| Date | November 2009 | Marks available | 2 | Reference code | 09N.3.HL.TZ0.1 |
| Level | Higher level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Suggest | Question number | 1 | Adapted from | N/A |
Question
The soapberry bug (Jadera haematoloma) feeds on the seeds of plants from the soapberry family (Sapindaceae). It does this by penetrating the fruit containing the seeds with mouthparts called the proboscis.
The diagrams below show sections through the fruits taken from four members of the Sapindaceae family.
In Florida, Cardiospermum corindum is native to the area while Koelreuteria elegans is a species that was introduced in the 1890s and is now common in Florida. In the South Central United States, Sapindus saponaria is native while Koelreuteria paniculata is an introduced species which has become more common over the past 70 years.
The graph below shows proboscis lengths of samples of adult female soapberry bugs in Florida between 1880 and 1980.
Outline the trends in proboscis length in soapberry bugs shown in the graph.
Suggest, giving a reason, the expected trend in the proboscis length of the soapberry bug in the South Central United States over the past 70 years.
Markscheme
proboscis length has decreased;
proboscis length has become less variable;
introduced fruit has a thicker flesh;
expect proboscis to get longer;
Examiners report
The trend required was often seen, the change in the variation of the data however, was rarely stated.
This was mostly very well answered with many students successfully suggesting that the proboscis length would increase over time due to the distance of the seeds from the outside of the fruit.
