{"id":13464,"date":"2023-02-02T12:37:42","date_gmt":"2023-02-02T18:37:42","guid":{"rendered":"https:\/\/uwm.edu\/field-station\/?p=13464"},"modified":"2024-07-24T14:53:25","modified_gmt":"2024-07-24T19:53:25","slug":"a-species-on-the-move-part-2-the-slender-bluet-damselfly","status":"publish","type":"post","link":"https:\/\/uwm.edu\/field-station\/bug-of-the-week\/a-species-on-the-move-part-2-the-slender-bluet-damselfly\/","title":{"rendered":"A Species on the March – Part 2, the Slender Bluet Damselfly"},"content":{"rendered":"\n

Note: Most link leaves to external sites. <\/small><\/p>\n\n\n\n

Howdy, BugFans,<\/p>\n\n\n\n

Back in the summer of 2019, in an episode about Lilypad Forktail damselflies entitled \u201cA Species on the March<\/a>,\u201d<\/em> the BugLady wrote, \u201cLake Twelve is famous because of the presence there of not one, but two rare (in Wisconsin) damselflies \u2013 the Slender Bluet and the Lilypad Forktail. The bluet has been on and off of our state radar since 2007; the forktail was first recorded at Lake Twelve in 2017 but has been seen intermittently in Wisconsin since 2010.\u201d<\/em><\/p>\n\n\n\n

The property on the west end of Lake Twelve is part of the Biehl Nature Preserve, one of the Ozaukee Washington Land Trust preserves, and along with these two species, there are lots of other dragons and damsels around (the pier is often partly submerged, so dress accordingly).<\/p>\n\n\n\n

This is the story of the Slender Bluet.<\/p>\n\n\n\n

Bluets are members of the Pond or Narrow-winged damselfly family Coenagrionidae – with 105 species, it\u2019s the most common damselfly family. In Wisconsin, the family includes the bluets, dancers, forktails, and sprites, and the (enigmatic) Eastern Red Damsel<\/a>. The Pond Damsels are a colorful bunch, with males more vivid than females. Adults tend to perch near the ground (routinely below the BugLady\u2019s knee level), and they fold their wings over their abdomen when they perch. Various species of Pond damsels are in the air from late spring to late summer – they (mostly) aren\u2019t long-distance flyers, and males are not territorial. Some species overwinter as eggs and others as naiads, and they are tolerant of cold and freezing at the north end of their range.<\/p>\n\n\n\n

A study of the naiads of a New Zealand Pond damsel revealed an array of body language used by the naiads to communicate predation threat, competition, and territorial behavior.<\/p>\n\n\n\n

\"Female<\/a><\/figure>\n\n\n\n

Canadian Naturalist John Acorn calls bluets \u201cfloating neon toothpicks.\u201d<\/em>  The American bluets are all in the genus Enallagma<\/em>, but we also have a few species of Eurasian bluets in the cosmopolitan genus Coenagrion<\/em>. Most male bluets have bodies that are blue and black in varying proportions \u2013 for \u201cease\u201d in identification, they are artificially divided into the \u201cblack-type\u201d bluets, the \u201cintermediate-type\u201d bluets, and the \u201cblue-type\u201d bluets. Females are a different ballgame \u2013 they are not brightly-colored, and while some species have identifying markings, others enjoy different color phases, and their ID is often up for grabs. Unless you have a hand lens.  And, alas, some of the dancers look bluet-ish<\/a>, too.<\/p>\n\n\n\n

\"Dragonfly<\/a><\/figure>\n\n\n\n

For their aquatic naiads<\/a> bluets choose unpolluted still or slowly moving water with plenty of submerged vegetation. Eggs are inserted into plant stems and the naiads (categorized as \u201cengulfing predators\u201d<\/em>) climb around among the plants and ambush their prey, which includes any aquatic critter smaller than they are.<\/p>\n\n\n\n

Slender Bluets (Enallagma traviatum<\/em>) aren\u2019t from around here, historically. The species is divided into two subspecies; one (Enallagma traviatum traviatum<\/em>) occurs on the east side of the Alleghenies\/Appalachians and the other, Westfall\u2019s Slender Bluet (Enallagma traviatum westfalli<\/em>) on the west. It is an Eastern, or maybe Southeastern, species that is moving west and north – an account from Vermont, where it was first seen in 2001, called it \u201canother southern species that may be expanding into our region.\u201d<\/em> It was first recorded in Wisconsin in 2007, and since then there have been 70 reports from just a few locations in about 20 counties in Wisconsin, with sightings getting more numerous in the past three years (thank you, lovely, searchable Wisconsin Odonata Survey<\/a> database. Its status is listed by the Wisconsin Natural History Inventory as Critically imperiled\/Vulnerable due to its restricted range and relatively few populations \u2013 understandable in an animal that\u2019s in the early days of establishing itself here. Among dragonfly enthusiasts, it\u2019s listed as a \u201cMost Wanted\u201d species.<\/p>\n\n\n\n

This is a beautiful, \u201cblack-type\u201d bluet whose blue is a striking sky-blue (except for the lilac-hued tenerals (juveniles). Males have a wide, black stripe on the dorsal side of their abdomen<\/a>, and in females that stripe is interrupted by a slim, blue line down the middle.  They\u2019re about 1 \u00bc\u201d long, and they have very large, very blue eyespots\/postocular spots \u2013 pigmented patches on the tops of their eyes. The male\u2019s claspers are described as \u201cpistol-shaped<\/a>\u201d (along with a few other features, eyespots and claspers are used in identifying bluets). Here\u2019s a nice set of pictures<\/a>.<\/p>\n\n\n\n

\"Two<\/a><\/figure>\n\n\n\n

Look for them from mid-June through July in Wisconsin.  Robert DuBois, in Damselflies of Minnesota, Wisconsin & Michigan<\/span> (the successor to Damselflies of the North Woods<\/span>) tells us that \u201cmales frequently hover over open water, sometimes while in tandem with the female\u201d<\/em> and that \u201coviposition usually occurs into vegetation at the water\u2019s surface with male contact-guarding in sentinel position, but female sometimes descends alone to oviposit into plant stems.\u201d<\/em> Bugguide.net says that \u201cTandem pairs will gather by the dozens perched on stems above the water or staking claims out over floating vegetation,\u201d<\/em> and the BugLady found numerous pictures of Slender Bluets ovipositing alongside other Slender Bluets<\/a>, reminiscent of Powdered Dancers. Like the other bluets of our area, they overwinter as naiads.<\/p>\n\n\n\n

When they pick a spot to oviposit, some Odonates (dragons and damsels) avoid bodies of water that contain fish, but Slender Bluet naiads can be found in fishy waters. The naiads have been subjects in a number of experiments designed to gauge the survival of naiads whose main predators are fish (bluegills) vs those that are preyed on by the hefty naiads of Common Green Darner dragonflies. Some experiments compared Slender Bluet naiads with those of Azure Bluets, and others compared Slender Bluets with forktail naiads.<\/p>\n\n\n\n

Some outtakes:<\/p>\n\n\n\n