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Identification: Generally, spine-waisted ants are thin with very long legs. Aphaenogaster tennesseensis queen and male have smooth, untextured bodies; workers have rough, textured head and thorax, abdomen smooth.
Head: Workers are dark reddish-brown and almost hairless; head has coarse texture. Small eyes. Mandibles small, curved inward and downward. Queen head almost entirely shiny, not rough. Male head is black, shiny, no texture; yellow mandibles; large prominent eyes placed nearer mouth.
Antenna: Base (scape) very low on face, near mouth. Female base extends past head. Antenna segments are hairy; no clubs at tip. Male antenna yellowish, base (scape) is extremely short = 4 antenna segments.
Note: The longest, and sometimes called the first antenna segment is actually the scape or base. The antenna segments are all very short compared to the base or scape.
Thorax: Dark reddish-brown. Neck (prothorax) narrower than head. First part of thorax is high, humped on top, rest of thorax is much lower or depressed. Very large pair of curved, thick spines at the end of the thorax on workers and queen. Worker thorax is rough textured. Queen has smooth shiny thorax.
Thorax on male is black, shiny, smooth; thorax end has two short, blunt protrusions. The joint between thorax and abdomen is wider at abdomen end. Queen and male entirely shiny, no texture.
Wings: Wings extend slightly past abdomen.
Legs: Legs dark. Male has mostly clear yellowish legs; hind thigh (femur) very long.
Abdomen: Abdomen is more yellowish-red on female, darker on worker; no hair. Male abdomen is black, with very few short hairs. Queen, worker and male all have shiny abdomens, no texture.
Similar Species: Aphaenogaster treatae has a thick appendage on the front of the base (scape) of the antennae and is found only in Pinery Provincial Park, Grand Bend, Ont. Males also look similar to the male Pavement Ant Tetramorium caespitum, but hind thigh (femur) is about 4 times as long in the Spine-waisted, and antenna are much longer. All Aphaenogaster males have longer hairs on abdomen, except Aphaenogaster tennesseensis.
Size: Worker, Queen and Male 4 to 5.5 mm long.
Flight Time: July and August.
Habitat: Forests with decaying logs, stumps.
Food: Scavengers of small insects and honeydew. Will eat mushrooms, apparently for moisture content. Aphaenogaster tennesseensis is a predator of the destructive oak borer long-horn beetle, Enaphalodes rufulus.
Spine-waisted ants take seeds of Wild Ginger and Trillium to the nest, eat the coating off the seeds, then return the seeds back to the forest. They also use leaves to soak up liquids and take the leaves back to the nest.
Life Cycle: Nests can be small or large, usually in rotting wood, but they may live in soil if taking over another Aphaenogaster species nest. A. tennesseensis is a Slave-maker of A. rudis and treatae. Typically, with parasitic species, queens, males and workers are all the same size.
Nest Mates: The Ant-like Stone Beetle Scydmaenus zimmermanni was found in their nests in Michigan Jun 21, 1933. Beetles were “numerous and quite unmolested by the ants.” Also the Short-winged Mold Beetle Tyrus humeralis can reside in these ant’s nests.
Comments: Essex County – Ojibway Prairies. Also in Michigan
For information on synonyms, references and type specimens see next page