BiodiverseCity St. Louis

Tiger Mosquito (Aedes albopictus)

This Southeast Asia native gets its vivid common name as a voracious all-day biter with distinctive stripes. Like all mosquitos, only females have the equipment to bite, the proboscis that male mosquitos lack. They “feed” on the blood of an animal host to get protein needed to produce eggs, so blood “meals” are a reproductive strategy, not nutrition. Mosquitos eat nectar from flowering plants, which means they are pollinators! Good to know—as you swat them.

Tiger mosquitos were first noted in the U.S. in Texas in 1988. Within 10 years, according to the CDC, this species was active in nearly 680 counties in 25 states. Documentation of their original spread from southern and California port areas into regions along interstate highways suggests that global container shipping was the travel agent for this (and other) tropical mosquito species to colonize temperate zones.

In fact, tiger mosquito females lay eggs on the sides of containers, just above a water line. Dehydrated eggs can stay viable for up to eight months! Eggs hatch when water rises, helping juicy new larvae survive in surface-feeding predators. Buckets, plant saucers, clogged gutters and your dog’s abandoned frisbee are all excellent breeding sites. One small grace from this habitat preference: Aedes albopictus is unlikely to reproduce in your yard’s soggy soil, so removing or inverting containers is a prime control for tiger mosquitos.

Also called the forest mosquito, Aedes albopictus lives outdoors as what’s called a cafeteria feeder, thriving on animal or human prey. This mixed-meal existence makes this species the least competent vector of diseases most effectively transmitted by its cousin, Aedes aegypti, an exclusively human-feeding, indoor dwelling and similarly striped fellow invader. St. Louis public health officials are on the lookout for A. aegypti, spreading north from ports of entry but not here yet.  

Both these Aedes species are small, about ¼″ long, and vividly black and white, but it’s easy to tell them apart: A. albopictus has one white stripe along its head and back; an A. aegypti head and back will be marked with a white lyre, the shape of a small harp. These mosquitos can transmit Zika Virus, Chikungunya and Dengue Fever, serious health concerns that necessitate a serious and ecological response.

Adult tiger mosquitos are active all day. Other species that can’t tolerate midday heat only feed at dusk and dawn, the times we’ve been traditionally told to stay indoors for mosquito bite protection—and when municipalities tend to do chemical fogging. Tiger mosquitos are here to stay, so we need to adapt our strategies. This includes understanding that fogging only affects flying adult mosquitos; fogging has NO EFFECT on aquatic mosquito breeding, as it pumps out death to beneficial insects. Money and lives are wasted.

Culicidae, the mosquito family, has over 3,500 unique species, but only a couple of species in three genera—Aedes, Culex and Anopheles—can be vectors of human diseases. Dragonflies, bats, birds, fish and amphibians all eat mosquitos, making them crucial food web contributors. Taxonomists classify them within Diptera (“two-winged”), the fourth-largest order of insects which includes all true flies. Dipterans’ membranous front wings are their aerodynamic surfaces; hind wings of bugs in this order have evolved to be small, club-shaped structures called halteres that vibrate during flight, working like a gyroscope to help the insect’s balance.

Tiger mosquitos don’t fly far from their breeding site, only about 300 feet. They can live in this kind of limited range because they have a diverse range of prey. Like most mosquitos, they are weak flyers. You won’t find them biting on a windy day. Use this limitation to your advantage: plug in one or more electric fans around outdoor seating areas to be refreshed by their breezes while your gathering stays mosquito-free.

All Dipteran larvae are aquatic, and all mosquitos need standing, stagnant water to progress eggs through their larval and pupal stages. They become terrestrial, flying insects for their brief time as adults. Males live to mate, only 3–5 days. Tiger mosquito females can live for 4–6 weeks and lay over 100 eggs at a time through multiple breeding cycles. After blood feeding, a female will rest for a few days to digest and develop eggs.

Most mosquitos morph from egg to adult in 7–12 days. This cycle accelerates to 3-5 days in very hot weather, 90s and up. All larvae feed on decomposing plant matter and microorganisms as they grow through four instars. These “wigglers” are easy to spot—and dump!

When you can’t eliminate standing water, you can treat it with Bti (Bacillus thuringiensis israelensis), a bacterium that occurs naturally in soil spores. It’s not synthetic and it only affects dipterons. Widely available and affordably sold as Mosquito Dunks, this stuff changes water chemistry, so mosquito larvae guts explode. Literally. Nature is so cool.

Aedes albopictus shares an extraordinary range of sensory capacities with all mosquitos, including primary attraction to a blood meal host by the CO₂ exhaled by all vertebrates. As a species that may feed on humans, the tiger mosquito then detects the long red-orange light wavelengths emitted by human skin, regardless of skin pigmentation. From a distance, mosquitoes are visually attracted by dark colors; hence our “light colored clothing” guidance during mosquito season. Fragrance attracts them too, so summer is a good time to go fragrance-free with products like detergent and body wash. Hygrosensation guides a female toward the humidity of standing water. In a typical yard or park with multiple species, sex pheromones help a mosquito find a con-specific mate.

