NESTING BEHAVIOR OF CRABRO ARGUSINUS AND 
C. HI LARIS (HYMENOPTERA: SPHECIDAE) 
By Robert W. Matthews, Allan Hook 1 and 
Joan W. Krispyn 
Department of Entomology 
University of Georgia 
Athens, Georgia 30602 
Introduction 
The Crabroninae comprise over 1200 species of small to large 
solitary wasps which exhibit considerable behavioral diversity (Bo- 
hart & Menke 1976). The Holarctic genus Crabro includes 85 spe¬ 
cies with 47 found in the Nearctic region (Bohart 1976). Males of 
about 3/4 of these species possess a rather bizarre tibial “shield” 
thought to function in courtship, a hypothesis which awaits confir¬ 
mation. Nesting information is recorded for members of 6 of the 10 
species groups recognized by Bohart, but few detailed studies have 
been made. Kurczewski and Acciavatti (1968) reviewed the biology 
of the Nearctic species listing a number of behavioral generaliza¬ 
tions applicable to Crabro. All known species are relatively uniform 
in their nesting behavior, compared to the diversity of behaviors 
found in other sphecid genera of comparable size. Evans et al. 
(1979) have recently extended our knowledge of Nearctic Crabro 
with observations on 7 species. 
The 2 species reported here, C. argusinus Packard and C. hilaris 
F. Smith, are “typical” members of the genus although each belongs 
to a different species group. This is the first record of nesting for C. 
hilaris; C. argusinus was studied briefly by Evans (1960) and again 
in 1970 (Evans et al. 1979) in New York. 
With the exception of one < population briefly observed on the 
mainland 11 mi E of Midway, Georgia, all observations were made 
on St. Catherine’s Island, GA, a coastal island situated about 30 
miles south of Savannah. The study spanned three seasons 1976— 
1978. Principal island study sites are located in Fig. 1. 
‘Present address: Department of Zoology and Entomology, Colorado State Uni¬ 
versity, Ft. Collins, CO 80523 
Manuscript received by the editor November 13, 1979 
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