The endemic Hawaiian amber snail Succinea caduca is unusual in a number of ways among Hawaiian land snails, including its multi-island distribution, mesic, coastal, lowland habitat preference, and the fact that its populations appear to be thriving despite the catastrophic declines experienced by almost all other native Hawaiian snail species. They are active only following heavy, sustained rainfall, when thousands of individuals can be observed mating and feeding, presumably on algal and/or fungal blooms on the surfaces of boulders and tree bark. The main photograph shows typical coastal habitat on the island of Lanai, with evidence of recent heavy rains seen in the turbid nearshore surface water. Insets show a haplotype network, S. caduca close up, and dozens of S. caduca adhered to a piece of tree bark. On pages 2422-2435, Holland and Cowie examine population structure among S. caduca populations from the main Hawaiian Islands, demonstrating deep genetic breaks and evidence for extensive over-water passive dispersal between islands.
Photo credits: Brenden Holland.