Applying geometric morphometrics to identify bee species in genus Halictus (Hymenoptera: Halictidae) and quantify island-mainland variation within species

Presenting Author(s)

Charlie N. Thrift

Undergraduate Student
University of California, Santa Barbara
Santa Barbara, California, United States

Co-Author(s)

Katja C. Seltmann (she/her/hers)

Katherine Esau Director
University of California Santa Barbara
Santa Barbara, California, United States

Bees (Hymenoptera: Anthophila) have unique wing venation and imaged bee wings can be used to accurately identify bees to species. Wing venation patterns alone may be sufficient to classify variation between populations of the same species using geometric morphometrics. An application of this method is presented to discriminate specimens from four species of Halictus (Hymenoptera: Halictidae). This genus of sweat bee was chosen for its abundance in local existing monitoring projects and relatively low number of possible species when compared to other Halictidae genera. Specimens were collected from Santa Cruz Island Reserve and Santa Barbara, California, a coastal mainland town. Santa Cruz Island is a 35-kilometer long island about 32 kilometers off the coast of Santa Barbara in the Pacific Ocean, which creates a physical barrier between mainland and island populations. To analyze wing venation patterns, both forewing and hindwing were removed, slide mounted, imaged, and annotated with digital landmarks using TPS morphometric software for approximately 300 specimens and 9 landmarks. Results from the principal component analysis to discriminate between Halictus species, and quantify the variation between mainland and island populations, are reported in this poster. Further investment in automated bee identification processes will aid future monitoring projects, which are often hindered by the taxonomic impediment.