Nuptial Ant Swarms

After scrubbing the place for a month, our realtor planted a "for sale" sign next to the road and we opened our home for inspection by total strangers. And that very Saturday the ants appeared. Thousands of ants. Millions of ants. Countless numbers of winged ants, raining down from ant clouds in the sky and covering the leeward walls of our lovely home.

Nuptial cloud of mating ants over Lone Pine State Park

Have you ever seen an ant swarm? Gleeful entomologists describe them as massive "nuptial flights." My first one felt more like an alien invasion to this nervous home seller. But by the time I raced back from the hardware store with toxins to spray into my own environment, all of the ants were gone. Vanished.

That was more than a dozen years ago. Just a few springs ago, we watched a massive cloud of tiny ants swarming over the rocky peak at Lone Pine State Park. And a few days ago, our neighborhood carpenter ants launched into their annual swarm here at 3,900' elevation. These are just several of at least 76 different ant species living in Montana. The reality might be double that number.

For some ant species, swarming males and females from different colonies embrace mid-air, tumbling slowly to the ground in a frenetic nuptial fervor. For other species, all of the males from local colonies fly to a specific location and wait on the ground for females to arrive, similar to bird breeding leks. Virgin queen ants land to be mobbed by competing males, but she determines the 1-4 males she'll mate with before ending the tango with a squeaking "female liberation signal" that sends the males scurrying away. She'll fly off to excavate a new nest, and the males will all be dead in a day or two.

One tiny ant from the cloud  photo above

These brief nuptial flights are the penultimate moment for large and successful ant colonies. A major portion of the colony leaves on a high-stakes, low-odds gamble to perpetuate the colony's shared genetics. Some ant species swarm in spring, some swarm in summer. But somehow, all of one species' colonies in a widespread region read the same cues and swarm on the same day. How do they know?

Most ant colonies consist of one queen and her daughters who tend to her, gather or grow food, defend against outsiders, and generally run the nest. Successful queens live for about five years, using sperm stored from her single nuptial flight to fertilize a lifetime of eggs.

Maybe one in 5,000 dispersing queen ants will survive the gauntlet of predators that includes birds, dragonflies, wasps, frogs, lizards, beetles, spiders, and more. But probably the most widespread danger is death from landing in another ant colony's territory, which is viciously defended by female workers.

A rare surviving new queen excavates a nest, lays eggs and raises a batch of daughters. The daughters then take over day-to-day operations and the queen focuses on producing eggs. All of her daughters have the exact same genetics, and the factors that determine which daughters will become new queens are strictly environmental.

Virgin queen carpenter ants ready to fly

Daughters in a small, new nest will never grow wings. That's because the queen secretes chemicals that retards wing growth. But in a large and successful ant nest, winged daughters are produced at certain times of the year. For some species, winged females are produced from larvae growing up when the nest reaches a specific temperature. For other species, it's the amount and quality of food the daughters feed to the larvae that determines which ones will grow wings.

Males, of course, are another story.

Fertilized eggs always produce daughter ants. But unfertilized eggs turn into small, winged males. They only live for a few weeks, and they only have one job. They wait around inside the nest for that fateful day when they'll rush out in a frenzy with their winged sisters. All of the queen's sons leave home in search of females from other nests to mate with during the brief swarm. Only a portion of them will find females to mate with, and only a tiny proportion will win the struggle to pass their genetic material forward.

But if you think about it, every single ant you'll ever see is the direct descendant of an over-achieving ant ancestor. The short ancestor who succeeded in spite of the long odds against it. Is this amazing enough for us to give a little credit where credit's due when our next picnic is interrupted?

Small spider captures a large, winged ant meal

Mummies invade Montana - Again!

(Halloween edition)

Montana is crawling with countless mummies, but not for Halloween. No, our mummy incursion takes place each summer, with all the makings of a low-budget horror/slasher movie.

When melting snow retreats to the mountains in spring, our native plants rise from the decay and set the stage for this invasion. It plays out on dogwoods and wild roses and fireweed flowers. But the scariest seat in the house has a front row view of a common thistle, because thistle is a favorite summer food for aphids.

Small healthy aphids and plump parasitized aphids, inspected by an ant.

Aphids - our tiny (1/32" to 1/8" long), native insects that suck the life fluids out of various host plants. They look sort of ghoulish themselves, but it's the aphids who are fated to become the victims of this gruesome plot.

Aphid populations increase quickly when summer days finally turn warm. A female aphid gives birth to 3-4 live young every day, without input from any males. (In fact, there aren't any males around until some are born in late summer.) Aphid numbers spike, and life looks good for a young female. Of course, this is always when strange things start to appear.

Around the edges of the colony, some of the small aphids suddenly swell up like balloons and start to change color. A week or so later, the plump aphids are dead and all that remains is empty exoskeletons, or what is known as "aphid mummies."

Countless aphids mysteriously turn into living mummies right before our eyes, as their bodies are slowly taken over by a parasitic creature. But by this time, we've already missed half the action. An inconspicuous stranger has already slipped in and out of the scene - a tiny, female wasp (Lysiphlebus testaceipes).

While our clueless aphid is happily slurping up plant juices, the little wasp sneaks up and injects a single egg into the aphid's abdomen. There are seldom any witnesses. The wasp egg hatches two days later, and a tiny grub begins happily slurping up aphid juices - from the inside out. The grub grows larger as it feeds, stretching and distorting the still-living aphid.

The parasitized aphid plumps up, stops reproducing, and stops secreting honeydew (the liquid that ants feed on). It turns a light tan color, and eventually dies 6-8 days after the infection.

