Bronze shield-backed bug

Stinkbug
Bronze shield-backed bug (Homaemus aenifrons) resting on a brown-eyed susan flower.

 

Summer is heating up and bug season is in full swing here and I don’t mean the mosquitoes. There are an estimated 85,000 species of bugs (Order Hemiptera meaning “half-winged”). Most go about their lives quietly and are seldom or not at all noticed by us. Some do get our attention if they are damaging crop or ornamental plants. This one in the above photo, the bronze shield-backed bug, Homaemus aenifrons, leads a very quiet life among the sedge and rush plants in marshes.

Description
Homaemus aenifrons is a subtly colored northern member of an otherwise very colorful group of bugs known as shield-backed bugs (Family Scutelleridae).

Adult H. aenifrons is about 7 to 9 mm long and ovate in outline. The scutellum, a triangular shield-like segment of the thorax, nearly covers the abdomen. This and the rest of the thorax are dull to pale yellow with dark brown to black variegation. Pits, called punctures, on the lower thorax are fine and not numerous. The front basal corners (humeri) of the wings are round with entire (not toothed) margins. The lower abdomen is pale with irregularly placed coarse black punctures. The head is bronze-black and without pubescence or pale bands along the margin. There are numerous coarse pits on the heads surface.

Habitat
H. aenifrons typical habitat is in marshes where it feeds on sedge (Carex) and rush (Juncus) but it can also be found in drier habitats of mixed upland prairie grasses. Like many northern species of shield-back bugs it overwinters as an adult.

Range and Distribution
H. aenifrons is a very common and widespread insect species found from Nova Scotia to Manitoba south to North Carolina and Nebraska. A subspecies, (H. a. ssp. consors), occurs from Alaska to Saskatchewan.

Taxonomy
Class: Insecta (Insects)
Order Hemiptera: (True Bugs including Cicadas, Leaf Hoppers, Aphids)
Suborder: Heteroptera (True Bugs)
Infraorder: Pentatomomorpha
Superfamily: Pentatomoidea
Family: Scutelleridae (Shield-backed Bugs)
Subfamily: Pachycorinae
Genus and Species: Homaemus aeneifrons

Next Time
Coming up soon another bug post. This one on the red-crossed shield bug (Elasmostethus cruciatus).

References Consulted
Bug Guide web page on Homaemus aeneifrons

McPherson, J. E. (1982). The Pentatomoidea (Hemiptera) of Northeastern North America. Southern Illinois University Press, 1982

Stoner, D. (1920). The Scutelleroidea of Iowa. University of Iowa Studies in Natural History. Vol. 8, No. 4:1-155.

A Mystery Bug

Brochymena quadripustulata
Brochymena quadripustulata

 

It’s winter here and the nighttime lows have been very cold. Daytime highs aren’t much better. The first two weeks of January were mild but very suddenly our temperatures went from 35 above to 24 below. So, as I often do on cold winter nights, I go through my photo files.

There are a number of photos in my files of insects and spiders that I have taken over the years. Some have been identified and others not. Recently, I was going over some old photos from 2007 and found one of a bug (Order Hemiptera, the true bugs) on an aspen leaf. This bug, one of my mystery insects, has puzzled me for years. What species is it? I went back to the Bug Guide web site and to look at bug photos. There are a lot of species of bugs and many resemble this one. It is gray-brown with 4 reddish spots, rough edged shoulders, and a scalloped black and red fringe coming from under the wings. By its shape I guessed it might be a stinkbug or shield bug. The scalloped red and black fringe reminded of an assassin bug although as it turns out the two are not closely related.

I began my search in the stink bug family Pentatomidae which has five subfamilies: Asopinae, Discocephalinae, Edessinae, Pentatominae, and Podopinae. Starting with the subfamily Asopinae I found a few suspects such as Apateticus lineolatus and Apoecilus bracteatus. But there were important differences such as no reddish spots and pointed or smooth-edged shoulders rather than jagged. Also, Apateticus lineolatus lives in the southern US and so its presence in Minnesota would be an anomaly to say the least.

