A snail's space sets a snail's pace: movement rates of lavigeria gastropods in lake tanganyika, East africa

Abstract

Endemic Lavigeria gastropods are diverse and common in the benthos of Lake Tanganyika. We used in situ studies of marked individuals to quantify rates of daily movement by three species, and test the effects of size, sex, reproductive status and parasitism on movement. Average net travel distance was 50 cm day 21 , which corresponds to about 20 times shell length. Male L. coronata moved significantly farther than L. coronata females or L. grandis, and L. nassa of either sex. There were also significant differences among individuals within each group; however, these differences were not predicted by size, reproductive status or parasitism. We interpret greater movement of L. coronata males as a reflection of mate searching; the ratio of males to non-brooding, non-parasitized females was three times as high in L. coronata (21:1) as in the other species (6:1). Our results indicate that these snails are capable of moving considerable distances, and that the highly localized distribution of L. coronata populations is not simply a reflection of limited movement by individual snails.