Goldenrod Galls

Parasitic Interactions

AnnouncementsDue today:

– Plagiarism exercise on ANGEL• Time lag in grade update

– Group research questions • Hold on to them until end of class. We’ll discuss

and edit.

• Reminder: On syllabus, weeks 8 & 10 are swapped

Goldenrod Galls (p 71-89)

Part I Objectives

• Investigate interactions of parasites, parasitoids and predators with goldenrods

• Develop testable hypotheses and predictions

• Collect measurements

• Begin statistical analyses

• Discuss Group Research Project

Symbiosis• Close relationship between two

organisms

• Types of Symbiosis: Mutualism (+/+)

Parasitism (+/-) Commensalism(+/0)

Goldenrod GallsSolidago spp.

A unique example of parasitism

Movie: The Goldenrod and the Gallfly: The Evolution of an Interaction

Dr. Warren Abrahamson (Bucknell University)

• Host: An organism that is infected with or is fed upon by a parasite or pathogen

• Parasite: An organism that consumes part of the blood or tissue of its host, usually without killing the host

The Parasite Line up

Midge

Gnorimoschema galloesolidaginus

FlyMoth

Eurosta solidaginis

Rhopalomyiasolidaginis

Elliptical Round Rosette

Parasitoids of gallfly larvae• Parasitoid: A parasite that ultimately destroys

its host. Spends a significant portion of its life cycle within a single host. Often 1 specific host.

• Wasps: – Eurytoma obtusiventris & Eurytoma gigantea

Q: Which wasp causes early pupation?A: E. obtusiventris. Wasp lays egg in fly

larvae early in larvae’s development.

Q: How does E. gigantea access the fly larvae?

A: Lays eggs in mature gall.

Predators of gallfly larvae

Predator: An animal that kills and eat animals

1) Beetle larva (Mordellistena unicolor)

Predators of gallfly larvae2) Downy woodpeckers and black-capped

chickadees

Photo: AP

Host

Parasites

Parasitoid Predators

Movie: The Goldenrod and the Gallfly: The Evolution of an Interaction

Informing Scientific Questions

Lab Activity• Come up with a question

– primary & alternative• Develop hypothesis and prediction • Make list of measurements that everyone

will collect• Dissect Galls• Share class data• Analyze your data

Materials & Resources

• Photos & preserved samples of organisms• Keys to determine likely parasite/parasitoid/predator• Dissecting Microscope• Calipers• Hand lens• Tweezers• Paper ruler• Knife • Laptops

Developing a Question

1) Develop biologically interesting question to answer using goldenrod galls2) Determine hypothesis & predictions3) What measurements will you need?4) Check with TA (Alycia)5) Write on board

- measurements needed

How will we collect the data?

• How to measure• Units• Collect nondestructive measures first

• Demo caliper use• Demo gall opening

• Enter in Excel

Your Group Project

• Is your question ecological?• Is it biologically interesting to all group

members?• Do you have enough time to do the

experiment and write it up?• Is your sample size big enough?• How is your budget?• Do you have the proper equipment?

Announcements• Turn in pgs. 87-88 (1 per group)• Submit group research project topic• Clean tables/floors

For next week- Read Goldenrod Gall Lab (Part II) (p 81-86)- Read Inferential Stats (p. 174-190)

- What stats will you use for your data?

Due in two weeks- Article analysis for research project