Promoting native insects via gardening is a worthwhile endeavor that is growing in popularity, but just because native insects are good to have in the garden, that doesn’t also mean all non-native insects are bad to have around. My guest this week, environmental studies professor Kaitlin Stack Whitney, Ph.D., encourages gardeners to examine the reasons why some insects are favored while others with similar behaviors are given a bad rap.
Kaitlin is an assistant professor in the Department of Science, Technology, and Society at the Rochester Institute of Technology in upstate New York, where she also runs the Stack / Whitney Entomology, Environment and Technology Col(LAB)oratory. Her expertise includes entomology — the study of insects — and science studies — the study of how science is done and how science is a human endeavor. She earned a social science bachelor’s degree in international agriculture and rural development from Cornell University and earned her doctorate in zoology from University of Wisconsin-Madison.
Kaitlyn is also a home gardener and a Master Composter, and she was a 2021 Richard P. Nathan Public Policy Fellow through the Rockefeller Institute of Government in Albany. “My background is looking at the environment, but also making sure that we’re looking at ways of understanding and exploring the environment that are beyond the sciences,” she says.
Kaitlin recently penned an essay for the science studies journal Catalyst: Feminism, Theory, and Technoscience that explores the problems with purchasing native ladybugs to provide biological control of pest problems in gardens and questions why non-native ladybugs, which also provide natural pest control, are hated by some. She gets into both topics in our discussion.
Kaitlin says most people who purchase ladybugs do so because they want to do something helpful, namely encouraging beneficial insects rather than using pesticides. But what they don’t realize is that purchasing ladybugs that were caught in the wild can cause harm, she says, such as depleting ladybugs from the area where they are being caught, much like overfishing occurring in an unregulated fishery.
When you get to know the insects that visit your garden, you may find that a number of them are non-native insects that were brought to your area, deliberately or unintentionally, via human activity. But regardless of where they originated, the insect-eating ladybugs living in your garden today are helping to control pests.
“We can think critically about why it is that we are willing to spend money on a native ladybug, but why wouldn’t we just promote the ladybugs that are already around us that can get us that pest control?” Kaitlin says.
How Kaitlin’s Interest in Gardening Grew
Kaitlyn grew up in suburban Long Island, New York, where her family had a beautiful ornamental garden. She became interested in agricultural topics and decided to pursue that field in college, studying not only how food is grown but also how policy affects international food issues. To get more hands-on experience, she started working on a farm while in college and worked on a community garden plot with friends, so she could gain first-hand experience on the things she was reading and learning about.
“Ever since, in the places that I’ve lived, it’s been a pleasure to try to find where there are community gardens and have plots there,” she says. Now that she has a home with a yard, she maintains a front yard vegetable garden — instead of a grass lawn — for her enjoyment and to educate passersby.
Kaitlin became interested in composting by way of thinking of ways to recycle. Today, she is a Master Composter, a certification offered through the Tompkins County Cooperative Extension, based in Ithaca, New York. There are rats where she lives, and she found that using chicken wire to keep the rodents out of compost bins on the ground is not effective. Her solution was to use compost tumblers, which keep the compost inputs off the ground and enclosed. “Nothing has chewed through them or attempted to,” she says.
Ladybugs by Any Other Name
You may call them “ladybugs” if you live in the United States or “ladybirds” if you live in the United Kingdom. And if you’re an entomologist, you probably prefer the term “lady beetle” or “ladybird beetle,” because ladybugs are not true bugs, which belong to the order Hemiptera. Rather, ladybugs fall under the order Coleoptera, which is the order that beetles belong to.
The ladybug family is Coccinellidae, which includes the pest-eating ladybugs we desire in our gardens and also some plant-eating ladybugs, in the subfamily Epilachninae, that are themselves considered pests, such as the Mexican bean beetle (Epilachna varivestis) and the squash lady beetle (Epilachna borealis).
Though pest-eating ladybugs are beneficial in gardens regardless of whether they are native ladybugs or they were imported from another continent, non-native ladybugs often get a bad rap anyway. Kaitlin sought to explore why people are invested in calling some insects “good” and some insects “bad.”
