Sap activity, which transforms excess ingested sugar into long-chain oligosaccharides." A much larger set of animals do however consume phloem sap by proxy, either "through feeding on the honeydew of phloem-feeding hemipterans. Honeydew is physiologically less extreme than phloem sap, with a higher essential:non-essential amino acid ratio and lower osmotic pressure," or by feeding on the biomass of insects that have grown on more direct ingestion of phloem sap. Maple syrup is made from reduced sugar maple xylem sap. The sap often is harvested from the Sugar Maple, "Acer saccharum". In some countries (e.g., Lithuania, Latvia, Estonia, Finland, Belarus, Russia) harvesting
Tonlé Sap the Tonle Sap River and surrounding wetlands, waters of the lake's basin drains via the Tonle Sap River into the Mekong. As a result the Tonle Sap River (length around 115 km/71 mi) flows six months a year southeast (Mekong) to northwest (lake) and six months a year in the opposite direction. The mean annual reverse flow volume in the Tonle Sap is , or about half of the maximum lake volume. A further 10 percent is estimated to enter the system by overland flow from the Mekong. The Mekong branches off into several arms near Phnom Penh and reaches