Ulkei field ant - an ant for the marshes.

 

I found large colonies of the ant species Formica ulkei, sometimes called the Ulkei field ants or more generically thatching ants, this summer as I was hiking around a farm near Elk Island National Park.  This particular variety of ant seems to prefer marshy environments; it builds large mounds with multiple exit points and are aggressive hunters for foods, most notably insects.  They may be considered either beneficial or pests, depending on the environment they are found in.  

The beneficial aspect of the ant is in regard to its ability to control local insect populations.  They also aerate the ground, facilitate drainage, and promote soil building.  The pest side of the equation involves their thatching habit.  Thatching refers to the building up of a nest by adding layers to the structure above ground.  Nests can become quite large and present a problem to manicured lawns such as golf courses.  They "farm" aphids and use the sugary extrusions as sustenance. Aphid populations can quickly increase to problematic numbers.

The genus Formica does not refer to the popular countertop coverings found in kitchens, but rather the groups's ability to produce formic acid.  Some ants have the ability to sting and introduce the painful chemical into the wound, but the Ulkei field ant can spray the iritant into the bite it inflicts.  If you have ever been brushed by a stinging nettle and experienced the plant's wrath, you know what it feels like. Nettles use formic acid, the same chemical used by Formica ants.

The formic acid spray is used both in a bid to protect the nest and to prevent the growth of bacteria in its nest.  The reason has to do with the strong association with this ant species and fungus.  Thousands of species of fungus have been found in the ants' nests.  There is still considerable debate and uncertainty regarding the presence of said fungi, but there appears to be a mutualistic component to the relationship.

Another interesting thing I found out about this particular ant species is that it practices social parasitism.  The specific variation of this behaviour involves capturing other ant species, often Formica fusa (a small black ant) and enslaving them.  

Thanks for reading.   www.ericspix.com