Consumptive emasculation: the ecological and evolutionary consequences of pollen theft

  title={Consumptive emasculation: the ecological and evolutionary consequences of pollen theft},
  author={Anna L. Hargreaves and Lawrence D. Harder and Steven D. Johnson},
  journal={Biological Reviews},
Many of the diverse animals that consume floral rewards act as efficient pollinators; however, others ‘steal’ rewards without ‘paying’ for them by pollinating. In contrast to the extensive studies of the ecological and evolutionary consequences of nectar theft, pollen theft and its implications remain largely neglected, even though it affects plant reproduction more directly. Here we review existing studies of pollen theft and find that: (1) most pollen thieves pollinate other plant species… 

Floral traits mediate the vulnerability of aloes to pollen theft and inefficient pollination by bees.

Species-specific floral and inflorescence characteristics, especially nectar accessibility and dichogamy, control the efficiency of pollen-collecting bees as pollinators of aloes.

Nectar quality changes the ecological costs of chemically defended pollen

The Ecological Context of Pollination: Variation in an Apparent Mutualism

This thesis documents a particular ecological situation in which a pollen-specialist bee and a nectar-collecting fly visit concurrently, and uses a simulation model to explore what ecological contexts will cause a floral visitor to increase or decrease overall pollen delivery.

PLANT-POLLINATOR INTERACTIONS FROM FLOWER TO LANDSCAPE Assessment of pollen rewards by foraging bees

1. The removal of pollen by flower-visiting insects is costly to plants, not only in terms of production, but also via lost reproductive potential. Modern angiosperms have evolved various reward

Native pollen thieves reduce the reproductive success of a hermaphroditic plant, Aloe maculata.

The results highlight the importance of social bees as pollen thieves, even of plants that have evolved in their presence, and the role of dichogamy in promoting pollen theft.

Bee pollination biology: buzzing, behavior, and biomechanics

This work describes some of the relationships between plants and pollinators and focuses on buzz pollination (or floral sonication), which is particularly useful when bees collect pollen from plants that have poricidal anthers that release pollen only from small pores.

High incidence of pollen theft in natural populations of a buzz-pollinated plant

It is concluded that insect size, relative to the flower, is the main determinant of whether a visitor acts as a pollinator or a pollen thief in S. rostratum.

Nectar Robbing: Ecological and Evolutionary Perspectives

The evolutionary ecology of nectar robbing is reviewed from both the plant and animal perspective, and how plants may be able to deter robbers through morphological and chemical traits is detailed.

Assessment of pollen rewards by foraging bees

How pollen impacts on the behaviour and foraging decisions of pollen-collecting bees is explored, drawing comparisons with what is known for nectar rewards, and advancements in the understanding of how bees forage for pollen and respond to variation in pollen quality are reviewed.

Plant–pollinator interactions along the pathway to paternity

This work presents a newly emerging idea that bodies of pollinators function as a dynamic arena facilitating intense male-male competition, where pollen of rival males is constantly covered or displaced by competitors.




  • Lucinda A. McDadeS. Kinsman
  • Environmental Science
    Evolution; international journal of organic evolution
  • 1980
Many angiosperm flowers produce substances (e.g., nectar, pollen, lipids) which serve as rewards for animals which are morphologically and behaviorally adapted to effect pollination by transferring

Bumble bee selection of Mimulus guttatus flowers : The effects of pollen quality and reward depletion

British bumble bees could discriminate among plants on the basis of pollen quality provided that flowers still retained most of the pollen, and the results have implications for the evolution of pollen production in Mimulus guttatus and reward production in other plants.

Evolutionary Options for Maximizing Pollen Dispersal of Animal-Pollinated Plants

On the average, nectar-collecting bumble bees deposited 0.6% of the pollen removed from the flowers of Erythronium grandiflorum (Liliaceae) onto the stigmas of subsequently visited flowers. Because

Floral Rewards: Alternatives to Pollen and Nectar

The occurrence of oil production in the Solanaceae (Nierembergia) is reported here for the first time and it is apparent that oil production has evolved independently many times, but plants which produce oils that are collected by female anthophorine bees show similarities in the chemistry of the oils and the types of structures that produce them.

Mating cost of large floral displays in hermaphrodite plants

Traditional interpretations of floral design and display are proposed to recognize their roles in reducing geitonogamous pollen discounting, which is observed to predict higher selfing and lower outcrossed siring success for larger inflorescences.

Adaptive plasticity of floral display size in animal-pollinated plants

  • L. HarderS. Johnson
  • Environmental Science
    Proceedings of the Royal Society B: Biological Sciences
  • 2005
By hand-pollinating some inflorescences, but not others, it is demonstrated plasticity in display size of the orchid Satyrium longicauda, and pollination-induced flower wilting serves the entire plant by allowing it to display the number of flowers that is appropriate for the current pollination environment.

The ecology and evolution of visual pollen signals

  • K. Lunau
  • Biology
    Plant Systematics and Evolution
  • 2004
The present contribution reviews several strategies that angiosperms have evolved to attract potential pollinators to the site of reward and considers evolutionary, ecological, sensory-physiological, and behavioural aspects of flower-pollinator interactions that are correlated with visual signals provided by pollen and pollen-producing organs, or imitations thereof.

Colored floral organs influence pollinator behavior and pollen transfer in Commelina communis (Commelinaceae).

The hypothesis that floral guides also prevent pollen-theft behavior by floral visitors (theft prevention hypothesis) is examined and findings support both the foraging facilitation hypothesis and the theft prevention hypothesis.

Behavioral responses by bumble bees to variation in pollen availability

Simulation results indicate that the observed movement patterns of bumble bees on Lupinus inflorescences would return the most pollen per unit of expended energy, and the increased foraging efficiency resulting from facultative responses by bees to variation in pollen availability, especially changes in the frequency and intensity of grooming, could correspondingly decrease pollen dispersal between plants.

The association between floral longevity and pollen removal, pollen receipt, and fruit production in flame azalea (Rhododendron calendulaceum)

Examining flower life span in the shrub flame azalea (Rhododendron calendulaceum (Michx.) Torr.