State which butterfly (sub)family contains the species with the greatest escaping ability.

Suggest one feature of butterfly wings that might help a butterfly to escape from a predator.

Explain how the ability of a butterfly to escape from predators could increase by natural selection.

The graph shows that distasteful butterflies tend to have a lower ability to escape from predators than palatable butterflies. Suggest reasons for this trend.

Limenitidinae

large wing size / camouflage/cryptic coloration / warning coloration / mimicry / powerful wing muscles / high flight speed / erratic flight pattern / OWTTE

natural selection favours survival of better-adapted individuals;
better-adapted butterflies have greater ability to escape predation;
and survive to reproduce;
allowing them to pass their characteristics/alleles/genes to offspring;
over generations, the number of butterflies with best-escaping ability increases in the population / frequency of alleles/genes for better
escaping ability increases in the population/gene pool;

palatable butterflies with high escaping ability can survive to pass on genes / palatable butterflies with low escaping ability are eaten and their genes are lost;
unpalatable/distasteful butterflies, regardless of escaping ability, are not eaten/are avoided by predators;
such butterflies survive to pass on their genes to the next generation;

This part required candidates to read the highest escaping ability correctly, which was done by the vast majority of candidates.

The vast majority of candidates suggested a plausible feature that could increase the escaping ability among butterflies, most mentioning camouflage.

This part seemed more challenging for candidates who nevertheless managed to gain marks. In (i), stating the principles of natural selection clearly in terms of adaptation, survival, reproduction and relating to populations and/or gene pools was the most difficult part, with many answers failing to include the words adaptation, population and gene pool.

In (ii), many candidates managed to state that unpalatable butterflies were not eaten by predators, but had much difficulty to figure out that it was regardless of escaping ability; many answers had a lamarckian connotation, stating that butterflies who could not escape had to evolve to become unpalatable, which is incorrect. Furthermore, candidates largely failed to explain palatable butterflies here. Very few marking points were awarded for “palatable butterflies with high escaping ability can survive to pass on genes / palatable butterflies with low escaping ability are eaten and their genes are lost.”