Who is Stronger?

VSModified from www.methacton.org/.../Bess%20Bug%20Lab.ppt

The Bess Bug Odontotaenius disjunctus

Aliases

• Betsy Beetle

• Patent-leather Beetle

• Passalid Beetle

Phylum Arthropoda Class Insecta

Order Coleoptera • Largest order of

organisms, including over 350,000 species.

• One out of every four animals in this world is a beetle.

• They all have hard, shell-like forewings.– A tough protector of the

beetle's delicate hind wings and soft abdomen.

– Protects beetles as they squeeze through narrow passageways and burrow into decaying wood or sandy soil.

It’s Alive!

“The bess bug is alive.” Defend this statement using the biological characteristics of living things..\CharacteristicsofLivingThings_000.ppt

http://www.connecticutvalleybiological.com/isotope/l/L%2051%20bessbug-95bab57e.jpg

Where Does it Live?

• Commonly found in decaying logs from Texas to Florida and as far north as Canada.

• There are only two species in the U.S., while over 500 species can be found in the tropics.

Physical Characteristics

• Large, shiny, black beetle

• 3 body parts - head, thorax, abdomen– The thorax of this

beetle has two sections, allowing its hard body to move more freely.

• 3 pairs of legs– gold-colored fringe

• A pair of feathery antennae

• Small horn and long jaws protrude from the front of the head

Diet

• They prefer hardwood—oak, elm, and other deciduous trees—that is well decayed and falls apart easily.

• Wood is an indirect food source. – Beetles don't have symbiotic

bacteria in their gut that help them digest the cellulose in decaying wood. Bess beetles process wood in their digestive system, and then a fungus grows on the beetles' feces. It is this fungus that give beetles nourishment.

• Larvae eat a well-chewed mixture of beetle feces and wood.

Other Fun Facts• They are social insects and raise young in adult

pairs.• Adults stridulate (shrill sound)by rubbing wings.• Larvae stridulate by rubbing legs.• Males have a prominent horn on their head.• They have 2 pairs of wings but rarely fly.

Lab Purpose

• Observe and calculate the pulling power of a Bess Bug.

• Determine the relative pulling strength of a Bess Bug compared to a human.

• Discuss how strength is an adaptive advantage for insects.

* Brute Strength - How much can you lift/pull/push?

* Relative Strength - How much can you lift/pull/push in comparison to your own body mass/weight?

Strength?

• size (relative to their own body mass)

• muscle arrangement

• muscle attachment

• body structure

• flexibility

• If the bugs are scared or feel threatened, they may not move.

• The harness should be placed between the thorax and abdomen. It should go down their back!

http://www.youtube.com/watch?v=4G2fzRshi18

• The beetle should start on the cloth.

• The Petri dish should start on the table.

Procedure Highlights

Procedure Highlights• Any time the bug moves the dish, add a washer.

• Move the bug and Petri dish back to its starting position if it gets off track. Do not pull or drag the bug. Pick it up!

• Handle the beetle gently and with respect!! Grasp it at the sides.

• Carefully remove the harness and return it to the container at the conclusion of the lab.

http://www.youtube.com/watch?v=GObVTjhuriI

Measurements

• Mass of a washer or penny

• Mass of the Petri dish

• Mass of the Petri dish with beetle

• Mass of the beetle

• Length, width, and height of the beetle

Calculations

• Total pulled of weights

• Beetle pulling power

..\1_Scientific_Method.pptx

Problem 2: Is a Bess Bug stronger than a human? (Hint – you will need to have a means of comparison)

Extra Credit