As a nature writer and photographer, I spend a lot of my time
peering closely at leaves, twigs, and flowers, seeking what lurks
in their midst. So it was that I discovered Phymata, the Ambush
Bug. I was walking slowly through a meadow, bent over almost double
as I carried a tripod-mounted camera instead of a magnifying glass.
Spotting a fly on a daisy, I approached slowly, finding it odd that
the insect didn't move away from me. Puzzled, I looked closer and
found a small, bulbous-eyed bug, his mouthparts embedded in the
Ambush bugs lurk in the foliage, waiting for prey to come near.
When they spot a victim they leap from cover, impale the hapless
creature with a penetrating beak, pump liquefying enzyme into its
body, and slurp up dinner. Although their specialty is disguise,
their appearance, revealed, is daunting. If they were blown up to
the size of a car, they would put a Bradley Fighting Vehicle to
shame. Armored and massively muscular, they easily capture and
overpower prey many times their own size. Of course, a little
perspective is in order: this is a bug that could easily fit on the
real estate of my smallest fingernail, with plenty of room to
Dr. David Punzalan, a Postdoctoral Fellow at the Royal Ontario
Museum's Department of Natural History, has extensively researched
ambush bugs. He explained that ambush bugs are "generalist
predators" that take a wide variety of prey that typically visit
flowers. Wasps, flies, and butterflies are all on the hit
list. Ambush bugs will prey on insects that are considerably larger
than themselves, including bumblebees.
I asked about their preferred hunting grounds. "The bugs don't
seem exceptionally picky about where they will hunt," Punzalan
noted, "as long as the insect traffic in the area is high." Ambush
bugs' location varies over time, in keeping with what wildflowers
are blooming. In late summer and fall, favorite host plants include
Queen Anne's lace, goldenrod, thistle, asters, daisies, and
Following my exchange with Dr. Punzalan, I returned to the
meadow and searched a bit more diligently for Phymata. Sure enough,
I found them on a variety of flowers, many of them in the act of
enjoying dinner. They're beautiful: because of their angular shape
they look almost prismatic, with colors ranging from emerald green
to bicolored tan and gold.
In a subsequent email, Punzalan explained that some of the
variation in color stems from sexual dimorphism (variations
according to the sex of the organism), others from age. "Males are
generally darker," he noted, "with some dark patches reduced or
absent in females." This darker coloration appears to enable the
males to better absorb heat energy from the sun, and thereby
increase their mobility. Why this color differentiation exists
between genders, however, is unclear.
In my second trip through the meadow, I had also noticed that on
quite a few flowers, one ambush bug was perched atop another.
"Piggybacking" is common, and symptomatic of the intense
competition for females. This is not a mating behavior, but instead
"mate-guarding" to prevent competing males from honing in on a
chosen female. Males also engage in courtship behaviors that
include twitching antennae, tapping forelegs, trembling pulses
throughout their bodies, and rapid squeaking.
Squeaking? "Yes," Punzalan confirmed. "Both sexes can stridulate
by scraping their beaks on a file under their thorax. In fact,
immatures appear to employ this technique when they're alarmed. If
you pick one up by the thorax and watch closely, you'll see rapid
head-nodding which is the scraping movement, and if you hold them
close to your ear you can even hear it."
There are two species of ambush bug in the northeast, Phymata
Americana and Phymata Pennsylvanica, although the nomenclature is a
bit contentious. Some authors have placed the two as related
sub-species, while others consider them to be altogether separate
species in spite of the fact that there has been no formal
demonstration of genetic or behavioral isolation.
Whatever the case, these are fascinating little creatures. Next
time you're out meadow-walking, take the time to look a little
closer at the flowers that surround you. But beware: there are
Dr. Steven Shepard is a professional author, photographer, and
educator; he can be reached directly at Steve@ShepardComm.com. The
illustration for this column was drawn by Adelaide Tyrol. The
Outside Story is assigned and edited by Northern Woodlands magazine
and sponsored by the Wellborn Ecology Fund of New
Hampshire Charitable Foundation.