Very hungry caterpillars very good for biodiversity

Widely considered a pest and a scourge, a leaf-chomping defoliator dedicated to decimating crops, boring into buds and biting down blossoms as it works to satiate its inexhaustible appetite, a new nature documentary reveals there’s more to the much-maligned caterpillar than meets the eye.

The larval creature takes centre stage in Winnipeg filmmaker Jeff McKay’s documentary feature The Extraordinary Caterpillar.

His hour-long film takes viewers on a journey to understanding why the famously “very hungry caterpillar” is a key player in maintaining biodiversity.

“Caterpillars are right at the centre of the food chain, they are key to the food chain working as it should,” McKay says.

Caterpillars play an essential role in Earth’s food webs, passing on more energy from plants to other animals than any other type of plant eater; more than 90 per cent of nesting birds eat only caterpillars.

Since 1970, insect populations have declined by 45 per cent globally, and North America has lost three billion birds. A key culprit is the loss of native plants, replaced by lawns and non-native ornamentals that cannot support local food webs.

“It takes between 6,000 to 9,000 caterpillars to raise one nest of chickadees in the first two weeks of their lives, and that’s just to get them out of the nest,” McKay says.

“The film is a way for people to understand how plants and insects work together. My intention is to bring people into this world of small things we don’t often get to see. A vast percentage of life on planet Earth is smaller than a bee but humans are ignorant to it. We see ourselves as being able to shape the planet to our needs and in the process we eliminate food and shelter for the natural world.”

The filmmaker harnessed the talent and knowledge of a host of experts, including naturalist Sam Jaffe of the Caterpillar Lab, an American educational research and outreach centre in Malborough, N.H.

McKay first encountered Jaffe’s work online and was taken aback by the diversity of the insects. He had come upon caterpillars while researching possible film subjects and quickly realized the importance of the creatures.

Jaffe, the lab’s founder and director, posts caterpillar photographs and videos on the lab’s website, revealing hitherto hidden aspects of the insects.

His work captures the four life phases of the bug — egg, larvae, pupa or chrysalis and finally moth or butterfly — in detail, giving visitors a closer look at, and hopefully a deeper appreciation of, its habits and behaviour.

“When I first saw his pictures I just couldn’t believe them,” McKay says of Jaffe’s macroscopic photography and videos “He has done incredible work documenting every single life stage of each caterpillar in the facility. His beautiful imagery features in the film and anyone who watches is going to see something so spectacular.”

He hopes the film will raise awareness of the role native species of plants play in sustaining food and habitats, and encourage viewers to plant native plants that insects rely on.

The documentary, narrated by a tomato-eating tobacco horn worm, also features experts such as entomologist Doug Tallamy, scientist and author David Wagner and Manitoba-based botanist Laura Reeves.

“Everything is connected and caterpillars are vital because they eat. They do a very important job because they control certain invasive species, or they can help keep native plant species under control, and then they in turn are eaten by other animals, which feeds the food chain up the line,” says Reeves, who was a botanist at Manitoba Tall Grass Prarie Preserve, Gardenton, for 18 years

The preserve is home to 450 native plant species, 18 of which are at risk. One of these is the Western Prairie Fringed Orchid. In North America the largest concentration of the endangered species is in a 100-square-kilometre area on the preserve.

In the film, Reeves breaks down the relationships between the caterpillar and native plants, illustrating how the orchid’s continued existence depends on the survival of a specific pollinator moth, which in turn relies on the northern bedstraw plant, considered a weed by many, as its larval food source.

“We’ve got this moth pollinating the orchid but what are the caterpillars feeding on? The caterpillars aren’t feeding on the orchid; the caterpillars are feeding on a totally different plant, so it’s not only important to protect the flower, you have to protect the whole habitat that that flower occurs in,” Reeves explains.

“Nothing happens if we don’t have plants. Everything relies on everything else. I wanted to the the film as entertaining as I could and to really amaze people because caterpillars are a fantastic vehicle to talk about nature. They are so surprising and wonderful, ” McKay adds.

The Extraordinary Caterpillar is currently streaming on TVO.

av.kitching@freepress.mb.ca