Sex Specificity in Innate Immunity of Insect Larvae

Abstract

The innate immunity of insects has been widely studied. Although the effect of sex on insect immunity has been extensively discussed, differences in immunity between the sexes of larvae insects remain largely unstudied. Studying larval sex differences in immunity may provide valuable information about the mechanisms underlying the insect immune system, which, in turn, can be valuable for the development and improvement of pest management. Here we compared the antibacterial activity in both the midgut tissue and cell-free hemolymph of Lymantria dispar L. (Lepidoptera: Erebidae) females and males at the larval stage without and after a challenge by entomopathogenic bacterium Bacillus thuringiensis Berliner. We also evaluated the sex-specific mortality of L. dispar induced by B. thuringiensis infection. We find that antibacterial activity in the midgut is activated by infection, but only in females. Thus, sex differences in immunity can have important effects even before sexual differentiation at adulthood.

Relationship between Changes in Intestinal Microorganisms and Effect of High Temperature on the Growth and Development of Bombyx mori Larvae

“…Growing research shows sex differences in insect immunity, such as sex-specific mortality of Lymantria dispar L. after larval infestation by the entomopathogenic bacterium Bacillus thuringiensis berlin. Interestingly, only the antibacterial activity of the female midgut is activated by infection [ 42 ]. Phenol oxidase (PO) is often used to estimate insect resistance to immune insults.…”

Sex-related immunity: could Toll-like receptors be the answer in acute inflammatory response?

“…Sex disparities in bacterial infections extend beyond mammals, with documented differences in defense against pathogens observed in insects and birds ( 38 , 39 ).…”