TOOL USE IN DIGGER WASPS 
(HYMENOPTERA: SPHECINAE)* 
By H. Jane Brockmann 
Department of Zoology, University of Florida 
Gainesville, FL 32611 
“Tool-use” by a digger wasp was first described by Williston 
(1892) and Peckham and Peckham (1898). They observed this 
remarkable behavior in two species of ground-nesting wasps, 
Ammophila urnaria and Ammophila aberti. The female digs a bur- 
row in the ground, provisions it with paralyzed caterpillars, lays an 
egg on top of the food cache and then fills the burrow with soil or 
stones. While closing the nest, the wasp picks up a pebble in her 
mandibles and pounds the substrate with it, thereby compacting and 
settling the soil that was used to fill the nest. The Peckhams said that 
in this behavior, the wasp had “...improvised a tool and made 
intelligent use of it.” The behavior received much publicity (see 
Frisch, 1940; Lamburn, 1955; Evans, 1959) and several authors saw 
tool using as evidence that wasps have highly plastic, intellectual 
powers (Rau and Rau, 1918; McDougall, 1923; Bouvier, 1922). 
Others have interpreted the behavior differently. Rather than think- 
ing of tool using as insightful, they described the behavior as a 
species-typical, instinctive act (Holmes, 1911; Frisch, 1940; Bae- 
rends, 1941; Evans, 1959) or possibly an example of trial-and-error 
learning (Thorpe, 1956). Although some have questioned whether 
the behavior should be considered true tool use (Frisch, 1940; 
Evans, 1959), the action clearly falls under the current definition 
(Alcock, 1972; Wilson, 1975). When Ammophila uses a pebble as a 
hammer, she is manipulating an object, not internally manufac- 
tured, with the effect of improving her efficiency in altering the 
position, form or condition of some other object in the environment 
(Beck, 1980; Alcock, 1972). How did such extraordinary behavior 
evolve? 
The Sphecidae are a large family of solitary (usually), hunting 
wasps. In general, the female constructs a nest which she provisions 
with one to several paralyzed arthropod prey as food for the single 
* Manuscript received by the editor September 24, 1984. 
309 