She notes that pest-eating ladybugs make for such great biological control because they are mobile and they are generalist predators — meaning they eat a lot of different things. “That means that if they eat all your aphids, then they can go on to moving and eating something else that’s around,” she says.
Personal Reasons for Gardening Influence Views on Pests
“As gardeners, when we have insects in our garden that are eating the plants that we want, that can feel really personal,” Kaitlin points out.
Gardeners tend to describe the insects’ behavior as “attacking.” She encouraged gardeners to reflect on using “violent, militarized language” when talking about insects that need to eat plants to live.
“It’s easy for us to just think we’re now in competition with those insects or with those pests,” she says. “… They want to eat that plant and we want to eat that plant. We actually have something in common, right? It doesn’t necessarily make us enemies.”
Your reason for gardening will also influence how you feel about insect activity, Kaitlin points out. If you are growing vegetables and flowers for the joy growing brings, you likely have different feelings than someone who is growing plants for food security and subsistence.
Gardeners with other food sources readily available can tolerate aphids eating their brassicas because crop failure won’t make them food insecure. But gardeners and farmers confronting food insecurity or a threat to their livelihood will have less patience for pests.
Enacting pest control measures can be costly for growers to implement, so they consider how the risk to their crops compares to the price of control. In the Integrated Pest Management approach to pest control, this is called the “economic threshold.” The threshold is met when the population level of insects on a crop would cause more financial damage than the price of control.
“Most of the time, those are really only calculated for commercial farm-scale crops, but the idea is that if you were going to do some sort of pest intervention — whether or not that’s adding a biological control agent, whether or not that would be spraying something — you want to do that based on evidence,” Kaitlin says.
When the damage is only aesthetic, like in the case of an ornamental home garden, how much damage is tolerable comes down to the personal preference of the gardener rather than the detriment to the plants.
Harnessing the Power of Ladybugs
When gardeners wish to control aphids and other pests without applying pesticides, they may wish to harness the power of ladybugs as an alternative. Kaitlin thinks that is a great idea, but what she does not agree with is the approach of buying ladybugs.
For one, are gardeners buying ladybugs because they saw one aphid? She urges gardeners to have a plant damage tolerance level that is greater than zero rather than rushing to purchase a control that is not necessary.
And there are a number of other reasons why purchased ladybugs are not a great solution to a pest infestation that rises to the level of needing control. Kaitlin points out that studies have shown that a purchased beneficial insect is likely to fly off to someplace else upon its release — immediately or within two days. And she says the timing can be sensitive and tricky. If a gardener orders ladybugs after noticing a big pest outbreak, the ladybugs will likely be too late to prevent the pest damage. Either way, it was not the best use of the gardener’s money.
Kaitlin says buying ladybugs for pest control is working in the same framework as buying a chemical spray for pest control. Neither is a one-and-done solution, but rather a stop-gap that may have unintentional consequences.
Some insects are reared for pest control in facilities called insectaries. However, the most popular ladybug sold for biological control, the convergent lady beetle (Hippodamia convergens) is generally harvested from the wild in California.
Kaitlin says to think of ladybug harvesting like a fishery. If too many fish are taken away, the population won’t be able to sustain itself and may collapse. If too many convergent lady beetles are harvested in California, there may not be enough local ladybugs around on the West Coast to control pest insects in the wild.
“What does this mean both for the ecosystem that I’m putting these into — my tiny ecosystem of my home garden — and then the ecosystem that I’ve removed these from,” Kaitlin says. “… It’s important to remember that when we’re gardening, we’re often just thinking about our little garden, right? But really at the end of the day, everything is connected.”
The Better Common Names Project
The Entomological Society of America has started the Better Common Names Project to acknowledge that many common names formally adopted for insects contain derogatory terms, include inappropriate geographic references and “inappropriately disregard what the insect might be called by native communities.”
“A lot of times the insects that we are villainizing, we are putting the country or continent of origin in the name,” Kaitlin says, “and this is part of a long and often bad history of conflating people and animals from other places in a way that can be dehumanizing to people and is often xenophobic.”
The project seeks to adopt better common names with the help of community input. For example, Lymantria dispar, formerly known as the “gypsy moth,” is now called the “spongy moth.”