When the wasp grub runs out of aphid juice, it cuts a small hole in the aphid's belly. It reaches out and anchors the aphid to a leaf or stalk, using silken threads. Then the grub spins a cocoon and pupates inside the aphid. Five days later, a new wasp emerges by slashing through its temporary host and flying away, leaving behind the crusty husk.

When about 20% of the aphids have been turned into empty husks, the aphid population begins to crash. By this time most of the living aphids have been parasitized - they just haven't been eaten yet.

The plot takes another twist in fall, when snow starts creeping back down from the mountains. When the outside temperature dips below about 60F, the wasp eggs delay their development. But the aphids remain active until the temperature falls below 40F, with some of the aphids overwintering as adults (in diapause, the insect equivalent of hibernation).

During Halloween, a single wasp egg silently hides inside of countless healthy aphids, waiting for the warm days of summer, ready to resume its gruesome incursion.

The re-runs start next June.

An ant searches through the empty husks of parasitized aphids, called "aphid mummies."

Captivating, Catapulting Spittlebugs

Larval spittlebug emerging from its spittle home

If you were ever a kid - as I was a couple centuries ago - then you know how irresistible a mysterious glob of spittle can be.

A golf ball-sized lump of white froth, found clinging to a plant stem in the local weed patch, is a captivating kid-magnet that simply must be investigated. We didn't have the internet or computers back then, and they didn't even invent guidebooks until we were much older. So for years I didn't know if the spittle was made by the plant or by the little bug that we sometimes found hiding in the foam.

Times have changed all of us kids, but the captivating "spittlebugs" remain.

Today we know that spittlebugs (family Cercopidae) are named for the white froth made by the larval stages of this very common insect. We also know the adults as "froghoppers," and as the high jump champions of the insect world, thank you very much. Move over fleas.

But first, about that froth.

Spittlebugs overwinter as egg masses that hatch in early summer. The wingless larvae, about one-quarter inch in size, create the frothy white abodes where they will grow through five moults before leaving home in late summer as adults. As larvae, they feed on plant sap sucked out through a specialized, needle-like feeding tube.

Sugar-rich phloem sap moves down from the plant's photosynthetic leaves, but for some reason the spittlebugs tap into the sugar-poor but mineral-laden xylem sap flowing up from the water-pumping roots. The larvae have to drink lots of liquid to grow into an adult, and therefore they also have to excrete lots of liquid.

So the so-called "spittle" is really a gentlemanly way of saying piddle. It really originates from the other end of the bug. But wait, it gets even better. The larvae also use the tip of their abdomen to, um, "blow bubbles" into this liquid to form froth. What possible body function combination could be more kid-captivating?

The sticky froth serves the spittlebug well. It hides the bug, protects it from parasites, and prevents it from drying out. It also deters some predators (and attracts some boys) with the "yuck factor."

1/4" long spittlebugs require five instars, or larval stages, before turning into adults and leaving the spittle behind.

In one experiment, predacious ants tended to leave the larval bugs alone even after the bugs were removed from their spittle. After touching the bugs or spittle, the ants immediately began grooming their antennae. But when the investigators (three grown-up boys at the University of Wisconsin) rinsed the spittle off, the ants carried most (67%) of the bugs home for dinner.

The ants, meanwhile, are one of our most underestimated critters. While the spittlebugs' froth apparently irritates their appendages, the ants have nonetheless learned how to use the sticky froth to build their own temporary housing. Up in some of the same plant neighborhoods where spittlebugs live, ground-dwelling ants also tend to their herds of aphids - yet another fascinating, plant-juice-sucking insect (more on aphids in a later edition).

Ants defend aphids from predators while drinking the sugar-rich "honeydew" excreted from the aphids' rear ends. Up in the plants, the ground-dwelling ants sometimes build temporary tents out of soil and thatch to corral and protect their aphid herds. What do they use to glue their aphid-tents together with?

Why, spittle of course. Sometimes the ants use rain-soaked soil, but spittle makes a better, stronger glue.

But the ants don't like to touch spittle, so they carry up pieces of dry soil and stick them to the outside of the spittle mass. The spittle gets soaked up by the soil and thatch and, presto, the ants have a tent to camp in and use to protect their herds. Sometimes, this also enables the ants to capture and consume the larval spittlebug.

Ant predation has localized effects on spittlebug populations, but many spittlebugs still piddle their way through youth to become high-jump-champion adults. When spittlebugs reach this golden age, about one month old, we call them "froghoppers."

Three froghoppers on a knapweed bud     

Froghoppers (adult spittlebugs) are golden-brown insects less than one-half inch long. They don't use their wings very often, and they never make spittle for protection from predators. When threatened, froghoppers simply leap away. They also use this Olympian talent to move from plant to plant.

Froghopper jumps have been measured at just over 27 inches high, a little higher than the best flea athlete. But froghoppers weigh in at more than 60 times heavier than fleas. If you compare how much force animals can generate per body weight, froghoppers win hands-down: froghoppers 400X, fleas 135X, humans 2-3X.

During a froghopper jump, the initial acceleration is somewhere in the neighborhood of 8,900 mph. A human astronaut blasting off into space experiences a g-force of 5 gravities or less. Our neighborhood froghopper, on the other hand, generates a g-force of more than 400 gravities on a good jump.

That's substantially more than a little bit impressive.

For a neighborhood bug that lives in a patch of weeds, grows up in spittle, and weighs less than 0.000026 of a pound, the froghoppers posses athletic skills that can impress and inspire kids of any age. If only we lived in a just world, we would see school mascots named, "The Spittlebugs," and professional sports teams named, "The Froghoppers." If only.

As adults, froghoppers turn golden-brown in a variaty of patterns.