If you want to attract dragonflies to your garden, there are several ways to create a habitat to bring these brightly colored creatures zooming, hovering and darting across your landscape. Two involve smart planning; the third requires a bit of luck.
One planning strategy is to build a water source such as a small pond. Dragonflies — the ancestors of which are among the Earth's oldest insects — are aquatic insects that need a freshwater environment to breed. The second is to provide a food source. A garden with a diversity of plants will serve that need quite well because the flowers will attract a variety of tiny insects on which the dragonflies can feed. A benefit to gardening for dragonflies is that they're aerial predators that devour insects. Not only do they feast on no-see-ums such as gnats, they also help control the No. 1 summertime outdoor nemesis, the annoying mosquito. Their appetite for mosquitoes and their fast-flying ambush acrobatics while on the hunt have earned them the nickname "mosquito hawk."
Where luck comes into play is if you don't have a pond or other water feature in your garden. In that case, you can still attract dragonflies if you're fortunate enough to be near a water source that will serve as a breeding area for them. "Near" is relative for dragonflies, which can travel significant distances in search of food. A mile, for instance, is well within the flight range of most dragonflies.
The good news about gardening for dragonflies is that you don't have to do anything fancy to attract them. "Almost any kind of water source or a diversity of plants both in the water and landscape will do," said John Abbott, chief curator and director of Museum Research and Collections at the University of Alabama. Abbott would know; he's published numerous works and photographs about dragonflies and damselflies that focus on their biogeography, systematics and conservation, and he also creates and maintains water features designed for dragonfly breeding. Perhaps the best thing about creating a dragonfly habitat, added Abbott, is that you don't have to have a big yard.
Here's a checklist of tips to create a landscape for dragonflies that Abbott said should entice them to your garden.
With dragonflies come damselflies
One of the first things to realize about gardening for dragonflies is that you'll also get damselflies, another beneficial aerial predator. Dragonflies and damselflies are closely related members of the insect order Odonata and, at first glance, may look alike. But, said Abbott, it's pretty easy to tell the difference between them.
"Most people, if they are familiar with them at all, might describe a dragonfly as large and robust and a stronger flier than the more dainty and less agile damselfly," he said. But, as with almost anything, there are exceptions. "The reality is there are some very tiny dragonflies and some very large damselflies."
The best way to tell them apart is to look at their wings. "All four wings of damselflies are the same size and shape. Dragonflies, on the other hand, have a broader hind wing than the forewing," said Abbott. Another telling wing characteristic can be seen when they land on a perch. "In Northern America, most dragonflies land with their wings spread out to the side of their body, whereas most damselflies land with their wings back behind their abdomen, so they are kind of collapsed together."
Again, of course, there is a damselfly exception that Abbott said people may notice in some common species that frequent home gardens. That exception in damselflies is called spreadwings, which earned their nickname because they land with their wings at about a 45-degree angle. "They are larger damselflies, so some people may initially confuse them with dragonflies," said Abbott. But if you remember that the wings of damselflies are the same size and shape whereas the hind wings of dragonflies are larger than the forewings, you will be able to tell whether the insect is a spreadwing damselfly or a dragonfly.
Why do you need a water source?
Ponds or water features are important in attracting breeding dragonflies and damselflies because both species lay their eggs in water. This begins with an aquatic stage that's usually the longest period of their life. Dragonflies in their immature stage, for instance, are called nymphs and live in a pond or stream for an average of eight months.
"Most people are surprised to hear that," said Abbott. "But that's common with insects."
Dragonflies and damselflies can have a nymphal life span from 30 days to 8 years depending upon the species. One migratory species has a short nymphal life span of only about a month because it follows monsoons and has evolved to breed in temporary rain pools that don't last very long.
As an adult, most species only live for about 4 to 6 weeks. "The adults have a short life span because they are primarily around to reproduce and get their genes into the next generation," explained Abbott. "This is true, the nymph being longer lived than the adult, for most insects for the same reason. It is all about reproduction."
What kind of a water source?
Abbott recommends creating a small pond as the most practical way for homeowners to incorporate a water source into their landscape. Prefabricated liners, for example, are readily available, inexpensive and fairly easy to install. People who are handy at building things could also create a pond using a heavy-duty fabric as a liner. He has co-authored an online manual for creating and maintaining a pond habitat for dragonflies and damselflies that's available through a free download.
If a pond isn't practical for your situation, you can also get creative and make your own water source. "My first introduction to dragonfly nymphs was on a horse farm where I grew up," said Abbott. "Certain species of dragonflies would breed in our horse troughs even though they had no vegetation in them whatsoever and were used exclusively for drinking water for the horses. So, a water feature doesn't have to be super fancy."
