  We report optical spectroscopic observations of the Be/gamma-ray binaries
LSI+61303, MWC 148 and MWC 656. The peak separation and equivalent widths of
prominent emission lines (H-alpha, H-beta, H-gamma, HeI, and FeII) are
measured. We estimated the circumstellar disc size, compared it with separation
between the components, and discussed the disc truncation. We find that in
LSI+61303 the compact object comes into contact with the outer parts of the
circumstellar disc at periastron, in MWC 148 the compact object goes deeply
into the disc during the periastron passage, and in MWC 656 the black hole is
accreting from the outer parts of the circumstellar disc along the entire
orbit.
  The interstellar extinction was estimated using interstellar lines. The
rotation of the mass donors appears to be similar to the rotation of the mass
donors in Be/X-ray binaries. We suggest that X-ray/optical periodicity of about
1 day deserves to be searched for.

Solar and Stellar Astrophysics