Harmonia axyridis is the scientific name of a ladybug known in the United States as the multicolored Asian lady beetle — a name currently accepted by the Entomological Society of America. In the United Kingdom, it is better known as the harlequin ladybird. Kaitlin makes a conscious choice not to use the common name that includes a continent of origin, and prefers harlequin.
Wildlife and plants from other places are often talked about in ways that can be demonizing, Kaitlin says. “If we actually look to, for example, the history of science, there are documented cases where people from other places and immigrants were conflated with insects from those places in ways that villainize both people and insects.”
The Movement of Plants and Insects
Kaitlin also questions what it means for an animal or plant to be “from” a place. The world is always changing and organisms are on the move. An insect may have lived on a continent 500 years ago but not 1,000 years ago. So what year is the cut-off when differentiating between native and invasive?
She says the concept of nativity for plants and insects arose relatively recently, developed by botanists in the 1800s. And invasion biology was not formalized until about 30 years ago.
“The term native is used in a bunch of different ways, but oftentimes what it means is we’re talking about the boundaries of a country,” Kaitlin says.
Federal agencies in the United States, for example, are concerned about what plants and insects are coming into the country because of what might happen if they spread. Think, for example, of kudzu, an imported vining plant now known as “the plant that ate the South.”
Then there are the plants and insects brought to the United States from other continents that have not had disastrous consequences and are even helpful. Ladybugs are a great example of this because there have been a number of non-native ladybug species introduced to the United States that are welcome in gardens and on farms because they are renowned for their pest control prowess.
In Kaitlin’s home state of New York, for example, there are numerous naturalized ladybug species that came from elsewhere, some that have been living in New York for 300 years, and they are not considered invasive.
Non-native and Good
Gardeners are often given messages — including on “The joegardener Show” podcast — that native plants and native insects are good. Kaitlin says people hear this and assume that the opposite must also be true; that is to say, they conclude non-native plants and insects must be bad. She says this is simply not true.
“We get lots of benefits from insects and plants that are not considered to be native, as in they’re not originally from here,” she says, pointing out that gardeners routinely grow plants that are not “from here.”
The honeybee is the epitome of an insect that is not from North America but is beneficial and beloved.
“Honeybees are not, quote, unquote, from here, but they’re really well adapted to pollinate lots of plants that are from the same part of the world that they are, which is why they make great pollinators of apple trees,” Kaitlin says.
But, she notes, having too many honey bees around can have a negative impact on native bees and other pollinators.
Promoting Ladybugs in Gardens
She says it’s important for gardeners to recognize that they can have an impact and to remember that they can be good stewards of the wildlife moving through their gardens. When it comes to ladybugs, the species gardeners come across may not be the species they were most hoping to find, but those species still present an opportunity for conservation.
Because ladybugs have coloration and patterns that are obviously different from species to species, studying them in your own garden makes for an easy and fun activity. And once you identify the ladybug species that come around your garden, it’s easier to engage in conservation biological control.
Conservation biological control means promoting and attracting ladybugs and other predatory beneficial insects that are already in the area — rather than purchasing biological control insects that were raised in an insectory or wild harvested.
“In New York State, that might mean that not all of those ladybugs that are in the area around me that might show up to my garden are going to be, quote, unquote, native,” Kaitlin says. “And personally, I’m OK with that because if what I’m concerned about is natural pest control, is about not putting chemical pesticides in my garden, then I am getting a benefit from those beneficial insects.”
Kaitlin has a stand-out memory from a college trip during which she and her fellow students were admiring a ladybug that had landed on the side of a van when their professor walked up and smashed the ladybug with his open hand. “That’s invasive,” he said as he walked away.
That moment really stuck with her because up until then, she never thought any ladybugs were labeled “invasive.” She says that the smashed ladybug was likely the harlequin ladybug, which is often viewed as a pest due to its habit of gathering in large groups, a behavior called aggregation, inside houses or under shingles for winter shelter. And some people are allergic to ladybug bites, so they really don’t want ladybugs inside their houses.
