Evaluation of diets for the development and reproduction of Franklinothrips orizabensis (Thysanoptera: Aeolothripidae).

The suitability of ten diets for the development and reproduction of Franklinothrips orizabensis Johansen, the key natural enemy of Scirtothrips perseae Nakahara, a pest of California grown avocados, was determined in the laboratory. The experimental diets evaluated were: (i) irradiated Ephestia kuehniella Zeller eggs; (ii) irradiated E. kuehniella eggs and avocado pollen; (iii) Tetranychus pacificus McGregor eggs; (iv) T. pacificus eggs and avocado pollen; (v) irradiated E. kuehniella eggs and T. pacificus eggs; (vi) irradiated E. kuehniella eggs, T. pacificus eggs and avocado pollen; (vii) Scirtothrips perseae; (viii) Heliothrips haemorrhoidalis (Bouchè); (ix) avocado pollen; and (x) a young avocado leaf. Franklinothrips orizabensis larvae were unable to develop to adulthood on diets 9 and 10. The remaining eight diets supported complete development of F. orizabensis, but only diets 1, 2, 5, 6, 7 and 8 produced fecund females. On diet 5, F. orizabensis exhibited high larval to adult survivorship (90%), mated females exhibited highest daily and lifetime fecundity, and the progeny of mated females were female biased (53%). Analysis of jackknife estimates of net reproduction (Ro), intrinsic rate of increase (rm), and finite rate of increase (lambda) were all significantly greater for F. orizabensis reared on irradiated E. kuehniella eggs and T. pacificus eggs (i.e. diet 5) than corresponding values for other diets on which female F. orizabensis were able to complete development and reproduce. Incorporation of avocado pollen into diets had an adverse effect on demographic statistics for F. orizabensis, and low quality diets resulted in male biased sex ratios for this predator.