Bumblebees in Pollination Biology

(1) Repellant foraging scent recognition across bee families
Nadine GAWALETA, Yvonne ZIMMERMANN, Thomas ELTZ
Apidologie 36 (2005) 325-330, 2005

Photo is taken from http://www.wildlife-gardening.org.uk/

Background:
It’s already established that social Honeybees, Bumblebees use scent mark to avoid the recently probed flowers, in which resources are already depleted. This indicates their efficient foraging ability. 　What about the solitary bees?

Problems:
1) What is the effect to Bumblebees if flowers previously visited by Anthidium manicatum? Or 　vice-versa.
2) Do Bumblebees discriminate different previous visitors?

Findings:
1) Anthidium manicatum also used repellant scent mark to reject previously visited flowers. So, the use of repellant scent mark is not confined to social Apidae. It also indicates that repellant scent marks are not a way of social communication in the Apidae.
2) Bumblebee can (and does) discriminate scent marks of different species.

Further Questions:
1) Are scent marking deposited actively? Or 　unavoidable footprints?

Please read the original article to know details.