But, a water feature does have to meet certain depth and other requirements. Dragonflies are not going to breed in bird baths, gutters or other places where there might be small amounts of water. "They need a little more water surface than that," said Abbott. "Also, the real key is that, ideally, you would have a permanent source of water."
"Obviously, you can do lots of neat things that are visually appealing and that attract other kinds of wildlife as well," Abbott said about water features. "But, the point is it can take on a variety of different traits. There's no one-kind-fits-all sort of thing. There are a lot of different ways to do it."
An interesting fact about dragonflies in the nymph stage is that they are predators even then. "Some large dragonfly nymphs can actually feed on small fish," said Abbott. An example is the common green darner nymph, which can approach two inches in length when fully grown. It will feed on mosquitofish, a group of fish in the genus Gambusia. These fish, which can grow to several inches in length, are sometimes introduced into ponds to help control mosquitoes because they feed on mosquito larvae, explained Abbott.
Won't a water feature attract mosquitoes?
You can be excused if about now you are asking yourself, "Wait a minute. Won't a water feature attract mosquitoes and won't that be self-defeating?" Mosquitoes, after all, breed in small bodies of water. It's a logical question to which Abbott has an answer. Yes, the water feature will attract mosquitoes, but there is an easy solution to stopping them in their watery tracks.
That solution is a mosquito dunk containing Bt israeliensis. Dunks containing Bti (Bacillus thuringienis israelensis) are basically big floating tablets. You simply place them on top of the water, where they will begin to dissolve. "They target mosquitoes, but not other things like dragonflies," said Abbott. "They are a good way to control mosquitoes in garden ponds or bird baths because they won't affect birds or other wildlife while they're helping to control mosquitoes."
The dunks, which are effective for about 30 days, slowly release the biocontrol agent, which the mosquito larvae will eat. The bacterial toxin kills them as well as black fly larvae. Because dunks are selective and biodegradable, they are considered environmentally safe.
What about plants?
Proper plant selection in and around ponds and in landscapes is a key part of successfully creating an environment for dragonflies and damselflies to breed and feed.
"I always say the worst thing you can do is manage a pond like a golf course, meaning just cut down everything and have uniform short grass right up to the pond edge," said Abbott. Proper plant selection is critical for dragonflies and damselflies in the nymph as a well as the adult stage.
Dragonflies are particularly vulnerable to birds and other predators when they first emerge from a pond or stream as an adult. They need a few days for their soft bodies to harden up and for them to become the strong fliers we see in our gardens. Because they are so vulnerable at this stage, they usually emerge at night under the cover of darkness and look for a place to hide. Designing your water feature with both horizontal and vertical surfaces such as rocks and varied vegetation in and around the water will give them those hiding places.
Unlike insects such as the monarch butterfly that need a specific plant on which to breed (any species in the genus Asclepias for the monarch), dragonflies and damselflies do not depend on a specific plant or plant type. "It's more about the form of the plant," said Abbott. "They are aerial predators, so they are feeding on things like mosquitoes. They need places to perch from which they can take off, catch their prey and return. In many cases they also need a perch to use as a vantage point to patrol a territory."
Vertical plants such as at the top of tall grasses or branches or horizontal surfaces in the form of a broad leaf make ideal perch sites. The main thing, explained Abbott, is to mimic nature by providing a heterogeneous environment with a variety of different types and styles of plants so you give dragonflies perching options. That goes for aquatic plants as well in the form of submerger, emergent and floating plants.
"It's more about diversity of habitat than a particular list of plants," said Abbott, adding "I always encourage native plants." But, he conceded, it's not like the dragonfly is going to turn its nose up at an exotic or invasive plant and can't or won't use it.
How effective are dragonflies at controlling mosquitoes?
Dragonflies are ferocious aerial predators that consume all their prey by snatching them in the air. If you are a tiny gnat or mosquito, the sight of one of these creatures with their huge eyes coming at you must be terrifying indeed. While they justifiably have earned the nickname mosquito hawk, there are no hard numbers on how many mosquitoes an individual dragonfly will consume in a day. "But, I think it's fair to say that, given the opportunity, an individual dragonfly could take 100-plus mosquitoes in a day without too much of a problem," said Abbott.
So, if you build a pond with the goal of attracting breeding dragonflies, will you notice a decrease in mosquitoes when you try to enjoy a summer evening outdoors? That's a definite maybe, allows Abbott.
"I think it depends on the specific situation that you have. They certainly help control mosquito populations, but how noticeable it might be is hard to say. If you build a pond and provide the right habitat you'll certainly attract dragonflies. But they may fly off to other ponds, and you might have other dragonflies coming in. It's a very dynamic situation. If somebody has a big mosquito problem, my advice would be definitely build a dragonfly pond and create a dragonfly habitat. I'm all for that. But, also look at where the mosquitoes are breeding. First and foremost, clean your gutters and get rid of anything that would have standing water, and try to get rid of the mosquito source."
