1969] 
Davis and Russell — Commensalism 
267 
Table 2. Food used in rearing 20 R. moerens nymphs to maturity. Range, 
mean total nymphal period, and number reared is given for 
6 Drosophila (frozen) and 22-27 
each food type.* 
23.0 
Mean total 
nymphal period 
Nymphs 
Food type 
Range 
(days) 
6 
Drosophla (frozen) 
22-29 
24.5 
7 
Avocado flower buds 
25-36 
31.1 
5 
Honeysuckle stamens 
22-27 
24.8 
2 
Drosophila (frozen) and 
Honeysuckle stamens 
22-24 
23.0 
*Fruit flies, Drosophila melanogaster , were cultured, frozen, then thawed 
before feeding to bugs. Honeysuckle stamens and avocado buds were col- 
lected from the study area, where they were seen being fed upon by the bugs. 
female reared on a mixture of honeysuckle stamens and Drosophila 
matured like the latter group. Four males reared on avocado buds 
matured in an average of 32.5 days. The average was 27 days for 
the 2 fed Drosophila and 24.8 days for the 5 using honeysuckle 
stamens. The single male fed a mixture of the flies and honeysuckle 
matured in 22 days. The resulting adults were maintained on one 
of the three dietary regimens on which the nymphs were reared. The 
8 females lived for an average of 41.3 days, while the 12 males sur- 
vived for an average of only 7.8 days. The females lived for an aver- 
age of 41 days on avocado buds and 44.5 days on Drosophila. The 
males averaged 12 days on Drosophila, 8.6 on honeysuckle and 5 days 
on avocado. The longest lived specimen was a female, reared on 
flies, which lived a total of 80 days; 56 of them as an adult. 
On two occasions, adult female spiders were put in a dish to spin 
a web for rearing mirids. The webs were in poor condition, but 
egg sacs were constructed in the corner of each dish. The female 
spiders spent about 80% of their time sitting on the egg sacs, appar- 
ently guarding them. To see if the mirids would feed on these eggs, 
the spider was removed and one adult and two nymphal mirids were 
placed in each of the two dishes. No other food was added, but a 
wick was provided for moisture. The mirids were never observed 
feeding, although from time to time they would walk across the egg 
sacs. All had died within a week. 
Spider Prey 
In the eleven trials using first and 2nd instar nymphs in cages with 
immature spiders, the mirids lived for an average of 4.4 days (range 
2-10 days) before being killed or eaten (eaten 9 of 1 1 times). Two 
