The Evolutionary Mechanism Of Web-building Spiders To Resist Ant Attack By Applying 2-pyrrolidinone

In nature,chemical defense is a very general defense behavior,which is widely used by animals of various large groups.Chemical defense can be divided into two forms: active and passive.Most of the chemical defenses that have been reported are passive forms,while active chemical defenses are relatively few.Previous laboratory studies have found that 2-pyrrolidinone can be used by Nephila antipodiana to actively defend against attacks of ants.So far,however,the evolutionary mechanism of this defensive behavior is unclear.I preliminarily investigated the utilization of 2-pyrrolidinone in various spider taxa,and studied the evolutionary patterns of this behavior,and analyzed the causes of this evolutionary pattern.My experiments were mainly divided into four parts:(1)spider collection and measurement of morphological feature-related data;(2)construction of evolutionary tree of spiders;(3)extraction and analysis of chemical composition on spider silk surface;(4)construction of evolutionary roadmap for spider chemical defense using 2-pyrrolidinone.Results:The origin of the chemical was in the common ancestor of a major araneoid clade uniting Araneidae.The ancestral web condition at this level is a typical orb web.The phenotypic expression of the chemical seemed to have evolved once,but lost up to seven times.The results of this experiment can not only help to fully understand the interaction between spiders and ants during evolution,but also provide a strong scientific evidence for the study of the evolutionary mechanism of animal chemical defense.