Speckled Wood

The Speckled Wood (Pararge aegeria) is a butterfly found in and on the borders of woodland areas throughout much of the Palearctic ecozone. The species is subdivided into multiple subspecies, including Pararge aegeria aegeria, Pararge aegeria tricis, Pararge aegeria oblita, and Pararge aegeria insula. The coloration of this butterfly varies between subspecies. The existence of these subspecies is due to variation in morphology down a gradient corresponding to a geographic cline. The background of the wings ranges from brown to orange, and the spots are either pale yellow, white, cream or a tawny orange. The Speckled Wood feeds on a variety of grass species. The males of this species exhibit two types of mate locating behaviors: territorial defense and patrolling. The proportion of males exhibiting these two strategies changes based on ecological conditions. The monandrous female must choose which type of male can help her reproduce successfully. Her decision is heavily influenced by environmental conditions.

The average wingspan of both males and females is 5.1 cm (2 in), although males tend to be slightly smaller than females. Furthermore, males possess a row of greyish-brown scent scales of their forewings that is absent in the females. Females have brighter and more distinct markings than males. The subspecies P. a. tircis is brown with pale yellow or cream spots and darker upperwing eyespots. The subspecies P. a. aegeria has a more orange background and the hindwing underside eyespots are reddish brown rather than black or dark gray. The two forms gradually intergrade into each other. Subspecies P. a. oblita is a darker brown, often approaching black with white rather than cream spots. The underside of its hindwings has a marginal pale purple band and a row of conspicuous white spots. The spots of subspecies P. a. insula are a tawny orange rather than a cream color. The underside of the forewings has patches of pale orange, and the underside of the hind wing has a purple tinged band. Although there is considerable variation with each subspecies, identification of the different subspecies is manageable.

The morphology of this butterfly varies as a gradient down its geographic cline from North to South. The northern butterflies in this species have a bigger size, adult body mass, and wing area. These measurements decrease as one move's in a southerly direction in the Speckled Wood's range. Forewing length on the other hand increases moving in a northerly direction. This is due to the fact that in the cooler temperatures of the northern part of this butterfly's range, the butterflies need larger forewings for thermoregulation. Finally, the northern butterflies are darker than their southern counterpart, and there is a coloration gradient, down their geographical cline.