Migration of bees
"Research could in turn enable policy makers to take steps to protect the vital migratory routes of these spectacular, charismatic pollinators and honey producers as they ‘surf the sweet wave’ of changing nectar availability. (Robinson, 2021)
Bees migrate in search of forage. Australian, African and all Asian species of Apis may utilise the migrating strategy and may show high levels of seasonal migration.
Migration is planned and is largely driven by varying patterns in resource abundance. Migration appears to occur due to availability of nectar, pollen or water. Migration tends to be seasonal. Most of the stored pollen and honey is consumed by the bees. As soon as the last young brood has emerged the colony will leave. By doing this they ensure they have a good number of relatively young bees and the consumption of pollen ensures their fat bodies will be full of stored protein, ready to start rearing new workers in the new place.
Apis dorsata and Apis laboriosa are the bees that have the best recorded migration behaviour In this instance there is a planned movement of all the colonies in a given area to a predetermined alternative migration site. According to Oldroyd and Wongsiri (2006) Asian honey bees do not usually store great amounts of honey. Their survival strategy is to put their effort into developing reproductive swarms rather than storing surplus food stuff and rather move to an area where food is more abundant. In most cases open nesting bee species will migrate twice each year.
Protection of migratory species in Australia
Migratory species listed under international agreements to which Australia is a party are protected under the Australian Government's central piece of environmental legislation, the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).
Convention on the Conservation of Migratory Species of Wild Animals
Bonn, 23 June 1979
Entry into force generally: 1 November 1983
Entry into force for Australia: 1 September 1991
The Convention on the Conservation of Migratory Species of Wild Animals, also known as the Convention on Migratory Species (CMS) or the Bonn Convention, is an international agreement that aims to conserve migratory species throughout their ranges. The agreement was signed under the auspices of the United Nations environment Programme and is concerned with conservation of wildlife and habitats on a global scale.
1. For the purpose of this Convention:
(a) "Migratory species" means the entire population or any geographically separate part of the population of any species or lower taxon of wild animals, a significant proportion of whose members cyclically and predictably cross one or more national jurisdictional boundaries;
(b) "Conservation status of a migratory species" means the sum of the influences acting on the migratory species that may affect its long-term distribution and abundance;
In Africa, Apis mellifera's migration patterns are largely determined by altitude and rainfall patterns. Broadly, a common seasonal pattern is for colonies to arrive at the end of the wet season. Then combs are built, there is a period of rapid colony growth and the strongest colonies produce reproductive swarms. By the end of the dry season, pollen availability is reduced, brood rearing diminishes and the adult population declines. Combs may be attacked by wax moths and predators while mite populations will be at the maximum. At this point colonies will move from the site and start a long migration to a new locality.
It is not clear how far migrating colonies can travel but it has been shown to be over 100km. As it travels the colony will settle in trees for rest periods in bivouacs. During this time the workers will forage for stores although a quiescent colony will have minimal energy needs. The colony will only move again once it has gathered sufficient stores for the next part of the journey. The movement is preceded by waggle dances on the surface of the colony that indicate the direction of movement. However, it is not known whether parts of the dance refer to the whole journey of just the part to be undertaken on that day.
Under the right circumstance, a colony can move up 20kms each day. Nor is it understood how the bees find their intended new nest site since none of the workers who are travelling will have done the journey before. The probability is that the bees follow an environmentally beneficial trajectory determined by sufficient forage and optimum temperatures.
Once they near the new nesting site it is possible that the remains of last years combs offer some scent indication that the migration is complete. Despite this, Apis dorsata colonies are always started from scratch even if they are quite close the last season comb although Apis florea may take wax from another comb and reuse it in a new site. Apis florea migrations track abundant forage and other suitable physical conditions such as shade in summer and warmth in winter. Apis mellifera move away from some locations to avoid a heavy rainy season or to avoid a long dry season.