1971] 
Alcock — Behavior of Stinkbug 
217 
to one side to achieve the same effect (Fig. 3). 1 his behavior pre- 
sumably increases the rapidity with which the bug is warmed by 
directly exposing the maximum surface area of the animal to the sun. 
By midday basking was on the wane (Fig. 2) although in those areas 
where the afternoon sun reached blackberry leaves some bugs could 
be seen basking in the late afternoon. (The figures are based on data 
collected from an area on the eastern side of the lot which was well- 
shaded by 16.00.) 
Feeding Behavior 
E. conspersus feeds on fruits and is in fact extremely catholic in 
its tastes (Borden, Madsen and Retan, 1952). Many bugs were 
watched as they fed on grasses and on the fruit and stems of the 
blackberry Rubus laciniatum. Although I have no quantitative evi- 
dence to confirm this point, it seemed clear that the bugs preferred, 
both as nymphs and adults, unripe pinkish-green blackberries to fully 
ripe fruit. Bugs also fed on an ornamental, Pyrecantha coccinea , and 
on the pods and stems of a sweet pea, Lathy rus latifolius. But by 
far the most remarkable choice of a foodplant was the bracken fern, 
Pteridium aquilinum. This plant occurred in scattered patches along 
the edge of the lot amidst the blackberry bushes. Both adults and 
nymphs were commonly found on the fern; adults were seen many 
times with their rostrums inserted into the stem of the plant. 
Groups of adults congregated on a few ferns in the early summer 
and second generation bugs occurred in large numbers on almost all 
living ferns in the late summer. Those few ferns which had hosted 
bugs in the early summer turned yellow and died while the remainder 
on which few or no stinkbugs had been seen remained quite healthy. 
The stems of dying ferns were covered with small reddish marks 
presumed to be points of insertion of the bugs’ rostrums. There was a 
complete die-off of all ferns in mid-September long before the first 
frosts. It seems likely that the stinkbugs were capable of killing their 
fern hosts. On the other hand, blackberry stems which supported 
large numbers of bugs for many days did not die back or appear 
injured in any way. 
Feeding activity was most pronounced during the afternoon with 
many bugs moving from leaves to blackberry stems during this time 
(Fig. 1). 
Natural Enemies 
E. conspersus was the prey of a number of wasps living in the lot. 
About six specimens of Dryudella sp., a tiny digger wasp, nested in 
an open path which passed through a grassy field bordering a large 
