Photo by Bill Reynolds
Sigmoid prominent (Clostera albosigma) is a medium-sized, heavy-bodied, nocturnal moth. It is the most common of the four Clostera species found in Minnesota. Adult moths are found from mid-May to mid-August in deciduous woodlands and forests, and in shrubby wetlands and fields.
A sigmoid prominent adult has grayish-brown wings, a dark brown head and upper thorax, and on the male, a dark brown tuft at the end of the abdomen. The wings are crossed by four pale lines. A dark, chestnut-brown area near the end of the forewing is sharply delineated by a prominent white “S”-shaped bar. The species name albosigma means “white S” and refers to this marking. Spring individuals are darker with more highly contrasting markings. Summer individuals are paler and less conspicuously marked.
The caterpillar feeds mostly on quaking aspen, but also on poplar and willow, and sometimes on alder, birch, maple, and elm. It is a solitary feeder. During the day it curls up a leaf of a host plant and sticks it together with silk webbing, make a shelter where it can feed in safety. Adults do not feed.
A planthopper is an insect in the superfamily Fulgoroidea that resembles a leaf in its environment. It often hops, like a grasshopper, for transportation, but usually walks slowly to avoid detection. There are more than 12,500 planthopper species worldwide.
Citrus flatid planthopper (Metcalfa pruinosa) is native and very common in eastern North America. It has been introduced into southern Europe and is now an invasive species of concern in orchards and vineyards there. It feeds on a wide variety of woody species including maple, elm, willow, black locust, dogwood, hawthorn, elder, grape, and raspberry.
The body of citrus flatid planthopper is flattened laterally, giving it a wedge-shaped appearance when viewed from above. The wings and body are moderately to densely covered with a mealy, bluish-white, waxy powder. When at rest, the wings are tent-like, almost vertically, over the body. There are two dark spots on the basal half of each forewing.
Meadow fritillary (Boloria bellona) is the most common and the most widespread of the lesser fritillaries. It is found from mid-May to mid-September throughout Minnesota in sedge meadows, grassy fields, hay fields, pastures, and roadsides. Males can be seen patrolling low over grassy areas with a slow, zigzagging flight during the day.
Adults feed on the nectar of flowers, mostly those in the Asteraceae family, and especially those with yellow flowers. Caterpillars feed on common blue violet, small white violet, and Canadian white violet.
Meadow fritillary is a medium-sized brush-foot butterfly. It is identified by the squared-off wing tip; the upper side of the wings lacking chevron-shaped, inward-pointing spots and usually lacking a black marginal line; and the underside of the wings having a pale purplish sheen on the outer half and lacking the white or silver spots found on most lesser fritillaries.
Photo by Bill Reynolds
Pink underwing (Catocala concumbens) is a medium to large sized, strikingly colored, underwing moth. It is common from northeastern United States, west to the Upper Midwest, and north to Manitoba and Alberta. In Minnesota it is more common in the northern half of the state.
Pink underwing adults are 1¼″ to 1½″ in length and have a wingspan of 2⅜″ to 3″. The forewings are a nondescript, mottled gray and tan with a pale, kidney-shaped spot and two thin, jagged, black lines. The hindings are pink two black bands and a wide white fringe. They are active at night. When at rest the wings are folded roof-like over the body. When approached or disturbed they spread their forewings revealing the startling color of the hindwings, possibly to scare off or give it time to escape a predator.
There are 39 underwing moth species found in Minnesota, and most are similar in appearance. Pink underwing is distinguished by the pale colors and paler reniform spot on the forewings; and by the pink hindwings with a wide, straight, uninterrupted, white fringe.
Arcigera flower moth (Schinia arcigera) is common and widespread across North America from the east coast to the Rocky Mountains. In Minnesota, it is found from late July to mid-September in fields with asters.
It is active at night and is attracted to light, but can be also found taking nectar on flowers during the day.
This is a small owlet moth. The adult is about ½″ long and has a wingspan of ⅞″ to 1″. It is distinguished from similar moths by dark brown and pale brown coloration, and by a white, smoothly curved, broadly S-shaped postmedial line.
