50 RECOLLECTIONS OF A FLY SEX THERAPIST | NATALIE VAN HOOSE
of any mention of it in publications. Scouring
articles, I only found two lines in the introduc-
tion to a decades-old source that acknowledged
who was penetrating whom. With more of the
literature online now than in 2005, I’ve seen
a few other articles that note the female fly’s
unusual agency, but these, too, are older studies.
To the larger scientific community, this role
reversal seemed long forgotten.
Another fascinating feature of housefly
sexuality is the male’s rapacious sexual appetite.
Unlike the female fly’s monogamous lifestyle,
the male spends his ephemeral adult life try-
ing to inseminate as many females as possible.
In publications, his desire to copulate is often
described as “avid.” Even males who have just
finished copulating for eighty minutes—house-
flies generally mate for an hour or more—will
hop back onto the female, who, by that point,
has all the sperm she will ever need and placidly
ignores his love-pats.
In the absence of responsive females, males
will attempt to mate with flies of different
species, other male flies, and inanimate objects.
I witnessed a male fly desperately trying to
mate with a pebble, lavishing caresses on it and
waiting in vain for it to respond. Verena and I
theorized on how the males could be so, well,
stupid.
“He has to know it’s not a female, right?” I
said. “It doesn’t smell like one, look like one, or
even feel like one.”
But what happened when the males were
unable to satisfy their lust was both funny and
tragic: they would literally drive themselves
insane. Consumed by the urge to procreate,
male f lies that were kept from females would
rocket out of control, f lying headlong into the
walls of their cage until they destroyed their
wings and lay at the bottom, spinning madly
on their backs. Eventually, they lost all will to
live. If I took out a cage of virgin males that
had been left alone for too long, I would find
hundreds of dead f lies in a furry heap, their
wings ripped to shreds, the fresh water and
food left untouched.verena and i poked fun at the self-destruc-
tive males, but secretly, I empathized with them.I knew exactly how they felt. I practiced
celibacy for religious reasons—maybe endured
is a better word. Many days, I was dizzy with
desire, locked in contention with my body,
unable to think clearly as I biked to the lab, my
eyes resting briefly on every man I passed.
My only brush with romance that year was
with a contemplative, cultured graduate student
who shared my faith. After a couple of dates, I
backed out, confessing a lack of attraction. He
chided me in an email for thinking love required
some kind of physical click and suggested I read
a Wendell Berry essay on marriage to amend my
views. I laughed, shook my head, and sent no
reply. But for a long time afterward, whenever I
thought of his words, my cheeks burned with an-
ger and, for a reason I could not explain, shame.because much of the experiment revolved
around different combinations of couples—
healthy female/infected male, infected female/
healthy male—I had to ensure that the females
were virgins. The only way to do that was to
segregate the flies according to sex as soon as
they hatched out of their pupal cases. There was
urgency to this; if I waited too long, the males
would mate with every female they could get
their hind legs around, rendering those females
indifferent to the males in the mating cages and
warping the data.
After knocking out the newly emerged flies
by putting them in a freezer for a few minutes,
I placed them in plastic trays on ice on a lab
bench, plucking out the males and dropping
them into a separate container. Abdomen
up, the size of the genitalia told me the sex.
Abdomen down, the eyes would give it away:
females’ eyes are fully separated while males’
eyes almost touch at the top of their heads, tilt-
ing downward like an upside-down “v.”
The flies would begin to stir and twitch after
just a few minutes under my breath, but I could
not afford to make a mistake. Just one over-
looked male could wreak havoc on a population
of virgin females.
During the trials in which the males were
infected with the virus, the males continued to
mate even when their salivary glands were so
bloated they could hardly fly.