Adaptation Of Tetrastichus Brontispae Ferrière(Hymenoptera:Eulophidae) On Two Host Species

Successful parasitism of a host is affected by a parasitoid female assessment of the host quality.It was reported that Tetrastichus brontispae Ferrast(Hymenoptera:Eulophidae)can successfully parasitize on the pupa of Brontispa longissima(Gestro)and Octodonta nipae(Maulik).To determine which host species is more suitable for T.brontispae,we measured the wasp's oviposition behavior and developmental performance on B.longissima and O.nipae by choice and none choice tests.We focused on several biological parameters to assess the fitness of this wasp.Such as parasitism percentage,emergence percentage,duration from egg to adult,number of progeny,adult longevity,sex ratio of offspring and lifetime fecundity of mother parasitiod.The main results in the present study are outlined below.1.Adult female of two strains T.brontispae did not show a preference for different host species,despite the host they reared.2.The highest parasitism percentage of wasps were on the first day and decreased by the time,regardless of the host species they parasitised.But the parasitism ability of the T.brontispae lost(reared by O.nipae)earlier than that reared by B.longissima.3.The biological parameters of two strains T.brontispae offspring had no significant difference when it was transferred host just for one generation.4.Except the parasitism ability of T.brontispae was improved when it was transferred from B.longissima to O.nipae.Higher numbers of eggs oviposited and offspring,as well as the duration from egg to adult of its progeny was shorter than that after transferring host.This suggested B.longissima is more suitable than O.nipae.5.More lifetime fecundity occured in T.brontispae reared by B.longissima when parasitized on the same host species.More offspring and higher emergence percentage but lower parasitism percentage appeared on T.brontispae reared by B.longissima when two strains wasp parasitized on B.longissima.In conclusion,the results revealed that mother's host experience has no effects on parasitism behavior of T.brontispae offspring.And comparing to O.nipae,B.longissima is more suitable for T.brontispae.