Tips for keying ants: Subfamily

Subfamily

  • Introduction: World Subfamilies
  • Minnesota's Subfamilies and diagnostic characteristics

    Once you have identified your specimen to the family Formicidae, and you know which caste it is, you can proceed to identify the subfamily. There are 16 extant subfamilies in the world (Bolton 1994).

    In the upper Midwest, only the world's four most speciose subfamilies are present: Ponerinae, Myrmicinae, Dolichoderinae, and Formicinae.

    There are a couple diagnostic characteristics that make differentiating between these subfamilies easy, but understanding these characteristics from ant keys may be difficult without reference pictures:

    Formicine petiole Dolichoderine petiole Myrmicine petiole Ponerine petiole

    The abdominal pedicle is made up of one or two segments, the petiole and postpetiole, that are between the thorax (the alitrunk) and the rest of the abdomen (the gaster). The petiole is the second segment of the abdomen. The prescence of a humplike node at the petiole is a diaognostic feature of most Formicids. Arrows point to the petiole of each of the four subfamilies pictured.

    Formicines and Dolichoderines have a single segment, the petiole, on the abdominal pedicle. Note that the Dolichoderine genus pictured, Tapinoma , has a reduced petiole that is small and tube-like.

    Myrmicines always have two segments on the abdominal pedicle, the petiole and the postpetiole. Note that the Myrmicine's postpetiole is very distinct from the gaster. Some Ponerines also have a postpetiole, which is differentiated from the rest of the gaster by a constriction. Note the constriction in the Ponerine genus pictured, Ponera , as compared to the severe contriction in the Myrmicine pictured, Aphaenogaster .

    These subfamilies can also be differentiated by looking at the tips of their gasters. The back end (=pygidium) of the Dolichoderine Tapinoma sessile shows that Dolichoderines have a slit-like opening at the distal end of the gaster. Formicines have a small circular acidopore that is often fringed by setae. Myrmicines and Ponerines often have stingers, but these stingers are often retracted into the body.

    Dolichoderine pygydium

    For more images of ants from these subfamilies, see the Image database. Also see the world ants page for images of ants from additional subfamilies found in Costa Rica, Australia, and New Zealand.

    The Japanese Ant Database Group has a description of the abdominal pedicel and gaster region of ants with features diagnostic to subfamilies described and a database of ant images from several subfamilies .

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    Please send any questions or comments regarding these pages to Tim Linksvayer or Andy McCall