Monday, August 29, 2011
Of course they need to eat now to have enough fat to overwinter in their cacoons and have the resources to emerge next spring as one of Minnesota's largest and most beautiful moths.
But since late May they have been eating machines.
Take a look below at the huge green eyes and the mouth on this caterpillar. It has a transparent upper lip! And pretty weird "teeth" below. I took these pictures in the last few days as I waited to photograph the caterpillars as they transformed into cacoon makers. Scrool down to see the action.
This moth is a member of the Saturnid moth group that includes the caterpillars that silk cloth comes from.
Notice the light blue "spiracles" on each segment of the caterpillar. These are the breathing holes that allow insects to breathe. Also notice the three little "true" legs near the head. Three more on the other side account for its six true legs. The large projections from its abdoman that look like legs are called pseudo or false legs. These "legs" will now dissappear for the rest of this insect's life.
You can see in the picture below how the caterpillar begins to have a glistening silk thread emerge from its mouth, wrapping it all around itself and the branch it is on. Meanwhile its body seems to begin turning white. The silk is sticky when it first comes out but hardens to one of the strongest tensile strength "lines" known on earth.
The caterpillar will continue inside to make a thick wall of silk, and after several days will stop, and in a couple of weeks it will turn into the pupae and wait for the warmth of next May and June to emerge as the adult moth. I'll post more pictures then of the moth.
Sunday, August 21, 2011
Some cicada species live underground for many years. 13 years is one, along with the well known 17 year cicada. But our common cicada is only underground one year.
Cicadas are in the group of insects called Hemiptera, or True Bugs. This group of insects all have straw-like sucking mouth parts and most use their "straw" to pierce plant tissue and suck out nourishment from the plant. After mating, female cicadas lay eggs in the stems of tree branches. The hatchlings drop to the ground and burrow down to one of the tree's roots. They attach their straw like mouth to the root and stay attached for the next year, growing as the tree feeds them.
After their year in the ground the larvae crawl out on a late summer night and climb a few feet up the trunk of the tree. In the picture below you can see the shell left after they emerge from the ground with the dirt still attached.
Cicadas are very heavy bodied insects and not very good fliers.
The females listen for the "singing" males, and pick one out that sounds perfect to her. She then flies to the tree and locates the male by his buzzing call. After introductions, if all goes well, they mate and the female then finds an appropriate branch to lay her eggs in.
Hearing the cicadas always means the peak of summer is past, and I'd better enjoy what is left.
Thursday, August 11, 2011
They are very curious, but still never get very far from mom, as you can see in the bottom photo. I took these pictures today by Springbrook's feeders