Oscheius tipulae in Italy: Evidence of an Alien Isolate in the Integral Natural Reserve of Montecristo Island (Tuscany)

Abstract

Montecristo Island is an integral natural reserve of the Tuscan Archipelago National Park (Central Italy), characterized by a peculiar assemblage of flora and fauna, with several endemic taxa, and also with a high number of alien species. During a soil survey, we found an alien Oscheius tipulae Lam & Webster, 1971 isolate, phylogenetically close to others from South America. In this article, we examined the possible pathways of introduction of this nematode. Because of the high number of alien plants in this protected area and the low desiccation survival ability of O. tipulae, we hypothesized that the presence of this alien nematode isolate may be related to the soil of introduced plants, although historical association with plant-associated invertebrates is also possible. Further studies with more populations and marker molecules are necessary to investigate the distribution of O. tipulae and the possible impact on this natural reserve.

Keywords: Central Italy; alien nematode isolate; desiccation assay; genetics; nematode introduction.

Fig. 1

Phylogenetic identification of Oscheius tipulae MC1 based on ITS locus. The tree is displayed in a condensed form with a 50% cut-off value and a 0.9 posterior probability limit; the identifying marks of strains are followed by their collection sites in brackets. Bootstrap support values maximum likelihood and posterior probability Bayesian inference were reported for each node.

Fig. 2

Distribution of Oscheius tipulae isolates used for the phylogenetic tree reconstruction. The inset shows the geographical position of the sampling locations in Italy and the phylogenetic groupings.

Fig. 3

Donor countries of alien plants found in Montecristo Island.

Fig. 4

Number of visitors in Montecristo Island from 1984 to 2014. Histogram describes the origin of people from “other countries.” Tourists from Russia, United States, Norway, Brazil, Canada, and Egypt are present in the register, but their number is unknown.

Fig. 5

Number of live Oscheius tipulae nematodes (mean ± SE) in desiccation stress tolerance trials. Different letters up the histograms indicate significant differences at P < 0.05.