| Darwin’s sexual selection theory was proposed in 1871 to explain the male and female traits that are not suitable for natural selection theory,and it is considered that both sexes are cooperative and harmonious in sexual selection.However,in the reproductive season of males and females,due to the adoption of different sexual and offspring investment strategies,reproductive benefits are usually unequal,resulting in sexual conflicts.The sexual catalepsy is a typical case of sexual conflict theory,the males for their reproductive interests,and let the female spider pay the price.Sexual catalepsy is an extreme sexual behavior unique to the funnel-web spiders(Araneae: Agelenidae),which is characterized by the female being in a state of catalepsy from the moment of successful courting of male spiders until mating is completed.However,the current reports on the sexual cataleptic behavior of the funnel-web spiders mainly focus on the phenomenon of this behavior and do not involve the regulation mechanism of sexual catalepsy.In this dissertation,the sexual behavior of 13 species from 10 genera of funnel-web spiders was observed by video recording system,and the common characteristic of sexual behavior was analyzed,and it was found that all the female funnel-web spiders were in a state of catalepsy during mating.The funnel-web spiders of Allagelena difficilis(Fox,1936)and Pireneitega luctuosa(L.Koch,1878)were used as objects to elucidated the chemical structure of male-produced pheromone and confirmed that the male-produced pheromone has the behavioral mediated function of inducing females sexual catalepsy during sexual process.The funnel-web spider of P.luctuosa was used as objects to clarified the male spider’s release route of catalepsy-inducing compounds and the female spider receiving organs of catalepsy-inducing compounds.The primary research results are as follows:(1)Revealed the common characteristic of sexual behavior of the funnel-web spidersIn this dissertation,the method of video recording system was used to study the sexual behavior of the funnel-web spiders,and it was found that all 13 species in 10 genera of study subjects have sexual catalepsy.The characteristics of each stage of sexual behavior of 6 species of funnel-web spiders,included Pireneitega luctuosa,Aterigena aculeata(Wang,1992),Allagelena difficilis,A.koreana(Paik,1965),Agelena silvatica Oliger,1983 and Platocoelotes luoi Chen & Li,2015 were described in details.Based on the results of the laboratory experiment,we proposed that the sexual behavior process of the funnel-web spiders can be artificially divided into 5 stages: male acclimating,male courting,male preparing,mating,female recovering.A statistical analysis of the duration of each stage of sexual behavior,it was found that the shortest duration of male acclimating is about 1.56 minutes for the Pireneitega luctuosa,and the longest is about16.51 minutes for the Platocoelotes luoi;the shortest duration of male courting is about 3.30 minutes for the Aterigena aculeata,and the longest is about 44.23 minutes for the Allagelena koreana;the shortest duration of male preparing was almost absent in the Aterigena aculeata,and the longest is about 111.48 minutes for the Allagelena difficilis;the shortest duration of mating is about 2.2 minutes for the Aterigena aculeata,and the longest is about 19.5 hours for the Pireneitega luctuosa.The female recovering only existed in the P.luctuosa,Agelena silvatica,and Platocoelotes luoi,time ranges from 5-25 minutes.(2)Identification of the chemical structure of male-produced pheromone in the funnel-web spidersThe experiment methods of solid-phase microextraction(SPME),headspace,and extraction methods were used to separated and detected the compounds of the whole body extracts from the single male/female spiders and the mating male/female spiders of the funnel-web spiders Agelena silvatica and Pireneitega luctuosa by gas chromatography-mass spectrometer(GC-MS)and thermal desorption-gas chromatography-mass spectrometer(TD-GC-MS);It was found that the compounds released by male spiders might be non-volatile or extremely weakly volatile compounds from cephalothorax.Further study of the cephalothorax extracts compounds of the single male/female,the courting male/female,and the preparing male/female spiders of the funnel-web spider Allagelena difficilis by GC-MS.After comparative analysis between groups,specific compound chromatogram peaks of male spiders were obtained.According to the retention time and mass spectrum characteristics of the compound,a highly matched compound Nonacosane was retrieved from the GC-MS library.Synthesize standard chemicals of Nonacosane and verify the retention time between artificial standard Nonacosane and the compounds in the extract by non-polar(HP5-MS)and polar(DB-17 M S)chromatographic columns.According to the characteristics of mass spectrometry,it was determined that the candidate compound of male-produced pheromone is Nonacosane.The same method preliminarily determined that the candidate compound of the male-produced pheromone of Pireneitega luctuosa is 13,17-Dimethylhentriacontane.(3)Proved the catalepsy-inducing function of the male-produced pheromone of the funnel-web spidersThe behavioral research methods were used to test the sexual behavior regulation function of Nonacosane,which is the male-produced pheromone of the funnel-web spider Allagelena difficilis.We have Compared the duration of each stage of sexual behavior between the Nonacosane-treated female spider group and the control group(solvent,dichloromethane),the results showed that the duration was no significant difference between the male acclimating,the male courting,male preparing,and mating stages;Compared the frequency of different behavior types of female spiders in the treatment group and the control group,the results showed that the cooperative behavior and cataleptic behavior of the female spiders in the Nonacosane treatment group were significantly higher than those in the control group.The differences in elude,standoff,and other behaviors between the groups were not significant,and at the same time,the mating rate of the Nonacosane-treated group was significantly higher than that of the control group.It shows that Nonacosane significantly increases the sexual catalepsy rate of A.difficilis,and thus significantly increases the chance of successful mating of male spiders.This is the first male pheromone isolated from animals that release at close range and induce its mate to sexual catalepsy.(4)Clarified the release and reception route of the compound that induces sexual catalepsyThe study found that the depth of sexual catalepsy at the completion of courtship is far less than that of the female spider at the completion of the preparation,suggesting that the male spider of the funnel-web spider Pireneitega luctuosa was deepened by releasing chemicals at a close distance during the preparation stage of about 38 minutes.We speculated that the male spider releases the chemical substance through the fang pores,while the female spiders receive the chemical substance through the chemoreceptors on its legs.Scanning electron microscope(SEM)was used to microscopically observe the fang of male spiders and the chemosensory hairs on the legs of female spiders.Sexual catalepsy rate and mating rate were tested after the fang of male spiders and female chemosensory hairs were sealing off.The results showed that: male fang blocking had no significant effect on the sexual catalepsy rate of female spiders,but it significantly reduced the mating success rate.After the female spiders’ chemosensory hairs were blocked,the sexual catalepsy rate of female spiders was significantly reduced,and no mating success was achieved.The results of the study confirmed that the catalepsy-inducing compound was released through the fang pores of male spiders,and the chemosensory hairs on the legs of female spiders were the receiving organs of the catalepsy-inducing compound. |
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