Popular Science - USA (2020 - Spring)

I’ve had a fascination with beer for a long time.

I had my first one in Bavaria in 1961 when I was

16. It was legal there, but when I got back to
    New York, the drinking age was 18. One time, I
    wanted a pint so badly, I dressed in lederhosen,
    went to a nearby tavern, and pretended I was
    German. It worked—they actually served me.
    I began studying alcoholic beverages in the
    1990s at the University of Pennsylvania
    Museum, where I now direct the Biomolecular
    Archaeology Project. My colleagues and I had
    been researching the design and engineering of
    ancient pottery, but inevitably we started to
    wonder what had been inside those jugs.
    Around that time, an archaeologist working
    in Iran brought us a roughly 5,500- year- old
    vessel with an unusual residue inside. It looked
    like calcium oxalate: a yellowish, crystalline res-
    idue that modern brewers call “beerstone.” It
    can harbor microorganisms that may warp a
    batch’s flavor or even be poisonous.
    When we compared the residue with a
    sample from a local brewery, they were virtually
    identical. Combined with the fact that the criss-
    crossed lines on the container matched those of
    the Sumerian symbol for beer (kaş), we were
    confident that we had found the oldest-known
    evidence of draft production.
    New discoveries always pop up. In 2018, a
    team in Israel found a 13,000- year-old recepta-
    cle with potential brewing evidence. I think beer
    goes back to our species’ beginnings. If sugars
    were there to ferment, humans were probably
    trying to get that buzz I felt back in Bavaria.

In 2007, I started a position

at the urban entomology

lab at the University of Flor-

ida. At the time, bedbugs

were spreading around the

United States—after a long

period of quiescence—so a

lot of research was focused

on understanding and

controlling the insects.

Bedbugs are ancient

critters with diets made up

entirely of blood. Before

they developed their taste

for humans, they dwelled in

caves and fed on bats.

When our species moved

into the caves, we became

one of their main meal

sources. Eventually we gave

them a free ride to our

more- modern residences.

They’ve had millennia to

get to know us. To become

scientifically acquainted

with them, we needed to

collect the bugs in the field

and recolonize them in

the lab, where we could

scrutinize their behaviors.

My colleagues and I vis-

ited homes heavily infested

with the common bedbug,

Cimex lectularius. Once,

however, we found a small

infestation of a far rarer

variety in the US: tropical

bedbugs, or C. hemipterus,

whose behavior we know

less about. We needed to

boost their numbers in the

lab to effectively study

them, which meant we had

to feed them. You can put

rabbit blood inside paraffin

film to mimic skin, but bed-

bugs can have trouble

biting it. Instead, I put their

cage on my arm or leg and

just let them feed for a bit. It

gets uncomfortable when

you have around 100 on

your skin, but I can’t ask my

students to do it. It’s far

more ethical to ask myself—

and I’m very agreeable.

PATRICK MCGOVERN,SCIENTIFIC DIRECTOR OF

THE BIOMOLECULAR ARCHAEOLOGY PROJECT

AT THE UNIVERSITY OF PENNSYLVANIA MUSEUM

ROBERTO PEREIRA,ENTOMOLOGIST

AT THE UNIVERSITY OF FLORIDA

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SPRING 2020 / POPSCI.COM
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i let bedbugs feast
on me—for science
beer has
always been
on the table
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