Estudo sobre o ciclo de vida e-fenologia de Ssemaeris Fissiecauda Fissicauda (Bruner.1908) (Orthoptera - Acrididae) em um lago de várzea da Amazônia Central, Brasil

Abstract

Stenacris fissicauda fissicauda ( B r u n e r ) ( o r t h o p t e r a -a c r i d i d a e ) i s found on paspazum repens (poaceae) an a q u a t i cmacrophyte,'wbich occurs i n l a r g e p o p u l a t i o n s i n slow w a t e r s o f várzea ( f l o o d p l a i n ) l a k e s i n c e n t r a l amazonia. i t s l i f e c y c i e . i s r e l a t e d t o t h e growth i n response o f paspatum repens t o t h e p e r i o d i c p u l s i n g of t h e water l e v e l between f l o o d i n g and d r y i n g c y c l e s o f t h e amazon. the f o l l o w i n g aspects o f t h e b i o l o g y o fstenacris f. fissicauda were s t u d i e d : phenology, l i f e c y c l e, d e v e l o h e n-t u n d e r - c o n t r o l l e d t e m p e r a t u r e and i i g h t c o n d i t i o n s ,and -fieding spec-if i c i t y . developmental stages were c h a r a c t e r i z e d by m o r p h o m e- t r y. The p o p u l a t i o n o f stenacris f. fissicauda p r e s e n t s two r e p r o d u c t i v e p e r i o d s : o n e d u r i n g t h e f l o o d i n g c y c l e (february-may) and one d u r i n g t h e d r y i n g c y c f e (august-october). d u r i n g t h ef l o o d i n g c y c l e , - t h e number o f males i s g r e a t e r t h a n t h e number o ffemales. the i n v e r s e i s t r u e d u r i n g t h e d r y i n g c y c l e . d u r i n g t h ef l o o d i n g c y c l e , paspazum repens i s abundant and occurs i n i t sa q u a t i c form. d u r i n g t h e d r y l n g c y c l e i t i s l e s s abundant and i s o n l y f o u n d - i n i t s t e r r e s t r i a l (adapted) form, the number o f nymphs was c o r r e l a t e d - w i t h t h e abundancle of p. repens, and consequently, w i t h t h e w a t e r l e v e l . the number õf days necessary f o r complete development from nymph t o a d u l t v a r i e s i n r e l a t i o n t o sex, tempera-ture and time o f emergence o f the nymphs. ~ ~ r n p hesm erging d u r i n g t h e r a i n y season t a k e m... ore t i m e t o b-ecome a d u l t s , H h i l e those which emerge d u r i n g t h e d r y season ( h i g h e r temperatures) t a k e l e s s time. Male presente five stages o f development and females s i x s t a g e s .thowever, with v a r i e d c o n d i t i a n s o f t e m p e r a t u r e and l i g h t , males can present s i x s t a g e s , and females f i v e s t a g e s . O v i p o s i t i o n o f stenacris f. fissicauda i s e n d o p h y t i c i n p. repens and f o u r o t h e r a q u a t i c macrophytes (echinochzoapotystachya, hymenachne amptexicautis, oryza perennis ( a l i ~ o a c e a e ) and eichhornia crassipes ( p o n t e d e r i a c e a e ) which occur t o g e t h e r . Laboratory t e s t s f o r f e e d i n g s p e c i f i c i t y show that stenacris f. fissicauda ccn f e e d on o t h e r macrophytes, most. of i which b e l o n g t o t h e f a m i l y poaceae. other t e s t s i n d i c a t e t h é i stenacris f. fissicauda i s n o t a p o t e n t i a l p e s t f o r v e g e t a b l e s ic u l t i v a t e d a t p r e s e n t near t h e s t u d y s i t e .