Individual foraging, activity level and longevity in the stingless bee Melipona beecheii in Costa Rica (Hymenoptera, Apidae, Meliponinae)

Foraging behaviour of individually marked workers of Melipona beecheii (Meliponinae) was monitored in Costa Rica to investigate individual specialisation for different materials and how this influences foraging longevity. The majority of the individuals harvested one commodity (pollen, nectar or resin) during a single day. Half of the age-marked foragers specialised on nectar or pollen during their complete foraging career, the other half collected two or three commodities. Most members of the latter group switched daily from early morning pollen (or resin) collecting to nectar collecting. Life-long foraging of one-material collectors was not more efficient than that of two-material collectors. The groups of foragers differed significantly in activity patterns and longevity: activity was traded off with longevity. Nectar foragers were active all day and died after an average of 3 foraging days. Pollen foragers were active for 1-3 hours per day, but lived for 12 days on average. However, pollen foragers and nectar foragers performed a similar number of flights in their career. How bees become pollen, nectar or mixed foragers is not clear. Age and performance of pre-foraging hive tasks did not influence forager specialisation in M. beecheii

Modelling collective foraging by means of individual behaviour rules in honey-bees

An individual-oriented model is constructed which simulates the collective foraging behaviour of a colony of honey-bees, Apis mellifera. Each bee follows the same set of behavioural rules. Each rule consists of a set of conditions followed by the behavioural act to be performed if the conditions are fulfilled. The set of conditions comprises the state of external information available to the bee (e.g. the dancing of other bees) and internal information variables (like memorised location of a food source and homing motivation). The rules are partly observational (i.e. they capture the observable regularities between the present external information and the individual bee's behaviour), and partly involve hypothesised internal-state variables (e.g. abandoning tendency and homing motivation), because no observ- able (physiological) aspect has as yet been detected in the bee which correlates with changes in the internal moti- vation. Our aim is to obtain a set of rules that is nec- essary and sufficient for the generation of the collective foraging behaviour observed in real bees. We simulated an experiment performed by Seeley et al. in which a colony of honey-bees chooses between two nectar sources of different profitabilities which are switched at intervals. A good fit between observed and simulated collective forager patterns was obtained when the model included rules in which the bees (1) relied on the infor- mation acquired from previous fiights to a source (e.g. profitability and time of day when the source was found), (2) used positional information obtained by at- tending recruitment dances and (3) did not abandon a (temporarily) deteriorated source too fast or too slowly. The significance of the following issues is discussed: the role of internal and external information, source prof- itability, the spatial precision of the dance communica- tion, the ability to search for a source after the source position has been transmitted, the tendency to abandon a deteriorated source, and the concepts of scout, recruit, (un)employed forager, and foraging history

Extinctions of aculeate pollinators in Britain and the role of large-scale agricultural changes

Pollinators are fundamental to maintaining both biodiversity and agricultural productivity, but habitat destruction, loss of flower resources, and increased use of pesticides are causing declines in their abundance and diversity. Using historical records we assessed the rate of extinction of bee and flower-visiting wasp species in Britain, from the mid 19th century to the present. The most rapid phase of extinction appears to be related to changes in agricultural policy and practice beginning in the 1920s, before the agricultural intensification prompted by the Second World War, often cited as the most important driver of biodiversity loss in Britain. Slowing of the extinction rate from the 1960s onwards may be due to prior loss of the most sensitive species and/or effective conservation programs

Bee conservation: inclusive solutions

Conservation Biolog

Exploration and exploitation of food sources by social insect colonies: a revision of the scout-recruit concept

Social insect colonies need to explore and exploit multiple food sources simultaneously and efficiently. At the individual level, this colony-level behaviour has been thought to be taken care of by two types of individual: scouts that independently search for food, and recruits that are directed by nest mates to a food source. However, recent analyses show that this strict division of labour between scouts and recruits is untenable. Therefore, a modified concept is presented here that comprises the possible behavioural states of an individual forager (novice forager, scout, recruit, employed forager, unemployed experienced forager, inspector and reactivated forager) and the transitions between them. The available empirical data are reviewed in the light of both the old and the new concept, and probabilities for the different transitions are derived for the case of the honey-bee. The modified concept distinguishes three types of foragers that may be involved in the exploration behaviour of the colony: novice bees that become scouts, unemployed experienced bees that scout, and lost recruits, i.e. bees that discover a food source other than the one to which they were directed to by their nest mates. An advantage of the modified concept is that it allows for a better comparison of studies investigating the different roles performed by social insect foragers during their individual foraging histories

Symmetry breaking in collective honeybee foraging: a simulation study

Symmetry breaking is the phenomenon that the numbers of foragers exploiting two equally profitable food sources will diverge. This phenomenon has been investigated in ants [1,4,5], but hardly in honeybees. It is even not clear whether in honeybees symmetry breaking can occur [3, p.190]. We present results of an individual-oriented simulation model showing that under specific circumstances symmetry breaking in the numbers of honeybee workers exploiting two or four identical nectar sources can occur. We studied factors that influence the occurrence of symmetry breaking, which include: size of the forager pool, number of bees initially exploiting the sources, and size of the flower patch. This study is part of an ongoing study which aims at developing an individual-oriented simulation model capturing the necessary and sufficient behavioural rules to generate the collective foraging patterns observed in bee

Honingbijensurveillance: rapport 2016-2017

Het Honingbijensurveillance-programma stelt de mate van wintersterfte onder honingbijen in Nederland vast en heeft tot doel de oorzaken te ontrafelen die de wintersterfte kunnen verklaren

Natuurlijk kapitaal: fundament voor onze toekomst

Oratie uitgesproken door Prof.dr. Koos Biesmeijer bij de aanvaarding van het ambt van hoogleraar op het gebied van Natuurlijk Kapitaal aan de Universiteit Leiden op vrijdag 9 maart 2018Oratie uitgesproken door Prof.dr. Koos Biesmeijer bij de aanvaarding van het ambt van hoogleraar op het gebied van Natuurlijk Kapitaal aan de Universiteit Leiden op vrijdag 9 maart 2018Conservation Biolog

Does the waggle dance help honey bees to forage at greater distances than expected for their body size?

A honey bee colony has been likened to an oil company. Some members of the company or colony prospect for valuable liquid resources. When these are discovered other group members can be recruited to exploit the resource. The recruitment of nestmates to a specific location where there is a patch of flowers should change the economics of scouting, that is, the search for new resource patches. In particular, communication is predicted to make scouting at longer distances worthwhile because a profitable resource patch, once discovered, will enhance the foraging not only of the discoverer but also of nestmates that can be directed to the patch. By virtue of having large colonies and dance communication, honey bees are predicted to be able to profitably scout, and hence forage, at greater distances from the nest than either solitary bees or social bees without communication. We test this hypothesis by first examining existing data on foraging distance to evaluate whether honey bees do indeed forage at greater distances than other bees given their body size. Second, we present a simple cost-benefit analysis of scouting which indicates that communication causes longer range scouting to be more profitable. Overall, our analyses are supportive, but not conclusive, that honey bees forage further than would be expected given their size and that the waggle dance is a cause of the honey bee's exceptional foraging range