Presenter Information

Anna E. Ledin

Location

Memorial Ballroom

Access Type

Campus Access Only

Presentation Type

Poster Presentation

Event Website

http://www.lynchburg.edu/academics/red-letter-day/student-scholar-showcase/

Start Date

6-4-2016 12:00 PM

End Date

6-4-2016 1:00 PM

Department

Biology

Abstract

Two species of orb-weaver spiders inhabit two ant-protected acacia species in central Panama. The spiders do not capture patrolling worker ants, but exploit their plant-guarding services to escape predation. Spiders may provide a second layer of defense for acacias against herbivores. Alternatively, spiders may parasitize the mutualism by capturing winged ants of the reproductive caste as they disperse on nuptial flights. 45-75% of insects captured on sticky card traps in each acacia species were strictly herbivorous, but no alate ants were captured. Analysis of prey items collected from spiders’ webs indicated that insect herbivores made up approximately 20% of spider prey for both species, but alate ants made up an additional 20-50% of spider prey. These results suggest that spiders both ‘cooperate with’ and ‘parasitize’ the ant-acacia mutualisms, but whether spiders can ultimately disrupt the mutualism depends on the overall percentage of dispersing alate ants the spiders actually capture.

Faculty Mentor

Dr. John D. Styrsky

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Apr 6th, 12:00 PM Apr 6th, 1:00 PM

Potential consequences of the exploitation of ant-acacia mutualisms by orb-weaver spiders

Memorial Ballroom

Two species of orb-weaver spiders inhabit two ant-protected acacia species in central Panama. The spiders do not capture patrolling worker ants, but exploit their plant-guarding services to escape predation. Spiders may provide a second layer of defense for acacias against herbivores. Alternatively, spiders may parasitize the mutualism by capturing winged ants of the reproductive caste as they disperse on nuptial flights. 45-75% of insects captured on sticky card traps in each acacia species were strictly herbivorous, but no alate ants were captured. Analysis of prey items collected from spiders’ webs indicated that insect herbivores made up approximately 20% of spider prey for both species, but alate ants made up an additional 20-50% of spider prey. These results suggest that spiders both ‘cooperate with’ and ‘parasitize’ the ant-acacia mutualisms, but whether spiders can ultimately disrupt the mutualism depends on the overall percentage of dispersing alate ants the spiders actually capture.

http://digitalshowcase.lynchburg.edu/studentshowcase/2016/Posters/2