Worms and Flowers

An Instar is Born

Posted in Bugs by Lzyjo on October 1, 2009

Caterpillars are remarkable little creatures. They are the competitive eaters of the insect world, each a connoisseur,  specializing in a limited group of favorite plants.

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Second Instar

They start as miniscule eggs and emerge as a tiny prickly-looking caterpillars less than .5 inch  (1.3 cm) long. Caterpillars are technically larvae, but caterpillar sounds much cuter doesn’t it? After all it comes from Ango-French and Middle English words meaning hairy cat!

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Third Instar

Caterpillars are incredibly hungry and fast growing. Undergoing five stages of growth called instars. They get as fat as possible then molt their exoskeleton four times until they are officially pupa. Instead of shedding their exoskeletons, the new layer is “digested” and reabsorbed, probably a move to save energy, since caterpillars only purpose is to eat as much as possibly, as quickly as possible.

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Fourth Instar

Caterpillars are peculiar. They are so tiny, yet they move with amazing intricacy. They are muscle bound eating machines. I know, they don’t look like muscle men, but they are. Each caterpillar has 4,000 muscles that allows its body in the strangest ways, like when they hang way out from a limb, searching and searching for something to grab on to. Caterpillars have more muscles on their head (248) than we have bones in your bodies.  (206)

For being such small creatures, caterpillars display a variety of defense mechanisms from the intriguing to deadly. A certain species of South American silk worm has barbed hairs, similar to the tarantulas, which contain a venomous anticoagulant powerful enough to cause death by uncontrolled bleeding in humans.

Aside from their camouflage appearances, they have an arsenal of tricks to ward of potential predators. The swallowtail caterpillar has a unique defense mechanism. When threatened the caterpillars emit a distinctly pungent pheromone from a pair brightly colored, orange or red glandular organs called the osmeterium, which resemble antennae and spring out of the head.

Can you see? This one is really chomping away! It is very close to being a pupa, one more molt and it will be a mature pupa, ready to find a safe place to make a chrysalis. Don’t they change remarkably, in such a short time?

Since I’m not an insectologist (oh, I just wanted to say that word!) check my sources:

Wikipedia Butterflies good overview

Butterfly School Metamorphosis great photos of every stage

Monarch Butterfly “What is an Instar?” explanation of molting

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Bt. Correction.

Posted in Pests by Lzyjo on September 29, 2009

Just an update on my last post Butterfly vs. Bt. Luckily, Daphne from Daphne’s Dandelions saved us all from the misinformation on Wikipedia.

Unbeknownst to me, there are three main strains of Bt used to target specific pests. Bt is not a broad-spectrum pesticide. Information about the three strains and their specific targets can be found on the Colorado State University Extension Website site.

The most commonly used strain is Kurstaki,which targets caterpillars, including cabbage worms, tent caterpillars and leaf rollers.  It is sold under the trade names Biobit, Dipel, MVP, Steward, Thuricide.

Mosquitoes and flies are treated with a separate strain Israelensis.

The third and fourth strains San diego/tenebrionis target beetles, like the Colorado Potato Beetle and others.

Check the ColoState page for more in depth info.

Sorry to scare you all. Bt is a safe pesticide, especially when compared with the alternatives.

Sheesh, I’d better stop using Wikipedia as the be all, end all. It certainly isn’t.

Thank you for clearing that up Daphne!

Successfully Managing the Colorado Potato Beetle

Posted in How To, Pests by Lzyjo on April 30, 2009

I love growing potatoes. What I don’t love are the pests that come with them. My archenemy in this department is the leaf-eating Colorado Potato Beetle (CPB). Not only are the beetles gut-wrenchingly disgusting, they spread diseases as they move from plant to plant. With diligence these pesky bugs can be controlled without toxic chemicals.

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The key to controlling the CPB is understanding its life cycle. There are three stages in the maturation of the beetle, eggs, larvae, and adults, they can killed during any one of these phases. Adults are easy to identify due to their distinctive striped exoskeleton. (Sorry, I dusted them up trying to get them in the shot.)

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Adults can be found feeding on the leaves and also near the base of the potato plant, where they emerge from their underground pupation chambers.

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Black beetle poop on the leaves are a tell-tale sign of beetle activity.

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Adults lay masses of bright orange colored eggs on the underside of the leaves. These should be wiped off and smooshed (I like to use gloves for this,) before they hatch anywhere from 4-10 days. If the eggs hatch, reddish brown larvae with black spots will emerge. These larvae will eat their fill of  leaves before retreating to underground chambers where they will complete the pupation process, emerging a few weeks later as full grown adults.

The best time to perform search and destroy missions is the early morning when the beetles are still sluggish from the cooler nighttime temperatures. I like to use the bottom of a stick to squish them. Okay, I don’t like it. It’s a matter of necessity. Be careful these guys will try to play dead, so make sure to squish ’em good!

For more information on the life cycle of the Colorado Potato Beetle see this article provided by a cooperative between the Universities of Wyoming, Nebraska, Colorado State, and Montana State.

Two-faced Spider and Walking Stick

Posted in Bugs by Lzyjo on December 25, 2008

Hey! What’s the stick on the foundation?! I always feel honored when I see a walking stick. After all, it’s not everyday that one sees this delicate sage-like creature.

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This guy has been living between the A/C compressor and our house. He’s so big he eats other spiders.

The coolest thing about this spider are his two faces. The photo below is his underside, which is perfectly colored to warn off any predators.

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It’s nearly impossible to tell which way he is facing, except the true back is more rounded with more yellow coloring.

garden spider

ETA: This spider is Argiope aurantia, commonly known as the black and yellow garden spider, or writing spider. The stabilimentum is an important identifier of this spider’s web. Although the purpose of the stabilimentum is disputed, only spiders that are active during the day use them. Some believe it provides a visual warning for animals too large to be captured by the web, while others contend it attracts insects. I think this particular spider is female, as their body can grow up to 1 1/2″ long, twice as large as the male. The female spins her web in a sunny field, or around outbuildings. Then she waits for the male to find her. Garden spiders breed once a year. The male will set up a separate web near the female’s and begin courting her by plucking the strings of her web. As seen in Isabella Rossellini’s Green Porno, the male spider sneaks up behind the female to slip his sperm into the female’s genital opening, which is called the epigyne or epigynum(if you look in the top photo you can actually see this spider’s epigynum, it looks like a brown circle on her underside). At this time of the year the spider has only a few months to lay her eggs and protect them, before the frost kills her. Next Spring, when the little baby spiders hatch, it will all begin again.