Bioassay Techniques in Entomological Research

BIOASSAY (Bio - life, Assay - determination) is the measurement of the potency of any stimulus (physical, chemical, biological, and psychological) and the reactions that it produces in living matter. In Entomology, to know about the potency, Specificity of any compounds, standardization of doses, and identify modes of action bioassay is needed. In addition to the basic bioassay methods such as poison food, dry film techniques, etc., depending upon the researcher’s necessity, they are modified or newly developed. Diet covering and diet incorporation for lepidopterans and homopterans have been developed as advancements over the poison food assay method, by using insecticide-incorporated artificial diet. WHO cone, Wire ball test, Susceptibility test, CDC bottle assay and MCD assay developed for mosquito resistance monitoring and Larval Packet Technique (LPT) for cattle ticks, Sandwich method, TIBS, and Adult vial test are advancements over dry film technique. In Thrips Insecticide Bioassay System (TIBS), treated vials can be stored for up to 3 weeks at 4˚C for future efficacy assays at the field level. Adult Vial Tests have been developed for pentatomid and mirid adult bug bioassays. Larval Immersion Technique (LIT), Adult Immersion Technique (AIT) for cattle ticks, and MEBS have been developed as advancements over topical bioassay. In Mite Egg Bioassay System (MEBS), entomopathogenic fungi have been tested against Tetranychus cinnabarinus. MTT colorimetric assay and Trypan Blue Dye Exclusion assay helps to identify cell viability in insect cell line cultures. Spodoptera frugiperda cell line, Sf – 21 was tested against a scorpion, Leiurus quinquestriatus toxin β– BUTX – LQQ1a and the toxicity was determined through the viability of cell lines. Various basic and advanced bioassay techniques are discussed elaborately in this review.