(Exema spp.)
Overview • Description • Distribution • Taxonomy
Exema adults are active from April to October in other parts of their range, but in Minnesota all sightings are from May to September. They are found in fields and roadsides. Most North American Exema beetles feed on several species of plants, and most of those plants are in the Aster (Asteraceae) family. |
||
Description |
||
Exema beetles are black to dark brown and very small. They are among the smallest case-bearing leaf beetles in North America. They are difficult to detect because they very closely resemble certain caterpillar droppings. Birds avoid them and humans overlook them unless they are specifically looking for these beetles. Adults are 1⁄16″ to ⅛″ (2.1 to 3.5 mm) in length. The body is compact, robust, oblong, and somewhat square or pentagonal in cross section. The color is dark brown to black, nonmetallic, and usually dull. Some species have many small coppery or yellow spots intermixed. The head is dark brown to black with coppery or yellow markings. It is inserted into the thorax up to the eyes. The antennae are short, thread-like, and widely separated at the base. They are broadened and sawtoothed (serrate) from the sixth segment to the end. They fit into grooves on the thorax. The eyes are large. The thorax and wing covers (elytra) are covered with wart-like bumps (tubercles). The inner (sutural) margin of each elytron is serrate, with each tooth fitting into a groove on the other elytron. |
||
Distribution |
||||
Sources |
||||
1/4/2024 | ||||
Taxonomy |
|||
Order |
Coleoptera (beetles) | ||
Suborder |
Polyphaga (water, rove, scarab, long-horned, leaf, and snout beetles) | ||
Infraorder |
Cucujiformia | ||
Superfamily |
Chrysomeloidea (leaf beetles and allies) | ||
Family |
Chrysomelidae (leaf beetles) | ||
Subfamily |
Cryptocephalinae (case-bearing leaf beetles) | ||
Tribe |
Fulcidacini (warty leaf beetles) | ||
Subtribe | Exema | ||
Subordinate Taxa |
|||
Canada case-bearing leaf beetle (Exema canadensis) case-bearing leaf beetle (Exema byersi) case-bearing leaf beetle (Exema chiricahuana) case-bearing leaf beetle (Exema conspersa) case-bearing leaf beetle (Exema deserti) case-bearing leaf beetle (Exema elliptica) case-bearing leaf beetle (Exema gibber) case-bearing leaf beetle (Exema globensis) case-bearing leaf beetle (Exema inyoensis) case-bearing leaf beetle (Exema jenksi) case-bearing leaf beetle (Exema neglecta) case-bearing leaf beetle (Exema parvisaxi) divided case-bearing leaf beetle (Exema dispar) goblin case-bearing leaf beetle (Exema mormona) |
|||
Synonyms |
|||
|
|||
Common Names |
|||
This genus has no common name. The common name of the tribe Fulcidacini is warty leaf beetles, and it is used here for convenience. |
|||
Glossary
Elytra
The hardened or leathery forewings of beetles used to protect the fragile hindwings, which are used for flying. Singular: elytron.
Tubercle
On plants and animals: a small, rounded, raised projection on the surface. On insects and spiders: a low, small, usually rounded, knob-like projection. On slugs: raised areas of skin between grooves covering the body.
Visitor Photos |
|||||
Share your photo of this insect. |
|||||
This button not working for you? Simply email us at info@MinnesotaSeasons.com. Attach one or more photos and, if you like, a caption. |
|||||
Babette Kis |
|||||
Exema warty leaf beetle Exema, warty leaf beetle, found at Barnes Prairie Remnant, Racine Co., WI; photos taken on June 3, 2023. |
![]() |
||||
![]() |
|||||
MinnesotaSeasons.com Photos |
|||||
|
|||||
Slideshows |
||
Visitor Videos |
|||
Share your video of this insect. |
|||
This button not working for you? Simply email us at info@MinnesotaSeasons.com. Attach a video, a YouTube link, or a cloud storage link. |
|||
Other Videos |
|||
Visitor Sightings |
|||||
Report a sighting of this insect. |
|||||
This button not working for you? Simply email us at info@MinnesotaSeasons.com. Be sure to include a location. |
|||||
Babette Kis 6/3/2023 |
Location: Barnes Prairie Remnant, Racine Co., WI Exema, warty leaf beetle, found at Barnes Prairie Remnant, Racine Co., WI; photos taken on June 3, 2023. |
||||
MinnesotaSeasons.com Sightings |
|||||
|
|||||
Created: 1/4/2024
Last Updated: