  We consider the $osp(1|2)$-invariant bilinear operations on weighted
densities on the supercircle $S^{1|1}$ called the supertransvectants. These
operations are analogues of the famous Gordan transvectants (or Rankin-Cohen
brackets). We prove that these operations coincide with the iterated Poisson
and ghost Poisson brackets on ${\mathbb R}^{2|1}$ and apply this result to
construct star-products involving the supertransvectants.
