Thymelicus acteon (Rottemburg, 1775)


Thymelicus acteon: Male (eastern Swabian Alb, southern Germany, July 2010) Thymelicus acteon: Male (eastern Swabian Alb, southern Germany, July 2010) Thymelicus acteon: Male (S-Germany, eastern Swabian Alb, July 2010) Thymelicus acteon: Male (S-Germany, eastern Swabian Alb, July 2010) Thymelicus acteon: Male (S-Germany, eastern Swabian Alb, July 2010) Thymelicus acteon: Male - portrait (eastern Swabian Alb, southern Germany, July 2010) Thymelicus acteon: Male (S-Germany, district of Würzburg, 03. July 2023) [N] Thymelicus acteon: Male (S-Germany, district of Würzburg, 03. July 2023) [N] Thymelicus acteon: Male (e.l. Greece, Samos Island, larva in May 2018) [S] Thymelicus acteon: Male (e.l. Greece, Samos Island, larva in May 2018) [S] Thymelicus acteon: Male (e.l. Greece, Samos Island, larva in May 2018) [S] Thymelicus acteon: Male (e.l. Greece, Samos Island, larva in May 2018) [S] Thymelicus acteon: Male (e.l. Greece, Samos Island, larva in April 2015) [S] Thymelicus acteon: Male (e.l. Greece, Samos Island, larva in April 2015) [S] Thymelicus acteon: Male (e.l. Greece, Samos Island, larva in May 2018) [S] Thymelicus acteon: Male (e.l. Greece, Samos Island, larva in May 2018) [S] Thymelicus acteon: Male (e.l. Greece, Samos Island, larva in May 2018) [S] Thymelicus acteon: Male (e.l. Greece, Samos Island, larva in May 2018) [S] Thymelicus acteon: Male (Greece, Samos, 23. May 2014) [N] Thymelicus acteon: Female (eastern Swabian Alb, southern Germany, July 2010) [N] Thymelicus acteon: Female (S-Germany, eastern Swabian Alb, July 2010) Thymelicus acteon: Female (eastern Swabian Alb, southern Germany, July 2010) [N] Thymelicus acteon: Female (S-Germany, eastern Swabian Alb, July 2010) Thymelicus acteon: Female (S-Germany, eastern Swabian Alb, July 2010) Thymelicus acteon: Worn female (eastern Swabian Alb, Southern Germany, August 2010) [N] Thymelicus acteon: Female (Greece, Samos, 23. May 2014) [N] Thymelicus acteon: Female (Greece, Lefkada, June 2021) [N] Thymelicus acteon: Female (Greece, Crete, early May 2013) [N] Thymelicus acteon: Female (Greece, Crete, early May 2013) [N] Thymelicus acteon: Male [N] Thymelicus acteon: Oviposition (eastern Swabian Alb, S-Germany) [N] Thymelicus acteon: Mating (Greece, Crete, 29. April 2013) [N] Thymelicus acteon: Mating (Greece, Crete, 29. April 2013) [N] Thymelicus acteon: Mating (Greece, Samos, 12. May 2018) [N] Thymelicus acteon: Eggs in dry grass leaf sheath (Greece, Peloponnese, Sparta, 19. May 2022) [S] Thymelicus acteon: Eggs in dry grass leaf sheath (Greece, Peloponnese, Sparta, 19. May 2022) [S] Thymelicus acteon: Eggs in dry grass leaf sheath (Greece, Peloponnese, Sparta, 19. May 2022) [S] Thymelicus acteon: Eggs in dry grass leaf sheath (Greece, Peloponnese, Sparta, 19. May 2022) [S] Thymelicus acteon: Eggs in dry grass leaf sheath (Greece, Peloponnese, Sparta, 19. May 2022) [S] Thymelicus acteon: Eggs in dry grass leaf sheath (Greece, Peloponnese, Sparta, 19. May 2022) [S] Thymelicus acteon: Hibernation resp. aestivation cocoons = hibernacula of the L1 larva (e.o. Greece, Peloponnese, Sparta, oviposition on 19. May 2022) [S] Thymelicus acteon: Hibernation resp. aestivation cocoons = hibernacula of the L1 larva (e.o. Greece, Peloponnese, Sparta, oviposition on 19. May 2022) [S] Thymelicus acteon: Hibernation resp. aestivation cocoons = hibernacula of the L1 larva (e.o. Greece, Peloponnese, Sparta, oviposition on 19. May 2022) [S] Thymelicus acteon: L1 larva fetched out of the hibernaculum (e.o. Greece, Peloponnese, Sparta, oviposition on 19. May 2022) [S] Thymelicus acteon: L1 larva fetched out of the hibernaculum (e.o. Greece, Peloponnese, Sparta, oviposition on 19. May 2022) [S] Thymelicus acteon: L1 larva fetched out of the hibernaculum (e.o. Greece, Peloponnese, Sparta, oviposition on 19. May 2022) [S] Thymelicus acteon: L1 larva fetched out of the hibernaculum (e.o. Greece, Peloponnese, Sparta, oviposition on 19. May 2022) [S] Thymelicus acteon: Larva L1 in moult rest into L2 (Greece, Samos, 24. April 2015) [M] Thymelicus acteon: Larva L2 (Greece, Samos, 01. April 2022) [M] Thymelicus acteon: Larva L2 (Greece, Samos, 22. April 2015) [M] Thymelicus acteon: Larva L2 (Greece, Samos, 24. April 2015) [M] Thymelicus acteon: Larva L2 (Greece, Samos, 01. April 2022) [M] Thymelicus acteon: Larva L2 (Greece, Samos, 24. April 2015) [M] Thymelicus acteon: Larva L2 (Greece, Samos, 24. April 2015) [M] Thymelicus acteon: Larva L2 (Greece, Samos, 22. April 2015) [M] Thymelicus acteon: Larva L2 in moult rest (Greece, Samos, 01. April 2022) [M] Thymelicus acteon: Larva L2 in moult rest (Greece, Samos, 01. April 2022) [M] Thymelicus acteon: Tube of larva L2 (Greece, Samos, 01. April 2022) [M] Thymelicus acteon: Tube of larva L2 (Greece, Samos, 01. April 2022) [N] Thymelicus acteon: Tube of larva L2 (Greece, Samos, 01. April 2022) [N] Thymelicus acteon: Tube larva L2 (Greece, Samos, 24. April 2015) [N] Thymelicus acteon: Tube larva L2 (Greece, Samos, 24. April 2015) [N] Thymelicus acteon: Tube larva L2 (Greece, Samos, 24. April 2015) [N] Thymelicus acteon: Tube larva L2 on Brachypodium sylvaticum (Greece, Samos, 24. April 2015) [N] Thymelicus acteon: Larva L3 (Greece, Samos, 01. April 2022) [M] Thymelicus acteon: Larva L3 (Greece, Samos, 01. April 2022) [M] Thymelicus acteon: Larva L3 (Greece, Samos, 01. April 2022) [M] Thymelicus acteon: Tube larva L3 (Greece, Samos, 