It was a long trek through hundreds of photos and pages of descriptions. Eventually I arrived at the subfamily Pentatominae. The Subfamily Pentatominae contains 14 tribes and the tribes include 43 genera. More browsing into the late hours of the night ensued. It was in the subfamily Pentatominae that I found images of bugs that looked very similar to mine. The bug was in the tribe Halyini, genus Brochymena and is known as Brochymena quadripustulata, the rough-shouldered stinkbug. Also, importantly, this species lives in the northern US and Canada.

Description
The rough-shouldered stinkbug is so named for the rounded and jagged-toothed shoulder (humeral angles) of its thoracic segment. The body (8 mm long by 6 mm wide in males, 17 mm long by 9 mm wide in females) is an elongate oval, brown in color with numerous irregularly spaced small black sunken (punctate) dots with yellow or yellow-white markings in between. On the thoracic plate (pronitum) and shield (scutellum) between the wing covers are four orange or red-orange lumps (calluses). The edge of the abdomen is scalloped and marked with alternating stripes of red and black. The fuzzy legs are marked irregularly with alternating spots and patches of yellow and black giving this bug another name “banded stinkbug”.

Life Cycle
Because it is not a serious pest of cultivated plants the rough-shouldered stinkbug is not well-studied but there is enough information available to make some statements about its life cycle. Rough-shouldered stinkbug over winters as an adult under leaf litter and loose bark. In the spring after mating the female lays eggs which incubate for about 10 days before hatching. Development form newly hatched nymph to mature adult takes about three months.

Both nymphs and adults feed on a wide variety of plant species but also on caterpillars. Otto Lugger (1900, as B. annulata) recorded this species as a pest of apple trees in Minnesota but he also notes an earlier observation of it feeding on caterpillars. Several other authors in the early part of the 20th century also noted that rough-shouldered stinkbugs feed on insect larvae.

Taxonomy
Class Insecta: Insects
Order Hemiptera: True Bugs, Cicadas, Hoppers, Aphids and Allies
Suborder Heteroptera: True Bugs
Infraorder: Pentatomomorpha
Superfamily: Pentatomoidea
Family Pentatomidae: Stink Bugs
Subfamily: Pentatominae
Tribe: Halyini
Genus/Species: Brochymena quadripustulata

Distribution
Rough-shouldered stinkbug is found from southern Canada and across most of the US (including Alaska) and northern Mexico. It is considered to be the most common member of its genus.

References consulted

Cuda, J. P. and McPherson, J. E. (1976). Life History and Laboratory Rearing of Brochymena quadripustulata with Descriptions of Immature Stages and Additional Notes on Brochymena arborea (Hemiptera: Pentatomidae). Annals of the entomological Society of America. 69(5): 977-983.

Lugger, O. (1900). Bugs (Hemiptera) injurious to our cultivated plants. Minnesota Agricultural Experiment Station Bulletin 69: 1–259.

McPherson, J. E. (1982).The Pentatomoidea (Hemiptera) of Northeastern North America. Southern Illinois University Press.

Paiero, S. M.; Marshall, S. A.; McPherson, J. E.; and Ma, M. S. (2013). Stink bugs (Pentatomidae) and parent bugs (Acanthosomatidae) of Ontario and adjacent areas: A key to species and a review of the fauna. Canadian Journal of Arthropod Identification No. 24.

Stoner, D. (1920). The Scutelleroidea of Iowa. University of Iowa Studies in Natural History. Vol. 8, No. 4:1-155.

Bumble beetle

Euphoria inda a flower beetle
Bumble beetle (Euphoria inda) sharing the sweet fermenting sap of my apple tree with a carrion beetle (Necrophila americana).

 

This is the last in the series on a collection of beetles (fireflies, Asian lady beetles, and carrion beetles) I found on an apple tree of mine. It was a butterfly that first piqued my interest about what was going on with the apple tree. The butterfly was a mourning cloak (Nymphalis antiopa) a species common around here. The mourning cloak was feeding on fermenting sap coming from a wound in the bark. Unfortunately the photo of this dark-colored butterfly was too dark in the wrong places and a bit blurry, too. The butterfly didn’t like my prying and so kept moving about. I looked closely at where the butterfly was feeding and saw the carrion beetles. I wondered why they were there.

