Light intensity limits the foraging activity in nocturnal and crepuscular bees.

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Light intensity limits the foraging activity in nocturnal and crepuscular bees. / Kelber, Almut; Warrant, Eric; Pfaff, M; Wallén, Rita; Theobald, Jamie; Wcislo, W; Raguso, R.

In: Behavioral Ecology, Vol. 17, No. 1, 2006, p. 63-72.

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Kelber, Almut ; Warrant, Eric ; Pfaff, M ; Wallén, Rita ; Theobald, Jamie ; Wcislo, W ; Raguso, R. / Light intensity limits the foraging activity in nocturnal and crepuscular bees. In: Behavioral Ecology. 2006 ; Vol. 17, No. 1. pp. 63-72.

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TY - JOUR

T1 - Light intensity limits the foraging activity in nocturnal and crepuscular bees.

AU - Kelber, Almut

AU - Warrant, Eric

AU - Pfaff, M

AU - Wallén, Rita

AU - Theobald, Jamie

AU - Wcislo, W

AU - Raguso, R

PY - 2006

Y1 - 2006

N2 - A crepuscular or nocturnal lifestyle has evolved in bees several times independently, probably to explore rewarding pollen sources without competition and to minimize predation and nest parasites. Despite these obvious advantages, only few bee species are nocturnal. Here we show that the sensitivity of the bee apposition eye is a major factor limiting the ability to forage in dim light. We present data on eye size, foraging times, and light levels for Megalopta genalis (Augochlorini, Halictidae) in Panama, and Lasioglossum (Sphecodogastra) sp. (Halictini, Halictidae) in Utah, USA. M. genalis females forage exclusively during twilight, but as a result of dim light levels in the rain forest, they are adapted to extremely low intensities. The likely factor limiting their foraging activity is finding their nest entrance on return from a foraging trip. The lowest light intensity at which they can do this, both in the morning and the evening, is 0.0001 cd m–2. Therefore, they leave the nest at dimmer light levels in the morning than in the evening. Lasioglossum (Sphecodogastra) foraging is limited by light intensity in the evening, but probably by temperature in the morning in the temperate climate of Utah. We propose that the evolution of nocturnality in bees was favored by the large variance in the size of females.

AB - A crepuscular or nocturnal lifestyle has evolved in bees several times independently, probably to explore rewarding pollen sources without competition and to minimize predation and nest parasites. Despite these obvious advantages, only few bee species are nocturnal. Here we show that the sensitivity of the bee apposition eye is a major factor limiting the ability to forage in dim light. We present data on eye size, foraging times, and light levels for Megalopta genalis (Augochlorini, Halictidae) in Panama, and Lasioglossum (Sphecodogastra) sp. (Halictini, Halictidae) in Utah, USA. M. genalis females forage exclusively during twilight, but as a result of dim light levels in the rain forest, they are adapted to extremely low intensities. The likely factor limiting their foraging activity is finding their nest entrance on return from a foraging trip. The lowest light intensity at which they can do this, both in the morning and the evening, is 0.0001 cd m–2. Therefore, they leave the nest at dimmer light levels in the morning than in the evening. Lasioglossum (Sphecodogastra) foraging is limited by light intensity in the evening, but probably by temperature in the morning in the temperate climate of Utah. We propose that the evolution of nocturnality in bees was favored by the large variance in the size of females.

KW - insects

KW - foraging

KW - ocelli

KW - visual ecology.

KW - sensitivity

KW - eyes

KW - bees

U2 - 10.1093/beheco/arj001

DO - 10.1093/beheco/arj001

M3 - Article

VL - 17

SP - 63

EP - 72

JO - Behavioral Ecology

T2 - Behavioral Ecology

JF - Behavioral Ecology

SN - 1045-2249

IS - 1

ER -