Pheidole citrina

Pheidole citrina

Pheidole citrina is a very small, bright yellow ant belonging to the flavens group. The species was described by Wilson in 2003 from Costa Rica. Major workers have a distinctive strongly curved propodeal spine that appears to have 'melted' backward, along with long scapes that reach the occipital corners of the head. The anterior half of the head has longitudinal carinulae while the posterior half is smooth and shiny. This dimorphic species has major and minor workers, with majors reaching about 0.66mm head width and minors around 0.46mm. The species gets its name from the Latin 'citrina' meaning citron, referring to its yellow coloration. In the wild, they live in wet tropical forests in the leaf litter layer.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Atlantic lowlands of Costa Rica, also found in Guatemala, Honduras, Mexico, and Nicaragua. In nature they live in wet tropical forests, specifically in leaf litter ^[1][2].
• Colony Type: Single-queen colonies (monogyne), typical for the genus Pheidole. Colony structure is not extensively documented but follows standard Pheidole patterns.
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Unknown, not directly measured in available literature. Estimated based on genus patterns at 4-5mm.
  • Worker: Major workers: 0.66mm head width (HW). Minor workers: 0.46mm HW.
  • Colony: Likely small to moderate, under 500 workers based on typical Pheidole leaf litter species patterns.
  • Growth: Moderate, tropical species typically develop faster than temperate species.
  • Development: Estimated 4-6 weeks at optimal tropical temperatures (25-28°C), based on typical Pheidole development patterns. (Development time is inferred from genus-level data, as species-specific measurements are not available.)
• Antkeeping:
  • Temperature: Keep at 24-28°C. Tropical species require warm, stable conditions. A heating cable on one side of the nest creates a suitable gradient.
  • Humidity: High humidity required, think damp tropical forest floor. Keep the nest substrate consistently moist but not waterlogged. Provide a water tube for drinking access.
  • Diapause: No, as a tropical species, they do not require hibernation. Maintain warm conditions year-round.
  • Nesting: In nature they nest in leaf litter and soil. In captivity, a small test tube setup works well for founding colonies. For established colonies, a small formicarium or naturalistic setup with moist substrate. They prefer tight, confined spaces scaled to their tiny size.
• Behavior: Typical Pheidole behavior, minor workers handle most tasks including foraging and brood care, while majors serve as soldiers for defense and seed processing. They are not aggressive toward keepers but majors can deliver a mild sting if provoked. Their very small size means escape prevention is critical, they can squeeze through tiny gaps. Foraging activity is moderate, with workers actively searching for small prey and sugar sources.
• Common Issues: escape prevention is critical due to their very small size, use fine mesh and tight-fitting lids, tropical humidity requirements can lead to mold if ventilation is poor, slow founding phase may cause beginners to abandon colonies prematurely, overfeeding can lead to mold in small nest setups, wild-caught colonies may contain parasites that can decimate the colony

Nest Preferences

In the wild, Pheidole citrina nests in leaf litter and upper soil layers of wet tropical forests. They prefer confined, humid spaces that stay moist. For captive colonies, a small test tube setup works well for founding queens. The test tube should have a tight water reservoir and be kept in a dark, quiet location during the founding stage. Once the colony reaches 20-30 workers, you can transition to a small formicarium with chambers scaled to their tiny size. A naturalistic setup with moist soil and leaf litter also works well. Avoid tall, open spaces, these small ants feel safer in tight, enclosed areas. Keep the nest humid but ensure some dry areas exist so ants can regulate their moisture exposure. ^[2][1]

Feeding and Diet

Pheidole citrina is omnivorous like most Pheidole species. They will collect small insects, aphids, and other tiny arthropods in the wild. In captivity, offer small protein sources like fruit flies, pinhead crickets, small mealworms, and other appropriately-sized insects. Sugar sources are readily accepted, you can provide honey water, sugar water, or small drops of honey. Feed protein 2-3 times per week and keep a sugar source available at all times. Remove uneaten food after 24 hours to prevent mold. Their small size means prey items should be tiny, fruit flies are an excellent choice. They are not specialized predators and will readily accept most offered foods.

Temperature and Care

As a tropical species from Costa Rica's wet lowlands, Pheidole citrina requires warm conditions year-round. Keep the nest area at 24-28°C. A heating cable placed on one side of the nest creates a temperature gradient that allows ants to self-regulate. Avoid temperature drops below 22°C, as this can slow development and weaken the colony. Room temperature may be sufficient if your home stays in the low-to-mid 20s°C range. They do not require hibernation or cooling periods. Maintain humidity by keeping the nest substrate moist, a water tube attached to the nest provides drinking water and helps maintain humidity through evaporation. Ensure adequate ventilation to prevent mold while maintaining humidity. ^[1]

Behavior and Colony Structure

Pheidole citrina is dimorphic, meaning colonies have two worker castes: minor workers handle most daily tasks including foraging, brood care, and nest maintenance, while major workers (soldiers) defend the colony and help process larger food items. This division of labor is efficient and fascinating to observe. Majors have the distinctive curved propodeal spine that helps identify this species. Colonies are not aggressive and rarely bother keepers. However, majors can deliver a mild sting if the colony feels threatened. Their small size makes them quick movers when foraging. Workers use chemical trails to recruit nestmates to food sources. The colony will grow from a founding queen to a moderate-sized colony over several months to a year. ^[2]

Growth and Development

A newly mated queen will seal herself in a small chamber and lay eggs without leaving to forage, this is claustral founding. She relies on stored fat reserves to survive and feed the first brood. The first workers (nanitics) are typically smaller than normal workers and appear after 4-6 weeks at optimal temperature. After the nanitics emerge, the queen stops caring for brood directly and the workers take over all colony tasks. Growth is moderate, expect the colony to reach 50 workers within a few months under good conditions. The colony will continue growing as long as conditions are suitable. Major workers typically appear once the colony reaches a certain size threshold, usually when there are enough workers to support the energy cost of producing larger individuals.

Frequently Asked Questions

References