Technically, mosquito repellants work by blocking some of the sensory cues the insect uses to find the body chemistry of preferred blood-meal prey, or because mosquitos dislike their odor. In practice, spraying on a repellant is like wrapping yourself in an Invisibility Cloak.   

U.S. EPA now recognizes eight repellant ingredients as being safe and effective, including Catnip and Citronella Oils and Oil of Lemon Eucalyptus alongside DEET and other synthetics. We all emit CO₂, but because body chemistry varies from person to person, and can change as we go through life, it’s useful to test repellants and keep a few kinds on hand. Plant-based DEET-free products are now readily available. Find a formula that works for you and use it!   

Our region’s longer, hotter summers and shorter, milder winters mean that climate change gives tiger mosquitos (and their kin) a long warm welcome. Here’s how you can chill their impacts:

• Wear loose, light-colored clothing when working outdoors. Long pants, long sleeves.
• Use mosquito repellant! Keep a basket of several kinds on hand for summer play and gatherings.
• Plug in an electric fan when sitting outdoors. Fan breeze will keep mosquitos off—and keep you cool!
• Find, dump and remove containers around your property to eliminate the standing water mosquitos need to breed. Treat water you can’t remove with Mosquito Dunks.
• DON’T resort to chemical fogging! Bug spray kills bugs, period. Don’t fall prey to advertising claims, fogging WILL harm pollinators.
• Educate your local officials about ecological mosquito control. Talk with your neighbors too.
• Garden with native plants to attract and support a variety of mosquito predators. Biodiversity is Nature’s tried and true mosquito population control.
• Join the Citizen Science project, Mosquito Alert STL, to help local public health agencies monitor and responsibly respond to mosquito activity.

Learn more at www.mobot.org/MosquitoAlertSTL.

—Jean Ponzi
Green Resources Specialist, EarthWays Center of Missouri Botanical Garden

New Grow Native! Guide “Native Plants for Stormwater Management”

Mosquito Alert on HEC-TV

Assessing Missouri wildfire risks

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Metro East expands bike trail connections

East-West Gateway’s Greenhouse Gas Reduction Plan technical draft open for public comment through July 18th

Tornado tree damage and deadly summer heat

Tower Grove Connector path upgrades cycling safety

Become a Community Stewardship Alliance ambassador with Open Space STL

One Water Missouri: Connecting Communities

Did you know that thirty-one states and two Canadian Provinces, drain into the Mississippi River? Use this watershed map simulator to learn how a raindrop in your backyard flows through your watershed and ends up in the Mississippi River.

Our actions near the river, such as in the St. Louis area, directly impact the river’s health. Over the past 50 years, the amount of nitrogen and phosphorus pollutants entering our nation’s waters has increased. Too much nitrogen and phosphorus can negatively impact human health, aquatic ecosystems, and the economy. Nutrient pollution of the Mississippi River is the leading cause of the formation of hypoxia in the Gulf of America. Hypoxia, or low oxygen levels in water, happens when there isn’t enough dissolved oxygen to support most aquatic life—like fish, crabs, and shrimp. Nutrient pollution has become one of the nation’s costliest and most challenging environmental problems.

Missouri Botanical Garden’s Sustainability Division is partnering with Ducks Unlimited, Missouri Department of Natural Resources, and BFA Engineering to increase awareness among urban and rural residents of Missouri about the Gulf hypoxic zones.

Clean water starts with you, no matter where you live! You can help improve water quality in your community by implementing rainscaping, sustainable landscaping that reduces stormwater runoff with features such as native Missouri plants, permeable pavement, and rain barrels. Native Missouri plants have deeper root systems that absorb stormwater where it falls and never require fertilizers that lead to excess nutrients in waterways. Learn more about rainscaping on Missouri Botanical Garden’s website.

This project was funded by the Missouri Department of Natural Resources through the U.S. Environmental Protection Agency.

On May 15th, The Missouri House of Representatives passed Senate Bill 105 to halt the sale of select invasive plants by a vote of 124 to 19. The law will halt the sale in Missouri of six invasive plants: Sericea lespedeza, burning bush (cultivar ‘Compactus’), Callery pear, Japanese honeysuckle, perilla mint, and wintercreeper (variety Coloratus). Learn more about the bill.

Missouri Governor Kehoe has until July 14, 2025 to sign the bill into law.

If you are so inclined, write a note of support to Governor Kehoe, letting him know how important this new law will be to Missouri and all Missourians, including you.

The Light Eaters by Zoë Schlanger

Covering climate change for seven years, science journalist Zoë Schlanger was burning out. She sought refuge reading academic botany journals—and her interest revived like lichen in fog. The Light Eaters, her 2024 pivot-project book, made a pipevine climb up the New York Times Bestseller list, subtitled with kindred feeling and biodiversity-restoring intent: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth.

