Insects are our friends: Here's what gardeners can do to help declining pest populations

·4 min read
A praying mantis was observed on a Shasta daisy this past summer.
A praying mantis was observed on a Shasta daisy this past summer.

Recently, as part of the Master Gardener Program, we saw a video of an Entomology professor in Florida who was an advocate for better education of the public about insects.

He also presented some very interesting research that he has done on how moths evade predation by bats. Both bats and moths are nocturnal and are natural foes. One moth with long swallowtails would sacrifice its tail to the bat in order to live another day. Another moth would emit sounds that confused the bats. It was interesting new research, but the main thrust was about the loss of insect biodiversity.

There are 5 million insect species and their biomass is equal to all the other animals and plants combined. That is a lot of insects.

According to an article in The Guardian, 40% of insect species are declining and a third are endangered. The rate of extinction is 8 times faster than that of mammals, birds and reptiles which are also in decline.

The total biomass of insects is falling by 2.5% a year, according to the best data available, suggesting they could vanish within a century. Butterflies and moths are among the worst hit.

For example, the number of widespread butterfly species fell by 58% on farmed land in England between 2000 and 2009. Researchers say that insects are “essential” for the proper functioning of all ecosystems, as food for other creatures, pollinators and recyclers of nutrients.

This beautiful dragonfly visited my dahlia garden this past summer.
This beautiful dragonfly visited my dahlia garden this past summer.

The reason for this decline is the number of humans and our consumption of habitats for our use to the detriment of other life on the planet. Climate change is also a factor. The conversion of natural areas to agricultural use to feed a growing world population and the widespread use of pesticides are the main cause of the insect decline.

We are nature’s worst enemy and seldom recognize that we are part of nature ourselves and that we are destroying many ecosystems on the planet to feed ourselves. Much of our food supply requires pollinators, so we need them if we like to keep eating melons, chocolate and many other fruits and vegetables.

So as gardeners what can we do to help deter this decline in insects? Kristin Green in an article in "Fine Gardening" magazine suggests that we not clean up the garden in the fall as it used to be the routine, but instead leave plants in place to provide habitat.

“Traditional methods are changing because our priorities have changed: aesthetics are tied to a higher purpose. Gardens, as carefully designed, maintained, and floriferous as they may be, are also living ecosystems, providing habitat and sustenance to all manner of wildlife," she said. "Many gardeners have become naturalists and stewards, more likely to measure success by the number of species of pollinators buzzing around their combinations than by how great those plants look together. Many insects, bees, butterflies, moths, and spiders overwinter as adults, eggs, or cocooned pupae. Some need the insulating shelter of leaf litter; others attach to stems and twigs.”

Amen to that. I am fortunate in having a front-yard that is not in lawn. The previous owner was a Master Gardener who employed a fellow Master Gardener with a wide knowledge of native plants and together they converted the lawn area to native plants which is a great habitat for insects. It has become a wild area that all the neighborhood cats love to explore apparently looking for prey and occasionally taking a lizard home.

In the back garden, I have a passion vine which is habitat for caterpillars of Gulf Fritillary butterflies. Hence I have lots of Gulf Fritillary butterflies visiting the flowers in my garden along with other butterflies such as the Western Swallowtail (Papilio Rutulus), Fiery Skipper (Hylephila phyleus) and Funereal Duskywing (Erynnis funeralis). You can find a long list of butterflies that are found in San Joaquin County here: https://bit.ly/3rt0rqQ.

Observing and identifying insects in your backyard keeps the mind active and engaged in the world around us. I also have observed praying mantis in the garden and they show up quite unexpectedly often on flowers where they are ready to catch pollinating insects. Praying mantises don’t choose between insects beneficial to us versus those we consider pests. Nature has rules that differ from what we humans might wish for. Happy insect conservation in your garden.

If you have a gardening-related question you can contact the UC Master Gardeners at (209) 953-6112. More information can be found on our website: http://sjmastergardeners.ucanr.edu/CONTACT_US/.

This article originally appeared on The Record: Insects are friends: What gardeners can do to help insects populations

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