Collective movement increases initial accuracy and path efficiency in talitrid amphipod orientation

Talitrid amphipods are an extensively studied system for navigation due to their robust ability to navigate back to the optimal burrowing zone after foraging, and could be a model system in which to study the impacts of collective behavior on short-distance navigation and orientation. We investigated whether talitrid amphipods (Megalorchestia pugettensis) differ in their orientation abilities when released individually versus in a group. When released individually, the amphipods took longer to start moving (p<0.001), traveled longer paths (p=0.003), moved faster (p=0.016), had a different initial bearing (p=0.003), and exhibited more spread in their initial bearing (p=0.009) than when released in groups. There was no difference between individuals and groups in terms of their trial time, nor in the direction or spread of their final orientation. This study introduces a tractable, invertebrate species in which to study the impacts of collective movement and reveals previously unexamin..., Experiments were conducted between July - August, in 2021 and 2023. Animals were collected from a 50 meter stretch of sandy beach in Seattle, WA (47.66, -122.43). All animals were collected within ~20 minutes of each other and used in experiments within 30 minutes of collection. The trials were conducted between 8:00 am and 1:00 pm while air temperatures ranged from 14°C to 26°C. The arenas consisted of a circular, clear plastic dish (diameter 27 cm, depth of 3.1 cm), held 43 cm over the ground by PVC pipes. The cameras used to film all trials were the Apexcam M80 Air Action Camera. The temperature was recorded at the beginning of each trial by using the My Location section of the iOS Weather app (iPhone 14, iOS version 16.5.1). Cloud cover was categorized as either “cloudy” or “sunny” where cloudy days were defined as days where more than 50% of the sky had cloud cover and the sun was obscured. In addition, there was a nearby forest fire from August 14th-17th 2021, so trials conducted ..., , # Data from: Collective movement increases initial accuracy and path efficiency in talitrid amphipod orientation

Dataset DOI: [10.5061/dryad.7m0cfxq3x](https://doi.org/10.5061/dryad.7m0cfxq3x)

## Description of the data and file structure

Talitrid amphipods are an extensively studied system for navigation due to their robust ability to navigate back to the optimal burrowing zone after foraging and could be a model system in which to study the impacts of collective behavior on short-distance navigation and orientation. We investigated whether talitrid amphipods (*Megalorchestia pugettensis*) differ in their orientation abilities when released individually versus in a group. When released individually, the amphipods took longer to start moving (p<0.001), traveled longer paths (p=0.003), moved faster (p=0.016), had a different initial bearing (p=0.003), and exhibited more spread in their initial bearing (p=0.009) than when released in groups. There was no difference between individuals ..., ,