A Comparison of Visual and Olfactory Learning Performance in the Bumblebee Bombus Terrestris

A comparison of visual and olfactory learning performance in the bumblebee Bombus terrestris

Supplementary Information

Karen E. Smith1*, Nigel E. Raine1,2

1 School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.

2School of Environmental Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada

* email:

Figure S1.Harnessing technique used for the proboscis extension reflex (PER) paradigm.

(a) Harness made from a cut down 2ml plastic syringe (internal diameter 8.2mm), with a v-shaped groove at the front to allow easy proboscis extension.

(b) Yoke to secure the bee’s head in place, made from 2 entomology pins (size 0) glued together at one end (c) and secured at the other end with a plastic earring backing (d).

(e) Tape used to fasten the yoke to the top of the harness on either side of the bee’s head.

Figure S2. Flower choices made by bees in the colour learning paradigm. Choices are broken down into mean (± SE) numbers of blue and yellow approaches (panel A) and lands (panel B) made during consecutive bins of 10 flower choices. The flower choices begin from when each bee probeda yellow flower for the first time. Data presented are pooled across the four colonies,and include all 89 bees that completed the colour learning task.

Figure S3.Boltzmann curve fit indicating the four parameters: A1 is the proportion of errors the bee makes at the start of the curve, and A2 is the proportion of errors the bee makes when it reaches saturation learning performance. Bees that learnt the task well have an A2 value  0. x0 is the centre point of the curve between the two asymptote values (A1 and A2), and is also the point at which this curve has the steepest slope. As such, lower values of x0 indicate bees that improve their task performance more rapidly once the learning process begins. The parameter dx indicates the relative rate the curve transitions from one asymptote to the other: the lower the value, the more rapid the transition and therefore the quicker the bee learnt the task.