[4] Both the larval and adult forms of the common brimstone have protective coloration and behaviour that decreases their chances of being recognised and subsequently preyed upon.

The high mobility of this butterfly allows it to search widely for new host plant locations and expand its range.

The butterfly inhabits wetlands during mating and breeding season, as they provide ideal areas for oviposition due to an abundance of host plants like the alder buckthorn.

[9] During the winter, adult brimstones travel to woodlands to hibernate, as they provide ideal overwintering sites with shelters such as evergreen foliage and holly.

[10][4] The common brimstone has an appearance that is highly similar to the leaves of these plants, so during hibernation it can remain hidden.

The common brimstone heavily feeds on the nectar of several flowering species including knapweed (Centaurea jacea) and scabious (Knautia arvensis and Succisa pratensis).

[10][15] The high mobility of G. rhamni enables the butterflies to find even the most isolated host plants in an area, which are more ideal for their offspring.

[9] Plants exposed to both sunlight and the open lead to reduced chances of predation and parasitism as well, and are more accessible to adult butterflies.

[15] During the day, they feed and then rest in the open, lying still on the midrib of leaves, where their colouration makes them difficult to distinguish.

[11] The pupae have a primarily green colouration, but right before adult emergence for males, the wing areas turn yellow.

[14] The common brimstone hibernates for the next seven months of winter, remaining inactive until April, where they then emerge and proceed to reproduce and lay eggs.

[6] Additionally, males have iridescent dorsal wings that change in colour and appearance under ultraviolet light, while females do not.

[7] Both males and females have orange spots in the discoidal cell of each wing, pink head and antennae, and a thorax covered in white hair.

After emerging from overwintering, adult brimstones that were previously in the wetlands are joined by those that hibernated in woodlands, and the population breeds and lays eggs.

[14] Uphill migration is potentially influenced by habitat limitations, such as a lack of the forest cover that is required during overwintering.

[9] Both larvae and adult brimstones fall victim to predation and use means such as protective coloration and mimicry to avoid this fate.

[17] These two species of parasitoid wasps are completely specialised for G. rhamni, possibly due to the wide distribution of the butterfly and the host plants in its habitats.

In the common brimstone, wing scales scatter light incoherently due to ovoid-shaped structures called beads that contain pigments.

[7] Through chemical extraction and analysis, two possible pigments have been identified that may contribute to the common brimstone's wing coloration.

[19] This demonstrates that the pattern appears to be optical, rather than pigmental, as the effect is only seen at certain angles and distances of light and changes with positions.

[21][12] G. rhamni also has a stronger reliance on visual indications such as colour compared with other butterfly species, which rely more on odour.

[22] This would contribute to more efficient foraging in adult butterflies, as odour could act as a cue for finding and distinguishing nectar plants, allowing more energy to be utilised for other activities such as reproduction.

[6] For females, eggs remain undeveloped as the butterflies overwinter, and no reproductive development occurs until after emergence from hibernation.

[1] However, the butterfly has experienced significant population and distribution reduction in areas such as the Netherlands, where its numbers have declined to the point that based on IUCN criterion, it has reached endangered species status.

Since the common brimstone is univoltine, it may have difficulties adapting to changing environmental conditions compared to species that have multiple generations a year.

[14][24] Nitrogen pollution, declining nectar supplies, and rapid ecological changes have also been suggested as other hypothetical factors.