Invasion ecology: Can the feeding on a non-indigenous plant influence the invasion success of a non-indigenous crayfish?

A non-indigenous tree, Ailanthus altiissma and crayfish, Orconectes rusticus have demonstrated to have considerable success in negatively impacting native flora and fauna in southeastern Pennsylvania. The objective of this study was to determine if the foliage of an invasive tree species, Ailanthus altissima affected the growth, survivorship and behavior of native and non-indigenous crayfish fauna. We conducted a feeding experiment in a third order, forested stream in Lancaster County, Pennsylvania (October – December). Field microcosms contained either an Orconectes rusticus or Cambarus bartonii (native species) crayfish and a 5g pack of Ailanthus altissima or Lireodendron tulipfera leaves as food. Preliminary results indicate that the C. bartonii grew significantly more over this period than O. rusticus when fed on the A. altissima leaves (Anova, F = 23.76; P < 0.01). Dominance behavioral experiments indicate that those C. bartonii crayfish exposed on the long term to A. altissima leaves were dominant over any O. rusticus feeding treatment. While encouraging, our results are very preliminary. However, they might illustrate an interesting relationship in the processing of organic matter between non-indigenous and native crayfish and how a non-indigenous plant may negatively influence the invasion success of a non-indigenous crayfish.