Why you see dragonflies on cars
A dragonfly phenomenon you may have noticed is seeing a dragonfly perched on the ornament on your car hood or, if you have a car of a certain vintage, perched on a vertical metal antenna. You may be surprised at why they do that.
"I love dragonflies dearly, but they are not the brightest things in the world," said Abbott. "They have evolved over a couple of hundred million years to find water and lay eggs in it. But it's only been in a very few decades where you have things like automobiles around that basically are fooling them." What's happening is that cars become an ecological trap because dragonflies think they are a body of water.
"The reason for that is dragonflies use polarized light to help them recognize a water surface," explained Abbott. "The paint on cars basically tricks them into thinking they are standing water. To a dragonfly, (hood ornaments and antennas make) a nice stalk, a nice perch that it can patrol from to look for prey, catch it come and back and land on it again." An example of a species that does this is the wander glider (Pantala flavescens). The phenomenon is not restricted to just cars.
Sometimes a black plastic or a black shiny headstone can have the same effect. "Various things like that have been documented as ecological traps for dragonflies, and they will lay their eggs on them," said Abbott. "The eggs, of course, will go nowhere on these kinds of things. It's a well-known situation. In fact, I just got an email from a colleague, Alejandro 'Alex' Cordoba Aguilar, who is trying to document all of the different kinds of ecological traps for dragonflies. He was wanting to know what different kinds of surfaces people have seen dragonflies laying eggs on. But cars are a good example. You see that readily in parking lots. Asphalt can be another one. So, if somebody sees a dragonfly going up and down trying to seemingly lay their eggs on these surfaces, that is what is happening."
Dragonfly resource sites
Home gardeners who are interested in dragonflies and damselflies and would like to identify the species they see in their gardens are much luckier than Abbott was when he began his career.
"When I got into dragonflies professionally there were no field guides," he said. "It was all (about looking at) technical manuals and the scientific literature, the same way every other entomologist looks at their particular groups. You went out and netted the insect, you brought it back, you looked at it under a microscope and you keyed it out.But now there are lots of state and regional field guides which are really great both for dragonflies and damselflies that will allow folks to start to get an understanding of not only the identification but, also, the biology of these insects, which Is really amazing."
Online resources Abbott recommends include:
- Odonatacentral.org “This is a great one,” says Abbott. The site includes a citizen-science element that allows dragonfly enthusiasts to upload information about dragonflies and photos of the insects they observe in their region through a list of approved vetters. Click here to find a vetter for your region. The site also includes a link to a Dragonfly ID Apple app that features bar charts built from the OdonataCentral database of recent sightings displayed on maps, crowd-sourced text, images and more. The app is not yet available for Android users.
- Migratorydragonflypartnership.org This site provides regular monitoring and centralized reporting in the United States, Mexico and Canada, which formed the Migratory Dragonfly Partnership. It is designed to help answer some of the many questions surrounding dragonfly migration and provides information needed to create cross-border conservation programs to protect and sustain the phenomenon. It also includes a citizen-science element that will allow you to submit dragonfly migration observations. An interesting fact about dragonfly migration is that the longest-known migrating insect is not the monarch butterfly. It's a dragonfly, said Abbott. The wandering glider (Pantala flavescens), also known as the globe skimmer, breeds in temporary rain pools as it follows the monsoons from southern India to southern Africa and back, about a 14,000-mile trip through multiple generations. "What's really amazing about this dragonfly is that you have it in your backyard," he added. "It is a species that is found worldwide and is very common in North America. It migrates here as well, though not from India. We still don't know quite what it is doing in North America, but it can certainly go from Mexico to Canada and back."
- A TED talk by marine biologist Charles Anderson in which he explains how he tracked the path of the globe skimmer when he was living and working in Maldives.
- Dragonfly Pond Watch is a volunteer-based citizen-science program of the Migratory Dragonfly Partnership that allows participants and site visitors to learn about the annual movements of five major migratory dragonfly species in North America: common green darner (Anax junius), black saddlebags (Tramea lacerata), wandering glider (Pantala flavescens), spot-winged glider (Pantala hymenaea) and variegated meadowhawk (Sympetrum corruptum). By visiting the same wetland or pond site on a regular basis, participants can note the arrival of migrant dragonflies moving south in the fall or north in the spring, as well as to record when the first resident adults of these species emerge in the spring.
- BugGuide.net This site is not dragonfly-specific.
- inaturalist Another site that is not dragonfly-specific.
There are also dragonfly communities on social media, especially Facebook groups that are regionally defined, that Abbott said are "popping up left and right" that you can join. "There's just a ton of digital resources now where you can get an ID on a dragonfly within literally minutes of posting something on any of these different sites. It's pretty phenomenal now."