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For a digraph $D$, the niche hypergraph $N\mathscr{H}\left(D\right)$ of $D$ is the hypergraph having the same set of vertices as $D$ and the set of hyperedges $E\left(N\mathscr{H}\right(D\left)\right)=\{e\subseteq V(D):|e|\ge 2$ and there exists a vertex $v$ such that $e=N_D^{-}\left(v\right)$ or $e=N_D^{+}\left(v\right)\}$. A digraph is said to be acyclic if it has no directed cycle as a subdigraph. For a given hypergraph $\mathscr{H}$, the niche number $\widehat{n}\left(\mathscr{H}\right)$ is the smallest integer such that $\mathscr{H}$ together with $\widehat{n}\left(\mathscr{H}\right)$ isolated vertices is the niche hypergraph of an acyclic digraph. C. Garske, M. Sonntag and H. M. Teichert (2016) conjectured that for a linear hypercycle...