14 Nebraskaland • June 2019
PHOTO
BY
CHRIS
HELZER
IN THE FIELD
It seems like predators already have all the advantages
they need. Most have some combination of size, speed,
strength, big teeth/claws, and/or venom. If you're a small,
relatively defenseless creature, all those predatory features
are enough to strike fear into your heart. Allowing a predator
to also look exactly like something harmless is a step too far.
Robber flies are among the scariest of predators (to small
insects). They are super fast flyers with huge eyes and quick-
acting venom that paralyzes and then liquifies the insides of
their prey. Robber flies can take down prey much bigger than
themselves, often knocking that prey right out of the air
like a surface to air missile. Most robber flies don't bother
concealing themselves because they don't need to. They can
sit on a prominent perch and just wait for prospective prey
to fly by.
It's completely unfair, then, that some big robber flies have
all the traits of normal robber flies but also look just like
bumblebees.
Imagine being a small invertebrate, flying from flower to
flower, just trying to eat enough pollen to survive. As you
fly, you're constantly scanning the air for birds and aerial
insect predators, scanning nearby vegetation for robber flies
and other threats, and before you land on a flower, you check
carefully for crab spiders, assassin bugs, praying mantids,
and other potential ambush predators lying in wait for you.
Life is scary and frenetic.
Then one day, you go through your entire checklist, avoid
all threats while in the air, and just as you're landing on a big
sunflower, you do a final scan for predators.
"Let's see, nothing hiding underneath the flower, no
spiders camouflaged on top of the flower, just a little weevil
on the left and a big harmless bumblebee on the right.
Nothing to worry…" BAM!
Life isn't fair at all.
BEE MIMIC ROBBER FLIES
By Chris Helzer