A few days later I went back to the tree to see what the carrion beetles were up to and if more had come. On the tree with the carrion beetles was another beetle. I recognized it as a species of scarab beetle called the bumble flower beetle (Euphoria inda). Flower beetles eat sweet substances like nectar and tree sap so it was in heaven on the tree.

Description
The bumble beetle’s light cinnamon colored wing covers (elytra) marked with broken rows of rectangular and linear black spots. The head, sides of the thorax and abdomen, and the legs are densely hairy. The body measures 12 to 16 mm long and 8 to 10 mm wide.

Life Cycle
The larvae of the bumble beetle are white grubs. Eggs are laid in the early summer in rich soil and decaying organic matter such as rotting hay piles, compost heaps, and manure piles. Time to hatching is eleven days. The grubs crawl on their backs as they tunnel through the soil and organic debris on which they feed. When the larvae are ready to pupate they burrow into the soil a few inches and build a cocoon of mud. Development time beginning with hatching and ending with emergence as adults takes about twelve weeks. From late August to September the adult bumble beetles are active feeding on sap, rotting fruit, and flower nectar. As the season winds down the adult bumble hibernate. In the spring they emerge to seek out mates and begin the process anew.

Taxonomy
Class: Insecta (Insects)
Order: Coleoptera (Beetles)
Suborder: Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles)
Superfamily: Scarabaeoidea (Scarab, Stag and Bess Beetles)
Family: Scarabaeidae (Scarab Beetles)
Subfamily: Cetoniinae (Fruit and Flower Chafers)
Tribe: Cetoniini
Genus/species: Euphoria inda

Distribution
Bumble beetles can be found over much of the US from Maine to Florida and westward to Oregon and Arizona. In Canada they range from British Columbia to Quebec. Bumble beetles also occur in Mexico. The tribe Cetoniini which includes the genus Euphoria with its 59 species is very diverse in Mexico and Central America.

References consulted
Beddes, T. and Davis, R. S. (2011). Utah Pests Fact Sheet, Bumble Flower Beetle. Utah State University Extension and Utah Plant Pest Diagnostic Laboratory.

Bug Guide Species Euphoria inda – Bumble Flower Beetle

Cranshaw, W. (2009) Colorado Insect of Interest, Bumble Flower Beetle. College of Agricultural Sciences, Colorado State University May 27, 2009 version.

Hayes, W. P. (1925). A Comparative Study of the History of Certain Phytophagous Scarabæid Beetles. Kansas Technical Bulletin 15. Kansas State Agricultural College, Manhattan, Kansas. 146 pages.

Hayes, W. P. (1930). Morphology, Taxonomy, and Biology of Larval Scarabaeoidea. Illinois Biological Monographs 12(2): 5-119.

Orozco, J. and Philips, T. K. (2010. Phylogenetic analysis of the American genus Euphoria and related groups based on morphological characters of adults (Coleoptera: Scarabaeidae: Cetoniinae: Cetoniini). Insect Systematics & Evolution 41: 39–54.

Richter, P. O. (1966). White grubs and Their Allies, A Study of North American Scarabaeoid Larvae. Oregon State Monographs Number 4. Oregon State University Press. 219 pages.

Careful!

Bald-faced Hornet feeding on plum
Bald-faced Hornet (Dolichovespula maculata) feeding on a rotting plum.

 

Bald-faced hornets (Dolichovespula maculata) are a common sight around here most years. This year, however, hornets were hard to find. Very few nests were started and the several I did see were soon abandoned. Finding these hornets in late September examining and feeding on rotting plums left on the porch was a good sight.

Bald-faced hornets build huge paper nests in trees and under the eaves of buildings. The nests are colonies consisting of one queen (sometimes two), who lays eggs, and many workers who tend the eggs and larva in their nest cells, hunt for food, enlarge the nest, and defend the colony from predators. The grub-like larvae eat macerated insects that the workers bring back to the nest. Barn flies seem to be a favorite prey at my place. Hornets also eat sweet foods like fruit and nectar and will scavenge from animal carcasses.

Description
Bald-faced hornets are yellow jackets but unlike yellow jackets their bodies are black with white markings. The face is marked with a white area between the eyes that extends to the jaws giving them the common name “bald-face hornet”. The large compound eyes are framed by white bands. There are white linear and triangular markings on the sides of the thorax and three white bands on the last three dorsal abdominal segments. The rest of the body is black. Wings are a translucent smokey brown. Overall body size is about 75 millimeters. Worker caste hornets are covered with fine hairs but the queens are hairless.