All ladybugs bite, not just harlequin ladybugs, and a bite from any species of ladybug can cause an allergic reaction, Kaitlin says. She notes this is something that ladybugs deemed “good” and ladybugs deemed “bad” have in common. And regardless of whether they are native or non-native, ladybugs don’t transmit diseases to humans, the way that mosquitoes or ticks can.
Being generalist predators is what makes ladybugs so good at pest control, but it is also one of the reasons why some see harlequin ladybugs as a problem. Not only do harlequin ladybugs eat aphids and other soft-bodied insect pests, they also eat the larvae of other ladybug species — including the native species we may be trying to promote in our gardens.
Kaitlyn says that, according to the most recent survey, completed in 2007, there have been 179 species of ladybugs released in the United States and of those, 27 have become established.
“Some of that same data found there was no difference in the number of ladybugs overall when you’re comparing before and after the harlequin ladybug becoming established,” she says. “So I think that anytime we’re talking about new life in an ecosystem and the impacts it might have, those are definitely important questions.”
Host-Specific Predators and Generalist Predators
The flip side to generalist predators is host-specific predators. For example, braconid wasps are parasitoid wasps that target hornworms specifically. That makes that effective biological control for tomato hornworms and tobacco hornworms, but not great at controlling other larvae that dine on our crops.
Various host-specific predators have been intentionally released in the United States in an effort to control pests, but it does not always go as planned. One of the challenges that prevent host-specific predators from maintaining a stable population is that once their prey’s numbers are diminished, they don’t have a reliable food source anymore. The predators don’t stick around and wait for another pest outbreak to occur.
Generalist predators can prey on an aphid outbreak, for example, then move around the garden to prey on another pest. So the generalists do stick around.
Getting Past the Good-Bad Binary
Kaitlin notes the scholarly work of University of British Columbia Assistant Professor Jennifer Berneda Grenz, Ph.D., whose family comes from the Lytton First Nation. Jennifer studies invasive plants and wrote her dissertation, titled “Healing the Land by Reclaiming an Indigenous Ecology,” on applying the Indigenous worldview to invasion biology and ecology.
Kaitlin says the baseline that considers what species are native and non-native, and “good” and “bad” erases the millennia of history of Indigenous management of ecosystems.
“It’s really important to go to other thinkers who are helping us think past this good and bad binary,” she says.
There have always been plant and animal species that humans have preferred over others, Kaitlin points out. Gardening is an example of this — promoting some plants over others and welcoming or excluding different wildlife. And what one gardener may consider a weed may be desirable to another gardener, and gardeners also differ on what insects they want to promote.
“It’s okay to have preferences,” Kaitlin says. “It’s okay to say, I want to grow this thing here and I really want to eat this, and I don’t eat these other things.”
A Role for Everyone
You don’t need to own a large piece of land to engage in insect conservation. Kaitlin says even if you only have enough room for a small container garden, you have a role to play. And with no garden at all, you can still engage in energy and resource conservation.
“When you are saving energy and you are wasting less water, you are broadly contributing to the conservation of resources and mitigating climate change and all of that is going to help all beneficial insects,” Kaitlin says.
Conservation-minded gardeners can grow flowers within a variety of bloom times to provide pollen and nectar during all the seasons that pollinators are active. In other ways, conservation means less work, Kaitlin points out, such as refraining from cleaning up leaves and spent plants, which provide a place for insects to overwinter
“Being a lazy gardener is underrated,” Kaitlin says.
You can also think of it as being “intentional” rather than “lazy.” For example, though I know bolted brassicas are not considered attractive in the garden, I leave them in place in May and June on purpose because I know brassicas are one of the few plants that will be in bloom at that time to serve pollinators. What may look like an untidy garden is a boon to insects that are struggling with habitat loss.
If you haven’t already listened to my conversation with Kaitlin Stack Whitney on native and non-native ladybugs, insect conservation and more, you can scroll to the top of the page and click the Play icon in the green bar under the page title to do so now.
What ladybug species do you find in your garden? Let us know in the comments below.
Links & Resources
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“Ladybugs: The (Natural) Enemy of My Enemy Is My Friend? Enlisting Ladybugs into the War on Insect Pests” by Kaitlin Stack Whitney, Ph.D.
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