Metallic wood-boring beetles: identification of Florida Chalcophora (Coleoptera: Buprestidae)

P. M. Choate, 2004
Photos by Dave Almquist and P. M. Choate, Entomology and Nematology Department, University of Florida

Introduction

Metallic wood-borers are so called because adults of many species have a metallic luster, giving them a shiny appearance while at rest. The name wood-borer refers to the larval stage. Larvae bore under bark or deeper into heartwood of a variety of tree species. The term "flat-headed wood-borers" is also used with these beetles, and refers to the dorsally flattened appearance of the larvae. Adults are quite active and quick to take flight when disturbed. Activity generally occurs during the hottest part of the day, and individuals may be seen sunning on logs or stumps. Many species also occur on plants, and may be collected by beating foliage. Members of the genus Chalcophora are the largest buprestids in Florida. These species (20-30mm) of metallic woodborers are frequently encountered by collectors in Florida. Individuals may be seen resting on sidewalks, on walls, and may actually land on people, especially if they walk around in bright clothing. This may be quite disconcerting to those that are intimidated by large insects. Florida species are attracted to turpentine-baited traps.

Biology

Members of Buprestidae utilize a variety of host plants as food and as larval habitat. Chalcophora, both georgiana and virginiensis are reported as general pests of a variety of species of Pine. Blatchley (1910) stated that C. liberta frequented scrub pine (Pinus banksiana Lamb.) in the dune region of Lake, Porter, and Laporte counties, Indiana. Adults fed on young buds and leaves of the pine while larvae lived as borers in the decaying wood. Females oviposit in cracks and crevices in the bark or in wounds. Larvae develop under bark, then bore deeper into heartwood where they pupate in a single cell. Adults emerge from the host tree leaving a characteristically shaped elliptical exit hole.

Distribution

The genus Chalcophora Dejean 1833 contains 5 species; (Bellamy 2004, pers. comm.); Chalcophora fortis LeConte, C. angulicollis (LeConte), C. georgiana (LeConte), C. liberta (Germar), and C. virginiensis (Drury). The first 2 are northern and/or western species that do not occur in Florida. The remaining 3 species have been recorded from Florida. There is some question concerning the occurrence of C. liberta in Florida. Literature records exist for this species but no recent verifiable specimens have been seen. An online checklist of the Chalcophorina of North America (north of Mexico)(C. L. Bellamy, 2004) [http://www.cdfa.ca.gov/phpps/ppd/Entomology/Coleoptera/Buprestidae/NorthAmerica/chalcophorina.html] lists C. liberta and C. virginiensis in Florida, with C. georgiana known from Georgia and Mississippi. Bellamy (per. comm.), now lists georgiana from Florida, and commented that the records for liberta, are based solely on literature records. As far as I have been able to ascertain C. liberta has not been collected in Florida. Instead C. georgiana seems to be the species that occurs with regularity with virginiensis. Peck and Thomas (1998) list georgiana and virginiensis from Florida. For the moment, due to the lack of verifiable specimens of liberta from Florida, we will consider that only 2 species of Chalcophora occur in Florida. However, for completeness and for the possibility that there may be occasional specimens of liberta found in southeastern states, we have included this species in the diagnostic key.

Distribution records (USA - from several sources):

  • Chalcophora georgiana (LeConte): Florida, Georgia, Mississippi, North Carolina, South Carolina;
  • Chalcophora virginiensis (Drury): Florida, Alabama, Arkansas, Colorado, Delaware, Georgia, Kentucky, Louisiana, Maine, Massachusetts, Minnesota, Mississippi, New Hampshire, New Jersey, New York, North Carolina, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Texas, Virginia;
  • Chalcophora liberta (Germar): Connecticut, Florida, Indiana, Maine, Michigan, Minnesota, New Hampshire, New York, Pennsylvania, Rhode Island, Texas.

