pest insects

Because I get a lot of requests for pest insect pictures, I’ve created a new gallery:

German Cockroach, Blattella germanica

Household Pests

Rather than the untrammeled nature I usually shoot, this collection is a bestiary of roaches, mice, flour beetles, bed bugs, ants, termites, and other creatures that enjoy the great indoors.