Whangarei student's plastic-eating caterpillar project wins science fair

Alexia Laybourn next to her winning display at the Central Northland Science and Technology Fair. Photo/Supplied

A Whangarei student's fascination with bugs - including one that eats plastics - has got her to the top of the science fair again.

Lexi Laybourn's project, called Greenie Grub, scooped her the overall winner prize at the Central Northland Science and Technology Fair for the second year running as well as the Best Overall Investigation.

"It was inspired by a Spanish scientist called Dr Federica Bertocchini. She discovered wax moth larvae, which is a pest, can eat through plastic.

"I wanted to utilise this idea to maybe help locally in the home to reduce plastic."

Whangarei Girls' High School student Alexia Laybourn won the best investigation award and was named overall fair winner. Photo/Supplied

In particular she wanted to target polyethylene, a common plastic which is used to make plastic shopping bags.

The Whangarei Girls' High School student said the aim of her project was to work out the types of plastic that would be degraded by wax moth larvae, and how efficient this would be. To test it, she put the larvae inside a plastic bag, tied it up, and left them for 48 hours.

"They had eaten it, most likely to escape, but they had eaten it."

The Year 10 student thought it was the enzymes in the larvae which were breaking down the plastic. So she created a mixture called homogenate by crushing up the larvae and spread it across the plastic.

"By the end of the 48 hours, the plastic was softer, which proved it was the enzymes."

She said that in the future, this could lead to a way to dispose of plastic in the household.

Ms Laybourn's dad is a beekeeper and she has always been fascinated by them - doing bee-based projects for the fair for the past three years.

"For some reason I'm quite drawn to the bugs, I just find it quite fascinating what they are capable of."

The larvae are a risk to beehives, and can eat through the honeycomb. Ms Laybourn bought her larvae from a supplier in Auckland. She did try to breed her own larvae using a bee-less hive, but the temperature was too cold at this time of year.

She is only the third person in the fair's 39-year history to win consecutive overall winner awards. The first was Whangarei Boys High School student Matthew Sothern in 1992 and 1993. Sarah Snell holds the record, winning it three years in a row from 1994 to 1996.

Ms Laybourn is not sure she will win it again, but is hoping she can win the consistent excellence award in Year 12.

The 15-year-old is not completely sure what she wants to do for a career, but said science is definitely an option.