NC insect of the week – number 12

Axion tripustulatum, as illustrated in plate 1 of Gordon’s (1985) opus on Coccinellidae.

Coleoptera: Coccinellidae: Axion tripustulatum (DeGeer, 1775)

A component of our recent NSF BRC grant is to database all of our ladybird beetle specimens. Well, those data are finally rolling in, so this week we’ll cover this beautiful North Carolina native: Axion tripustulatum (DeGeer, 1775).

This cool beetle is fairly easy to diagnose. Its general habitus is strongly convex, and the color pattern is very consistent (unlike the introduced Asian multicolored ladybird beetle!) – all black, with two red spots anterolaterally and (usually) one posteromedially. They’re usually about 6 mm long and 5 mm wide, and their elytra have strong lateral margins.

A. pustulatum is one of only two species of Axion found in North America. It was described by DeGeer in 1775 as Coccinella 3-pustulatum, was transferred and respelled by Mulsant in 1850 as Exochomus tripustulatus and was finally transferred to Axion by Crotch in 1874. The type locality is “Pensylvania” (the species is distributed throughout eastern North America). Type specimens for A. tripustulatum and its synonym Coccinella verrucatus Melscheimer, 1847 are apparently lost, but the type for the synonym A. incompletus Nunenmacher, 1911 is at the California Academy of Sciences.

Like most other ladybird beetle species, A. tripustulatum dines on other insects and apparently specializes on Sternorrhyncha. Prey records include Kermes (Kermesidae) and Quadraspidiotus (Diapsididae) scales. A. pustulatum overwinters as adults.

The NCSU Insect Museum has 32 specimens right now, the vast majority of which were collected between 1900-1950. Our most recent specimen was collected at Lake Wheeler in 1969 by our very own Lew Deitz. The Museum’s georeferenced specimens can be explored by downloading this KML file – AxionPustulatum.kml (right click, save as) – and opening it in Google Earth. Has it really been 40 years since we last saw this species in North Carolina?! Only one specimen has shown up at the Lost Ladybug Project!