|Coenagrion resolutum |
common name Taiga bluet
Small ponds, roadside ditches, marshes, streams – anywhere with grassy or marshy borders. Prefer shaded habitats.
Adults fly late-May to mid-August depending on the location.
The taiga bluet has pale blue to almost turquoise colouration (Westfall and May 1996). It is similar in size and proportions to the subarctic bluet (C. interrogatum) but has different colour patterns and markings (Walker 1953). Males do not have a black mark on the underside of the thorax like that which is found on the subarctic bluet (Westfall and May 1996). On each side of the top of the thorax are narrow blue stripes (appear to be on their shoulders) that are sometimes broken and resemble an exclamation mark. These shoulder strips are narrower than the black strips below and come to point above the dot in the exclamation mark (Westfall and May 1996). Abdominal segments are mostly pale blue on top and yellowish-green on bottom with distinctive markings: segments 1 and 2 have narrow dark rings; segment 2 has a black U-shape on top with arms of the U on each side of the segment; segments 3 and 4 segments are blue at the end; half of segment 5 and segments 6 and 7 form one large black ring; segments 8 and 9 are blue and the terminal segment is black (Walker 1953, Cannings 2002, Acorn 2004). Female taiga bluets can be coloured like the males or yellow-green to brownish (Walker 1953). Females do not have a black mark on the underside of the thorax. Most of the abdomen is dark with pale rings, some in the mid-abdomen are interrupted, more prominent on the terminal segments (Walker 1953, Westfall and May 1996, Acorn 2004). ). Taiga bluets are small to medium damselflies that can be just over 3 cm in length.
Larvae of the taiga bluet are difficult to distinguish from the other Eurasian bluets (C. angulatum and C. interrogatum) or even American bluets (genus Enallagma) or forktails (genus Ischnura).
The taiga bluet has no obvious characters that allows for identification in the field; two published keys use very finely detailed characters (Baker and Clifford 1980, Canning and Canning 1980). Coenagrion larvae are of average stature with the posterior margin of the head rounded and eyes not very prominent (Walker 1953).
Sawchyn and Gillott (1975) performed a detailed study on the biology of taiga bluets in Saskatchewan. Females lay soft, creamy-white eggs during June and July in cuts made in living, aquatic plant tissue. Embryonic development takes 2 to 3 weeks. Larvae develop rapidly and near completion by October. Baker (1981) reported that taiga bluet larvae have a hierarchy of dominance where they aggressively defend preferable feeding sites They over-winter in one of the final three stages (instars) of development, frozen in the ice that forms in their shallow habitat. The larvae intentionally place themselves where they become embedded in the ice but do not freeze. The larvae remain dormant until April when the ice melts and then continues development. Larvae leave the water to become adults by mid-June. This adaptation may not be necessary in the southern part of the range. Newly emerged adults disperse from the larval habitat to feed and mature. Maturation requires about 1 week and mating occurs away from the water, oviposition occurs within 2 weeks of adult emergence. Oviposition occurs with the male still attached to the female. Eggs are always deposited above the water surface on floating or emergent vegetation. Baker and Clifford (1981) reported that taiga bluets can take two years to complete their life cycle as opposed to the one observed by Sawchyn and Gillott (1975).
Not currently a concern. The taiga bluet is one of the most common damselfly species in Canada.
Adults feed on flies (e.g. midges) (Sawchyn and Gillott 1975). Larval diet consists of fly larvae, water fleas, other odonate larvae and assorted invertebrates (Baker and Clifford 1981).
Found coast-to-coast throughout most of Canada and the northern United States. Records from as far north as Alaska and south to Arizona. It is one of the most widely distributed damselfly species in North America and the most northerly along with the subarctic bluet (C. interrogatum).
|species page author||Jones, B. C.||2005 |