| Date | May 2015 | Marks available | 3 | Reference code | 15M.3.SL.TZ2.13 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | Evaluate | Question number | 13 | Adapted from | N/A |
Question
Honey bees (Apis mellifera) were fed with sucrose solution only or with low doses of ethanol in sucrose solution to examine how a slightly intoxicated state could affect their behaviour. Individual behaviour involves walking and grooming while social behaviour includes contact of antennae between bees to show recognition (antennation) and asking other bees for food when hungry (begging). The graphs show individual and social behaviour changes observed in successive five minute intervals two hours after honey bees were fed sucrose solution either with or without ethanol.
State the percentage of time the honey bees engaged in begging during the first five minute interval.
Bees fed with ethanol: .....................%
Bees fed without ethanol: .....................%
Describe the trends in antennation for honey bees fed with ethanol and without ethanol.
Distinguish between the times spent walking and grooming for honey bees fed with ethanol and without ethanol.
Evaluate the hypothesis that ethanol affects the social behaviour of honey bees.
Markscheme
a. without alcohol (antennation starts at a high level and) decreases with time;
b. with alcohol, the value (starts low and) very slowly increases;
c. the values of both group become very similar with time;
a. (time spent) walking is greater in bees without alcohol (than alcohol);
b. (time spent) grooming is greater with alcohol (than without alcohol);
c. the end point difference is greater in walking;
d. (time spent) walking increases whereas grooming decreases for both groups of bees;
a. (hypothesis supported as) alcohol decreases antennation at the start of the experiment;
b. (hypothesis supported as) alcohol increases begging at the start;
c. begging time is more variable/has less significant differences with alcohol so less clear than in antennation;
d. (hypothesis is supported as) the effect of alcohol on social behaviours becomes less distinguishable over time (with the effect of sucrose);
Examiners report
Option E data consisted of four graphs describing how the behaviour of honey bees changed when fed with alcohol. The candidates had a lot of information provided in the data and this did cause considerable confusion particularly among weaker candidates.
Option E data consisted of four graphs describing how the behaviour of honey bees changed when fed with alcohol. The candidates had a lot of information provided in the data and this did cause considerable confusion particularly among weaker candidates.
Option E data consisted of four graphs describing how the behaviour of honey bees changed when fed with alcohol. The candidates had a lot of information provided in the data and this did cause considerable confusion particularly among weaker candidates.
The question confused weaker candidates as they were unsure what distinctions had to be made.
Option E data consisted of four graphs describing how the behaviour of honey bees changed when fed with alcohol. The candidates had a lot of information provided in the data and this did cause considerable confusion particularly among weaker candidates.
The candidates tended to look at trends in the data and did not realise that they simply had to look at the first points in the graph to show that ethanol had affected the behaviour of the bees.
