DOI: 10.5061/dryad.djh9w0w5q
title: Data from: predator-induced defences under tropicalisation: a biogeographic approach

description: Aim: The biogeography of predator-induced defences is an
 understudied area of predator-prey dynamics. Range overlap with predators
 that induce the response and local demographics (e.g., prey abundances)
 are likely to be important factors for determining the biogeographic
 distribution of induced defences within species. However, with climate
 warming, range expanding warm-water predators are increasingly preying
 upon temperate species. This is a consequence of a wider phenomenon known
 as tropicalisation. We aim to determine: (i) if individuals of a temperate
 barnacle with induced defences (“bent morphs”) are primarily present where
 they co-occur with range-expanding warm-water predators (muricid snails)
 and, (ii) if bent morphs are size-structured within populations. Location:
 North-eastern Pacific rocky intertidal zone (~26-40ºN)
 Taxon: Tetraclita rubescens (Nilsson-Cantell, 1931), Balanomorpha
 Methods: We use photo quadrats from sites across the range of T.
 rubescens to determine the biogeographic distribution of populations with
 bent morphs and to assess size-structure. We use a combination of field
 surveys, literature, and museum occurrences to assess range overlap
 between cool and warm-water predators of T. rubescens and their
 association with populations with bent morphs and abundance patterns of T.
 rubescens. Results: Bent morphs are commonly found within the
 equatorward portion of the species’ range (where abundances are highest),
 in populations overlapping with range expanding warm-water predators. Bent
 morphs primarily occur within the smaller size classes. Main
 conclusions: To be partly resilient to the effects of
 tropicalisation, temperate prey must acclimatize/adapt to altered
 predator-prey dynamics. Predator-induced defences are one way to do this.
 We show that bent morphs within a temperate prey species (T. rubescens)
 are largely restricted to populations that overlap with large-bodied and
 range-expanding warm-water predators. This is evidence for the partial
 resilience of T. rubescens to tropicalisation and provides the rationale
 for further exploration of the eco-evolutionary consequences of
 tropicalisation in this study system and others.
description: The datasets come from analysis of photo quadrats taken in the
 field from sites spread across the geographic range of
 <em>Tetraclita rubescens</em>.  Size data of each barnacle and
 morph were taken using the software programme ImageJ. We also used
 occurrence records from iNaturalist to supplement our datasets. The
 methods section of the paper provides more detail. 
description: # Predator-induced defences under tropicalisation: a biogeographic
 approach # Authors: # Phillip B. Fenberg, Rodrigo Beas-Luna, Boris Igi,
 Moira A. MacLean, David A. Paz-Garca, Peter T. Raimondi, Jacqueline L.
 Sones, Karolina M. Zarzyczny, Eric Sanford *** ## Description of the data
 and file structure The datasets are in a single excel file with five
 sheets. Each sheet is clearly labelled beginning with which figure the
 data are from (Fig 3, 4, and 5). The data in sheet Fig\_3\_data\_iNat come
 from iNaturalist. Each cell represents a single iNaturalist photograph
 arranged by latitude. No bent morphs were found in these records. The data
 in sheet Fig\_4\_data contains the size-frequency data used in Fig. 4 for
 each site. Individual basal shell diameters (mm) in column A, Morph (conic
 or bent) in column B, and site in Column C. The data in sheet
 Fig\_5\_data\_abundance have the abundance data (expressed as % cover;
 column B) versus Latitude (column A). These data are from field surveys
 undertaken by MARINe (https://marine.ucsc.edu/index.html). The data in
 sheet Fig\_5\_muricid\_ranges are the geographic range data for each
 predator known to feed on T. rubescens are in columns H-L. More
 information about methodology used to obtain all data can be found in the
 main paper and the supplementary file.