Pararge aegeria

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 tircis, Pararge aegeria oblita, and Pararge aegeria insula. The color 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 speckled wood belongs to the genus Pararge, which comprises three species: Pararge aegeria, Pararge xiphia, and Pararge xiphioides. Pararge xiphia occurs on the Atlantic island of Madeira. Pararge xiphioides occurs on the Canary Islands. Molecular studies suggest that the African and Madeiran populations are closely related and distinct from European populations of both subspecies, suggesting that Madeira was colonized from Africa and that the African population has a long history of isolation from European populations. Furthermore, the species Pararge aegeria comprises four subspecies: Pararge aegeria aegeria, Pararge aegeria tircis, Pararge aegeria oblita, and Pararge aegeria insula. These subspecies stem from the fact that the speckled wood butterfly exhibits a cline across their range. This butterfly varies morphologically down the 700 km cline, resulting in the different subspecies corresponding to geographical areas. 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 grayish-brown scent scales on 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 hindwing 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 moves 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. The speckled wood occupies a diversity of grassy, flowery habitats in forest, meadow steppe, forest, woods, and glades. It can also be found in urban areas alongside hedges, in wooded urban parks, and occasionally in gardens. Within its range the speckled wood typically prefers damp areas. It is generally found in woodland areas throughout much of the Palearctic ecozone. P. a. tircis is found in northern and central Europe, Asia Minor, Syria, Russia, and central Asia, and the P. a. aegeria is found in southwestern Europe and North Africa. Two additional subspecies are found within the British Isles: the Scottish speckled wood (P. a. oblita) is restricted to Scotland and the its surrounding isles, and the Isles of Scilly speckled wood (P. a. insula) is found only on the Isles of Scilly. P. a. tricis and P. a. aegeria gradually intergrade into each other. The eggs are laid on a variety of grass host plants. The caterpillar is green with a short, forked tail, and the chrysalis (pupa) is green or dark brown. The species is able to overwinter in two totally separated developmental stages, as pupae or as half-grown larvae. This leads to a complicated pattern of several adult flights per year. Larval food plants include a variety of grass species such as Agropyron (Lebanon), Brachypodium (Palaearctic), Brachypodium sylvaticum (British Isles), Bromus, (Malta), Cynodon dactylon, (Spain), Dactylis glomerata (British Isles, Europe), Elymus repens, (Lebanon), Elytrigia repens (Spain), Holcus lanatus (British Isles), Hordeum (Malta), Melica nutans, (Finland), Melica uniflora (Europe), Oryzopsis miliacea (Spain), Poa annua (Lebanon), Poa nemoralis (Czechoslovakia), Poa trivialis (Czechoslovakia), but the preferred species of grass is the couch grass (Elytrigia repens). The adult is nectar feeding. The growth and development of the speckled wood butterfly is dependent on the larval density and the sex of the individual. High larval densities result in decreased survivorship as well as a longer development and smaller adults. However, females are much more adversely affected by this phenomenon. They depend on their larval food stores during oviposition, so a high larval density in the larva stage can result in lower fecundity for females in the adult stage. Males can compensate for their smaller size by feeding as adults or switching mate-locating tactics, so they are less affected by high larval densities. A high growth rate can also negatively affect larval survivorship. Those with high growth rates will also have high weight-loss rates if food becomes scarce. They are less likely to survive if food becomes available once again.