An Introduction to Foraging Behavior of Honey Bee and Floral Fidelity

Behaviour is the ways in which an insect adjusts to and interacts with its total environment. Various types of behaviour occur in insects among which foraging behaviour is an important behaviour the foraging can be defined as searching for and exploiting food resources. It affects an insect's fitness because it plays an important role in an insect's ability to survive and reproduce (Danchin, et al., 2008). Each flower provides a variable but generally small reward that is often hidden. Flowers are patchily distributed in time and space, and are erratically depleted of rewards by other foragers. Insects that specialise in visiting flowers have evolved an array of foraging strategies that act to improve their efficiency (Goulson, 1999). Flowering plants provide floral cues, such as odour, colour, size, shape by which pollinator insects recognize the flowering plants (Chittka and Raine, 2006).Flowering plants often have species-specific odours (e.g. from pollen) which allow bees to distinguish between different plant species as well as between rewarding and non-rewarding flowers of the same species (Howell & Alarcon, 2007). A important foraging behaviour flower constancy has been shown to occur in a wide range of insect pollinators. Flower constancy is beneficial for plants because it prevents pollen loss to allospecific plants and stigma blocking with heterospecific pollen (Gegear and Laverty, 2001).

Floral Constancy in Pollination

Floral constancy is the behavior exhibited by pollinators that restrict visits largely to a single floral type (Waser 1986); this phenomenon has been recognized since Aristotle about 350BC (Grant 1950). In insects two type of floral fidelity has been observed viz., innate and learnt floral fidelity. In case of innate floral fidelity the fixed constancy all the individuals show preference for the same floral resource and the plant is usually dependent upon the visitor as the pollinator. This type of constancy is distinct from learned fidelity, where different individuals of the same species show preferences for alternative floral resources at the same time and locality (Waser 1986).

Reasons of Floral Constancy of Bees

Floral constancy is an extensive behaviour in honeybees that is also found in other types of bees and insects, as well as in vertebrate nectivores. Given the variability in the seasonal and daily floral landscapes, it is fascinating why individual bees would show fidelity to any one species of flower. Although flower constancy has been specially studied in honeybees, models have also included other groups of organisms and have posed diverse explanations: cognitive limitations of the pollinator (Lewis 1986; Waser 1986), the formation of a search image by foragers (Heinrich 1975; Goulson 2000), individual constancy due to colour context-specific behaviour (Wells and Wells 1983), energy maximization (Stephens and Kress 1986).

References:

Chittka, L. and Raine, N. E. 2006.Recognition of flowers by pollinators.Current Opinion in Plant Biology9: 428-435.
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Stephens, D. W.; Krebs, J. R. 1986.Foraging Theory.Princeton University Press. Princeton, New Jersey. 247 p.
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Ph D student, IARI, New Delhi