Propolis season. Normally, it is dark brown in color, but it can be found in green, red, black, and white hues, depending on the sources of resin found in the particular hive area. Honey bees are opportunists, gathering what they need from available sources, and detailed analyses show that the chemical composition of propolis varies considerably from region to region, along with the vegetation. In northern temperate climates, for example, bees collect resins from trees, such as poplars and conifers (the biological role of resin in trees is to seal wounds and defend against bacteria, fungi and insects). "Typical" northern temperate
Animal glue The advent of synthetic adhesives heralded the collapse of the animal glue industry. Today, animal glues are sparsely industrialized, but still used for making and restoring objects, paintings, illuminated parchment manuscripts, and other artifacts. Gelatin, a form of animal glue, is found in many contemporary products, such as gelatin desserts, marshmallows, and pharmaceutical capsules, and is used to reinforce sinew wrappings, wood, leather, bark, and paper. Hide glue is also preferred by many luthiers over synthetic glues for its reversibility, creep-resistance and tendency to pull joints closed as it cures. This adhesive is mostly used as glue, sizing, or varnish,