I planted dill hoping to get Black Swallowtail butterfly caterpillars on
it; it worked way too well. You can
have to many caterpillars.
I was so happy to have one caterpillar a month ago. Now it's the middle
of July. Here's what's happened in between:
I never saw the eggs, and I was looking for them here and there. Then I
found these, LOTS of these! Over a hundred tiny Black Swallowtail
Caterpillars! (...and unfortunately only a few
plants, but I was
new to butterfly gardening, so at first I didn't know that wasn't
The caterpillars are tiny; at a glance, they look like little brown
worms with a white stripe in the middle.
The Black Swallowtail caterpillars ate and grew so fast it was amazing. They ate every leaf, and they
ate every bloom, and then they started chewing the green off the fattest stems,
the only part of the Dill that remained:
Once there was nothing left of the dill, they started chewing on my only parsley
That's when I figured out I had a problem. One plant left, and a
multitude of very hungry caterpillars... oops!
Mom to the rescue! This situation is one of the reasons it's good to
have a butterfly garden buddy - extra host plant (caterpillar food plant)
reserve. I was out of food, but she had dill, parsley, fennel and rue in
her garden. Black Swallowtail Caterpillars will eat all of those herbs,
and she was willing to adopt some of my caterpillars so they wouldn't
She gave me some dill plants and
a fennel plant, which I put in my garden by the caterpillars, and took
her new caterpillars home. The caterpillars that remained chewed all the dill,
fennel, and parsley down to nothing but stubs, and then vanished.
I searched all over, but never found a single chrysalis from that batch
of caterpillars. Fortunately, others visited.
Here's a Black Swallowtail butterfly laying eggs on a Dill flower:
The tiny yellow dot in this
next picture is a Black Swallowtail
Butterfly egg on dill. I can't wait until they come back so I can get a
better picture now that I've upgraded my camera!
Of course, those tiny eggs hatch into wee little caterpillars, but they
don't stay small for long.
They eat for a couple of weeks and then suspend themselves with
tiny bits of silken thread chrysalis:
I never found my Black Swallowtail Chrysalides, but my mom found this caterpillar hanging for the change and
this one that's just made its chrysalis in her
So now you know the life cycle of the Black Swallowtail Butterfly:
Egg, Larvae (caterpillars), Chrysalis, & Butterfly.
the Black Swallowtail caterpillars look different at different ages;
those stages are called instars, and the caterpillars shed their skin
between each one. Did you notice the shed skin below the caterpillar in
the top photo on this page?
Here's another thing that's neat about
Black Swallowtail butterfly caterpillars; see that orange 'Y' shaped
thing sticking out the top of this one?
managed to bother the caterpillar long enough for it to try to scare me
away with its scent gland (stink gland), the osmerterium. I think
Giant Swallowtail stink glands smell
worse than the Black Swallowtails do.
Oops - this page got too long, so I'm continuing on Black Swallowtail
Butterflies page 2.