Intra-population variation in reproductive potential offers scope for enhancing the parental stock in mass-reared insect bio control agents. Laboratory cultures of two cold adapted strains of Trichogramma chilonis, along with a local strain and T. pretiosum were studied for such variation in fecundity by evaluating randomly chosen iso-female lines. The indicative fecundity (in first 3 days of adult life) was compared among 10 iso-female lines each among the strains/species. The results showed considerable variation in fecundity among the iso-female lines in Nilgiris, Kodaikanal and local strain of T. chilonis, besides T. pretiosum, from such selective pooling as parental stock, there was enhancement in overall progeny production capacity by 37.3, 19.7, 28.0 and 21.0, (for five pairs of adults) in Nilgiris, Kodaikanal and local strains of T. chilonis and T. pretiosum, respectively.
The progeny from the top 3 lines for fecundity were selected for pooling as parental stock leading to enhancing the progeny production capacity by 26 and 15 per cent in the two cold adapted strains, besides 17 per cent for the local strain while for T. pretiosum such enhancement was 19 per cent. The utility of selecting among iso-female line within Trichogramma species/strains for parental stock improvement in commercial mass production is indicated. This initiative enabled the culturing of strains/ species with more robust genetic base for pursuing future studies on diapause induction in these strains/species.
Trichogramma strains, fecundity enhancement, iso-female lines, parental stock
Abraham, C. 1970. Exploration of the feasibility of developing races of Trichogramma australicum Girault (Hymenoptera: Trichogrammatidae) suitable for different environments. Ph.D. thesis, IARI, New Delhi, p.126.
Babi, A. 1990. Bioecologie de Trichogramma cacoeciae Marchal et T. daumalae Dugast & Voegele (Hymenoptera: Trichogrammatidae). Utilisation en lute biologique contre Lobesia botrana Den. & Schiff. (Lep.: Tortricidae). Ph.D Thesis, Aix-Marseille, France, p.143.
Ballal, C. R., S. Joshi, S.K. Jalali and N.S Rao. 2001. Quality control parameters in mass produced bioagents. In: Augmentative biocontrol: proc. ICAR-CABI workshop on augmentative biocontrol, (eds: Singh, S. P., Murphy, S. T. and Ballal,
C. R.), CABI, Wallingford, pp. 141–161.
Baya, J. M., S. Sithanantham, L.M, Gitonga, E.O. Osir and V. Agong. 2007. Scope for genetic enhancement of the parasitisation potential of four native strains of Trichogrammatoidea sp.nr.lutea Girault (Hymenoptera: Trichogrammatidae) in Kenya. Biocontrol Science and. Technology., 17: 743-755.
Jalali, S. K., T. Venkatesan and M. Nagesh. 2009. Development of genetically improved strain of egg parasitoid Trichogramma chilonis with combined tolerance to insecticide and high temperature for the biological control of lepidopterous pests. Final Technical Report, DBT project. NBAII, Bangalore, pp. 117.
Jalali, S. K. and S.P. Singh. 1992. Differential response of four Trichogramma species to low temperatures for short term storage. Entomophaga, 37: 159-165.
Judy, S., S. Sithanantham, K.P. Sanjayan, V. Thamaraiselvi and K.R. Manikandan. 2013. Reproductive attributes of a warm–temperature tolerant strain of Trichogramma chilonis. Hexapoda, 2 (1&2): 11-13.
Larralde, A.G and E.C. Chavez. 2014. Genetic variation and the performance of a mass-reared parasitoid, Trichogramma pretiosum (Hymenoptera: Trichogrammatidea), in laboratory trials. Journal of Applied Entomology, 138 (5): 346-354.
Mimouni, F. 1991.Genetic variations in host infestation efficiency in two Trichogramma species from Marocco. Redia, 74: 394-400.
Roitberg, B. D.1990. Variation in behaviour of individual parasitic insects: bane or boon? In: Critical Issues in Biological Control (Eds.): Mackauer, M., L..E Ehler and J. Roland ), Jonh Wiley and Sons, New Jersey, U.S.A, pp. 25-39.
Sithanantham, S. C.R Ballal and S.K. Jalali. 2013. Future Thrusts for Egg Parasitoids Research in India, (Eds.) S.Sithanantham, Biological Control of Insect Pests Using Egg Parasitoids. Springer, India: 1-10.
Sithanantham, S., S. Judy, K.R Manikandan, C. Thamaraichelvi, R. Pandiyan, S. Jeyarajan Nelson and K.P. Sanjayan. 2014. Characterization, adaption and utilization of beneficial insect biodiversity, Trichogramma chilonis R&D in bio control of crop pests. In: Proc. National seminar on “Biodiversity conservation status, Future and way forward” , KSR college of Technology, Thiruchengode, Tamil Nadu, India, pp. 657-672.
Smith, S. M. 1996. Biological control with Trichogramma: advances, successes and potential of their use. Annual Review of Entomology, 41: 375-406.
Wajnberg, E. 1994. Intra-population genetic variation in Trichogramma, Biological Control with Egg parasitoids . In: Genetics, Evolution and Biological Control, (Eds.) Ehler, L. E., R. Sforza and T. Mateille, CABI Publishing, Oxfordshire, pp. 245-271.
Consoli, F. L., J. R. P. Parra and R. A. Zucchi. 2010. Egg parasitoids in agro ecosystem with emphasis on Trichogramma. In: Progress in biological control, Springer, Heidelberg, London, New York, 479p.
Singh, S. P. and S. K. Jalali. 1994a. Trichogrammatids. Tech.Bull (7), Project Directorate of Biological Control, Bangalore, Karnataka, India,47p.
Li, L.Y. 1994. Worldwide use of Trichogramma for biological control on different crops: a survey. In: Biological control with egg parasitoids, (Eds.) Wajnberg, E. and S.A Hassan, C.A.B. International Oxon, U.K., pp. 37–54.