▁As ▁in ▁most ▁T ett ig oni idae , ▁the ▁male ▁attract s ▁females ▁with ▁a ▁high - p itch ed ▁call , ▁which ▁it ▁produces ▁by ▁rub bing ▁one ▁fore - wing ▁over ▁a ▁scra per ▁on ▁the ▁other ▁fore - wing . ▁This ▁sound ▁has ▁been ▁suggested ▁to ▁double ▁as ▁inter ference ▁for ▁the ▁e ch ol ocation ▁of ▁b ats , ▁one ▁of ▁its ▁many ▁natural ▁pred ators . ▁When ▁a ▁female ▁appears , ▁the ▁kat yd ids ▁first ▁inspect ▁each ▁other ▁with ▁their ▁anten na e , ▁then ▁sh ake ▁their ▁bodies ▁to ▁gauge ▁each ▁other ' s ▁size ▁and ▁strength . ▁If ▁the ▁male ▁does ▁not ▁retre at , ▁the ▁female ▁will ▁approach ▁and ▁they ▁couple . ▁Cou pling ▁last s ▁a ▁few ▁hours , ▁during ▁which ▁the ▁male ▁will ▁produce ▁the ▁s per mat oph y lax ▁and ▁attach es ▁it ▁to ▁the ▁female ' s ▁ov ip os itor . ▁The ▁s per mat oph y lax ▁is ▁a ▁gel atin ous ▁structure ▁that ▁contains ▁the ▁male ' s ▁s perm ▁cells ▁as ▁well ▁as ▁nut ri ents ▁in ▁the ▁form ▁of ▁car bo h yd r ates ▁and ▁prote ins ▁as ▁a ▁contribution ▁towards ▁the ▁surv ival ▁of ▁the ▁female ▁and ▁the ▁off spring . ▁The ▁male ' s ▁invest ment ▁in ▁the ▁s per mat oph y lax ▁is ▁considerable ; ▁it ▁may ▁exceed ▁more ▁than ▁ 2 0 % ▁of ▁his ▁body ▁mass . ▁The ▁couple ▁then ▁separate ▁and ▁the ▁female ▁doubles ▁over