Crematogaster scutellaris

Crematogaster scutellaris - "Fourmi Du Liège"

Crematogaster scutellaris is a medium-sized arboreal ant native to the western Mediterranean region. Workers measure 3.5-5 mm and are easily recognized by their striking red head that contrasts with their dark brown to black mesosoma and black heart-shaped abdomen ^[1]. The abdomen can be raised vertically above the head in a defensive posture, giving them their common name 'scorpion ant.' This species forms large colonies of several thousand workers and nests in dead wood within trees, wooden structures, or walls ^[2]. They are a dominant species in Mediterranean ant communities, known for their aggressive behavior and effective venom defenses.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Western Mediterranean region including France, Italy, Spain, Portugal, Morocco, Algeria, Tunisia, Croatia, and Greece. Found in arboreal habitats including cork oak forests, olive groves, and orchards. Nests in dead or decaying wood in trees, wooden structures, and sometimes walls ^[1][2].
• Colony Type: Monogyne (single queen) colonies with polydomous structure, one main nest with satellite nests connected by trails. Genetic analysis confirms single queen per colony, though multiple queens can temporarily coexist before one is eliminated ^[3][4].
  • Colony: Monogyne
  • Founding: Claustral, Pleometrosis
• Size & Growth:
  • Queen: 6-7 mm (estimated based on genus)
  • Worker: 3.5-5.0 mm ^[1]
  • Colony: Up to several thousand workers ^[2]
  • Growth: Moderate
  • Development: Approximately 11 weeks (77 days): 3 weeks egg to larva,3 weeks larva to pupa,5 weeks pupa to first worker ^[4] (Development occurs faster in larger nests. Single queens in large nests produce more eggs than in small nests.)
• Antkeeping:
  • Temperature: Keep at 20-26°C. Mediterranean species that thrives in warm conditions. Activity peaks between 9AM-4PM. Can tolerate higher temperatures but will shift foraging to shaded areas during peak heat ^[5].
  • Humidity: Moderate humidity preferred. As an arboreal species, they need access to moisture but not saturation. Provide water via test tube setup.
  • Diapause: Yes, reduced activity from November to February in natural range. In captivity, provide a cool period (10-15°C) during winter months ^[5].
  • Nesting: Arboreal nesting, requires access to wood or cork material. Y-tong nests with cork inserts, wooden formicaria, or naturalistic setups with dead branches work well. They also build carton-like structures from chewed wood and plant material ^[5].
• Behavior: Aggressive and territorial. Uses Dufour's gland venom as contact defensive secretion, emits strong acetic acid smell when disturbed ^[6]. Forms well-defined foraging trails and recruits nestmates to food sources. Raises abdomen vertically as threat display. Dominant species that competes aggressively for food resources. Generally diurnal but can shift activity based on temperature. Not a particularly strong escaper compared to tiny ants, but standard barriers recommended.
• Common Issues: colonies can become aggressive and may bite if threatened, use caution during feeding and nest maintenance, polydomous colonies may expand into multiple areas of the setup, monitor for satellite nest formation, requires arboreal setup with wood/cork, standard dirt nests are not appropriate, queen replacement is not possible, when queen dies, colony will eventually die out as no worker replacement reproductives exist, can be outcompeted by more aggressive species if housed in community setups

Housing and Nest Setup

Crematogaster scutellaris is an arboreal species that requires nesting opportunities mimicking their natural tree-hole habitat. Y-tong (AAC) nests with cork inserts work exceptionally well, as do wooden formicaria or naturalistic setups featuring dead branches, cork oak bark, or similar wood materials. The nest chamber should be dark and provide protection from light. These ants are skilled at building carton-like structures from chewed wood fibers and salivary secretions, so providing soft wood materials allows them to create their own galleries. Outworld setup should include climbing structures (branches, cork pieces) to facilitate their natural arboreal behavior. A water test tube with cotton plug should be provided as a humidity source. ^[5][2]

Feeding and Diet

This species is omnivorous with a strong preference for sugary substances. In nature, they primarily feed on honeydew from aphids and coccids, often tending these sap-sucking insects on trees. They also hunt small insects and arthropods. In captivity, offer sugar water, honey, or diluted maple syrup as a constant carbohydrate source. For protein, provide small insects like fruit flies, small crickets, or mealworm pieces. They are efficient foragers that form trails to food sources, so place protein foods in a consistent location to encourage trail formation. Remove uneaten protein within 24-48 hours to prevent mold. Their predatory behavior also makes them useful for controlling small pest insects in vivariums. ^[2][5][8]

Temperature and Seasonal Care

As a Mediterranean species, Crematogaster scutellaris prefers temperatures in the range of 20-26°C. They are most active during the warmer months (March through October) when foraging trails are clearly visible on trees. During this period, they exhibit peak activity between 9AM and 4PM, though they adjust their activity patterns based on temperature, shifting to dawn and dusk during hot summer months. In winter (November through February), they enter a period of reduced activity or diapause. During this time, temperatures should be lowered to 10-15°C to simulate natural conditions. Do not feed during the deep winter rest period. Activity resumes in March with solitary workers appearing on tree trunks, followed by trail formation in April. ^[5][9]

Behavior and Defense

Crematogaster scutellaris is one of the most aggressive and territorial ant species in the Mediterranean. When threatened, they raise their distinctive heart-shaped abdomen vertically above their head in a scorpion-like threat display. Their Dufour's gland produces a venom containing long-chain acetates that, when released, creates a strong smell of acetic acid. This venom is applied topically through their spatulate stinger during fights with other ants. Workers are highly aggressive toward conspecifics from distant colonies and show a 'nasty neighbor' effect, aggression increases with proximity until a threshold, then decreases at very short distances (likely due to polydomous colony structure). They form extensive foraging trails and can recruit large numbers of workers to food sources. Their dominance in Mediterranean ecosystems makes them excellent competitors but challenging to house with other ant species. ^[6]

Colony Development and Reproduction

Colonies are monogyne, founded by a single claustral queen who seals herself in a chamber and raises the first brood alone. Development from egg to worker takes approximately 77 days under optimal conditions. The queen can live up to 20 years, making this a long-lived species in captivity. Colonies grow gradually, small colonies after one year may have only 20-30 workers, while mature colonies can reach several thousand individuals. Polydomous colony structure means that as colonies grow, they may establish satellite nests connected by trails, particularly during spring and summer. In autumn, these satellite nests are typically abandoned and all ants return to the main nest for winter. Multiple queens can temporarily coexist during colony founding (pleometrosis), but eventually only one survives, the lighter queen dies first in about 77% of paired queen situations. ^[4][10][11]

Unique Biological Traits

This species exhibits several remarkable traits. They possess a well-developed stridulatory organ, workers, queens, and males all produce vibrations by rubbing a scraper on their abdomen against a file on the first gastral segment. These signals differ between castes and contexts, workers produce different signals when restrained versus when feeding. They also demonstrate trans-generational immunization: queens exposed to non-lethal doses of pathogens pass increased resistance to their offspring. Additionally, they are known to store live aphids in protected locations like oak galls during winter, effectively 'farming' their honeydew source. Their cuticular hydrocarbons vary significantly between colonies, which helps in nestmate recognition and contributes to their aggressive inter-colony behavior. ^[11]

Frequently Asked Questions

References