Explanation of Names
Trigonorhinus limbatus (Say 1827)
Range
NY-SK-WA south to Honduras
(1)Food
T. l. limbatus feeds on pollen of various composites, especially Helenium (sneezeweed), Coreopsis, and some similar daisy-like flowers, and the larvae bore in the flower receptacle and stem. (Barry Valentine, pers. comm.)
Life Cycle
Sneezeweed flowers with damage; larva; larvae; cocoon with dead adult; adult
Remarks
This sp. is being slowly reduced to isolated populations by competition with a related phenotype - T. l. vestitus (Say). I believe vestitus emerged from a hybrid stew (limbatus x griseus (LeC.) originating in Texas, spreading and out-competing the two parental populations. There used to be (in the early 1900s) places in Texas where no two specimens looked alike. Now at those sites only vestitus phenotypes occur, and, in fact, vestitus has now taken over the entire seUS except peninsular Florida.
The explosion and rapid spread of
T. l. vestitus in seUS was tremendously aided by the emergence of
Helenium amarum (=
tenuifolium) as a very aggressive weed which now occurs almost everywhere in the southern states. (Barry Valentine, pers. comm.)
