Pheidole bessonii

Pheidole bessonii

Pheidole bessonii is a small ant species native only to Madagascar, belonging to the genus known for their distinctive major workers (soldiers) with enlarged heads. Workers are typically 2-3mm with majors noticeably larger, and they feature the characteristic big-headed morphology that gives Pheidole their common name of 'big-headed ants.' This species was originally described as a subspecies in 1891 before being raised to full species status. They inhabit diverse environments across Madagascar ranging from lowland savanna to montane rainforest, demonstrating remarkable adaptability to different conditions ^[1].

These ants nest in varied locations including rotten logs, soil, and under stones, with workers commonly found foraging through leaf litter. Their elevation range spans from 30 meters to over 1700 meters, indicating they can thrive in both lowland and highland Madagascar environments. The species shows flexibility in habitat preferences, being found in Uapaca woodland, gallery forest, tropical dry forest, and rainforest zones.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Madagascar only, found across the island in diverse habitats including Uapaca woodland, montane rainforest, tropical dry forest, savanna, gallery forest, and rainforest at elevations of 30-1732m^[1].
• Colony Type: Colony structure is unconfirmed, Pheidole species are typically monogyne (single queen) but polygyne colonies have been documented in some species. No specific data exists for P. bessonii.
• Size & Growth:
  • Queen: Estimated 5-7mm based on genus patterns
  • Worker: 2-3mm minor workers, majors larger at approximately 3-4mm
  • Colony: Unknown for this specific species, typical Pheidole colonies reach several hundred to a few thousand workers
  • Growth: Moderate, estimated based on genus patterns
  • Development: Estimated 6-8 weeks based on typical Pheidole development at warm temperatures (Development time is not directly studied for this species. Estimates based on related Madagascar Pheidole species.)
• Antkeeping:
  • Temperature: Keep at 22-26°C as a starting point. Their Madagascar range includes both warm lowlands and cooler highlands, so they likely tolerate a range. Observe colony activity to fine-tune, workers should be actively foraging.
  • Humidity: Provide moderate to high humidity (60-80%). Their natural habitats include rainforest and montane areas, but they also tolerate drier conditions. Keep nest substrate moist but not waterlogged, with some drier areas available.
  • Diapause: Unknown if this species requires hibernation. Madagascar has mild temperatures year-round, so they may not need a true diapause. Consider a slight cooling period (15-18°C) during winter months if colony shows reduced activity.
  • Nesting: In captivity, they do well in test tube setups for founding colonies, then transition to Y-tong or plaster nests. They naturally nest in soil, rotten logs, and under stones, provide a substrate they can burrow into. A naturalistic setup with soil and hiding spots works well ^[1].
• Behavior: Pheidole bessonii is generally calm and not aggressive toward keepers. Like other Pheidole, they have major workers (soldiers) with enlarged heads used for seed processing and defense, though their primary defense is fleeing. Workers are active foragers through leaf litter searching for seeds, insects, and honeydew. They are not known to be escape artists but use standard escape prevention. Their small size means fine mesh barriers are recommended.
• Common Issues: colonies may fail if humidity drops too low, monitor substrate moisture regularly, slow founding phase can cause keepers to abandon colonies before workers emerge, wild-caught colonies may contain parasites that can devastate captive populations, test tube setups can flood if water reservoirs are overfilled during setup, major workers develop later than minors, don't be alarmed if early workers are all small

Housing and Nest Setup

For founding colonies, a simple test tube setup works well. Fill a test tube with water, plug the end with cotton, and place the queen in the tube. The cotton should be damp but not soaking wet, you want moisture without flooding. Cover the tube with a dark cloth and leave it undisturbed for several weeks until the first workers emerge. Once the colony reaches 20-30 workers, you can transition to a more elaborate setup.

For established colonies, Y-tong (acrylic) nests or plaster nests work well. These allow you to control humidity more easily than soil-based setups. If using a naturalistic setup, provide a layer of moist soil or coconut fiber as substrate, with pieces of rotten wood or flat stones as hiding spots. Ensure the outworld (foraging area) is escape-proof, these ants can squeeze through surprisingly small gaps despite their size. A barrier of fluon or petroleum jelly on the rim of the formicarium helps prevent escapes. ^[1]

Feeding and Diet

Pheidole bessonii is omnivorous like most Pheidole species. In captivity, they readily accept protein sources such as small insects (fruit flies, pinhead crickets, mealworms), and they particularly enjoy seeds which their major workers can process with their powerful jaws. Offer a varied diet: protein every few days, and a constant sugar source (honey water or sugar water) in a small dish.

Their natural diet includes seeds, insects, and honeydew from aphids. In the wild, major workers specialize in seed processing, they can crack open seeds that minor workers cannot handle. When feeding seeds, ensure they are small enough or already cracked. Remove any uneaten food after 24-48 hours to prevent mold. A varied diet promotes healthy colony growth and faster brood development. ^[1]

Temperature and Seasonal Care

Maintain temperatures between 22-26°C for optimal colony development. This range covers their natural elevation range in Madagascar. If your room temperature falls below this range, use a heating cable or heating mat on one side of the nest to create a gentle gradient. Place heating on top of the nest, not underneath, to avoid excessive drying.

Regarding diapause or winter rest: Madagascar experiences mild temperatures year-round, so this species may not require a true hibernation. However, if you notice reduced activity during winter months, providing a slight cooling to 18-20°C is appropriate. Do not cool dramatically, a sudden drop can stress colonies. Monitor worker activity levels and adjust accordingly. During cooler periods, reduce feeding frequency.

Colony Development and Growth

Pheidole colonies grow through a distinct caste system. The queen lays eggs that develop into either minor workers (small, foraging ants) or major workers (soldiers with enlarged heads). Major workers typically appear after the colony is established with 50+ workers, as producing the larger majors requires more resources.

The founding phase can be lengthy, queens may take 2-4 weeks to lay their first eggs, then another 4-8 weeks for those eggs to develop into workers. During this time, the queen is sealed in her chamber and should not be disturbed. Once workers emerge, the colony enters a growth phase where populations can expand rapidly if fed well. A healthy colony can reach several hundred workers within a year under good conditions.

Behavior and Observation

These ants are fascinating to watch due to their clear division of labor. Minor workers handle most tasks: foraging, caring for brood, and maintaining the nest. Major workers specialize in seed processing, nest defense, and carrying larger items. When you offer a large piece of protein, majors will often take over the task of breaking it down.

They are not aggressive toward humans and rarely sting. Their primary defense is fleeing or retreating into the nest. When threatened, majors may display by raising their heads or charging, but actual attacks are rare. Observe the tandem running behavior during food discovery, one worker will lead others to food sources, which is one of the most interesting behaviors to watch in established colonies. ^[1]

Frequently Asked Questions

References