Four native honey bee proteins (AMP-1, -2, 3, -4) were detected on the IEF gel by the polyclonal antiserum at 1 : 1000 dilution in immunoblotting. AMP 1 and/or AMP-2 were found in all Africanized honey bees (AHB). AMP-3 was found in 88% of AHB. All European honey bees (EHB) had only AMP-4. However, AMP-4 was also found in 53% of AHB. The same antiserum detected three denatured proteins on the SDS-PAGE gel with M(r)s around 39,000, 42,000 and 60,000, All three were found in AHB and EHB.