Photo by Bill Reynolds
Sword-bearing conehead (Neoconocephalus ensiger) is a common, large, meadow katydid. It is often heard at night but seldom seen in daylight. During the day it perches head down on the lower stalk of vegetation with only its wings and hind legs visible, appearing like a grass blade. At night the female can be found near a calling male feeding on the seed head of a grass plant.
Sword-bearing conehead has two color phases, leaf green and dark tan. It is most easily identified by the song of the male. The male has sound-producing organs, a “scraper” at the anal edge of the right front wing and a “file” near the base of the left front wing. By rubbing the file against the scraper the male produces a distinctive song. It is a continuous series of high-pitched lisps, clearly separated, produced at the rate of 10 per second. It is often compared to the sound of a distant locomotive.
Aside from its song, sword-bearing conehead is identified by the long wings and antennae; the rounded “cone” at the top of the head that is separated from the head by a gap; the narrow yellowish edging on the thorax and the front wing; and the curved, sword-like ovipositor on the female.
Photo by Bill Reynolds
Masked hunter (Reduvius personatus) is native to Europe and was accidentally introduced into North America. It is now common in eastern and central North America, including Minnesota, but has been reported across the continent.
Masked hunter inhabits woodlands but is often found in human homes. It eats bed bugs and other small insects, spiders, centipedes, and millipedes. It is active at night and hides during the day. If handled or trapped between clothing and skin, it can deliver a painful bite. The swelling and stinging from the bite will last up to a week.
At ⅝″ to ⅞″ in length, masked hunter is much larger than any otherwise similar assassin bugs in North America.
Photo by Bill Reynolds
There are five Zelus species native to North America. Pale green assassin bug (Zelus luridus) is the most common. Due to variation in body color, this species has often been misidentified in the past as Zelus exsanguis. However, that species is very rare. With the exception of a single collected specimen, all sightings of Zelus exsanguis in the United States should probably be recorded as Zelus luridus.
Pale green assassin bug is an elongated, ½″ to 11 ⁄16″ long, nearly parallel-sided true bug. The overall body color is usually pale green, the color of a Granny Smith apple, but may be yellowish-green, yellow, or reddish-brown. Its beak is short and curved. When at rest it is tucked into a groove between the forelegs.
Pale green assassin bug is distinguished by its color; a spine at both rear corners of the pronotum; and a band at the end of the femur that may be dark or red and conspicuous or barely visible.
Oil beetle (Meloe impressus) is an infrequent, medium-sized, blister beetle. Its metallic blue body stands out in sharp relief against green foliage. It lives about one year but has a short season above ground. Adults are active for just two months between August and October. They are found on the ground or on foliage close to the ground. When threatened or mishandled, they exude an oily yellowish liquid that causes blistering on human skin.
Oil beetle larvae pass through four stages and seven molts (instars) before pupating. They live in the nests of solitary, ground-nesting bees, feeding on bee eggs, honey, and stored pollen.
Oil beetles (genus Meloe) are identified by head, body, and legs all metallic blue or black; oval-shaped abdomen; small outer wings (elytra) that overlap at the base and are much shorter than the abdomen; lack of functional inner wings; and antennae that are bent in the middle. This oil beetle (Meloe impressus) is distinguished by the usually brilliant metallic blue, violet, or green, sometimes black coloration; upper margin of the eye that is nearly straight; fifth segment of the antennae enlarged and flared outward; sparse, fine pitting on the head and thorax; thoracic plate with straight sides that converge toward the rear; and a spur on the fourth segment of the hind leg that projects toward the rear.
Lake darner (Aeshna eremita) is the largest mosaic darner (genus Aeshna) in North America. It is a late-season dragonfly, flying to the end of September. It is found throughout Canada, the northern United States, and the Rocky Mountains. In Minnesota it is fairly common in the northern third of the state.
The adult hunts mostly during the day but also sometimes at dusk. It is a strong flier but does not hover during flight. When hunting it cruises above the water surface with its abdomen slightly arched. It often feeds in swarms, sometimes in great numbers, often with other dragonfly species. It often perches vertically on tree trunks, rarely on the ground.
There are at least ten blue darner dragonfly species found in Minnesota and they are notoriously difficult to tell apart in the field. Lake darner is distinguished by its large size, the first lateral thoracic stripe that is deeply notched and has a dot in the notch, and a black line through the upper face.