The speckled wood (Pararge aegeria) is a butterfly found in and on the borders of woodland areas throughout much of the Palearctic realm.

[2] The males of this species exhibit two types of mate locating behaviors: territorial defense and patrolling.

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 underside of its hindwings has a marginal pale purple band and a row of conspicuous white spots.

The northern butterflies in this species have a bigger size, adult body mass, and wing area.

Finally, the northern butterflies are darker than their southern counterpart, and there is a coloration gradient, down their geographical cline.

[7] 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 (Czechia/Slovakia), Poa trivialis (Czechia/Slovakia), but the preferred species of grass is the couch grass (Elytrigia repens).

[7] 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.

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.

[10] In order to locate females, males employ one of two strategies: territorial defense and patrolling.

[4] During territorial defense, the male defends a sunny spot in the forest, waiting for females to stop by.

[6] Males employing different strategies, territorial defense or patrolling, can be differentiated by the number of spots on their hindwings.

[4] Territorial defense involves a male flying or perching in a spot of sunlight that pierces through the forest canopy.

The speckled wood butterfly spends the night high up in the trees, and territorial activity commences once sunlight passes through the canopy.

[11] If a previous owner of the sunspot tries to reclaim his territory after he has left for mating, a longer and more costly fight ensues.

Sunspots are more attractive when temperatures are low, as they provide the warmth needed for higher levels of activity.

[12] Both genders of the speckled wood butterfly exhibit asymmetrical wings; however, only males show directional asymmetry (likely to be caused by genetic factors).

[13] In addition to body mass, the number of eggs laid by a female may also be related to the time spent searching for an oviposition site.

One explanation may be that there is a tradeoff between the number of eggs laid and the time spent searching for the optimal oviposition site.

[14] During copulation in butterfly species, the male deposits a spermatophore in the female consisting of sperm and a secretion high in proteins and lipids.

[15] Since most females in the speckled wood butterfly behave monandrously, there is decreased sperm competition, and the male's spermatophore is much smaller relative to other species.