Samples from populations of Hylyphantes graminicola(Araneae: Linyphiidae) were collected from Wuhan(WH) (Hubei Province), Laifeng(LF)(Hubei Province), Weinan(WN)(Shanxi Province) and Heze(HZ)(Shandong Province) in China and their susceptibility to fenvalerate, deltamathrin, phoxin and methamidophos were investigated using dipping methods. The results showed that the populations of H. graminicola from Wuhan and Heze were susceptible to 4 species of insecticides, and those from Weinan and Laifeng had developed middle levels of resistance to phoxin and methamidophos. All four populations were susceptible to fenvalerate and deltamathrin, It indicated that pyrethroids had a high toxicity to H. graminicola than organophosphates.
The biology and reproduction of the Weinan (resistant) population and Wuhan (susceptible) population were carefully observed and relative fitness was determined by net reproductive rate (R0). The results showed that resistant population suffered reproductive disadvantages including having lower mean fecundity and a decrease in oviposition and hatching rates. No developmental defect was observed in resistant population. Resistant population was calculated to have a fitness value of 0.74 relative to susceptible population.