▁move ▁side ways ▁as ▁a ▁c rab ▁would ▁and ▁one ▁pair ▁for ▁sens ory ▁purposes . ▁They ▁capture ▁pre y ▁using , ▁arm - like ▁ped ip al ps . ▁P . ▁margin em ac ul atus ▁eng age ▁in ▁ag on istic ▁interactions , ▁where ▁oppon ents ▁use ▁a ▁series ▁of ▁displays . ▁ ▁Re production ▁To ▁reproduce , ▁the ▁male ▁and ▁female ▁P . ▁margin em ac ul atus ▁by ▁exhib iting ▁rit ual ized ▁displays ▁in ▁a ▁s tere ot yp ed ▁sequence . ▁M ales ▁depos it ▁a ▁s per mat oph ore ▁which ▁the ▁female ▁retr ieves ▁to ▁fert il ize ▁eggs . ▁After ▁a ▁few ▁weeks ▁to ▁months , ▁she ▁ex udes ▁a ▁bro od ▁sac ▁containing ▁from ▁ 1 2 ▁to ▁ 2 0 ▁eggs . ▁These ▁develop ▁over ▁a ▁three - month ▁period , ▁and ▁after ▁h atch ing ▁the ▁female ▁will ▁then ▁carry ▁the ▁first ▁inst ars ▁on ▁her ▁back ▁for ▁about ▁ten ▁days ▁until ▁they ▁molt . ▁About ▁two ▁years ▁are ▁needed ▁for ▁the ▁young ▁to ▁reach ▁ad ul th ood , ▁with ▁adult ▁life ▁expect ancy ▁around ▁another ▁two ▁to ▁three ▁years . ▁ ▁References ▁▁ ▁http :// www . the w ild class room . com / bi om es / species profile / species / amb ly p ig id . html ▁ ▁Category : Am b ly py gi ▁Category : A ra chn ids ▁of ▁North ▁America ▁Category : Anim als ▁described ▁in ▁ 1 8 4 1