Submission Type

Poster

Start Date

April 2021

Abstract

Myrmarachne formicaria (Salticidae) is an ant-mimicking spider which arrived in North America fairly recently, first noted in Ohio in 2001. It is important to understand how M. formicaria will impact other species as it spreads throughout North America. The goal of this study was to assess the success of Batesian mimicry used by the ant-mimicking spider in avoiding predation when in a staged encounter with another salticid spider. Myrmarachne formicaria mimic ants in the movement of their forelegs to resemble ant antennae, as well as bob their abdomen. The predator spiders were placed in a small petri dish with either M. formicaria or a non-mimic salticid spider of a different species. M. formicaria was attacked less frequently by the predator compared to the non-mimic (p= 0.045). We scored the frequency of behaviors in the ant-mimics including abdominal bobbing and movement of their enlarged chelicerae. Preliminary analysis of the videos showed that ant-mimics benefit from some of these movements as individuals that were not attacked exhibited a longer duration of chelicerae movement. We found no significant difference in abdomen movement between ant-mimics that were attacked or not. Ant-mimics do seem to benefit from a lower incidence of attack. Further investigation is needed to understand the benefit that Batesian mimicry provides for these spiders.

Comments

Faculty mentor is Jennifer L. Apple

This work has also been presented at the UR Exchange for the Council on Undergraduate Research, ABS & ASAB Global Animal Behavior Twitter Conference, TriBeta Symposium and the Northeast Natural History Conference.

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Apr 26th, 12:00 AM

085— Success of Batesian Mimicry in the Ant-Mimicking Spider Myrmarachne formicaria

Myrmarachne formicaria (Salticidae) is an ant-mimicking spider which arrived in North America fairly recently, first noted in Ohio in 2001. It is important to understand how M. formicaria will impact other species as it spreads throughout North America. The goal of this study was to assess the success of Batesian mimicry used by the ant-mimicking spider in avoiding predation when in a staged encounter with another salticid spider. Myrmarachne formicaria mimic ants in the movement of their forelegs to resemble ant antennae, as well as bob their abdomen. The predator spiders were placed in a small petri dish with either M. formicaria or a non-mimic salticid spider of a different species. M. formicaria was attacked less frequently by the predator compared to the non-mimic (p= 0.045). We scored the frequency of behaviors in the ant-mimics including abdominal bobbing and movement of their enlarged chelicerae. Preliminary analysis of the videos showed that ant-mimics benefit from some of these movements as individuals that were not attacked exhibited a longer duration of chelicerae movement. We found no significant difference in abdomen movement between ant-mimics that were attacked or not. Ant-mimics do seem to benefit from a lower incidence of attack. Further investigation is needed to understand the benefit that Batesian mimicry provides for these spiders.

 

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