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Psyche 
[Vol. 90 
elucidate the within-nest biology of E. pugnata, including develop- 
ment, nesting and provisioning behaviors, and nest architecture. 
Methods and Materials 
Within-nest behaviors were observed from a wooden box 
(lXlX3m) located in a green house (6X6X5m). Nests of 2 types were 
fastened to cardboard sheets which were then mounted onto the 
observation box. 1. Elderberry sticks that had been drilled (9mm 
diameter) and planed lengthwise, were covered with a glass plate to 
expose the boring; and 2. Glass tubes with plastic inserts were taped 
to cigarette filters to facilitate handling (8mm diameter) (Fig. 1). 
The end of the glass tube that served as the nest entrance was dipped 
in black India ink and inserted into a cork ring to allow the bee 
secure footing (Torchio 1972). Nests were darkened with paper slip 
covers until cell construction began. Removal of slip covers after the 
onset of nesting did not appear to affect females, though no females 
nested in uncovered nests. A small swamp cooler mounted above 
the wooden box maintained temperatures below 40° C in order to 
avoid egg-larval mortality due to heat buildup. 
Commercial Helianthus annuus L. and 3 garden variety compos- 
ites (Cosmos, Bachelor’s Button, Callendula) were provided as 
pollen and nectar sources in beds of approximately equal size. 
Because of its usefulness in similar studies of other megachilids 
(Parker & Tepedino 1982, Frohlich 1983) Oenothera hookeri 
T. & G. was used as nest partition material. A tape recorder, 
otoscope, and stopwatch facilitated within nest observations. 
As nests were completed, most were removed and replaced. Com- 
pleted nests were incubated at 30° C and used to study aspects of 
larval development and behavior. The glass plates on the elderberry 
sticks were removed prior to incubation and replaced with clear 
plastic food wrap. The plastic inserts of the glass tube nests were 
also removed and provisions containing eggs were cut away and 
placed separately in BEEM® capsules, commonly used in electron 
microscopy. As each egg eclosed, the emergent instar was marked 
with a tiny spot of pink fluorescent Day-Glo® powder applied with a 
watchmaker’s forceps. Disappearance of spots indicated molting 
and new marks were made. Larvae were inspected several times a 
day and various behaviors associated with each instar were observed 