The syrphid fly Spilomyia fusca is a bald-faced hornet mimic.

Life Cycle
Nests are begun in the spring by fertile queen hornets that have overwintered. A small nest is started and the queen lays eggs in hexagonal paper cells. In about one week the eggs hatch into larva. The queen feeds these larva and after eight days the larva pupate. It takes another ten days for the pupating larva to develop into adults of the worker caste.

 

Hornet nest in a tree
Hornet nest on a tree branch showing entrance and cupolas.

 

The new workers begin the next stage of stage in nest development enlarging the nest and raising the young. The queen now devotes her time fully to egg laying. The queen lays eggs that will become diploid sterile females and sterile males. As more workers are produced the colony grows and can have as many as 700 hornets but usually there are around 400. The nest is enlarged with additional layers of brood cells enclosed in a paper cover. The paper is made from wood fibers the hornets collect from dried plant stems, bark, trees, and even paper. The fibers are chewed and mixed with saliva to make a sort of papier-mâché. Because they use so many fiber sources the nest will have dark and light patches of gray, white, brown, and yellow. The shape of the nest is initially rounded but later becomes conical with the narrow end at the bottom where there is an opening for the hornets to enter and exit. The outer paper cover is also layered and fitted with cupolas near the top. Most nests are about a foot across and two feet long but I have found some as long as three feet.

In late summer the reproductive phase of the colony’s life begins. Bald-faced hornet workers are female and can lay eggs. However, the eggs are not diploid but haploid (half the chromosome compliment) and become males which are fertile. These males will mate with the fertile females the queen produces at this phase.

After mating the colony begins to dwindle and work on the nest stops. There may be infighting among the workers and against the queen. Newly mated queens will leave the colony and prepare for winter hibernation to wait until spring when they will start new colonies of their own.

 

 

Taxonomy
Class: Insecta (Insects)
Order: Hymenoptera (Ants, Bees, Wasps and Sawflies)
Superfamily: Vespoidea (Yellowjackets and Hornets, Paper Wasps; Potter, Mason and Pollen Wasps and allies)
Family: Vespidae (Yellowjackets and Hornets, Paper Wasps; Potter, Mason and Pollen Wasps)
Subfamily: Vespinae (Hornets and Yellowjackets)
Genus/species: Dolichovespula maculata

Habitat
Bald-faced hornets live in a variety of habitats from forests to suburban areas. They prefer to build their nests in trees often

Range and distribution
Bald-faced hornets occur from Alaska east to Labrador south to Florida, Louisiana, and California but are not known from the Plains States and desert regions of the US.

Beware of Stings
The sting of bald-faced hornet is extremely painful and can cause allergic reactions in susceptible people. The old adage about stirring up a hornets nest is a good one to heed. But when the potential danger is respected hornets can make good neighbors and their appetite for insects makes them helpful in the garden.

References consulted
Archer, M. E. (2006). Taxonomy, distribution and nesting biology of species of the genus Dolichovespula (Hymenoptera, Vespidae). Entomological Science 9: 281-293.

Balduf, W. V. (1954). Observations on the White-faced Wasp Dolichovespula maculata (Linn) (Vespidae, Hymenoptera). Annals Entomological Society of America 47:445-458.

Bug Guide Species Dolichovespula maculata – Bald-faced Hornet

Hicks, B. and Baker, K. (2014). The nests of Dolichovespula norvegicoides (Hymenoptera: Vespidae) from Newfoundland. Journal of the Acadian Entomological Society 10:6-9.

What are these beetles doing on an apple tree?

 

The beetles in the above photos are American Carrion Beetles (Necrophila americana, Superfamily Staphylinoidea, Family Silphidae) and typically feed on the flesh of dead and decaying animals. But here are three carrion beetles feeding on or getting ready to feed on the sugary, slightly fermented sap oozing from a wound in an apple tree. There isn’t a scrap of meat in there but their feeding on sap is not as unusual as it may seem.

