Sunday, April 05, 2009
Surprise Visit from the Stagmomantis Stork
So I was walking through the backyard, Harry Potter and the Half-Blood Prince and a bowl of cheese puffs in hand on my way to the rocking chair for a read when I happened to look down and see tiny mantis nymphs tumbling in slo-mo out of the oothecum that was placed under the styrofoam crow's tail early last November. These are stagmomantis californica, California mantis.
The first thing you see of an emerging nymph is the rounded top of its head and two dark flattened eyes . I'm not sure what the mechanism is for them to come out, but it looks like they are being squeezed out of a tube. As the nymph comes out, it jerks its body a bit and finally is fully free of the foam casing of the oothecum. At this point it is roughly cylindrical, with the segments of the abdomen reinforcing the resemblance to a worm or even a maggot. But mantids are insects with gradual metamorphosis, meaning the young will resemble the appearance of the adults, unlike (for example) maggots which do not resemble flies. As more and more nymphs squeeze out, the older ones unfurl their legs and antennae; their body lengthens and their heads expand into that characteristic mantis shape with a pointy beak in the middle and bulging eyes on each side. This expansion happens quite quickly: I started watching at 10:45 when there were maybe three emerged; everyone was out and pumped up by 11:11. I counted 24 of them; just over 1 minute each for the emergence.
After they hatch the tiny mantids move slowly away from the oothecum, giving their legs a test while their abdomens curl up. They tend to form ranks, all facing about the same direction, although a few adventurous individuals went off the opposite way. Iconoclasts, I guess. The rest reminded me of the scene in Star Wars Ep I, The Phantom Menace, where rank after rank of battle droids methodically unload from a large, oothecum-like ship onto a pastoral field, ready to do battle upon the people of Naboo.
By late afternoon/early evening the baby mantids had moved off of the mother crow and into the nearby plants. Overnight their exoskeletons had cured to a darker brown with some light brown stripes and markings. They leave their siblings behind for a solitary life in the planet of my garden munching insects (usually) smaller than themselves.