Temnothorax muellerianus

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Mediterranean region. Found in dry, sunny localities, rock crevices, under stones, and occasionally in arboreal nests ^[8]. In the Iberian Peninsula it prefers higher altitudes (over 1000 m) in forests ^[7]. On Crete, infected nests were in very dry and sunny spots ^[2]. Also recorded in riparian forest ^[8] and open Juniperus-Quercus woodland ^[9]. Nests of host species are in various habitats from seacoast to 1587 m ^[3].
• Colony Type: Monogyne (single queen) obligate slave-maker ^[10]. Each colony has one parasite queen, a few dozen parasite workers, and a larger number of enslaved host workers from various Temnothorax species ^[11]. The queen kills or drives out adult host ants and keeps only the brood to raise as slaves ^[12].
• Size & Growth:
  • Queen: Size data unavailable, inferred from Temnothorax genus (~3-4 mm total length).
  • Worker: Size data unavailable, inferred from Temnothorax genus (~2.5-4 mm total length).
  • Colony: Small: typically one queen plus a few dozen parasite workers and many host workers, total rarely over 100 individuals ^[11].
  • Growth: Moderate, based on typical Temnothorax development.
  • Development: Unknown, direct data not available. Inferred from Temnothorax genus: roughly 6-10 weeks at 20-24 °C. (Development has not been directly studied for this species.)
• Antkeeping:
  • Temperature: Keep at room temperature (18-24 °C). The species occurs in Mediterranean climates and at higher altitudes in forests, suggesting moderate temperatures ^[7]. Avoid extremes.
  • Humidity: Provide moderate humidity. In nature they nest in rock crevices and under stones in dry habitats, so avoid waterlogging ^[2][13]. A humidity gradient with a slightly moist area is ideal.
  • Diapause: Yes, inferred from its Palearctic distribution and relationship with temperate Temnothorax hosts. Likely needs a winter rest period around 10-15 °C for 2-3 months.
  • Nesting: Prefers tight spaces: rock crevices, small cavities under stones, narrow gaps in Y-tong or plaster nests. Use flat stones or narrow chambers. A host colony must be present for long-term survival.
• Behavior: Temnothorax muellerianus is an active slave-maker. Workers sting opponents to death during raids ^[14] and use tandem running to recruit nestmates to target colonies ^[15]. They never capture adult hosts, only steal brood ^[12]. The parasite queen invades a host colony, kills the adult ants, and raises the remaining brood as slaves ^[12]. Workers imprint on their host species during development and prefer to raid colonies of that same species ^[14]. They are not aggressive toward humans and are too small to sting noticeably. Escape risk is moderate due to their small size.
• Common Issues: cannot survive without a host colony, you must maintain both the parasite and a suitable host Temnothorax species simultaneously., host species like Temnothorax unifasciatus are not always available in the hobby and have their own care requirements., colony failure is likely if the host workers die out, the parasite workers cannot forage and rely entirely on slaves., finding a parasite queen with a host colony is extremely difficult in the wild, the species is rare and protected in some regions., slow growth due to small colony size and dependence on host reproduction., may be infected by the fungal parasite Myrmicinosporidium durum, which can kill workers after hibernation ^[20].

What Makes This Species Unique

Temnothorax muellerianus is a slave-making ant, one of six independent origins of slavery in the Formicoxenini tribe ^[4]. Unlike typical ants, it cannot survive without enslaved workers from other Temnothorax species. The parasite queen invades a host colony, kills or drives out the adult hosts, and uses the remaining brood to raise a workforce of slaves ^[12]. This creates a system where you must keep two ant species to keep one. The parasite shows strong host preference, with Temnothorax unifasciatus accounting for about 74% of parasitized wild colonies ^[16]. Workers and queens imprint on their host species during development, they learn the identity of the host they were raised with and later search for and attack colonies of that same species ^[14]. This makes them a research model for studying social parasitism and host specialization, but extremely challenging to keep in captivity. The species is the only member of the muellerianus group recorded on Crete ^[2].

Housing and Setup

You cannot keep T. muellerianus without a host colony, this is a biological requirement, not an optional addition. The setup should include two connected areas: one for the host colony and one for the parasite. Both species nest in tight spaces like rock crevices, under flat stones, or in narrow cavities, so a Y-tong or plaster nest with small chambers works well ^[13]. You must ensure the host colony remains strong enough to support both populations. The connection between nests allows the parasite workers to raid the host colony and maintain their slave workforce. If the host workers die, the parasite colony will quickly perish. Many antkeepers find this setup impractical because managing two interacting colonies is complex and risky.

Feeding and Diet

The enslaved host workers handle all foraging and feeding. In captivity, you feed the host colony standard ant foods: sugar water or honey for carbohydrates, and small insects like fruit flies or pinhead crickets for protein. The parasite workers stay inside the nest and receive food from the slaves through trophallaxis (mouth-to-mouth feeding). You should not expect to see parasite workers foraging. The diet depends on which host species you keep, but most Temnothorax accept typical ant foods. Ensure food is available to the host colony, the slaves will distribute it to everyone.

Host Species Selection

Choosing the right host is critical for success. The most common wild host is Temnothorax unifasciatus, used in about 74% of observed parasitized colonies ^[16]. Other recorded hosts include Temnothorax recedens, Temnothorax tuberum, Temnothorax exilis, Temnothorax flavicornis, Temnothorax nigriceps, Temnothorax bulgaricus, Temnothorax albipennis, Temnothorax grouvellei, and many others ^[17][3]. In Greece, hosts include Temnothorax brackoi, Temnothorax bulgaricus, Temnothorax flavicornis, Temnothorax cf. nigriceps, and Temnothorax recedens ^[3]. The host species you choose determines much of the care, since you are essentially keeping two species with possibly different needs. Temnothorax unifasciatus and Temnothorax tuberum are relatively common in the antkeeping hobby and may be easier to obtain. Avoid using host species that are themselves rare or protected.

Behavior and Raiding

Raiding is the most distinctive behavior. Parasite workers use tandem running (one worker leads another to the target) to recruit nestmates ^[15]. They do not kill adult host workers during raids, they only steal brood (eggs, larvae, pupae) and carry it back to their nest ^[12]. The stolen brood emerges as enslaved host workers that do all the colony work: foraging, nursing, nest maintenance. The parasite workers are largely useless for practical tasks. Interestingly, workers and queens imprint on their host species during development and later prefer to raid colonies of that same species ^[14]. This learned preference is so strong that colonies raised with one host will usually ignore other potential hosts. Queens also imprint and will attempt to invade colonies of the species they were raised with ^[14]. In a small percentage of colonies (around 3.4%), mixed slave species have been observed ^[16].

Legal and Conservation Status

Temnothorax muellerianus is classified as Vulnerable (VU D2) on the IUCN Red List in some regions, including Bulgaria and Spain, due to its rarity and specialized habitat requirements ^[18][19]. It is protected in certain European countries. Before attempting to keep this species, check your local laws regarding collection and possession of native ants. Additionally, consider the ethics of keeping a social parasite that depends on host colonies that may also be protected or declining. For most antkeepers, observing this species in the wild or supporting conservation efforts is more appropriate than captive keeping. This species is best appreciated as a remarkable example of social parasitism, not as a pet. If you can no longer keep your colony, never release it into the wild, contact a local entomologist or conservation organization.

Frequently Asked Questions

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References