Whats Bugging You?

Whats Bugging You?Designer Larvae

Day 1

Time! As you come into class, go directly to your team and talk about the two items below. How much do you know about them?

Invasive speciesLarvaeInvasive SpeciesThese are species that do not occur naturally in an area. Their introduction into that area causes economic or environmental harm.

One example of an invasive species is the Cabbage White Butterfly.

LarvaeThis is a larva of the Cabbage White Butterfly. Larvae are newly hatched insects that are wingless and often wormlike before they change into adults. This particular larva is causing quite a problem in the South.

ALERT! ALERT!Student Agricultural Engineers! We need you to solve this problem.

Stop the destruction of crops by the larvae of the Cabbage White Butterfly larvae!

5Larvae of Cabbage White Butterflies

Crawl on the stems and leaves, and eat the leaves of plants like cabbage, broccoli, cauliflower, collards, and kale.

Are green and hard to see on the leaves.

Are small about an inch long and not highly visible.

Have some natural predators that will eat them if they see them.

The students will use this information to help them decide which characteristic is beneficial to reduce the impact of the CWB on the Cole crops. They need to think about which gene is important in slowing down the reproductive cycle.6Your Engineering ChallengeYour team will decide on some traits that might be altered to prevent the larvae from successfully feeding and surviving.

Genetic Engineering, Inc. will alter the butterflies DNA to produce the traits you asked for. They will send you two parent butterflies.

Your Engineering Challenge continuedYour team will then breed the genetically engineered butterflies and select larvae that will be the least likely to survive and destroy crops.

Each team will construct a model of the larva it produced that is least likely to live and damage crops.

Engineering Design Process

Traits to Alter or not!We are going to look at 6 possible traits that you might ask a Genetic Engineering, Inc. to alter.

Your teams job is to select traits to make the larvae less likely to survive and reproduce. Body Size and Color

11Legs

Eye Spot

Whats Bugging You?Designer Larvae

Day 2Traits Carried by Parent ButterfliesModel A (female)

2 antennae small body green in color long legs smooth feet eye spots

Model B (male) 4 antennae large body white in color short legs hooked feet no eyespot

15Larval phenotypes and genotypes present in the parent butterflies Parent A (Female)Parent B (Male)2 antennae AA 4 antennae aasmall body bb large body Bbgreen Tt white tt long legs ll short legs Ll smooth feet gg hooked feet Ggeye spots ee no eye spots EECapital letter = dominant trait; Lowercase letter = recessive trait.

Create 3 LarvaeTo randomly select genotypes of the offspring (the larvae), place a small paper clip on the pointed end of a pencil to make a spinner. Place both the pencil and paper clip on the circle at the center of the Punnett square.Thump the paper clip with your finger to make it spin.This spinner will decide which parents genotype is used in the offspring. Record the genotype on the Create Larvae page. Repeat the procedures until your team has 3 larvae.