While checking my email Monday I
received this report from Sean McGuire in Harris, County, Texas:
“I
ride my bike on a concrete bike trail between Pasadena and La Porte along
Fairmont Parkway. I've notice several times, especially during wet
weather, that fire ants will form long trails down the trail. Not too
unusual, except that they seem to exactly follow the tire tracks of bicycles -
picture the muddy track that a bicycle would make if it had gone off in
the mud then tracked the mud down the trail including where the front and back
tire separate in a turn. Except that is not the case - the concrete is
clean, just long trails of fire ants. I can only think that the
bicycle tire leaves behind some unseen trail or scent that the fire ants
follow. The other unusual thing is the mass quantity of ants and how far
they follow the tire track - at least 1/4 miles or more. Again they
perfectly follow the apparent unseen track of a bicycle.
I've
attached a picture. Just curious if you have seen anything like this
or could explain this behavior.
Regards,
Sean
McGuire”
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| Photo of fire ant foraging trail on bike path |
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| Additional view of fire ant foraging on bike path |
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| Closer view of fire ant foraging trail on bike path |
Wow, what an
interesting observation. Thanks Sean for
recognizing this as an unusual phenomena and documenting it for us. It does appear that the ants were attracted
to the path of the bike tires for some reason.
This email was
passed along to several researchers who are an authority on fire ant
behavior.
Dr. Bradley Vinson, Professor,
Department of Entomology, Texas A&M University, College Station, TX replied:
“It
does look like the ants are following a trail. What is interesting to me is
that they are following the edge of the bike tires rather than the center. It
would appear that they are following an odor or contact chemical trail. It
would be interesting to pull a bike tire across a pavement and see if ants
follow it. But tires from different companies might or might not have the same
chemicals. Also the tire that led to the trailing could have gone through
something that contaminated the tire and this would likely lead to 2 parallel
trails (something on the side of the tire). It appears to be really attractive;
a lot of fire ants are out on the trail.”
Dr. Bob Vander Meer, Research
Leader, Imported Fire Ant and Household Insects Research Unit, USDA, Agricultural
Research Service, Gainesville, FL, replied:
“That
is an impressive photo!!! A while ago there was interest in fire ants being
attracted to rubber bands used to hold newspapers together. Consistent results
were hard to get so the mini-project was abandoned. A similar episode occurred
when it was observed that fire ant workers followed a trail made with a
ballpoint pen. So, it is possible that compounds in bicycle tires are
influencing fire ant behavior. Maybe a colony was caught in migration mode and
became trapped by the irresistible smell of tire residues on pavement! The
number of ants suggests colony migration.”
Foraging fire ants respond to
various odors. In fact they use odors (pheromones)
for all kinds of communications. A
simple explanation of this communication activity can be found here:
and
here:
Fire ants use their stingers to
periodically mark the ground and leave a chemical pheromone trail:
- To mark trails to food
- To mark trails home
- To recognize their queen
- To recognize other worker ants from their colony
- To alert the other ants of danger or intruders
It would appear from this photo that
some foraging ants were attracted to an odor that was on the tires of the
bicycle. Who knows what is was, but they
were attracted to it. Once they started
following the trail they laid down a pheromone trail for other ants to
follow. The original attractant may be
long gone, but the pheromone trail remains, and intensified as others ants
pass. With the rains we have had
recently in the Houston area, the fire ants could be migrating to a higher area
and the cement bike trail is a perfect highway to do this on.
Informational video on fire ants moving a
colony from eXtension site:
Now that is just just plain fascinating.
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