A simple way to tell insects apart - Anika Hazra
A whip-like straw.
Powerful, crushing blades.
A pointed, piercing tube.
There are nearly a million
known insect species in the world,
but most have one of just
five common types of mouthparts.
And that’s extremely useful to scientists
because when they encounter
an unfamiliar insect in the wild,
they can learn a lot about it
just by examining how it eats.
Scientific classification, or taxonomy,
is used to organize all
living things into seven levels:
kingdom,
phylum,
class,
order,
family,
genus,
and species.
The features of an insect’s mouthparts can
help identify which order it belongs to,
while also providing clues about how
it evolved and what it feeds on.
The chewing mouthpart is the most common.
It’s also the most primitive—
all other mouthparts are thought to have
started out looking like this one
before evolving into something different.
It features a pair
of jaws called mandibles
with toothed inner edges that cut up
and crush solid foods,
like leaves or other insects.
You can find this mouthpart
on ants from the Hymenoptera order,
grasshoppers and crickets
of the Orthoptera order,
dragonflies of the Odonata order,
and beetles of the Coleoptera order.
The piercing-sucking mouthpart consists of
a long, tube-like structure called a beak.
This beak can pierce plant
or animal tissue
to suck up liquids like sap or blood.
It can also secrete saliva
with digestive enzymes
that liquefy food for easier sucking.
Insects in the Hemiptera order
have piercing-sucking mouthparts
and include bed bugs,
cicadas,
aphids,
and leafhoppers.
The siphoning mouthpart,
a friendlier version
of the piercing and sucking beak,
also consists of a long, tube-like
structure called a proboscis
that works like a straw
to suck up nectar from flowers.
Insects of the Lepidoptera order—
butterflies and moths—
keep their proboscises rolled
up tightly beneath their heads
when they’re not feeding
and unfurl them when
they come across some sweet nectar.
With the sponging mouthpart,
there’s yet another tube,
this time ending in two spongy lobes
that contain many finer
tubes called pseudotracheae.
The pseudotracheae secrete
enzyme-filled saliva
and soak up fluids
and dissolved foods by capillary action.
House flies,
fruit flies,
and the other non-biting
members of the Diptera order
are the only insects
that use this technique.
But, there’s a catch.
Biting flies within Diptera,
like mosquitoes,
horse flies,
and deer flies,
have a piercing-sucking mouthpart
instead of the sponging mouthpart.
And finally, the chewing-lapping mouthpart
is a combination of mandibles
and a proboscis with a tongue-like
structure at its tip
for lapping up nectar.
On this type of mouthpart,
the mandibles themselves
are not actually used for eating.
For bees and wasps,
members of the Hymenoptera order,
they serve instead as tools
for pollen-collecting and wax-molding.
Of course, in nature, there are always
exceptions to the rules.
The juvenile stages of some insects,
for example,
have completely different kinds
of mouths than their adult versions,
like caterpillars, which use chewing
mouthparts to devour leaves
before metamorphosing into
butterflies and moths
with siphoning mouthparts.
Still, mouthpart identification can,
for the most part,
help scientists—and you
—categorize insects.
So why not break out a magnifying lens
and learn a little more about
who’s nibbling your vegetable garden,
biting your arm,
or just flying by your ear.
