The Effect of Acid-Hydrolysed Sucrose on Honeybees

SUMMARYSucrose, or starch, hydrolysed with mineral or organic acids is toxic for honeybees, whereas sucrose hydrolysed with invertase is not. The best-known products of the action of acids on hexoses, 5-hydroxymethylfuraldehyde (HMF), laevulinic acid and formic acid were similarly toxic to bees when fed to them, but only if more concentrated than in acid-hydrolysed sucrose. Neither the acids used to hydrolyse the carbohydrates, nor the salts formed by neutralizing them, were toxic, so unknown products of acid hydrolysis must cause most of the harm to bees. Heated honey or old honey was less suitable for bees than fresh honey or sucrose; their suitability was inversely correlated with the concentration in them of HMF, but this was too small to cause the harm observed. Evidently substances that are more toxic than HMF must accumulate along with it in heated honey; these may be similar to those in acid-hydrolysed carbohydrates. Bees fed acid-hydrolysed carbohydrates developed ‘dysentery’ before they died, possibly because essential solutes and water were lost from the body into the rectum, the contents of which were doubled, but only slightly diluted.