European Sand Hopper

Appearance

"Talitrus saltator" reaches lengths between 8.2 millimetres and 16.5 millimetres, with males being slightly larger than females. The body is greyish-brown or greyish-green in colour, with a single pair of black eyes. It has a distinct pair of antennae, with one antenna more robust than the other.

Distribution

"Talitrus saltator" is found around the coasts of the North Sea and north-east Atlantic Ocean from southern Norway to the Mediterranean Sea. In most of its range, its daily cycle is strongly linked to the tides, with daily migrations of up to 100 metres, but where there are no significant tides, visual cues are used instead.

Behavior

Mating occurs in "T. saltator" once the photoperiod exceeds 14 hours; this is in contrast to other shoreline animals such as isopods which use air temperature or sea temperature to control breeding times. Mating occurs during the animal's nightly migration down the beach, after the female has moulted. Broods of 13–15 eggs are carried by the females. When they first hatch, juveniles are sensitive to desiccation but are unable to burrow, and so they live in washed up seaweed with a humidity of 85%–90%. Although the juveniles become sexually differentiated within a few months, they do not contribute to the second reproductive wave later in the year, but first reproduce the following year. Females die before the males, in their second winter. During the winter, adults burrow into the sand until they reach a moisture content of 2%; this may require them to dig up to 50 centimetres deep.

Habitat

"Talitrus saltator" spends the day buried at depths of 10–30 centimetres above the strandline, but emerges at night on the falling tide to feed. Their diet is composed chiefly of the rotting seaweed which accumulates on the strandline. "T. saltator" is an important food source for shore birds.