Checkered white (Pontia protodice) is a medium-sized butterfly with a wingspan of 1½″ to 2½″. It is a southerly species and is uncommon in Minnesota. There are two overlapping broods here, early June to August (spring form) and July to mid-October (summer form). The wings are white with dark markings, including a checkered pattern on the outer margin. The female has more extensive markings than the male, and the spring form has darker markings than the summer form. The larva (caterpillar), known as the southern cabbageworm.
Checkered white populations have drastically decreased in eastern Unites States, and the butterfly is now scarce or extirpated in some areas where it was once common. It appears stable in the west. The cause of the decline is unknown, though habitat loss is certainly a contributor. It is possible that the extremely abundant introduced species cabbage white is displacing native whites, including checkered white. It is also possible that checkered white is a western and midwestern species that only sporadically became abundant in eastern agricultural fields. It remains to be seen whether the decline will continue to spread westward.
Photo by Dan W. Andree
At 1¾″ long, eyed click beetle (Alaus oculatus) may be the largest click beetle in our area. With its boldly-outlined eye spots it is certainly the most distinctive.
The body is long, thin, and black, with mottled patterns of minute, whitish scales. The thorax has a pair of large black spots boldly outlined with white. The spots look like eyes and give this beetle its common name.
On the underside, an elongated lobe on one plate fits into a groove in another plate, allowing the insect to produce an audible click. This feature gives the insect family the common name “click beetles”. If put on its back, the beetle uses this click mechanism to catapult itself up to six inches in the air, righting itself and potentially escaping a predator.
Click beetle larvae are called wireworms. Most wireworms eat plant roots, and can be serious agricultural pests. Eyed click beetle wireworms are carnivorous. The feed on the larvae of other insects, especially wood-boring beetles. This makes them a beneficial insect.
Photo by M.j. Horgan
There are more than 3,000 species of walkingsticks worldwide, 29 species in North America north of Mexico, and probably just 2 species in Minnesota. Northern walkingstick (Diapheromera femorata) is the most common walkingstick in North America and in Minnesota. The extremely long, thin, almost cylindrical body strongly resembles a leafless twig making it invisible to predators.
In Minnesota, the northern walkingstick population fluctuates on a two-year cycle. The odd numbered years are the “boom” years, the even numbered years the “bust” years. They mate in late summer. The female drops eggs to the ground one at a time. During heavy infestations, female egg-dropping can sound like falling rain. The eggs remain on the ground until the second following spring. After almost two years, they hatch between mid-June late July. During the night, the nymph crawls up the first vertical object it encounters. If that is a stem of a shrub or tree, it begins feeding. Otherwise, it returns to the ground and seeks another vertical object.
The other walkingstick known to be found in Minnesota, prairie walkingstick (Diapheromera velii), is very similar in appearance. Northern walkingstick is distinguished by its occurrence in forested habitats, the dilated and banded femur on the middle leg of the male, and the much shorter sensory appendages at the end of the abdomen of the female.
Photo by Bill Reynolds
Minnesotans are seeing the huge influx of painted lady (Vanessa cardui) butterflies in the summer of 2017. Observers from the Twin Cities to Detroit Lakes and Pennington County have reported seeing “15 plus,” “dozens”, “lots and lots,” and “plentiful” painted lady butterflies this year. Lora in Corcoran reports them “swarming the soy bean field across the road.” Ruth in Big Stone County reports seeing “clouds of them.”
Painted ladies are both migratory and cyclic. They overwinter in the southwestern United States and in northern Mexico. They migrate north in the spring in most years, temporarily repopulating the United States and Canada. Some years they do not migrate at all. In years of much rain on the wintering grounds the northward migrations are enormous. They migrate south beginning in August and continuing through November. They are cyclic because some years their populations are large, some years small.
Painted lady butterflies are very similar in appearance to American Lady (Vanessa virginiensis) butterflies. Painted lady is less orange above. The large spot near the tip of the forewing is always white, never pale orange. The black band in the middle of the forewing creates an isolated orange spot. The dark spots on the hindwing are smaller, do not touch, and do not have blue centers. There are four eyespots on the underside of the hindwing.
Photo by Bill Reynolds
Downy yellowjacket (Vespula flavopilosa) is an uncommon, medium-sized, predatory, social wasp. It is found in the northeastern United States from Minnesota to Maine, south to Virginia, and along the Appalachian mountains to northern Georgia. It closely resembles eastern yellowjacket. It is thought by some to be a hybrid between eastern and common yellowjackets. Others suggest that it probably arose as a hybrid but now queens mate with drones of the same species.
The overwintering queen emerges from hibernation in April or May. She builds a nest of 20 to 45 cells and cares for the grubs as they hatch. In about 30 days the workers emerge and take over nest building duties. Through spring and summer the queen produces a large number of worker wasps. In mid-summer, the nest grows exponentially, as more and more workers become available, ultimately with 3,500 to 15,000 cells. Only the new queens survive the winter, hibernating under loose tree bark, in a decaying stump, or in another sheltered location.
In eastern North America, four yellowjacket species, common, downy, eastern, and German yellowjackets, closely resemble each other, making identification difficult. Downy yellowjacket is distinguished from the others by a continuous, uninterrupted yellow band on the face below the compound eye; and by the shape and pattern of black markings on the first and second abdominal segments.
Photo by Christa Rittberg
With 7,003 species in 530 genera worldwide, robber flies are one of the largest and most abundant families of insects alive today. Bee-like robber flies, as the common name for the genus suggests, resemble bees. There are 240 species of bee-like robber flies, 62 species in North America north of Mexico. Few of the species have been given a common name. Laphria sacrator is one of several species famous for being a bumble bee mimic, so “bumble bee mimic robber fly” will stand in for the common name.
Bumble bee mimic robber fly (Laphria sacrator) is a short, robust, medium-sized, bee-like robber fly. It is fairly common in northeastern and north-central United States, including Minnesota. It has a stout thorax and a short abdomen, both partially covered with long yellow hairs making it resemble a bumble bee. It is one of the hairiest of the bee-like robber flies. Adults are ⅝″ to 1″ long.
Photo by Christa Rittberg
Two-spotted bumble bee (Bombus bimaculatus) is small, colonial bumble bee. It is common in eastern North America and in Minnesota. It emerges very early in the spring and is active until mid-summer.
Two-spotted bumble bee usually nests underground but sometimes in the cavity of a dead tree. Like other bumble bees, it will sting to protect itself or its nest. The stinger is not barbed and the bee can sting multiple times. It feeds on the pollen and nectar of flowers. It has a very long tongue that allows it to feed on nectar of plants with long corolla tubes.
Two-spotted bumble bee is identified by the thorax which is yellow except for a small, round, black spot in the middle; the first abdominal segment is entirely yellow, the second has a broad, yellow, W-shaped spot in the middle, and the remaining (on the female) are all black; and the hairs on the back of the head are yellow.
Photo by Christa Rittberg
Brown-belted bumble bee (Bombus griseocollis) is a small, very common, colonial, ground-nesting bumble bee. It is the second most common bumble bee in eastern North America, after only the common eastern bumble bee. It is less common in Minnesota and the other northernmost states.
Bumble bees are the first bees out in the spring and the last bees out in the fall. Brown-belted bumble bees emerge earlier in the spring than most other bumble bees. They nest in the ground in small colonies of 50 or fewer individuals.
Brown-belted bumble bee is identified by the thorax which is yellow except for a small, round, black spot in the middle; the first abdominal segment is entirely yellow; the second has a single yellow, narrowly U-shaped spot in the middle and a brown band that swoops around the yellow spot; and the remaining are all black.
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.