{"id":872,"date":"2018-04-01T19:22:23","date_gmt":"2018-04-01T19:22:23","guid":{"rendered":"http:\/\/blogs.oregonstate.edu\/mgmetro\/?p=872"},"modified":"2018-04-01T19:22:23","modified_gmt":"2018-04-01T19:22:23","slug":"carpenter-ants","status":"publish","type":"post","link":"https:\/\/blogs.oregonstate.edu\/mgmetro\/2018\/04\/01\/carpenter-ants\/","title":{"rendered":"Carpenter Ants"},"content":{"rendered":"

Natter\u2019s Notes:
\n<\/strong>Carpenter Ants<\/strong><\/h1>\n

Jean R. Natter, OSU Master Gardener
\n<\/strong><\/h3>\n
\n \"\"<\/a>\n
Fig 1: Relative size of carpenter ants: Top row: Winged queen (L) and winged male (R); 3 sizes of workers in bottom row: minor (L); media (center); and major (R). (http:\/\/faculty.spokanefalls.edu\/LHansen\/SummaryCarpenterArtBiology.htm)<\/figcaption>\n <\/figure>\n

Carpenter ants, sometimes referred to as \u201ctermites of the northwest,\u201d can be important structural pests which typically nest in moisture-damaged wood. In our region, swarms of flying reproductives (males and females) often leave the nest during January. After mating, the surviving queens will shed their wings and search for a new nest site.<\/p>\n

Once a thriving colony is established, it has 10,000 to 50,000 or more individuals. The main nest is in dead wood, perhaps a tree, stump, or landscape timbers.<\/p>\n

But that\u2019s only part of the story.<\/p>\n

The pupae and some workers are in a secondary nest, one that\u2019s in a relatively warm, dry structure such as a house, garage, or shed. When a colony is about 6 to 10 years old, it produces its first winged swarmers (reproductive males and females). The females, at 16- to 18-mm (about 5\/8-inch), are larger than the males, the latter a scant 1\/2-inch long.<\/p>\n

It doesn\u2019t matter which Camponotus<\/em> species is in an infestation. In western Oregon, C. modoc<\/em> (black with red legs) is more common than C. vicinus<\/em> (black with red thorax and legs). A mature colony has 3 sizes of workers: minors (the smallest); media; and majors. They may invade households, just as nuisance ants will, but are unaffected by over-the-counter ant bait.<\/p>\n

\n \"\"<\/a>\n
Fig 2: Characteristics of carpenter ant workers are elbowed antennae; evenly rounded thoracic profile; and a large node on the narrow connection between thorax and abdomen. (https:\/\/bugguide.net\/node\/view\/779340)<\/figcaption>\n <\/figure>\n

All ants have elbowed antennae, and a petiole (a slender connection between thorax and abdomen) with a noticeable node (a bump).\u00a0 Carpenter ant workers are recognized by their particularly large node and an evenly convex thoracic profile. The additional musculature for the swarmers\u2019 wings creates a beefier profile changing the thoracic outline to somewhat flattened and table-like. After females drop their wings, close examination of the lateral thorax with a hand lens will reveal small indentations \u2013 the places where the wings were attached.<\/p>\n

Key points<\/strong><\/p>\n