The giant garden slug Limax maximus Linnaeus, 1758 (Limacidae, Pulmonata) is considered one of the most widely spread terrestrial molluscs in the world and is a formidable pest of agricultural and horticultural crops. This slug was recently introduced to Japan, where its population is now rapidly increasing and spreading. A naturalised population of L. maximus was first discovered in Hokkaido, Japan, in 2012 in the isolated natural forest of Maruyama Forest Park in Sapporo City, and the species has become common in this area. In the present study, we investigated observations of L. maximus reported by ordinary citizens acting as "citizen scientists" to assess the recent expansion of this invasive slug. We posted an announcement in the local newspaper requesting reports of the occurrence of L. maximus via e-mail and analysed 38 observations provided by local citizens. As a result of these reports, 16 naturalised populations of L. maximus were detected in Hokkaido, several of which were quite far from the original population in Sapporo City. Moreover, a terrestrial macrophagous leech, Orobdella kawakatsuorum Richardson, 1975 (Arhynchobdellida, Orobdellidae), is reported as a potential native predator of L. maximus for the first time.

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Background: The Bahamas is a region with high diversity of marine molluscs and a high rate of endemism. In certain groups of heterobranchs it is common to observe a distribution pattern consisting of an endemic species from the Bahamas, sister to a widespread western Atlantic species living in the same kind of habitat. This would suggest an allopatric speciation process and lack of gene flow between the Bahamian and the Caribbean subprovinces. However, the Bahamian aeolidacean mollusc Spurilla dupontae is sister to an eastern Atlantic congener. Results and Conclusions: In this paper, S. dupontae, to date considered endemic to the Bahamas, is recorded for the first time in the Caribbean subprovince (Martinique).