Figure 1.
Ant-mimicking spider and two potential predators: i) Peckhamia picata, ant-mimicking jumping spider; ii) Camponotus nearcticus, putative ant model and a predator; iii) Sceliphron caementarium, spider-hunting predatory wasp.
(Figures not to scale. Ant and ant-mimic photos by J. Coddington, wasp photo by D.Uma).
Figure 2.
Ant-mimicking spider does not elicit predatory response from chemically-oriented spider-hunting wasps: Sceliphron caementarium wasps readily stung non-mimetic jumping spiders (Phidippus putnami) but never stung ant-mimicking spiders (Peckhamia picata) (binomial probability, P = 0.035).
Figure 3.
Ant-mimicking spider does not elicit aggressive response from ants: Camponotus nearcticus ants contacted all test subjects equally (Friedman non-parametric ANOVA, F = 1.71, P = 0.63 d.f. = 3), but displayed differences in aggressive response towards them (Friedman non-parametric ANOVA, F = 31.12, P = 0.0001, d.f. = 3).
Ants also bit non-nestmate ants significantly more often than they bit their own nestmates (Bonferroni-Dunn test, P<0.01). In addition, ants bit non-mimic spiders significantly more often than they bit ant-mimic spiders (Bonferroni-Dunn test, P<0.05).
Figure 4.
Ant-mimicking spider (Peckhamia picata) is not a chemical mimic of its model ant (Camponotus nearcticus).
Two-dimensional non-metric multidimensional scaling plot of chemical profiles of mimic and ants (Stress value: 0.11). Purple dots represent ant mimic profile, dark blue dots represent model ant profile, and light blue dots represent non-nestmate ant profile.
Figure 5.
Ants (Camponotus nearcticus) and non-mimic spiders (Paraphidippus aurantius) have significantly higher levels of cuticular hydrocarbons than do mimics (Peckhamia picata): Ant vs. mimic, Mann-Whitney U = 20, Z = 2.4, P 0.015; Non-mimic vs. mimic: Mann-Whitney U = 16, Z = 2.3, P = 0.014).