Comparison of the Differences in Response to the Change of the Extrafloral Nectar-ant-herbivore Interaction System Between a Native and an Introduced Passiflora Species

Abstract

How introduced plants associate with native biotic is one of the fundamental questions in evolutionary biology and invasive biology.Extrafloral nectar (EFN) bearing plants usually use nectar to attract ants while those ants could help plants defense herbivores;establishing a plant-ant-herbivore interactive system.In this study,we conducted artificial ant-exclusion,EFN-exclusion,herbivore exclusion,ant and herbivore exclusion to compare the differences in response to the change of the extrafloral nectar-ant-herbivore interaction system in an native passionflower (Passiflora siamica) and an newly introduced species (P.coccinea).A total of about 24 ant species were recorded consuming the EFN resource.There was no significant difference in the total number of visiting ants while ant species composition was different in the two Passiflora plants (χ2=14.76,df=4,P0.01).The most abundant ant species for P.siamica was Dolichoderus thoracicus while for P.coccinea was Paratrechina sp.The herbivorous insects observed were mainly generalists,including snails,katydisds (Pseudophyllidae) or some larvae of butterflies and moths.The amount of nectar per leaf produced from P.siamica is significantly higher than P.coccinea (Willcox,z=-3.87,P0.01).Ant-exclusion in this experiment did not significantly influence the average leaf loss per plant.The treatments for ant-exclusion,herbivore exclusion,and ant+herbivore exclusion all did not significantly influence the EFN production.As a whole,the plant-ant-generalist herbivore in thetwo Passiflora species did not show a significant difference in the response to the change,while the interactive system with specialist herbivores request further investigation.