Bear River Casino 090208

today

9 a.m. Doris Niles Humboldt County Science Fair Humboldt State University

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10 a.m. Annual Juggling Festival Humboldt State University

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10:30 a.m. Green Jobs Fair College of the Redwoods Downtown Site

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11 a.m. Baby Read and Grow Program Humboldt County Library

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1 p.m. Apple Solutions for Small Business See Event Description

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4 p.m. Young Parent Support Group College of the Redwoods Kinship Site

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6 p.m. The Tumbleweeds (cowboy songs) Chapala Cafe

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6 p.m. Bon Swing Libation

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6 p.m. Annual Pisces Party See Event Description

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6 p.m. Annual Pisces Party See Event Description

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7 p.m. DJ Ray Boiler Room

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7:30 p.m. Arianna String Quartet Calvary Lutheran Church

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7:30 p.m. A Midsummer Night's Dream Arcata High School

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8 p.m. Eureka Symphony Concert Arkley Center for the Performing Arts

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8 p.m. Humboldt Folkdancers Arcata Presbyterian Church

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8 p.m. On the Wings of a Dove Carlo Theater (Dell'Arte)

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8 p.m. Antigone College of the Redwoods

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8 p.m. So Hum Tales Mateel Community Center

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8 p.m. Gentle Thunder Arcata Playhouse

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8:30 p.m. The Last Minute Men (international) Cafe Mokka

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9 p.m. Taxi (rock & roll) Bear River Casino

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9 p.m. Vintage Soul (R&B) Cher-Ae-Heights Casino

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9 p.m. Bump Foundation Pearl Lounge

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9 p.m. The Brothers Comatose (folk) Six Rivers Brewery

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9 p.m. The Malone (rock Red Fox Tavern

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10 p.m. Music by DJ Sidelines

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10 p.m. DJ Ninja Retro Dance Party Aunty Mo's Lounge

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previous columns

July 3, 2008

Lagoons and Beaches

Lagoons Shelter Cove Much of our coastal topography is generated ...

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June 26, 2008

Alien Plants

Pampas grass (Cortaderia selloana).Photo by Don Garlick. Which are the ...

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June 19, 2008

Our Mattole Canyon

Just west of Cape Mendocino there exists a submarine escarpment ...

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  • Diagram by Don Garlick. Diagram by Don Garlick.
Pupal Memories

Pupal Memories

By Don Garlick

I remember watching a chick emerge from an egg. It was miraculous. I have also seen a mosquito dragging itself from its pupa, standing on water for a moment to inflate its wings, and then flying away in search of blood. It was equally awesome. I mention the mosquito to quell the enthusiasm of those who think that miracles created all life.

I herein explore insect metamorphosis in more detail, inspired by experiments regarding learning and memory. Insects mature though stages, called instars, separated by molts. Some insects undergo a spectacular transformation from larva to adult imago, while encased in a pupa. Such holometabolic insects include beetles, bees, butterflies, moths, flies, fleas and mosquitoes. Examples of insects that mature more gradually are grasshoppers, dragonflies, cicadas and aphids.

To quote the New World Encyclopedia: “In the pupal stage, the insect excretes digestive juices to destroy much of the larva’s body, leaving a few cells intact, while groups of cells, called imaginal disks, develop into tissues of the adult, using the nutrients from the broken down larva.” I was astonished, therefore, to learn of the following experiments by Douglas Blackiston, Elena Casey and Martha Weiss (Dev. Bio. July 2006 and Plos.org March 2008):

“During metamorphosis, insects undergo a drastic re-organization of the body; including widespread cell death and the proliferation of new tissue. The present study examined the ability of memory to survive metamorphosis, from the larval to adult stage, in Tobacco Hornworm Manduca sexta. Fourth instar larvae were electro-shocked in the presence of ethyl acetate to generate an odor avoidance behavior. Larvae were assayed for learning in a Y-choice chamber, and were additionally assayed as adults to assess if memory persisted through metamorphosis. Larvae demonstrated strong aversive learning, which was retained in subsequent adults. These are the first studies in Lepidoptera demonstrating memory through metamorphosis.”

So, we gain an appreciation for the learning ability of caterpillars and are astonished by the persistence of memory through a drastic redesign and restructuring of their bodies and lifestyles. The brain must surely retain some integrity during the process. Go find a Tomato Hornworm in your garden, teach it a trick like bright-light avoidance, guard it through the three weeks of metamorphosis, watch in amazement as it bursts from its pupa, and then test whether your moth resists its inherent tendency to spiral into bright lights.

comments

1. svemir:

July 11, 7:23 a.m.

This is indeed thought-provoking. I am glad our work at New World Encyclopedia was of some help. The quote above is from the Metamorphosis article.

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