Post by Deleted on Oct 31, 2011 23:59:18 GMT 1
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| [bg=fbd9bd] Taxonomy: Myrmicinae (Tetramoriini) Anergates atratulus Colony type: Polygynous Colony founding: Inquiline social parasite Color: Queen dark brown / Male pale brown Size: Queen 2-4mm / Male 2.5mm Distribution: Eastern North America, Europe, and parts of Eurasia Environmental status: Vulnerable Mating season: June-July Nutrition: Insects, honey/sugar water (as with Tetramorium) Temperature: 20-27 degrees C Hibernation: Recommended Air humidity: 20%-40% (moderate) Nest building: Soil Planting: Not necessary Class: Moderate First described by: Schenck (1852) Description: Queen: "Head strongly emarginate posteriorly; clypeus rounded posteriorly, deeply cut-out anteriorly; mandibles moderate, terminal border short, and furnished with one tooth at the extremity; maxillary palpi two-jointed; labial palpi one-jointed; antennae eleven-jointed, scape cylindrical, broadest anteriorly, funiculus with first joint long, third very short, those following gradually increasing in length, last joint as long as the two preceding taken together, club indistinct, composed of the last three or four joints; eyes large, situated in the centre of the lateral borders of the head; ocelli moderate. Thorax short; epinotum furnished with two distinct tubercles. Fore-wings with one cubital cell, no discoidal cell, and radial cell open. Petiole transverse, thick; post-petiole twice as broad as long, soldered to the first segment of the gaster; sting wanting, or rudimentary. Legs without spurs on the intermediate and posterior pairs." Donisthorpe (1915) Male: "Head less deeply emarginate posteriorly; clypeus as in the female, but less deeply cut out; mandibles narrow, rounded, not distinctly toothed; maxillary and labial palpi as in the female; antennae eleven-jointed, but shorter and broader than in the female. Thorax composed of usual sclerites possessed by winged male ants; pronotum short; mesonotum without Mayrian furrows; a post-petiole short, very broad and resembling segments of the gaster; gaster broad, thick and strongly bent beneath the body, convex above, and concave beneath; genital organs large, prominent." Donisthorpe (1915) |
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| [bg=fbd9bd] Anergates atratulus is the only member of its genus, a race of strange, worker-less myrmicine ants. Very small in size, it can be easy to confuse males with females. Males are wingless, pale in coloration, and often larger than the queens; they are often only seen above ground when they have been ejected by the Tetramorium which they parasitize. Queens are tiny, with a small head and mandibles, which makes them easy to mistaken for males as per other species of ant. When accepted into the nest of their host species, the A. atratulus queen's gaster will expand rapidly, effectively doubling the length of the insect. Young queens are barely the size of their host workers. Anergates is a social parasite of Tetramorium, targeting the nests of old, orphaned colonies. Since this species does not produce any workers, Anergates colonies will only survive as long as the youngest Tetramorium worker's lifespan. Males are flightless and mate with their sisters inside of the nest; the females fly out at around June to search for a suitable host colony. Each male can mate up to three times before it is time for him to die; colonies are very carefully proportioned so that there are only enough males for every female to be mated. Anergates are very small, and rare within their range. |
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| [bg=fbd9bd] Anergates is wholly dependent upon the workers of its host genus, Tetramorium. Queens only seem to be accepted into old, orphaned Tetramorium colonies, though there have been accounts of Anergates temporarily coexisting with queen colonies of Tetramorium. Anergates queens have a very short lifespan, lasting only as long as the youngest Tetramorium worker in the colony. In this time, the queen may make a prodigious output for her size. Anergates is sluggish and clumsy on the ground, preferring to grab onto passing workers and be dragged into a nest. Adoption is a more common occurrence than with other parasitic species. If the queen is adopted, then all of the reproductive Tetramorium in the colony will be killed, sliced up, and put into a pile. |
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| [bg=fbd9bd] Nests in soil, wherever Tetramorium colonies occur. |
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| [bg=fbd9bd] Anergates cannot feed itself, and so relies on the care of Tetramorium workers and whatever they find appetizing. |
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| [bg=fbd9bd] Queens like to latch onto the antennae workers in order to be carried into the nest. Anergates may climb and latch onto the head of a living Tetramorium queen and steal the food that her workers offer to her; most Anergates, however, are killed by colonies possessing a Tetramorium queen. Males are occasionally ejected from the nest by Tetramorium workers, where they perish helplessly. This may be part of the carefully managed male:female ratio that exists within Anergates colonies, though males of most ants are typically the first to go in any kind of crisis. Anergates is a totally dependent species, and does not exhibit significant behavior outside of its reproductive functions. |
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| [bg=fbd9bd] Anergates colonies hibernate over the winter. |
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[bg=fbd9bd] An Anergates dealate queen. Image copyright by A. Buschinger  A mature Anergates queen. Image copyright by A. Buschinger |
