OBSERVATIONS ON SWARM EMIGRATIONS AND 
DRAGGING BEHAVIOR BY SOCIAL WASPS 
(HYMENOPTERA: VESPIDAE)* 
By Ruth Chadab and Carl W. Rettenmeyer 
Biological Sciences Group, University of Connecticut 
Storrs, Connecticut 06268, U.S.A. 
Naumann (1975) reported the first evidence that several species of 
social wasps (Vespidae: Polybiini) use chemical trails to direct 
swarms to a new nest site. His observations were based on absconding 
swarms following army-ant raids. Those observations were corrobo¬ 
rated by Jeanne (1975, 1980), and most recently by Forsyth (1978) 
and us. Incidental to investigating raids by army ants on social wasps, 
we observed that the movement of absconding wasp swarms did not 
always conform to the trail-following behavior as it has been de¬ 
scribed. In this report the typical emigrations of absconding swarms 
will be summarized followed by our observations on two unusual 
swarm movements and related dragging behavior. 
Prior to the movement of a wasp swarm to a new site, some wasps 
run a few millimeters to centimeters on vegetation dragging their 
gasters in a zig-zag motion which deposits a chemical produced in 
Richards’ gland (Naumann 1975, Jeanne 1980). Such dragging runs 
occur first on prominent vegetation near the swarm site and then in 
various directions from the swarm. Eventually dragging activity 
consolidates along a path to the new nest site. The behavior of 
subsequent wasps visiting the dragging sites differs: their gasters do 
not touch the substrate or move back and forth but they antennate 
the dragging sites. Those wasps use the chemical traces for orienta¬ 
tion and are called “followers.” 
At the swarm site some workers returning to the swarm behave 
differently than do regular foragers. They run excitedly through, 
among, or over clusters of calm wasps. Since increased activity and 
flight follow, such behavior is considered important for stimulating 
the wasps to emigrate and is called “breaking behavior” (Naumann 
1975). 
Increasing numbers of wasps drag on vegetation along the route to 
the new nest and are gradually replaced by increasing numbers of 
follower wasps until numerous wasps are flying along the entire 
* Manuscript received by the editor Feburary 4, 1980. 
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