  Circumstellar debris disks are important because of their connection to
planetary systems. An efficient way to identify these systems is through their
infrared excess. Most studies so far concentrated on early-type or solar-type
stars, but less effort has gone into investigating M dwarfs.
  We characterize the mid-infrared photometric behavior of M dwarfs and search
for infrared excess in nearby M dwarfs taken from the volume-limited RECONS
sample using data from the WISE satellite and the 2MASS catalog. Our sample
consists of 85 sources encompassing 103 M dwarfs. We derive empirical infrared
colors from these data and discuss their errors. Based on this, we check the
stars for infrared excess and discuss the minimum excess we would be able to
detect.
  Other than the M8.5 dwarf SCR 1845-6357 A, where the excess is produced by a
known T6 companion, we detect no excesses in any of our sample stars. The
limits we derive for the 22um excess are slightly higher than the usual
detection limit of 10-15% for Spitzer studies, but including the [12]-[22]
color in our analysis allows us to derive tight constraints on the fractional
dust luminosity L_dust/L_star. We show that this result is consistent with M
dwarf excesses in the mid-inrared being as frequent as excesses around
earlier-type stars. The low detection rate could be an age effect. We also
present a tentative excess detection at 22um around the known cold debris disk
M dwarf AU Mic, which is not part of our statistical sample.
  There is still no clear detection of a mid-infrared excess around any old
(>30 Myr) main-sequence M dwarf. It is unclear whether this is due to a
different dust evolution around M dwarfs or whether this is an age effect
combined with the diffculties involved in searching M dwarfs for infrared
excesses. A significantly larger sample of well-studied M dwarfs is required to
solve this question.
