1976] 
Jackson — Phidippus johnsoni 
245 
numbers table. All observations were made between one and 
four hours after the lights came on in the laboratory. 
Interactions Between Herpyllus hesperolus and 
Phidippus johnsoni Females Inside Their Nests 
After oviposition, P. johnsoni females tend to remain in their 
nests with their eggs; and each P. johnsoni in this set of observa- 
tions had eggs in her nest. Observation began when a H. hes- 
perolus was taken from its cage and introduced through a hole 
in the cage of the P. johnsoni. Once the H. hesperolus touched 
the nest, observation continued for 15 min. 
During one of the five observations, the P. johnsoni slowly 
departed her nest and approached the gnaphosid that was walk- 
ing past the nest, approximately 2 cm away. When 1 cm from 
the H. hesperolus, the P. johnsoni leaped on the gnaphosid and 
subsequently consumed it. The H. hesperolus was 8 mm, and 
the P. johnsoni was 1 1 mm. The other four gnaphosids had 
body lengths greater than that of the salticids, approximately 
15 mm compared to 10 to 11 mm in each case. In each of these 
observations, the H. hesperolus walked onto the nest, and the 
P. johnsoni responded with various behavioral elements that 
have been previously described in detail for interactions between 
conspecific males and females at nests (Jackson, 1976). These 
will be briefly described again here. 
Pull on Nest. With the tarsi of her first pair of legs in contact 
with the inner dorsal surface of the nest the female moves her 
legs ventrally, pulling the dorsal layer of silk until it contacts 
the ventral layer. 
Bump. The female rapidly extends her legs, causing her cephalo- 
thorax to hit the inner dorsal nest surface. 
Stab. With her tarsi oriented toward the silk, the female rapidly 
moves her first pair of legs ventrally. As her tarsi hit the silk, 
pin-point bulges are made temporarily in the silk. 
Strike. The female’s elevated first pair of legs are rapidly moved 
forward and downward, such that the tarsi contact the substrate 
or the other spider. This behavior was performed with the P. 
johnsoni standing in the nest door, facing outward. Doors are 
slit-shaped openings in the nest through which the spider enters 
and departs. 
