Uma, D. | Search bioRxiv

bioRxiv2021

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

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.

animal behavior and cognition↗

bioRxiv2018

Look before you jump: jumping spiders discriminate different ants by visual cues

Ants, being ubiquitous, aggressive, and top predators, play a predominant role in terrestrial ecosystems. Jumping spiders are another prominent invertebrate predator that are present in similar habitats as that of ants. Most jumping spiders are thought to avoid ants, yet little is known if they discriminate among them. In this study we examined the response of jumping spider genus Plexippus towards three different ant species (Oecophylla smaragdina, the weaver ants; Camponotus sericeus the golden-back carpenter ants, and Leptogenys processionalis, the procession ants). In a behavioral assay that excluded tactile and chemical cues, we tested if spiders distinguish the three ants by visual cues alone. We recorded and analysed behaviors such as look, approach, stalk, attack, and avoidance by spiders towards ants. Our results show that the three ants differ in their color, movement and aggressive behavior. Spiders gave short looks to live ants, suggesting movement is important in detecting ants. Furthermore, spiders gave significantly more long looks to procession and golden-back ants compared to weaver ants. Spiders approached, stalked and attacked procession ants more compared to weaver ants. Numerous jumping spiders and ants overlap in their habitat, and it is advantageous to selectively avoid some ants over others. Our results suggests that jumping spiders can indeed distinguish ants that co-occur in their habitat by visual cues alone, however, the precise nature of visual cues warrants further studies.

animal behavior and cognition↗