DOI: 10.5061/dryad.9zw3r22sc
title: Relative size matters: Eyespots on large insect prey deter small arthropod predators

description: Circular chromatic patterns that appear to resemble vertebrate eyes
 (“eyespots”) are commonplace in the animal kingdom and are widely believed
 to have evolved as an anti-predator defence. For example, experiments have
 shown that eyespots on caterpillar-like pastry baits can deter predation
 by domestic chicks. However, little is known about the extent to which
 eyespots deter (or promote) attack by arthropod predators. Here we
 describe two separate experiments in which salticid spiders (Salticus
 scenicus) and Chinese mantids (Tenodera sinensis) were presented with a
 choice of mealworm (Tenibrio molitor) larvae with or without eyespots. In
 a complementary experiment we observed the time taken for adult Chinese
 mantids to attack hawkmoth (Manduca quinquemaculata) larvae of two
 different sizes, with and without eyespots. All three experiments indicate
 that eyespots on insect larvae can deter predation, so long as the larvae
 with eyespots are sufficiently large compared to the size of the arthropod
 predator. In smaller caterpillars the selective benefit of eyespots may
 diminish and may even be selected against. Our results suggest that small
 arthropods can show an aversion to large prey with eyespots and help
 explain the presence of eyespots in medium-sized caterpillars, since these
 traits are unlikely to deter avian predators.
description: # Relative size matters: Eyespots on large insect prey deter small
 arthropod predators Three separate experiments were conducted to assess
 whether eyespots on insect larvae detered predation by arthropod
 predators. **Experiment 1** presented mealworms with and without eyespots
 to zebra jumping spiders (*Salticus scenicus*) of different sizes in a
 binary choice experiment. The variable names in the spider binary choice
 dataset are as follows: * spider: spider ID (1-50) * size: the
 spider's total body length in mm * Neither0Eye1NoEye2: code for the
 type of mealworm attacked by the spider in its binary choice (0 - neither,
 1 - eyespotted, not eyespotted) **Experiment 2** presented mealworms with
 and without eyespots to Chinese mantis (*Tenodera sinensis*) of different
 sizes in a binary choice experiment. The variable names in the spider
 binary choice dataset are as follows: * Individual: the individual mantis
 (1-80) * Instar: its instar (3-6) * Neither0Eye1NoEye2: code for the type
 of mealworm attacked by the mantis in its binary choice (0 - neither, 1 -
 eyespotted, not eyespotted) **Experiment 3** presented hawkmoth larvae
 (*Manduca quinquemaculata*) of two size classes to adult Chinese mantis
 (*Tenodera sinensis*) and evaluated the time taken for the mantis to
 approach and attack these larvae. The variable names in the mantis attack
 latency dataset are as follows: * Day: Experimental day (1-4) *
 Individual: Mantis ID (1-12) * Order: Order of presentation of the 4
 treatments (1-4); see SI for the exact sequences * Treatment: 0 -
 mealworm; 1 - large, eyespot; 2 - large, no eyespot; 3 - small, eyespot; 4
 - small, no eyespot * Eyespot: 0 - no, 1 - yes * Size: 1 - small, 2 - big
 * First: time to first base or end of observation (in seconds) * Attacked:
 time to attack or end of observation (in seconds) * Status1: 1 - event
 (passing first base) occurred, 0 - event did not occur in observation
 period * StatusA: 1 - event (attack) occurred, 0 - event did not occur in
 observation period.