American Carrion Beetles beetles are part of a larger family of beetles known as Silphidae and not all are scavengers or even strictly carnivorous. One species, Aclypea bituberosa, eats spinach and other crop plants. Adult American Carrion Beetles, while principally feeding on carrion and the fly larvae that eat carrion, will feed on sweets. Cultivated food crops like sugar beet and pumpkin are particular favorites and it can become a pest insect on these. I have seen them on rotting mushrooms where they were probably eating fly maggots and on rotting soybean meal which smelled like decaying meat. Feeding on sap may be a way to acquire carbohydrates before winter hibernation.

Description
The length of the American Carrion Beetle is between 13.8-20 mm. It is readily distinguished by its bright finely to roughly pitted (punctate), yellow thoracic shield (pronotum) that is usually marked by a large roundish black spot. The wing covers (elytra) are black (rarely bluish) although in females the apical tips are yellow. There are three raised veins (costae) running down the elytra. There may also irregularly shaped tubercles usually connected to the costae. The last few segments of the abdomen protrude from beneath the elytra.

Life Cycle
Larva are elongate, black and armored with wide scale-like coverings on each body segment. Reproduction is from late May to July. Eggs of American Carrion Beetles are laid on dead carcasses shortly after flies arrive. Upon hatching the larva eat fly eggs and maggots, decaying flesh, dried skins, and each other. Development for egg to adult takes about 10 to 12 weeks. There is only one generation per year. Adults over winter and in the spring emerge to begin the reproductive cycle anew.

A type of mutualism (symbiosis beneficial to both organisms) exists between American Carrion Beetles and certain mites (often Poecilochirus spp.) that reduces competition for food resources. The mites shelter on the bodies of adult American Carrion Beetles leaving when the beetles arrive at a carcass. Once there the mites begin eating the eggs of flies whose larva would compete for food resources with the beetle larva. The adult beetles also eat fly eggs and maggots as well as the not too decayed flesh. The mites will lay eggs of their. After the eggs hatch the immature mites feed on fly eggs. When mature they will attach to (but not harm) the new adult beetles.

Taxonomy
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga (Scarab, Lady, Rove, Lightning Beetles and several others)
Infraorder: Staphyliniformia (Rove, Scavenger and Water Scavenger Beetles)
Superfamily: Staphylinoidea (Rove and Carrion Beetles)
Family: Silphidae (Carrion Beetles)
Genus and Species: Necrophila americana (American Carrion Beetle)

Habitat
American Carrion Beetles prefer open habitats like fields and low marshy ground but can also be found in forests.

Range
American Carrion Beetles occur east of the Rocky Mountains from Manitoba to New Brunswick and south to Florida and Texas.

References consulted
Anderson, R. S. (1981). Resource partitioning in the carrion beetle (Co1eoptera: Silphidae) fauna of southern Ontario: ecological and evolutionary considerations. Canadian Journal of Zoology 60: 1314-1325.

Bug Guide Series Staphyliniformia

Fitcher, G. S. (1949). Necrophily vs. Necrophagy. The Ohio Journal of Science 49(5): 201-204.

Majka, C. G. (2011). Journal of the Acadian Entomological Society. 7: 83-101.

Knox, T. T. and Scott, M. P. (2006). Size, operational sex ratio, and mate-guarding success of the carrion beetle, Necrophila americana. Behavioral Ecology 17 (1): 88-96.

Ratcliffe, B. C. (1996) The Carrion Beetles (Coleoptera: Silphidae) of Nebraska. Bulletin
of the University of Nebraska State Museum Volume 13. Published by University of Nebraska State Museum Lincoln, Nebraska.

Steele, B. F. (1927). Notes on the Feeding Habits of Carrion Beetles. Journal of the New York Entomological Society Vol. 35 (1): 77-81.

A variation on a theme

Arctiinae
A variation of the yellow-spotted tiger moth (Lophocampa maculata) caterpillar

 

I Become Obsessed With Moths
The past summer found me spending a lot of time looking at insects especially moths and butterflies. Two books that got me very interested in moths are the Peterson Field Guide to Moths by David Beadle and Seabrooke Leckie and Tiger Moths and Woolly Bears edited by William E. Conner. A few websites have also been very helpful including Bug Guide, the North American Moth Photographers Group, and Insects (Insecta) of the World.

