Effects of prolonged mass rearing on life history traits of Habrobracon hebetor (Hymenoptera: Braconidae)

Abstract

Long-term mass rearing of parasitoids under laboratory conditions may affect their quality. We studied the quality of Habrobracon hebetor (Say) (Hymenoptera: Braconidae) reared for more than 20 generations (G) using two-sex life table parameters. We found that G2 had the longest pre-adult development time (12.4 d) and the highest fecundity (1304.00 eggs/female) compared with the other generations. While no significant differences in the intrinsic rate of increase (r) and net reproductive rate (R₀) were found among G4, G6, G8, G15, and G20, the highest values of r (0.3273 day⁻¹) and R₀ (436.28 eggs/individual) as well as the shortest mean generation time (T) were observed in G10. In addition, significant differences in sex ratio (F/F + M) were observed among different generations, ranging from 17% in G2 to 60% in G10. These results suggest that up to a certain number of generations (G10), the quality of H. hebetor significantly increased without adding field-collected parasitoids or changing the factitious host. To maintain the quality of the colony beyond this point, it should be rejuvenated by periodically adding field-collected individuals.

Keywords:

• Fecundity
• intrinsic rate of increase
• sex ratio
• net reproductive rate
• life table

Disclosure statement

No potential conflict of interest was reported by the author(s).