Of the multitude of discoveries that every summer offers us, one of the most magical is that of a Monarch Butterfly chrysalis. While locating a Monarch larva is not all that difficult, especially when they are as prolific as they are this summer, finding a chrysalis doesn’t happen all that often. Most butterfly chrysalises are a rather drab brown, but the Monarch’s is a beautiful green which serves to camouflage it in fields where the caterpillars feed on milkweed and eventually pupate (form a chrysalis). The Monarch caterpillar, when mature, usually seeks a sheltered spot under a leaf or branch where rain will not cause the silk button by which it hangs to disintegrate. The chrysalis in the photograph is attached to a blade of grass which was anchored with silk to another blade of grass in order to make it more secure. No matter how many I’ve seen, each one still takes my breath away.
August 4, 2012 | Categories: Adaptations, Arthropods, August, Butterflies, camouflage, Chrysalises, Insect Signs, Insects, Invertebrates, Metamorphosis, Pupae | Tags: Butterflies, Chrysalis, Danaus plexippus, Lepidoptera, Metamorphosis, Monarch Butterfly, Pupa | 2 Comments
If you’ve never heard of a Spongilla Fly, you’re not alone. We don’t see its larval stage, as it lives under water, where it feeds exclusively on fresh water sponges. You can find these sponges living in the still waters of large rivers, lakes and wetlands. The beautiful silken net, as well as the small cocoon inside the net, are created by a Spongilla Fly larva after it crawls out of the water and chooses a spot on land on which to pupate (in this case on a seat cushion). The entire structure is less than ¼” in diameter.
July 31, 2012 | Categories: Arthropods, Cocoons, Insects, Invertebrates, July, Metamorphosis, Pupae | Tags: Cocoon, Insect Metamorphosis, Metamorphosis, Net-winged Insects, Neuroptera, Pupa, Sisyridae, Spongilla Fly | 4 Comments
Congratulations on some very creative guesses! Yesterday’s post was a botfly puparium – a hard case made from an insect’s larval exoskeleton (skin) that covers and protects the pupa. Most insects that go through complete metamorphosis (egg, larva, pupa, adult) don’t have this added protection for their pupal stage, but certain flies, including botflies, do. Botflies are fairly large, hairy flies that resemble bumblebees and are internal parasites of many species of mammals, including humans. Depending on the species, the botfly deposits its eggs on or near the host animal, or on another insect, such as a mosquitoe or housefly, which carries them to their host. The eggs of some species of botflies are ingested or inhaled; those of other species hatch and the larvae bore into their host. After entering and crawling around inside of the host animal for a week or so, most species of botfly larvae settle in a spot just under the host’s skin and remain there for three to ten weeks, consuming the flesh of its host. The lump, or “warble,” that forms just under the host’s skin where the botfly resides increases in size as the larva grows. A tiny hole chewed in the skin allows the larva to breathe, and eventually it exits through this hole. The larva falls to the ground, where it pupates in the soil and later emerges as an adult botfly. (The two yellow bumps at one end of the puparium are spiracles, through which the pupa breathes.) The whole story of this particular puparium is that Jeannie Killam found it in her old farmhouse’s kitchen cupboard, where it probably popped out of a visiting mouse. (Illustration is of a human botfly.)
July 28, 2012 | Categories: Arthropods, Diptera, Flies, Insect Signs, Insects, Invertebrates, July | Tags: Botfly, Flies, Internal Parasites, Metamorphosis, Myiasis, Ostridae, Parasites, Pupa, Puparium, Spiracles, Warble | 7 Comments