author(s)
Ipsita Samal and Bhupen Kumar Sahu

abstract
The nutrition and survival of insects are regulated by tiny microbes inhabiting in close association with them, known as symbionts, either ectosymbionts or endosymbionts. Endosymbionts may be again categorised into 2 types such as extra-cellular and intracellular symbionts. These may be described as primary/ P-type/obligatory and secondary/S- type/facultative symbionts. Depending on their role in survival, reproduction/ defence, they are useful in nutritional and non-nutritional roles in insects. This behaviour of endosymbionts can be further manipulated to develop para-transgenic insects, which are modified genetically. Due to developed biotechnological and biochemical studies, the detailed study on endosymbionts has been carried out and this knowledge can be further helpful in pest management approaches.