''Megacyllene robiniae'', commonly known as the locust borer, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

longhorn beetle The longhorn beetles (Cerambycidae), also known as long-horned or longicorns, are a large family of beetles, with over 35,000 species described. Most species are characterized by extremely long antennae, which are often as long as or longer than ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to eastern North America. It is a serious pest of ''

Robinia pseudoacacia ''Robinia pseudoacacia'', commonly known in its native territory as black locust, is a medium-sized hardwood deciduous tree, belonging to the tribe Robinieae of the legume family Fabaceae. It is endemic to a few small areas of the United States, ...

'', the black locust tree, with which it is

sympatric In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sh ...

Etymology

The specific name, ''robiniae'', is derived from the name ''

Robinia ''Robinia'' is a genus of flowering plants in the family Fabaceae, tribe Robinieae, native to North America. Commonly known as locusts, they are deciduous trees and shrubs growing tall. The leaves are pinnate with 7–21 oval leaflets. The flowe ...

'', which is the

generic Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...

name of the black locust tree, ''

'', on which the larvae feed. The name ''Robinia'' was coined by

Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

to honor the royal French

gardener A gardener is someone who practices gardening, either professionally or as a hobby. Description A gardener is any person involved in gardening, arguably the oldest occupation, from the hobbyist in a residential garden, the home-owner suppleme ...

s Jean Robin (father) and Vespasien Robin (son).

Description

From a distance, ''M. robiniae'' can easily be mistaken for a wasp or bee, due to its black and yellow striped pattern. It can also be mistaken for two closely related species: '' M. caryae'' and '' M. decora''. The adult beetle can be long, and it has a W-shaped third stripe on the

elytra An elytron (; ; , ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometimes alterna ...

. The antennae of both sexes are dark brown to black. The male's antennae are two-thirds its body length, and the female's are one-half. The legs are reddish brown. The full grown larvae are legless, white, and robust, growing to roughly long.

Geographic range and habitat

Because there has been increasing use of '' R. pseudoacacia'' as an ornamental tree, the range of ''M. robiniae'' has expanded along with that of the tree. It is, however, still confined to North America and has not been recorded on any other continent where black locust has been introduced. The beetle can be found almost anywhere that unprotected black locust trees grow, and the beetle is often more abundant when ''

Solidago ''Solidago'', commonly called goldenrods, is a genus of about 100 to 120''Solidago''.
F ...

'', commonly called goldenrod, is also present. Adults feed on the pollen of goldenrod. Because of the adults' floral preferences, they tend to stay in uncultivated

field Field may refer to: Expanses of open ground * Field (agriculture), an area of land used for agricultural purposes * Airfield, an aerodrome that lacks the infrastructure of an airport * Battlefield * Lawn, an area of mowed grass * Meadow, a grass ...

s and

meadow A meadow ( ) is an open habitat, or field, vegetated by grasses, herbs, and other non-woody plants. Trees or shrubs may sparsely populate meadows, as long as these areas maintain an open character. Meadows may be naturally occurring or artifi ...

Life cycle and diet

Male and female Megacyllene robiniae 321331624

The females are often found running up and down black locust trunks in search of wounds in which to lay their eggs in the fall. Both sexes are most common from late day to dusk. Adults feed on pollen of goldenrods of the genus ''

Solidago ''Solidago'', commonly called goldenrods, is a genus of about 100 to 120''Solidago''.
F ...

''. They lay eggs in crevices and near wounds of the locust tree. The eggs hatch and the larvae spend the winter hibernating within the bark. Once winter ends, the larvae burrow into the tree trunk and start to tunnel. These tunnels are around long by wide, and serve as a primary infection site for wind-borne spores of the fungus ''

Phellinus robiniae ''Phellinus robiniae'', commonly called the cracked cap polypore or Phellinus rimosus, is a fungus of the family of Hymenochaetaceae. The fungus primarily infests black locusts, aided by openings caused by '' Megacyllene robiniae'' infestation, b ...

'', which causes a damaging

heart rot 300px, The bracket fungus '' Fistulina hepatica'' is one of many that cause heart rot. In trees, heart rot is a fungal disease that causes the decay of wood at the center of the trunk and branches. Fungi enter the tree through wounds in the bark ...

disease of ''

'' species, causing them to be more susceptible to wind damage. The larvae

overwinter Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal activi ...

within the tree and then pupate in late July and early August, and adults start to emerge in late August and throughout September. Adults are generally active from August through October.

Pest status

In 1900, due to attack by ''M. robiniae'', the value of ''

'' (black locust tree) was reported to be practically destroyed in nearly all parts of the United States beyond the mountain forests which are its home. Were it not for these beetles and their larval tunnels promoting fungal infections, it could be one of the most valuable timber trees that could be planted in the northern and middle states; young trees grow quickly and vigorously for a number of years, but soon become stunted and diseased, and rarely live long enough to attain any commercial value. Currently, only one registered product,

carbaryl Carbaryl (1-naphthyl methylcarbamate) is a chemical in the carbamate family used chiefly as an insecticide. It is a white crystalline solid previously sold under the brand name Sevin, which was a trademark of the Bayer Company. The Sevin tradem ...

, is effective against ''M. robiniae''. It is applied in a single dose when adults are most active (August/September).

References

* * * * * * * * {{Taxonbar, from=Q3008694 robiniae Beetles of North America Insect pests of temperate forests Insects of the United States Beetles described in 1771 Taxa named by Johann Reinhold Forster