To date I have identified the larva of seven species of moths in the lepidopteran Subfamily Arctiini, the tiger moths, on my land. A few days ago while walking in the woods I came across the one pictured above. For a while I was puzzled as to its identity but this is the larva of the yellow-spotted tiger moth (Lophocampa maculata). It is a bit different from the typical form. The entire body is covered in tufts of yellow bristles even the head and tail. The row of black bristles along the back are a clue to its identity. After looking over many photos of L. maculata caterpillars it seems that the larva show a range of color and pattern variation. The long white hairs (setae) which project from the head and tail and the row of black or dark bristles (rarely red or pink) down the back are characteristic of the species.

Documenting Biodiversity Where You Live
There is a lot of biodiversity to observe, document, and cherish. Not all of it is found in wilderness areas set aside by law or resolution. Even urban areas have abundant wildlife if you know where and how to look. Here where I live I am continuing to document the species in the woods, wetlands, and fields. The list keeps growing and one of these days, maybe this winter, I will get the species checklist cleaned up with proper spelling and nomenclature and post it here.

A firefly without a light

 

This little apple tree has been a magnet for many kinds of beetles, butterflies, and wasps. Not so much for the flowers but for sap oozing wounds and the ripe apples. The narrow, flat, dark-colored beetles feeding on overripe apples are fireflies known as Diurnal Fireflies (Ellychnia corrusca). Unlike other fireflies the Diurnal Firefly does not possess bioluminescent organs and is active by day than night. Another name this firefly goes by is “Snow Firefly” because they are sometimes active on warm winter days. The genus name Ellychnia is from the Greek and means “a lamp-wick.”

Description
Body shape is oblong to oval, 10-14 mm long, and overall body color is black. The half-moon shaped thorax central disk and margins are black, the area between red or reddish-yellow. The wing cover (elytra) surface is dark brown to black, finely granulate and covered in a fine, flattened yellowish pubescence. Along the edges of the abdomen are small pinkish markings where the larva’s light organs used to be.

The larvae are black with pinkish light producing organs on the edges of the abdominal segments. In overall appearance they look like some sort of dark black flattened millipede but the presence of three pairs and not many pairs of legs will quickly identify them as insects. The body is narrow and the body long with shingle-like segments.

Taxonomy
Class: Insecta (Insects)
Order: Coleoptera (Beetles)
Suborder: Polyphaga (Rove, Scarab, Lady Beetles, Weevils)
Superfamily Elateroidea: (Click, Firefly and Soldier Beetles)
Family: Lampyridae (Fireflies)
Subfamily: Lampyrinae
Tribe: Photinini
Genus/species: Ellychnia corrusca

Life Cycle
Diurnal Fireflies hibernate as adults and emerge in April to mate. Larva hatch from eggs laid in woody debris. The larvae are carnivorous feeding on grubs and other small invertebrates and possibly slugs which they find in soft, rotting wood. Unlike the adults, the larvae can flash light from specialized organs on the abdominal segments of their bodies. Adults lose this ability shortly after emerging from pupation.

Adult Diurnal Fireflies feed on nectar, tree sap, and juices from ripe fruits. They pass the winter under loose bark of trees but will come out on very warm days and feed on sap dripping from tree wounds.

Habitat
Adults can be found in moist fields and coniferous and deciduous forests. The larvae live in soft decaying wood where they prey upon small invertebrates.

Range
Diurnal Fireflies occur over most of eastern North America to British Columbia and at higher elevations in the western mountains of the US.

References consulted
Blatchley, W. S. (1910). The Coleoptera or Beetles of Indiana. Bulletin 1, Indiana Department of Geology and Natural Resources.

Bug Guide (Genus Ellychnia – Diurnal Fireflies)

Luk, S. P. L.; Marshall, S. A.; and Branham, M. A. (2011). The Fireflies of Ontario (Coleoptera: Lampyridae). Canadian Journal of Arthropod Identification No. 16:1-105.

Majka, C. J. (2012). The Lampyridae (Coleoptera) of Atlantic Canada. Journal of the Acadian Entomological Society 8:11-29.

Rooney, J. A. and Lewis, S. M. (2000). Notes on the Life History and Mating Behavior of Ellychnia corrusca (Coloeptera: Lampyridae).