Tetramorium caespitum

School of Ants collection
Literature record

Tetramorium caespitum

From Dr. Eleanor's Book of Common Ants

A.K.A.: Pavement ant

Size: 0.19 in

Where it lives: Pavement ants most often nest under bricks or pavement, but they are also found in grassy areas near sidewalks and even in extreme environments, like salt marshes.

What it eats: Ultimate opportunists, pavement ants eat anything from dead insects to honeydew, a sugary food leaf hoppers produce. They also dine on pollen, food in your kitchen and garbage.

What’s the big deal?

Wars happen across America every spring. Just as the trees begin to give us their first peek of color and the sun warms us enough to stretch our legs and venture outdoors for a look around, the animals begin stretching their legs too.

Each spring ants peek their antennae out of earthen holes, getting a feel for their new year on the beat. Pavement ant (Tetramorium spE, although it is common scientists have yet to give this species a real name) workers push out of their nests with a mission: to establish their neighborhoods before ants from other nests nudge in and squeeze them out. These ladies are territorial, and they don’t like any other ants walking on their turf. When they first emerge in spring all last year’s boundary lines have been wiped away with winter and all bets are off (Plowes 2008). They draw their property lines with warfare so gruesome it would make Atilla the Hun blush.

Pavement ants are built for battle. At 3/16 of an inch, workers are about half as long as one of your shirt buttons is wide. They are dark reddish-black and have antennae that bulge out at the tips so they look like they’re waving little clubs off their foreheads. They have tough, armor-like skins called exoskeletons that can withstand the knocks of war. If a pavement ant was the size of a dog and you could get a good close-up look, you would see a beautiful landscape. Their faces and bodies are covered with hilly peaks, rivers of grooves and hairs, and they have two little mountains of spines poking out from their backs toward their rear ends.

Where neighborhoods overlap, huge numbers of workers from each side collide. They furiously drum one another on the head with their antennae; they rip one another apart with their mandibles. They’ll separate an individual from the pack and close in around her, gnashing at her body with their jaws, grabbing her with their claws, turning her into ant dust (Plowers 2008, Myrmecos, and ANTWEB). These ants mean business when it comes to setting boundaries. After the melee, the carnage is astounding. Thousands of ants litter sidewalks across the country, a jumbled dark reddish/black line of body parts and pieces that blow around in the wind.

When they aren’t out cruisin’ for a bruisin’, pavement ants move along slowly compared to other ant species as though they don’t have anything to do in this big old world but go for a walk in nature. They won’t sting you, and they aren’t easily spooked. Whereas some ants shoo away quickly, pavement ants usually continue to bumble along unbothered.

Pavement ants are not native to the United States, but they are one of the most common species around. They sailed over here in ships from Europe more than 100 years ago and flourish in the stone-slab environments of cities that humans created (McCook 1909). They most often build their nests under bricks and in sidewalk crevices (Pecarevic et al. 2010, Slipinski et al. 2012) and will eat everything from sugary foods to dead insects to flower pollen to human garbage (Czechowski 2011, Pecarevic et al. 2010, Collignon and Detrain 2010).

Sometimes, pavement ants act like miniature farmers. They collect seeds from plants and accidentally plant them by burying them in their nests (Dostal 2005). They also tend insects called planthoppers like a rancher tends cattle, “milking” them for a sugary food the planthoppers produce called honeydew. If a planthopper predator comes lurking around, pavement ants pick the planthoppers up in their mouths and carry them down to their nests, where they’ll wait out the trouble (Lehouck et al. 2004, Katayama and Suzuki 2003). They also keep interlopers off their property and will wipe out any upstart fire ant nests that try to pop up on the homestead (King and Phillips 1992). But this is all during peace time.

Back to spring. The birds are practicing their songs, and you and I are hopping off the school bus, picking up lucky pennies, walking our dogs, going to get coffee on our sidewalks that zig and zag from New York City down to Florida, across Tennessee, the Dakotas and Wyoming all the way to California. Each day, as we walk around in our world, the human world of sidewalks that point us to and from where we want to go, we are also walking over the world of the pavement ant, with devastating wars, property disputes, and peace times filled with farming and baby making. Their world so similar to ours, so close to us that we step over it everyday without noticing how unusual it is.

Find out more about this species at Antweb and see more photos at Alex Wild's photography site.