Changes in biological parameters of green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), in contact with the sub-lethal concentrations of thiamtoxam, imidacloprid, and acetamiprid
Research/Original Article (دارای رتبه معتبر)
Background and Objectives The lacewings are predatory insects which are widely used in biological control programs. Meanwhile, the green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), has attracted considerable attention as a promising biological control agent for greenhouse and field pests. Green lacewing is considered as an important bio-control agent due to its geographical distribution, broad host range, potency of suitable compatibility in agro-ecosystems, high searching ability, easy mass rearing in laboratory, high reproductive potential and broad resistance to numerous insecticides especially in larval and pupa stages. In this regard, it is highly important to reduce the consumption of the conventional pesticides which are compatible with predators and have low negative effects on beneficial organisms. In addition, life tables should be highlighted as the most reliable and effective technique for assessing the fitness of a population. Among the methods for selecting suitable pesticides in integrated pest management (IPM) programs, evaluating all of its effects on the different biological parameters of both sexes is the prime tool for population ecology studies. Materials and Methods Laboratory bioassays were investigated to evaluate the sub-lethal effects (LC30) of thiamtoxam, imidacloprid, and acetamiprid on biological characters and population parameters of C. carnea. The sub-lethal effects of thiamtoxam, imidacloprid, and acetamiprid on the demographic parameters of green lacewing were evaluated in vitro at 25±2° C, relative humidity of 65±5%, and light period of 8:16 h (light: dark). The raw data were analyzed based on two-sex life table analysis. Results All sub-lethal concentrations caused a significant decrease in oviposition period, total fecundity, longevity, and total life span in comparison to the control. Maximum and minimum mean lifespans of C. carnea individuals were observed in the untreated group and LC30 concentration of thiamtoxam. Total fecundity varied from 208.7 (offspring/individual) in treatment with LC30 thiamtoxam to 302.3 (offspring/individual) in the control treatment. The intrinsic and finite rates of increase (r, λ) were not affected by the imidacloprid concentration. The net reproduction rate (R0) reached its lowest level (141.1 offspring /individual) in acetamiprid treatment. Discussion The adaptability of pesticides with biological agents is one of the major concerns of IPM practitioners. Hence, it is essential to have necessary information about the action mode of pesticides on non-target insects. Furthermore, finding efficient biological control agents is considered as the first step in developing biological control programs. Therefore, the effects of sublethal concentrations of thiamtoxam, imidacloprid, and acetamiprid in combination with C. carnea were discussed in order to design integrated management programs.