Selfish herd effects in aggregated caterpillars and their interaction with warning signals

Larval Lepidoptera gains survival advantages by aggregating, especially when combined with aposematic warning signals, yet reductions in predation risk may not be experienced equally across all group members. Hamilton’s selfish herd theory predicts that larvae that surround themselves with their group mates should be at lower risk of predation, and those on the periphery of aggregations experience the greatest risk, yet this has rarely been tested. Here, we expose aggregations of artificial ‘caterpillar’ targets to predation from free-flying, wild birds to test for marginal predation when all prey are equally accessible, and for interaction between warning colouration and marginal predation. We find that targets nearer the centre of the aggregation survived better than peripheral targets and nearby targets isolated from the group. However, there was no difference in survival between peripheral and isolated targets. We also find that grouped targets survived better than isolated targets ..., , , # Selfish herd effects in aggregated caterpillars and their interaction with warning signals

[https://doi.org/10.5061/dryad.1ns1rn928](https://doi.org/10.5061/dryad.1ns1rn928)

The dataset contains all data collected in the field. Data related to the predation rate of artificial 'caterpillar' targets were separated into various treatments based on target colour and position relative to one another.

## Description of the data and file structure

The data file ('field_data.csv) contains all data collected in the field.

Variables (columns) in all data files are described as follows:

* 'Platform_ID' = numbers for individual platforms
* 'Block' = experimental block number
* 'Colour' = colour of target (Apos = aposematic)
* 'Group_pos' = position of targets in the 'grouped' treatment
* 'Plat_pos' = position of the targets on the platform, either grouped or isolated
* 'Survival_4h' = individual target survival after the 4h check (0/1 = predated/survived)
* 'Survival_24h' = in...