Schlanger tracks changes in the sacred objectivity of science, stepping into suspect stuff like “consciousness” for plants! She didn’t totally flee from distress. For some science types, this realm is equivalent to flood-and-fire upheavals, but she’s confident that the focus she’s found is “the most exciting thing to happen in a generation, depending on how comfortable you feel with seismic shifts in what you once thought to be true.”

As a diligent science writer will do, Schlanger enters the exploration of how plants communicate and facilitate community thriving by visiting labs, conferences and field sites. Discovery! Turns out she’s reporting on an evolution in Botany itself, as a theme through individual scientists’ work:

“…epiphanies in plant science, and the struggle along the way over how scientific knowledge is made…a glimpse of a field in true turmoil, debating the tenets of what it knows, about to birth a new conception of its subject.”

The force in this genesis is nothing less than fierce debate about Plant Intelligence. Schlanger take us ringside to an academic ruckus, where she knows the stakes and the rules:

“Plants don’t have brains, as far as anyone can tell. But, some posit, they should be considered intelligent regardless, based on the remarkable things they can do. We determine intelligence in ourselves and other species by inference—by observing how something behaves…so it’s illogical, a sign of unreasonable zoo-centric bias, not to ascribe the language and functions of intelligence to plants.”

She spends time with botanists who are grappling with questions about plant intelligence within a system of knowledge that, as she well knows, can’t ask questions about something it doesn’t see as existing in the first place. It’s a willingly brave embrace of schismatic shift in scientific dogma. Talk about being in a climate of change!

One is Monica Gagliano, a plant scientist who Schlanger says is occupying a precarious space in the sciences right now. She’s responsible for a paper that found plant roots could hear the sound of running water in sealed pipes. “Hear” in this case means physically sensing the acoustic vibrations, through a physical stimulus. Every human music lover physically hears, with a brain in the chain of vibrational and electronic exchanges. So what does “intelligence” mean if plants, who don’t have what we call brains, deliberately, rapidly move their roots toward that running water sound?

“The game changed (for Dr. Gagliano) when she published a memoir describing how the structure of her lab experiments were given to her through her interaction with a plant, ayahuasca. There’s a real separation of church and state in sciences. She still has a lot of support from humanities and other funding bodies, but that is no longer the purview of the straight science that peer review works with at this point.”  

With enthusiastic curiosity, Schlanger spotlights a cultural shift in the sciences, recognizing the value of lessons from traditional ecological knowledge, aka TEK or Indigenous science:

“…broadening our scientific imagination to include plants as creatures that have spontaneous, willful, so to speak, behaviors. This is not news to Indigenous Sciences. Thinking of plants as having lifestyles and proclivities and dealing with multiple variables in their environment to make very quick dynamic choices—these are all things that Indigenous sciences and belief in plants as persons of a kind have always held to be true…there is this interesting bridging going on, and I think it’s a really exciting time in the plant sciences because of it.”

I discovered Zoë Schlanger and this work through her December 2024 interview with Emergence Magazine, one of my top five online bookmarks. There she said:

“I think the more time we spend considering the ways our lives are absolutely interwoven with the non-human, the more it settles us back into our rightful place in the world in terms of not being just this pinnacle of evolutionary hierarchy but rather being just one more node of biological creativity.”

Without hammering the point, Schlanger firmly de-colonizes the human exceptionalism that holds us to be superior to all other kinds of beings (and many within our own kind), buttressing (some) humans to dominate everything.

The Light Eaters affirms that something must, and is very well about to, change how science—an entrenched global human institution—approaches and relates to our massive, ancient sister “kingdom.” How, this book implicitly asks, might such a change with respect to plants change us?

I think of “weeds” sprouting through concrete, of trees thriving on sheer rock, of the fact that Fungi has only been acknowledged as a unique taxonomic kingdom since 1969. And that Ecology, as an official discipline, and I are just the same age; getting old for a person, darn new for a science, especially one willing to look at life through the prism of relations versus poking into pigeonholes. Most encouraging to read this super-fun report, from creative margins of some ossified spheres!

How fortunate for us, and the scientists whose stories she vividly tells, that Zoë Schlanger’s consciousness laid her “weary apocalyptic attention” in the leafy lap of plants. Her experience of changes in the Plant Science climate can help evolve our worldview, and gave her life a positive, richly useful new lease:

“Now when I gaze around (at any plant communities) I see more than a soothing wash of green. I see a masterclass in living to one’s fullest, weirdest, most resourceful potential.”

Harper Collins 2024, now in paperback from Harper Perennial Buy it from your local independent bookstore or go to the library!

—Jean Ponzi
Green Resources Specialist, EarthWays Center of Missouri Botanical Garden