An arachnid’s guide to be an ant: morphological and behavioural mimicry in ant-mimicking spiders

Abstract

Batesian mimicry imposes several challenges to mimics and evokes adaptations in multiple sensory modalities. Myrmecomorphy, morphological and behavioral resemblance to ants, is seen in over 2000 arthropod species. Ant-like resemblance is observed in at least 13 spider families despite spiders having a distinct body plan compared to ants. Quantifying the extent to which spiders’ shape, size, and behavior resemble model ants will allow us to comprehend the evolutionary pressures that have facilitated myrmecomorphy. Myrmaplata plataleoides are ‘accurate’ mimics of the weaver ants, Oecophylla smaragdina. In this study, we quantify the speed of movement of model, mimic, and non-mimetic jumping spiders. We use traditional and geometric morphometrics to quantify traits such as foreleg and hindleg size, body shape between the model ant, mimic, and non-mimics. Our results suggest that while the mimics closely resemble the model ants in speed of movement, they occupy an intermediate morphological space compared to the model ants and non-mimics. We suggest that ant-mimicking spiders are better at mimicking ants’ locomotory movement than morphology and overall body shape. Our study provides a framework to understand the multimodal nature of mimicry and helps discern the relative contributions of such traits that drive mimetic accuracy in ant-mimicking spiders.

And the Oscar goes to… – Species‐specific ant behaviour related to predator defence in ant‐mimicking spiders

“…Ant mimicking or myrmecomorph spiders have received considerable attention in studies of evolution through natural selection because they include examples with remarkable morphological adaptations (reviewed by Cushing, 1997; Mclver & Stonedahl, 1993) and are easy to manipulate in laboratory experiments (e.g., Zeng et al., 2023). Experiments have demonstrated that jumping spiders, mantises and mud‐dauber wasps avoid ant‐resembling spiders while readily preying on non‐mimicking spiders (see Subramaniam et al., 2021 for references). However, considering that the largest part of the diversity of ant resembling spiders is found in tropical rainforests, which mostly lack research facilities to perform laboratory trails, several studies support ant mimicry with the identification of species‐specific morphological resemblance in members of sympatric ant and spider communities (e.g., Hashimoto et al., 2016; Perger et al., 2021; Perger & Rubio, 2020a; Reiskind, 1977).…”

“…These behaviours are assumed to have evolved before morphological mimicry (reviewed by Cushing, 1997) and may be considered adaptations to general ant resemblance. In contrast, species‐specific mimetic behaviour (behaviour that is only observed in specific ants and imitated by their mimics) has not been observed in most studies of behavioural ant mimicry (see Ceccarelli, 2008; McLean & Herberstein, 2021; Nelson & Card, 2016; Oliveira, 1988; Shamble et al., 2017; Subramaniam et al., 2021; Zeng et al., 2023). The mimetic behaviour most likely to be described as species‐specific was the similar speed of three inaccurate spider mimics and their ant models (Pekár & Jarab, 2011).…”