chesson_alpha           Chesson's alpha, or Vanderploeg and Scavia's
                        selectivity coefficient (W)
electivity              Algorithms for electivity indices and measures
                        of resource use versus availability.
ivlev_electivity        Ivlev's electivity, E
ivlev_forage            Ivlev's forage ratio, E'
jacob_electivity        Jacob's modified electivity, D
jacob_forage            Jacob's modified forage ratio, Q
moth_distrib            Distribution of gypsy moth larvae, Lymantria
                        dispar, feeding in a deciduous forest in
                        southwestern Quebec, Canada.
moth_elect              Electivities of gypsy moth larvae
strauss_linear          Strauss' linear index, L
vs_electivity           Vanderploeg and Scavia's relativised
                        electivity, E*
