  Using the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope, we
have obtained mid-infrared photometry for 25 and 18 low-mass members of the IC
348 and Chamaeleon I star-forming clusters, respectively (>M6, M<=0.08 Msun).
We find that 42+/-13% and 50+/-17% of the two samples exhibit excess emission
indicative of circumstellar disks. In comparison, the disk fractions for
stellar members of these clusters are 33+/-4% and 45+/-7% (M0-M6, 0.7
Msun>=M>=0.1 Msun). The similarity of the disk fractions of stars and brown
dwarfs is consistent with a common formation mechanism and indicates that the
raw materials for planet formation are available around brown dwarfs as often
as around stars.
