RANGE EXTENSION AND SOLITARY NEST FOUNDING 
IN POLISTES EXCLAMANS 
(HYMENOPTERA: VESPIDAE)* 
By Mary Jane West 
Museum of Comparative Zoology, Harvard University 
It is generally difficult to document temporal changes in the geo- 
graphic distribution of insect species because of the sporadic nature 
of collections made primarily for taxonomic study and specimen 
identification. Therefore some new distribution data providing an 
unusual amount of evidence for range extension in the social wasp 
Polistes exclamans Viereck seem of interest. Several states have been 
added to the known range of P. exclamans in the last twenty years; 
and P. exclamans is now abundant in east-central Missouri, where 
it was almost certainly absent two decades ago. Solitary nest founding 
by P. exclamans queens may enhance the ability of this species to 
colonize new areas. 
Porter (1963) first suggested that P. exclamans may be extending 
its range. He reported new records from Maryland and New Jersey, 
noting that these states are considerably north of the northernmost 
previous records for P. exclamans in the Atlantic Coast states. 
A collecting trip to St. Louis and Jefferson Counties, Missouri, 
in July, 1967, provided the first evidence of range extension by 
Polistes exclamans in the midwestern United States. The purpose of 
the trip was to collect specimens of Polistes species observed by the 
Missouri naturalist Phil Rau prior to his death in 1948. Rau re- 
peatedly mentioned ( e.g ., in Rau 1929, 1942a, 1942b) that only four 
species of Polistes existed in Missouri: P. pallipes (= metricus) , P. 
rubiginosus, P. annularis , and P. variatus (= fuscatus ) (Rau’s de- 
terminations by J. Bequaert). However, I found P. exclamans nests 
common in barns and abandoned buildings in southern St. Louis 
County, and collected specimens of P. exclamans in six of the eight 
localities where Polistes wasps were found (other species collected 
were P. metricus , P. fuscatus , and P. rubiginosus) . Three of the 
1967 P. exclamans localities were frequented by Rau during his 
studies of Polistes: “Meramac Highlands”, an area near the Mera- 
mac River about eight miles southwest of St. Louis (first mentioned 
in Rau and Rau, 1918 ) ; Kirkwood, Rau’s home town for 24 years 
(first mentioned as a study locality in Rau, 1941) ; and a farm near 
*Manuscript received by the editor 17 June 1968 
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