Dependence of the endangered arboreal snail Satsuma (Luchuhadra) eucosmia eucosmia (Camaenidae) on Ficus (Moraceae) trees as its main habitat

ABSTRACT

The specific vegetation required by the endangered arboreal snail Satsuma (Luchuhadra) is subtropical rainforest characterised by Ficus tree species (Moraceae), such as Ficus virgata and Ficus microcarpa. This study aimed to elucidate the tree habitat preference of Luchuhadra eucosmia eucosmia inhabiting the northern part of Okinawa Island, which is an area characterised by different tree communities containing various species of Ficus. First, the preference for Ficus trees by the snails was evaluated by comparing the number of empty shells in quadrats where Ficus trees were present and absent. Noticeably, more shells were found in Ficus-occupied quadrats. Second, a belt transect survey was conducted to analyse the relationship between the abundance of live snails and the horizontal crown width of six Ficus species. In total, 72 live snails were recorded, but their presence was not proportional to the relative dominance of Ficus species, with more snails occurring on established F. virgata and Ficus ampelas. Overall, our results support previous studies, demonstrating that Ficus trees represent a critical habitat resource for S. (L.) eucosmia eucosmia. However, further investigation of the aerial distribution of snails at night and during the reproductive season is necessary to determine the true resource usage pattern of this snail species.

KEYWORDS:

• Habitat choice
• mantle climbing plants
• Ryukyu Islands
• sub-tropical
• tree preference

Acknowledgements

We thank Dr Yuichi Kameda for identifying snails and providing comments. The paper was greatly improved by the useful comments from an anonymous reviewer and the editor.

Disclosure statement

No potential conflict of interest was reported by the authors.