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Context. Most observational studies so far point towards brown dwarfs sharinga similar formation mechanism as the one accepted for low mass stars. However,larger databases and more systematic studies are needed before strongconclusions can be reached. Aims. In this second paper of a series devoted tothe study of the spectroscopic properties of the members of the Lambda OrionisStar Forming Region, we study accretion, activity and rotation for a wide setof spectroscopically confirmed members of the central star cluster Collinder 69to draw analogies and/or differences between the brown dwarf and stellarpopulations of this cluster. Moreover, we present comparisons with other starforming regions of similar and different ages to address environmental effectson our conclusions. Methods. We study prominent photospheric lines to deriverotational velocities and emission lines to distinguish between accretionprocesses and chromospheric activity. In addition, we include information aboutdisk presence and X-ray emission. Results. We report very large differences inthe disk fractions of low mass stars and brown dwarfs (~58%) when compared tohigher mass stars (26+4-3%) with 0.6 Msun being the critical mass we find forthis dichotomy. As a byproduct, we address the implications of the spatialdistribution of disk and diskless members in the formation scenario of thecluster itself. We have used the Halpha emission to discriminate amongaccreting and non-accreting sources finding that 38+8-7% of sources harboringdisks undergo active accretion and that his percentage stays similar in thesubstellar regime. For those sources we have estimated accretion rates.Finally, regarding rotational velocities, we find a high dispersion in vsin(i)which is even larger among the diskless population.

Spectroscopy of Very Low Mass Stars and Brown Dwarfs in the Lambda Orionis Star Forming Region