Question 22N.2.SL.TZ0.g
| Date | November 2022 | Marks available | [Maximum mark: 1] | Reference code | 22N.2.SL.TZ0.g |
| Level | SL | Paper | 2 | Time zone | TZ0 |
| Command term | Suggest | Question number | g | Adapted from | N/A |
The biodiversity of insects worldwide is in decline. Destruction of habitats, pollution and climate change have contributed to the decline in global insect populations and to the extinction of insect species. A comprehensive literature review was carried out to determine the annual global rate of decline in insect species. The graph shows the results for three major orders of terrestrial insects and the total decline in insect biomass worldwide.
One species of the order Hymenoptera is the buff-tailed bumblebee (Bombus terrestris), which feeds on pollen and nectar obtained from specific plants.
Destruction of preferred habitats has affected the size of bumblebee populations and for survival, bumblebees have to feed on pollen from other available plant habitats. To simulate different pollens, researchers fed bumblebees on eight diets consisting of a mixture of proteins and lipids in different ratios (P:L). The bumblebees also had access to sucrose. There was no restriction on the amount of each food the bumblebees could consume. The chart shows the mean daily mass of food eaten for eight diets with different P:L ratios.
[Source: Buhl, V., 2010. Bombus terrestris. [image online] Available at: https://commons.wikimedia.org/wiki/File:2010-04-
28_(35)_Erdhummel,_Buff-tailed_bumblebee,_Bombus_terrestris.jpg [Accessed 6 December 2021].
[chart] Adapted from Vaudo, A.D., Stabler, D., Patch, H.M., Tooker, J.F., Grozinger, C.M and Wright, G.A., 2016.
Bumble bees regulate their intake of essential protein and lipid pollen macronutrients. Journal of Experimental
Biology 219, pp. 3962–3970.]
Suggest a reason that the mass of protein and lipid mixture eaten at 25:1 is lower than at 50:1.
[1]
- the mixture was closer to what the bees ate naturally;
- the bees like the taste better/prefer sucrose;
- there was more lipid in the 25:1 mixture so they achieved their daily lipid/energy requirement with less mass of food;
- the bees eating 50:1 diet ate more to reach their daily lipid requirement;
- prefer the higher proportion of protein (in the 50:1)
