Objective   Reproductive biology of Anagrus nilaparvatae strains (Ans) that lay eggs on different pests was studied to determine the best parasitoid/host matches for biocontrol.

  Method  Nilaparvata lugens (Nl),Sogatella furcifera (Sf), Laodelphax striatellus (Ls), and Ishiharodelphax matsuyamensis (Im) were used in an indoor experiment as the hosts to study the reproductive behavior of Ans. Fitness of parasitoid/pest pairings as well as host preference by specific stains of An were determined based upon the size, body color, egg load, parasitism capacity, larva emergence, sex ratio, and lifespan of the wasps.

  Result   The body lengths of different species of adult Ans varied significantly, as it was 728.03 μm for those hosted on Nl (AnNl), 715.5 μm on Sf (AnSf), 633.17 μm on Ls (AnLs), and 509.1 μm on Im(AnIm) . The color of wasp body also varied depending upon the pests they chose to lay eggs on. For instance, AnNl, AnSf, and AnLs were mostly light orange, with a few yellowish green, in color, but all AnIm had dark reddish orange bodies. Significant differences in fecundity existed among the strains as well. The egg counts per female were similar between AnNl at 32.93 and AnSf at 32.97 but 27.47 for AnLs and 11.83 for AnIm. The parasitism of these wasps ranked AnNl or AnSf＞AnLs＞AnIm. On the other hand, no significant differences were detected on the rate of larvae emerged from eggs, male/female ratio, or lifespan of them. Nor was on host selection—they simply deposited eggs randomly based on availability. The intrinsic rate of increase (r_m) of AnNl was the highest at 0.1531 followed by 0.1482 of AnSf, 0.1307 of AnLs, and 0.0427 of AnIm.

  Conclusion   The strains of An that parasited on Nl and Sf had significantly greater egg load, parasitism capability, and r_m than those did on Ls or Im . Hence, they could be the better candidates to be artificially propagated for biocontrol on the pests.