( ( After ( eating ( the ( infected crayfish ) ) ) ) ( , ( ( smallmouth ( bass ( and ( other vertebrates ) ) ) ) ( ( are ( ( ( utilized ( as ( secondary hosts ) ) ) , ) ( providing ( ( an environment ) ( that ( ( is ( suitable ( for ( the flukes ) ) ) ) ( to ( reproduce sexually ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN After) (S (VP (VBG eating) (NP (DT the) (JJ infected) (NN crayfish))))) (, ,) (NP (NN smallmouth) (NN bass) (CC and) (JJ other) (NNS vertebrates)) (VP (VBP are) (VP (VBN utilized) (PP (IN as) (NP (JJ secondary) (NNS hosts))) (, ,) (S (VP (VBG providing) (NP (NP (DT an) (NN environment)) (SBAR (WHNP (WDT that)) (S (VP (VBZ is) (ADJP (JJ suitable) (PP (IN for) (NP (DT the) (NNS flukes)))) (S (VP (TO to) (VP (VB reproduce) (ADVP (RB sexually))))))))))))) (. .)))
After eating the    infected crayfish, smallmouth bass and other vertebrates are utilized as    secondary hosts, providing an environment that is suitable for the    flukes to reproduce sexually.
(ROOT (S (NP (NNS Vertebrates)) (VP (VB reproduce) (ADVP (RB sexually))) (. .)))