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Data from: New drivers of the evolution of mimetic accuracy in Batesian mimics: body size, habitat stratification and geographic zone affect accuracy of myrmecomorphic spiders

Citation

Pekar, Stano (2021), Data from: New drivers of the evolution of mimetic accuracy in Batesian mimics: body size, habitat stratification and geographic zone affect accuracy of myrmecomorphic spiders, Dryad, Dataset, https://doi.org/10.5061/dryad.7sqv9s4sw

Abstract

Aim: The evolution and maintenance of accurate Batesian mimicry has been explained by several hypotheses built upon relaxed selection. Such selection can be influenced by ecological factors, such as habitat type or geographic distribution, which have not been considered. I investigated whether the mimetic accuracy is influenced by habitat stratification where mimics occur (ground, low vegetation, bush, tree), their body size, and geographic distribution (temperate, subtropical, tropical).

Location: Worldwide

Taxon: Araneae

Methods: I gathered data on body size, geographic area of distribution, and habitat stratification from literature on more than 400 ant-mimicking (myrmecomorphic) spider species from 18 spider families and ranked them into four accuracy levels based on morphology, from poor inaccurate mimics to very accurate ones. Then I used regression to study the effect of body size, distribution, and habitat on mimetic accuracy while controlling for phylogeny.

Results: Mimetic accuracy increased with spider body size but differently at four types of habitat strata. On the ground and in low vegetation majority of smaller species were inaccurate, whereas on shrubs and trees even smaller species were accurate. The accuracy increased from temperate to the tropics but differently at the four habitat strata. In the temperate zone only species occurring on bushes were accurate, but in the tropical zone even ground-living species were accurate.

Main conclusions: Higher accuracy at lower latitudes is likely due to stronger predation pressure from visually-hunting predators. Similarly, lower accuracy in species occurring near to the ground is presumably due to predation pressure by non-visually hunting predators. Inaccurate myrmecomorphy in spiders appears to be further driven by smaller body size due to lower profitability to predators; and higher latitude due to increased occurrence of generalist predators.

Methods

Extracted from literature.

Funding

Grantová Agentura České Republiky, Award: JBI-21-0438