Applied Entomology and Zoology
Online ISSN : 1347-605X
Print ISSN : 0003-6862
ISSN-L : 0003-6862
Special Feature:
Ecological Risk Assessment of Introduced Bumblebees
Is Bombus terrestris (Hymenoptera: Apidae) a stronger competitor against native Japanese species? A comparison of foraging efficiency
Maki N. InoueTakashi T. MakinoJun YokoyamaSatoki Sakai
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2010 Volume 45 Issue 1 Pages 71-75


The introduced Bombus terrestris has recently become naturalized in Japan and it may be responsible for the observed decline of native bumblebee populations. We compared the foraging ability of B. terrestris and a Japanese native bumblebee, B. ignitus, in an experimental cage. The 6-day experiment showed no significant difference in mean foraging load between them even though B. terrestris was significantly smaller than B. ignitus. However, B. terrestris was significantly more efficient, with a higher mean foraging load per unit time, and also brought back more forage per unit body mass than B. ignitus. The proboscis length of B. terrestris workers was more suited to the flower size of Salvia farinacea and the species may thus be more efficient in foraging. Once it has invaded a new region, B. terrestris can become the dominant bumblebee. When resources are low, B. terrestris, with a large number of superior foragers, can disadvantage native bees through resource depletion.

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© 2010 by the Japanese Society of Applied Entomology and Zoology
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