01. April 2022) [N] Thymelicus acteon: Tube larva L3 (Greece, Samos, 22. April 2015) [N] Thymelicus acteon: Tube and larva L3 (Greece, Samos, 22. April 2015) [N] Thymelicus acteon: Tube and larva L3 (Greece, Samos, 22. April 2015) [N] Thymelicus acteon: Tube larva L3 on Brachypodium retusum (Greece, Samos, 22. April 2015) [N] Thymelicus acteon: Larva L3 in moult rest (Spain, Cadiz, Rio Barbate, 03. March 2019) [M] Thymelicus acteon: Larva L3 in moult rest (Greece, Samos, 07. April 2022) [M] Thymelicus acteon: Larva L4 (Spain, Cadiz, Rio Barbate, 03. March 2019) [M] Thymelicus acteon: Shelter of a half-grown larva (Spain, Cadiz, Rio Barbate, 03. March 2019) [N] Thymelicus acteon: Larva L4 (Greece, Samos, 22. April 2015) [M] Thymelicus acteon: Larva L4 (Greece, Samos, 25. April 2015) [S] Thymelicus acteon: Larva L4 (Greece, Samos, 25. April 2015) [S] Thymelicus acteon: Larva L4 (e.l. Greece, Samos, 20. April 2022) [S] Thymelicus acteon: Tube larva L4 (Greece, Samos, 22. April 2015) [N] Thymelicus acteon: Tube larva L4 (Greece, Samos, 22. April 2015) [N] Thymelicus acteon: Larva L4 in moult rest (Greece, Samos, 22. May 2014) [S] Thymelicus acteon: Larva just in the final instar L5 (e.l. Greece, Samos, 2015) [S] Thymelicus acteon: Larva L5 (e.l. Greece, Samos, larvae found in early April 2022) [S] Thymelicus acteon: Larva L5 (Greece, Samos, 22. May 2014) [M] Thymelicus acteon: Larva L5 (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Larva L5 (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Larva L5 (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Larva L5 (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Larva L5 (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Larva L5 (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Larva L5 (Greece, Samos, 14. May 2017) [S] Thymelicus acteon: Larva L5 (Greece, Samos, 14. May 2018) [S] Thymelicus acteon: Larva L5 (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Larva L5 (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Shelter of L5 larva on Phragmites (Greece, Lesbos island, late May 2019) [N] Thymelicus acteon: L5 larva on Phragmites (Greece, Lesbos island, late May 2019) [M] Thymelicus acteon: L5 larva (Greece, Samos island, mid-May 2018) [M] Thymelicus acteon: L5 larva (Greece, Samos island, mid-May 2018) [M] Thymelicus acteon: L5 larva (Greece, Samos island, mid-May 2018) [M] Thymelicus acteon: Larva (eastern Swabian Alb, southern Germany, 19. June 2010) [M] Thymelicus acteon: Larva (eastern Swabian Alb, southern Germany, 19. June 2010) [M] Thymelicus acteon: Larva (caudal, eastern Swabian Alb, southern Germany, 19. June 2010) [M] Thymelicus acteon: Prepupa (e.l. Greece, Samos, 31. May 2014) [S] Thymelicus acteon: Pupa (e.l. Greece, Samos, 01. June 2014) [S] Thymelicus acteon: Pupa (S-Germany, eastern Swabian Alb) [S] Thymelicus acteon: Pupa (S-Germany, eastern Swabian Alb, June 2010) [S] Thymelicus acteon: Pupa (S-Germany, eastern Swabian Alb, June 2010) [S] Thymelicus acteon: Pupa (Greece, Samos, 14. May 2018) [M] Thymelicus acteon: Pupa (Greece, Samos, 14. May 2018) [M] Thymelicus acteon: Pupa (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Pupa (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Pupa two days before emergence (e.l. S-Germany, Heidenheim, June 2010) [S] Thymelicus acteon: Male pupa prior to emergence (e.l. Greece, Samos, larvae found in April 2015) [S] Thymelicus acteon: Habitat on the eastern Swabian Alb, Southern Germany: dry nutrient-poor grassland with occasional Brachypodium pinnatum [N] Thymelicus acteon: Larval habitat in a rocky limestone grassland with Brachypodium pinnatum (S-Germany, eastern Swabian Alb, Heidenheim, June 2010) [N] Thymelicus acteon: Habitat in extraordinary summer drought (S-Germany, Würzburg, 03. July 2023) [N] Thymelicus acteon: Larval habitat with Brachpodium sylvaticum along a shady river (Greece, Samos island, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachpodium sylvaticum along a shady river (Greece, Samos island, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachpodium sylvaticum along a shady river (Greece, Samos island, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachpodium sylvaticum along a shady river (Greece, Samos island, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachpodium sylvaticum along a shady river (Greece, Samos island, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachpodium sylvaticum along a shady river (Greece, Samos island, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachpodium sylvaticum along a shady river (Greece, Samos island, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachpodium sylvaticum along a shady river (Greece, Samos island, late April 2015) [N] Thymelicus acteon: Habitat in the mountains of Samos (Greece, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachypodium retusum (Greece, Samos, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachypodium retusum (Greece, Samos, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachypodium retusum (Greece, Samos, late April 2015) [N] Thymelicus acteon: Larval habitat with Brachypodium retusum (Greece, Samos, late April 2015) [N] Thymelicus acteon: Larval habitat with Dactylus, other grasses and many larvae L3 and L4 (Spain, Cadiz, Rio Barbate, 03. March 2019) [N] Thymelicus acteon: Larval habitat with reed in a coastal wetland (Greece, Lesbos island, late May 2019) [N]

