Tuesday, April 3, 2018

What do we know about flying ants?

When I began my research career I had the snobbish idea that I would not study a particular organism, site, or system.  I would instead come up with a grand question, and study any aspect of the world I needed to in pursuit of the answer.  This, I thought, was the way real scientists work.

Nearly a decade in, I have mostly tossed that archaic idea.  Rather than imposing ideas upon the world, I am more productive when I let nature guide me.  The best way for me to discover is to pick one thing in the world around me and try to figure out how it works.  Each answer reveals more questions, setting off a chain reaction of discovery.  An added consequence of this inspiration from the world is love for it.

I have come to realize, for example (despite my earlier snobbish pretensions), that I love ants.  Queens in particular—the mothers, explorers, and true individuals of ant societies.  I don’t just mean that I find them interesting or practical to study (although they are endlessly fascinating and useful).  When I see them in the wild, read about them, think about them, I get pangs of excitement and sympathy.  I occasionally dream about them.  On optimistic days, I even dare to think I understand them.

In most ant species, young queens have wings and fly to find mates or disperse to new nest sites (Aphaenogaster flemingi queen, photographer April Nobile, from AntWeb)

About a year ago, letting my mind wander during a particularly boring meeting, I realized I had devoted a good chunk of my life to understanding what it means to be an ant queen.  I spent years trying to wrap my mind around that dangerous part of their life when they leave their birth nests to fly through the atmosphere to find mates and new homes.

“The swarms of some ant species are among the more dramatic spectacles of the insect world.”
Bert H̦lldobler & E.O. Wilson РThe Ants

One of the only other people to devote their research so thoroughly to ant flight was the 20th century ecologist Mary Talbot.  And our knowledge of ants has advanced a lot in the decades since Talbot’s pioneering work.

“…the brief interval between leaving the home nest and settling into a newly constructed nest is a…dangerous odyssey that must be precisely timed and executed to succeed.” – The Ants

My idle musings led eventually to a review paper, published recently in Myrmecological News.  In the paper, I use new conceptual developments to weave together all that we know about what flying ants do in the air.

“No encompassing theory exists to explain the extreme variation in the patterns of mating behavior so far observed.” – The Ants

Several discoveries stand out.

Queens face hard choices.  They can, for example, choose to store lots of fat and protein in their bodies before they leave their nest to fly.  Doing so makes it easier to survive alone while they are trying to rear their first offspring.  But it may also make them less able to evade predators, find mates, or discover a suitable home.

Queens carry heavy burdens.  The pressure to load up on nutrients and still be able to fly has led to the evolution of extreme weight-carrying ability.  Some ant queens can carry ~1.5 times as much weight as other flying insects.

Ants can fly longer than we thought.  Some queens can fly for over an hour straight and some males may fly repeatedly over several days or weeks.  Queens of some species occasionally fly 20 miles in one go.

Ants are part of the atmosphere.  Queens and males enter the atmosphere in their millions, flying high to find mates, ride on air currents, and search for new homes.  There they form a major food source for birds, dragonflies, bats, and other predators.  They also transport energy and materials, including toxins like mercury, long distances across landscapes or among food webs.

I have spent much of my career trying to understand what ants do in the air (Dorylus driver ant male with author, photographer Alex Wild)

There is still much more that we don’t know about ant flight, especially when you consider that there are probably over 20,000 ant species in the world.

“…the reproductive behavior of ants is still a poorly explored domain with rich possibilities for general evolutionary biology.” – The Ants

In other words, there’s plenty of room for me and everyone else to continue exploring (and loving) ant queens.