Disjunct Populations of Western Insects Occur on Black Belt Prairies of Southeastern North America

The Black Belt Prairie region extends through Alabama and Mississippi with additional isolated patches in Georgia and Tennessee.  There is a different Black Prairie region in east Texas.  The chalky soils of Black Prairies favor grass over trees, and in the southeast they produce a mosaic of forest and prairie.  Western species of plants such as little bluestem grass grow on Black Prairie landscapes, and they attract species of insects not normally found in southeastern North America.  At least 15 species of insects that occur on western grasslands exist as disjunct populations on the Black Prairies located in southeastern North America.  This includes the white bee (Tetralonella albata)–a pollinator of prairie clover–as well as 4 species of long-horned beetles and 10 species of moths.  The red-femured long-horned beetle (Tetraodes femorataand the Texas long-horned beetle (T. texanus) feed upon milkweed.  Most of the moths are hosts on flowers in the aster family.

Image result for map of blackland prairie region in southeastern U.S.

Map of Black Belt prairie region in southeastern North America.  (Shaded orange.)  Although the map doesn’t show it, some isolated pockets of Black prairie occur in Georgia as well.

Bee on Dalea - Tetraloniella albata

The white bee occurs in disjunct populations in Mississippi and Arkansas.  The main population occurs from Colorado and Illinois to California.

Milkweed Longhorn Beetle (Tetraopes sp.) - Tetraopes femoratus

The red-femured long-horned beetle ranges from the Great Basin to Mexico.  Disjunct populations occur in the Blackland Prairie Region.

Image result for Epiblema iowana

Epiblema iowana–another western species found in the Black Belt prairie region plus 1 site in Florida.

A grassland corridor formerly must have connected the Great Plains grasslands with the Black Belt prairies of the southeast.  Some scientists speculate that before the last Ice Age this corridor may have existed along the Grand Prairie of Arkansas or through the Arkansas River Valley.  The Mississippi River was lower then and interspersed with lightly vegetated sandbars that allowed for insect passage between the 2 regions.  After the last Ice Age glacial meltwater expanded the Mississippi River, blocking insect passage, but a grassland corridor between the Great Plains and the southern Black Belt Prairie may have existed through cedar glades in Tennessee to Kentucky to Illinois where the Mississippi River was more narrow. Currently, the Mississippi River and forested habitat separate the 2 grassy regions.

During Ice Ages the Black Belt prairies may have served as a refuge for many species of grassland insects found in the Great Plains today.  Forests of jack pine and spruce replaced Great Plains grasslands during glacial phases.  Summers were cooler and shorter.  Species of insects that preferred grassland communities and long warm summers retreated to the Black Belt prairies and Gulf Coast grasslands of southeastern North America.  Populations considered disjunct today may actually be seed populations that replenish Great Plains insect fauna following the end of Ice Ages.

Reference:

Peacock, Evan; and Timothy Schauwecker

“Blackland Prairies of the Gulf Coastal Plain”

University of Alabama Press 2003

 

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3 Responses to “Disjunct Populations of Western Insects Occur on Black Belt Prairies of Southeastern North America”

  1. ina puustinen-westerholm Says:

    In it’s way..a ‘head-up’..for those of us..on the left coast..as with heat indexes..rising fast..and the..white bee..in California..already..we may find some of them..hop-skipping on up..to us. Also..when one looks at assorted scratched images..across the plains states..from ancient tribal groups..perhaps some of the drawings that are not easy to identify..were not prey animals..but assorted insects. Ones which could be used to eat, inhabited the night skys en masse..sometimes, or..provided dye potential? More to ponder..thanks much.

  2. ina puustinen-westerholm Says:

    Hmm..went googling the white bee..and they show white wasps..feeding on flower nectors. Now I wonder..what percent of ‘white’..will show up..event. Do those living in heat and..extreme heat..become a higher..proportion..of ..white?

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