Host plants:
The larva feeds on grasses, in Central Europe especially Brachypodium pinnatum. In the south the larvae use also other Brachypodium (e.g. B. retusum), but also other grasses like Dactylus (own larval records from Andalusia and Samos) and even Phragmites (larval records in Lesbos Island).

Habitat:
In Central Europpe Thymelicus acteon needs xerothermic, but often mild to moderate dense and higher growing grasslands in the lower mountain ranges (e.g. Jura) and in lowlands. Best is a mosaic of gappy or stony, low growing parts with loosely and single brachypodium pinnatum and the higher growing edges with denser Brachypodium facies in limestone regions. Thymelicus acteon is missing in the northern Alps.

In the south Thymelicus acteon can live in many types of habitat, including wetlands (e.g. along the coasts) and river valleys. I recorded many larvae on Brachypodium sylvaticum along rivers in the semi-shade of woodlands in Samos Island. In this island also hot garrigues and ruderal places are settled.

Life cycle:
The oviposition occurs in small numbers (3-15, often around 6-10 eggs) in leaf sheaths of grasses. The female lands on a blade and climbs backwards with searching abdomen tip downwards. If there is a suitable gap between the blade and a leaf sheath the eggs are deposited. The eggs are not visible from the outside. They are longer oval than the rounder eggs of T. sylvestris. The L1 larva with black head capsule (brown in T. sylvestris, also black in T. lineola) hatches a few days later (around 10 days), consumes the egg shell and creates directly the winter cocoon (hibernaculum) which it usually does not leave until spring. In the south the larvae start feeding sometimes already after the autumnal rainfalls so that larvae may be found also in winter in the lowlands there. The caterpillars are mature in May and June (in Central Europe) and can be easily found where Brachypodium pinnatum grows on more gappy ground and partly also in denser vegetated areas on the same square with those of Thymelicus lineola and Thymelicus sylvestris (observations on the Swabian Alb in Germany). The adults fly from late June or July to early September, in the south already from April.

Endangerment factors:
As species with a narrow ecological licence and a distinct restriction to nutrient-poor, extensively managed grasslands, Thymelicus acteon is endangered and in strong decline in many, especially northern regions. In southern Germany it declines dramatically at the moment, probably due to less grazing intensity and subsequent decline of the pastural grass Brachypodium pinnatum.

In the south Thymelicus acteon is still common and widespread.

Remarks:
The distribution extends from the Canary Islands (subspecies christi, partly regarded as a separate species, see in this taxon) across Northwest Africa and Central and southern Europe to western Asia.



Thymelicus christi | Thymelicus hyrax | Thymelicus lineola | Thymelicus sylvestris