Said Freda, “It was amazing watching it chew its way out of the egg. It worked almost constantly and you could tell that it was putting forth major effort.  Between its hand-like mouthparts and box-cutter-like forelegs, it was punching and chewing and slicing at an amazing pace for such a tiny thing.”

“It looked like it wasn’t only busy chewing on the dry, outer edge, but there was also what appeared to be gelatinous stuff on the inside that it scooped up and worked into its mouth.] Imagine slurping up a slimy spaghetti noodle the diameter of your open mouth and having to use your hands to stuff it in. There were some pauses where you could almost hear it thinking, “I’m so stuffed, but gotta keep going – or die.” It seemed like a tremendous feat!” 

The gelatinous stuff was undoubtedly the last of the yolk material that nurtured it until it hatched.

“The caterpillar made it out and is resting now.   : )”

“As of this morning, the ‘baby’ is 3 to 3.3 mm long. As the last photo shows, it’s been eating and pooping healthily.”

Thanks, as always, for sharing your photography, Freda.

Monarch caterpillars have one pair of filaments on the front end and another on the rear end – anterior and posterior tentacles.  According to Monarch Joint Venture, these tentacles are sensory, “The caterpillar’s tentacles are sensory organs. Caterpillar’s eyesight is poor, and tentacles are tactile. They aid in navigation on the front. They may also play a role in defense/predator confusion on the rear, leading a potential predator to think that the monarch’s rear is its head.”  How do you tell one end of the caterpillar from the other (if, of course, it’s not eating)?  The longer tentacles are in the front.  There is also a tiny pair of actual antennae near the mandibles, to pick up olfactory signals and help the caterpillar find food.    

Quick review: the short-lived, early and mid-summer generations of Monarchs have one job – to goose the Monarch population.  Hatch, eat, mate, lay eggs (and they’re doing a great job here this year).  The final generation, sometimes referred to as Gen 5 or the Super generation, in the air from late-August on, have a different imperative – hatch, eat, metamorphose, and migrate (which is why they’re the only generation that’s tagged).  How do they know what to do?  The message comes in the form of old, leathery, bitter milkweed leaves (they prefer young and tender), fewer nectar plants, shorter day length, cooler nights, and the lowering angle of the sun (57 degrees above the horizon).  And yes – we do see monarchs who seem not to have gotten the memo, flying in tandem at the end of the season.  Apparently some of the penultimate generation may drift south, laying eggs as they go. 

They set their courses for a destination they’ve never seen, orienting themselves via the sun (with a dash of magnetic compass thrown in), with calculations so intricate that monarchs in Michigan, Maine and Montana set correct (but different) flight plans for central Mexico.  And they find not only Mexico, but the overwintering spots in the mountains west of Mexico City.

And now a brief sermonette from the BugLady (Freda is not planning on fostering this infant until it forms and then emerges from its chrysalis, so she is exempt from the sermon).  It has become popular to try to help the yo-yo-ing Monarch population by collecting eggs and hand-raising the caterpillars.  The rationale (besides the facts that it’s great fun and very sciencey) is that the caterpillars are safer in a controlled, predator-free environment. 

And indeed, they are, as long as their keepers practice good caterpillar hygiene, but caterpillars raised in the garage or basement or family room are not exposed to the environmental signals that will allow them to navigate properly.  Some captive-raised butterflies do muddle through and arrive at their destination, but it’s a lower percentage than their wild-reared brethren. 

The bottom line, if raising Monarchs is your thing, park them in the back yard.  The Xerces Society for Invertebrate Conservation (https://xerces.org/) suggests that we could do a lot more for Monarchs if we would plant native milkweed for the caterpillars and native wildflower gardens that will bloom through the season for nectaring butterflies. 

Go outside -watch the Monarchs!

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/