Sirex nigricornis Fabricius, 1781

John M. Leavengood, Jr. & Smith, Trevor Randall, 2013, The Siricidae (Hymenoptera: Symphyta) of Florida, Insecta Mundi 2013 (309), pp. 1-16 : 10-11

Sirex nigricornis Fabricius, 1781

( Fig. 17-21 )

Diagnosis. Females of S. nigricornis have black legs with reddish tarsi, an ovipositor which is shorter than the forewing, and the abdomen is mostly reddish-orange except for the black basal segments. Sirex behrensii is similar, but has, sometimes subtly, black-banded forewings. Sirex longicauda and S. areolatus both have longer ovipositors. The other North American females of Sirex are separated by having entirely bluish-black abdomens. The males of S. nigricornis are best distinguished by the apical two segments of the metatarsi being reddish-yellow while the basal segments are black, the basally black but otherwise reddish abdomen, and black antennae. Sirex cyaneus is separated by its entirely black metatarsi. The antennae of S. behrensii differ, being basally pale. The other males of North American Sirex have reddish abdomens which are both basally and apically black, the apical portion often reduced to only dorsal or ventral expression. Males of Sirex varipes are best separated by association with females.

Bradley (1913) differentiates the races of S. nigricornis .

Natural history. The known hosts of S. nigricornis include Picea sp. , Pinus clausa (Chapman ex Engelm.) Vasey ex Sarg. , Pinus echinata Miller , Pinus palustris Miller , Pinus taeda Linnaeus , Pinus rigida Miller , Pinus strobes Linnaeus , and Pinus virginiana Miller (Pinaceae) ( Smith and Schiff 2002; Schiff et al. 2006).

Ibalia leucospoides (Hochworth) ( Hymenoptera : Ibaliidae ) has been collected from trees infested with S. nigricornis and S. edwardsii and may be a parasitoid of either of them ( Smith and Schiff 2002). Sirex nigricornis also harbors the fungal symbiont Amylostereum chailettii (Pers.) Boidin , as do many other species of Sirex and Urocerus ( Smith and Schiff 2002) .

All but four of the Florida specimens were collected in Lindgren funnel traps baited with alpha-beta pinene, ethanol, or frontalin and turpentine. Adults have been collected in January, March, June and September to December. Florida specimens have been collected nearly throughout the year, contrary to July to October ( Schiff et al. 2012), likely referring to more northern latitudes.

Distribution. Alabama, Arkansas, Delaware, District of Columbia, Florida, Georgia, Indiana, Louisiana, Maryland, Massachusetts, Mississippi, New York, North Carolina, Ohio, Oklahoma (new state record), Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia, Wisconsin and Canada ( Bradley 1913; Stange 1996; Smith and Schiff 2002; Schiff et al. 2006, 2012). In Florida specimens have been collected in Alachua, Bay, Columbia, Duval, Escambia, Leon, and Santa Rosa Counties.

Specimens. USA: Arkansas: Nevada County: Bluff City seed orchard, ex. Pinus taeda , 16-XI-1976, 17- XI-1976, 24-XI-1976, 14-X-1976, H.N. Greenbaum ( FSCA; 8) ; Florida: [probably Alachua County: Gainesville ], frontalin/ turpentine Lindgren funnel trap, X-1997 or XI-1997 ( JLFC; 1) ; Alachua County: Gainesville , ex. Pinus elliottii bolt, 25-XI-1974, R.C. Wilkinson ( FSCA; 1) ; X-1950, R.E. Sher ( FSCA; 1) ; Gainesville, Farmer’s Market , 19-III-1998, C. Chu ( JLFC; 1) ; Gainesville, University of Florida, Natural Area Teaching Lab, Surge / Natural Area Drive, frontalin/ turpentine Lindgren funnel trap, 15-XI-1999, J.L. Foltz ( JLFC; 1) ; Bay County: Panama City, Division of Forestry Office , on Highway 98, alpha-beta pinene-baited Lindgren funnel trap, 19-XII-2006, L. Smith ( CAPS; 1) ; Panama City, FSU Panama City Campus , ethanol-baited Lindgren funnel trap, 28-XI-2006, L. Smith ( CAPS; 1) ; Columbia County: Lake City, 5 miles northeast of Osceola National Forest , 30-XI-1968, L. O’Berry ( FSCA; 1) ; Duval County: Jacksonville, Fort George Island , alpha-beta pinene-baited Lindgren funnel trap, 5-XII-2006, J. Eickwort ( CAPS; 2) ; Jacksonville, on Heckscher Drive , alpha-beta pinene-baited Lindgren funnel trap, 29-XI-2006, 20-XII-2006, A. Silagyi ( CAPS; 2) ; Jacksonville, on Yellow Bluff Road , ethanol-baited Lindgren funnel trap, 20-XII-2006, A. Silagyi ( CAPS; 1) ; Escambia County: Pensacola, at Boardwalk Park near Bayview Cemetery , alpha-beta pinene-baited Lindgren funnel trap, 19-XI-2006, 28-XI-2006, 15-XII-2006, C. Street ( CAPS; 3) ; Leon County: Tallahassee , 1/ 4 mile south of SR 20, alpha-beta pinene-baited Lindgren funnel trap, 26-I-2007, M. Bentley ( CAPS; 1) ; Tallahassee , 1/ 4 mile south of SR 20, ethanol-baited Lindgren funnel trap, 17-XI-2006, M. Bentley ( CAPS; 1) ; Tallahassee, 4.8 miles south of Capitol Circle , on CR 373, alpha-beta pinene-baited Lindgren funnel trap, 7-XII-2006, M. Bentley ( CAPS; 1) ; Santa Rosa County: Gulf Breeze, Gulf Islands National Seashore on Gulf Breeze Parkway , alpha-beta pinene-baited Lindgren funnel trap, 15-XII-2006, C. Street ( CAPS; 2) ; Oklahoma: Latimer County: X-1986, XI-1992, XI-1987, K. Stephan ( FSCA; 3) ; Pennsylvania: Berks County: Douglasville , 14-VI-1982, F.W. Skillman, Jr. ( FSCA; 1) .

Figures

Figures 14-21. 14-16) Sirex areolatus female. 14) Lateral habitus. 15) Dorsolateral habitus. 16) Wings. 17-19) Sirex nigricornis female. 17) Lateral habitus. 18) Dorsolateral habitus. 19) Wings. 20-21) Sirex nigricornis male. 20) Dorsal habitus. 21) Lateral habitus.