Involved in the recognition of invading microorganisms causing their aggregation (PubMed:12770576, PubMed:15084591). Activates the phenoloxidase cascade (PubMed:12770576, PubMed:15084591, PubMed:23237493). Binds specifically to beta-1,3-glucan (PubMed:12770576, PubMed:15084591, PubMed:21697086, PubMed:23237493). Binds to curdlan, a linear water-insoluble beta-1,3-glucan polysaccharide, and to laminarin, a water-soluble beta-1,3-glucan polysaccharide containing beta-1,6 branches (PubMed:15084591, PubMed:21697086, PubMed:23237493). Binds also to lipopolysaccharide and lipoteichoic acid (PubMed:15084591). Denaturates after heat treatment at 100 degrees Celsius for 10 min. The N-terminal region (18-198) is thermostable and retains its ability to bind to curdlan after heat treatment at 100 degrees Celsius for 10 min. The C-terminal region (199-488) is heat-labile after the same treatment. Monomer. Fat body and hemolymph. Expression is maintained at a moderate level throughout development from embryo to adult. The N-terminus is blocked. Belongs to the insect beta-1,3-glucan binding protein family.