Silver-studded blue (Plebejus argus)

The silver-studded blue (Plebejus argus) is a butterfly in the family Lycaenidae. This eye-catching butterfly has bright blue wings rimmed in black with white edges and silver spots on its hindwings, lending it the name of the silver-studded blue. P. argus can be found across Europe and Asia, but is most often studied in the United Kingdom in which the species has experienced a severe decline in population due to habitat loss and fragmentation.

Importantly, P. argus engages in mutualism with ants that contribute to the butterflies’ reproductive fitness by providing protection from predation and parasitism from the point of egg laying to their emergence as adults. P. argus adults emerge in the end of June and beginning of July and engage in flight into the beginning of August.

The butterfly is adaptable to different habitats and is found in heathland, mossland, and limestone grassland. Tending towards a sedentary lifestyle and typically flying less than twenty meters a day, P. argus maintains a small radius home range. Their habitats lend themselves well to both foraging and egg laying as the host plants are ubiquitous in all three environments they occupy.

Appearance
Adult
Male P. argus have royal blue wings with a black border, white, wispy fringe, and metallic silver spots on the hindwings as well as spurs on their front legs. Females of this species are generally brown and more subdued in color, but also have the metallic spots on the hindwings. The undersides of the male and female butterflies are very similar. They are taupe in color, with rings of black spots along the edge of the wing.

Larvae
The caterpillar of P. argus is green with a dark stripe along the length of its body and can reach 1.3 centimeters in length.

Sexual Dimorphism
P. argus exhibit sexual dimorphism, as evidenced by the color of their wings. This eventually acts as an important visual cue when searching for suitable mates. Experiments have shown that species that have overlapping habitat distribution and are of similar color (according to the human eye) have distinct absorbance values within the UV range. This shows that the UV range colors are important for butterflies when recognizing members of its own species.
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https://en.wikipedia.org/wiki/Silver-studded_blue