Agapostemon (Agapostemon) texanus Cresson, 1872

Portman, Zachary M., Arduser, Mike, Lane, Ian G. & Cariveau, Daniel P., 2022, A review of the Augochloropsis (Hymenoptera, Halictidae) and keys to the shiny green Halictinae of the midwestern United States, ZooKeys 1130, pp. 103-152 : 103

Agapostemon (Agapostemon) texanus Cresson

Diagnosis.

The females of Agapostemon texanus have the metasoma metallic green (Fig. 4C ) and can be recognized by the “double-punctured” scutum, which has a combination of intermixed large and small punctures (Fig. 5A ). Females cannot be reliably distinguished from Agapostemon angelicus , so they should be separated based on range or DNA barcodes (see remarks for Agapostemon angelicus above).

Male Agapostemon texanus have S3 and S4 with a low transverse swelling and generally have distinct yellow marks on the apical sterna (Fig. 7B, D ). They are extremely similar to Agapostemon angelicus , but Agapostemon texanus have the hind tibia with black stripes on the front and back (Fig. 8D ), whereas Agapostemon angelicus has the hind tibia yellow anteriorly (Fig. 11 ). In addition, the two species can be separated based on the genitalia characters given in the key (Fig. 12 ), and at least in the midwestern US, the range of the two species largely does not overlap.

Male Agapostemon texanus are also similar to (and frequently misidentified as) Agapostemon sericeus but can be distinguished based on the relative lengths of F1 and F2: Agapostemon texanus has F1 about three-fourths the length of F2 (Fig. 10A ), whereas Agapostemon sericeus has F1 slightly more than half the length of F2 (Fig. 10B ).

Remarks.

Agapostemon texanus and Agapostemon angelicus largely do not overlap in range in the midwestern region, though Roberts (1972) reports Agapostemon angelicus from Iowa and eastern Kansas (see remarks under Agapostemon angelicus , above).

Figures

Figure 4. Agapostemon female metasomas A entirely black (Agapostemon virescens pictured) B dark brown with amber (Agapostemon melliventris pictured), note this is a darker specimen C metallic green (Agapostemon texanus pictured).

Figure 5. Agapostemon female pronotal collar and scutum A Agapostemon texanus doubly punctate B Agapostemon sericeus rugosopunctate with sharp pronotal angle outlined in red C Agapostemon splendens densely punctate with obtuse pronotal angle outlined in red.

Figure 7. A Agapostemon virescens metasomal sterna with unmodified S 3 and S 4 B Agapostemon texanus metasomal sterna with swelling on S 4 (and S 3 to a lesser extent) C Agapostemon sericeus modified S 3 and S 4 D Agapostemon texanus modified S 3 and S 4.

Figure 8. Male Agapostemon hind legs A Agapostemon melliventris B Agapostemon sericeus C Agapostemon splendens D Agapostemon texanus E Agapostemon virescens. Scale bar 1 mm, all images at the same scale.

Figure 10. Male antennae with segments highlighted with bars to help illustrate their relative lengths A Agapostemon sericeus B Agapostemon texanus. Scale bars: 500 µm, both images at same scale.

Figure 11. Agapostemon angelicus hind tibia A anterior view of tibia lacking a dark mark B posterior view of tibia with dark mark present.

Figure 12. Agapostemon texanus and Agapostemon angelicus genitalia. Abbreviations: bs = basal stylus, mp = medial plate, as = apical stylus. Figure modified from Roberts (1972).