Identification

At a quick glance one may identify georgiana and virginiensis based on size (larger species is virginiensis) and color (virginiensis black, georgiana coppery). However, there may be overlap in size, and color is also variable. Therefore, the following diagnostic key and pictures are presented as an aid in identification of the Florida Chalcophora species. Images were taken using AutoMontage imaging in the Entomology Department at the University of Florida.

Chalcophora 
georgiana
Fig. 1a.Chalcophora georgiana (LeConte)
photo Dave Almquist.
Chalcophora 
virginiensis
Fig. 1b.Chalcophora virginiensis (Drury)
photo Dave Almquist.
Chalcophora
georgiana
        head, shallow frontal furrow
Fig. 2a.Chalcophora georgiana head,
showing shallow frontal furrow
photo P. M. Choate.
Chalcophora
virginiensis
        head
Fig. 2b.Chalcophora virginiensis head,
showing deep frontal furrow
photo P. M. Choate.
Chalcophora
georgiana
        elytra
Fig. 3a.Chalcophora georgiana elytra,
fine apical microserrations
photo P. M. Choate.
Chalcophora
virginiensis
        elytra
Fig. 3b.Chalcophora virginiensis elytra,
coarser apical serrations
photo P. M. Choate.
 
Diagnostic characters for separating species of Florida Chalcophora
    1. Elytral sutural stria effaced in anterior half (Fig. 1b); Apical margin of elytra distinctly serrated (Fig. 3b); head with anteriorly expanded deep median furrow (Fig. 2b); overall color usually black, with a faint copper reflection...virginiensis (Drury)
     
    - Elytral sutural stria complete, extending forward as far as scutellum or to base (Fig. 1a); Apical margin of elytra feebly or not at all serrated (Fig. 3a, 4c); median furrow of head shallower and not anteriorly expanded (Fig. 2a); overall color coppery green or yellow....2. (georgiana and liberta)
     
    2. Elevated elytral costae similar in color to depressed areas (Fig. 1a.); Apical margin of elytra feebly serrate; subscutellar stria reduced, shallow, (Fig. 2a) punctures lacking or in single row, green or copper colored...................georgiana (LeConte)
     
    - Elevated elytral costae black, strongly contrasting with coppery color of depressed areas (Fig. 4a.); Apical margin of elytra not serrate; subscutellar stria deeply impressed (Fig. 4b), with numerous coarse copper-colored punctures....................liberta (Germar)(Florida distribution based on literature records only).

    Note: Bright (1987) commented that liberta was the smallest species of Chalcophora. It could be distinguished from our other species by its coppery tinge in the punctured areas of the elytra and pronotum, contrasting with the shining black, elevated, broken costae (raised areas).

Chalcophora liberta
Fig. 4a. Chalcophora liberta (Germar)
Monmouth, ME, C. A. Frost collr.
Photo P. M. Choate

Fig. 4b. Chalcophora liberta head

Fig. 4c. Chalcophora liberta elytra
Selected References

  • Bellamy, C. L. & R. L. Westcott. 2003. Correction to the Buprestidae and Schizopodidae listings from Nomina Insecta Nearctica (1996). Zootaxa 147:1-20.
  • Bellamy, C. L. 2004. The Chalcophorina of North America (north of Mexico). http://www.cdfa.ca.gov/phpps/ppd/Entomology/Coleoptera/Buprestidae/NorthAmerica/chalcophorina.html
  • Blatchley, W. S. 1910. An illustrated descriptive catalogue of the Coleoptera or beetles (Exclusive of the Rhyncophora) known to occur in Indiana. W. S. Blatchley, Indianapolis, Indiana. 1385p.
  • Bright, Donald E. 1987. The metallic wood-boring beetles of Canada and Alaska (Coleoptera: Buprestidae). The insects and arachnids of Canada. Part 15. Agric. Canada Res. Br. Publ. 1810:1-335.
  • Peck, S. B. and M. C. Thomas. 1998. A distributional checklist of the beetles (Coleoptera) of Florida. Arthropods of Florida and Neighboring Land Areas. Vol. 16. Florida Dept. of Agric. and Consumer Services. Entomology Contribution no. 862. Gainesville, Fl.