Pollinators Pollinators_1 | Page 2

BayG.A.P. SERVICE PROGRAM MODULE 11 Bees and plants live in a symbiotic relationship which developed over millions of years. The bee obtains its most important foods (nectar and pollen) from the plant and, in doing so, pollinates the plant. Honey bees have adapted to their food supplier: Their mouthparts are extremely well-suited to sucking nectar from the flower. Together, the lower jaw and lower lip form the proboscis which the bee penetrates into the flower’s interior. Using the proboscis, the bee can reach into the depths of the flower to access the nectar there. The pollination performance of honey bees increases yields and quality in many agricultural cultures, and can be summarized in impressive figures: Its worldwide annual market value amounts from $235-577 billion (in 2015; Value adjusted to 2015 United States dollars taking into account inflation only). BUMBLE BEES Bumble bees are mostly wild-living insects. They live in colonies (size: 50–500 bees) but have a less complex social structure than honey bees. Bumble bees have comb cells of wax and various nest sites: most of them prefer dry, dark cavities. Bumble bee castes: THE QUEEN who starts and dominates the colony and lays eggs; WORKERS who forage, fulfil nest duties such as brood care, and work as defenders (5–6 weeks life expectancy); DRONES who mate with new queens (and die 2–3 weeks after mating). Only the queens overwinter. Bumble bees feed on nectar and pollen. Their foraging radius is typically less than 1.7 km. Since they do not produce more honey than they need to feed themselves, their role is limited to pollination. SOLITARY BEES Solitary bees are wild-living insects, that live on their own (or close together). They nest mainly in the ground (75%) but there are various other nesting sites such as deadwood. They do not have a queen. Their FEMALES lay eggs, prepare the nesting site and forage. The MALES die after mating. Adult solitary bees collect nectar and pollen. Their foraging radius is normally between 0.1 and 1.2 km. Roughly 2% of all wild bee species act as pollinators in 80% of crops worldwide. STINGLESS BEES Stingless bees are eusocial insects and live in colonies of 300-80,000 individuals in the tropical and subtropical regions of America, Africa, East Asia, and Australia. Stingless bees belong to the tribe Meliponini which comprises 350-500 species. They are the only bee species, besides the honey bee, which form permanent colonies with wax combs. Nests of most species are in cavities of deadwood or in the soil. Castes: A colony has a QUEEN and DRONES as reproductive individuals. Female WORKERS take care of colony maintenance including foraging and brood care. Some species also have SOLDIERS for colony defense. Stingless bees are unable to sting with their reduced stinger so they have developed other means of defense such as biting. Stingless bees forage on a variety of plants, collecting nectar and pollen. They are active all year round and have a foraging radius up to several kilometers. The location of foraging sources is communicated within the colony by scent marks, not by dancing as with the honey bees. Stingless bee larvae are not continuously fed but are instead provided once with food for their entire development. Some stingless bee species are cultivated for honey and wax production, or for pollination. The importance of managed crop pollination in the tropics and subtropics is increasing. 4