Invertebrate Inquiry (The Mystery of the Sawfly)


Sylvie Archambault, UBC Teacher Candidate

As part of my Bachelor of Education degree I spent 3 weeks volunteering with the Landed Learning Program.  During this time we were asked to develop curriculum out of the questions that arose for us during the 3 weeks.

The issue:

When nature becomes the classroom, new and unique perspectives of education flourish. Students take an active role in their education by participating in exciting hands on motivational initiatives which are academic, imaginative and enjoyable.

As we learn in nature, we quickly recognize the different beings that form our planet and how we are interconnected. Everything in the universe is a part of a single whole. Whether you’re a human, an animal, a plant, a rock and invertebrate or water to name a few, we are all united and dependent of each other. This fact highlights the importance for students to understand and respect all forms of nature and discover in innovating ways our reason of existing and our different life cycles.



Invertebrate species are integral parts of the ecosystems in which they live. They are important as members of our food webs, as decomposers, and as pollinators woven in mother earth’s life cycle. While they may be considered pests in some circumstances, all invertebrates are equally important for our planet’s survival. Communicating this reality offers the opportunity for students to reflect on their own existence while exploring an invertebrate with their senses, imagination, and hopefully expose them to their environmental responsibilities.

The story:

Inquiring on an invertebrate in a holistic, reflective, experiential and relational setting offers students a hand on experience while investigating its life cycle. During my Community Field Experience at UBC Farm, I had the privilege to discover and understand the life cycle of a small creature inhabiting a beautiful gooseberry bush. The gooseberry sawfly also known as Nematus ribesii appears in April and May and ongoing till October. Usually they appear at  distinctive times during that time (June and August).

The sawfly is named for its saw-like teeth, which the female uses to insert eggs (1.2 mm) laid in rows on the underside of leaves, each held in an incision made in a major vein of the leaf. The eggs then hatch 8-10 days later.

Sawfly eggs are laid along the veins of this jostaberry leaf.

At first, the larvae, live in flocks near the bottom center of the bush, enjoying gooseberry leaves and developing quickly during a period of 3 weeks. Half way through this phase, they disperse and feed on the remaining foliage.

They pass through four (male) or five (female) instars and then molt to an active non-eating prepupal phase.

When I began this inquiry, I could not find the sawfly pupa and this was the great mystery.

These sawfly larvae devour jostaberry leaves, leaving only the veins.

In a 15 minute exploration, I guided small groups of students to observe, and inquire into the life cycle of the sawfly. The objective was to have them inquire on the last phases of the invertebrate and use prior knowledge and direct experiences with nature to help them better understand its cycle. The activity went as follows:

Students observe sawfly life cycle using photos and in situ.

  • Brief exploration of the roles of invertebrates on planet earth and the different types in the Pacific Northwest;
  • Exploring prior knowledge of an invertebrate and its life cycle (examples: butterfly);
  • Introduction to an invertebrate currently invading a gooseberry bush at UBC farm (sawfly);
  • Observation of the gooseberry sawfly (Nematus ribesii) life cycle through photos
  • All students are invited to explore the gooseberry bush and find samples of its life cycle while referring to the images available to them;
  • Inquire about the prepupae and pupa phases and predict its shape, form, location, etc.
  • Students brainstorm on their hypothesis related to the answers related to the life cycle of the gooseberry sawfly;

It took some research to find out why we couldn’t find the prepupa and pupa stage. Prepupae poke into the soil as deep as 10 to 15 cm and build a dark brown, oval cocoon called the pupa phase. After a week underground, the adult takes another week to emerges from the ground and start their new journey with a set of wings. We did eventually find pupa casings directly beneath the jostaberry bush. The casings were open and we assume the flies that laid these eggs were inside!

These pupa casings were found in the soil beneath the jostaberry bush.

A wasp eats a sawfly larva.

Although it would be easy to say the sawfly larva are pests, we also learned that they are an important food source for wasps. We wonder what other roles they play in our food web!

Possible Extensions

Following this life cycle example, teachers might go deeper with this experience by engaging students in storytelling about the life cycle of invertebrates. Have students imagine shrinking down until they are the size of their invertebrate and imagine which part of the life cycle they would be.

Inquiry questions:

Where in the garden might you like to live?

Where were you born?

What do you look like?

What does the garden look like from your height?

What might you eat for a snack?

What things will you look forward to as you grow into an adult?


The students can choose their preferred invertebrate or work in teams, observe its cycle in nature, if possible, engage in discussions with teammates, and create a legend or story that illustrates that invertebrate’s life cycle. Students may interpret the cycle via storybook, comic book, diary, play or even with felt boards, yarn and objects found in the invertebrates’ environment.


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