Dolichoderus pastorulus

Dolichoderus pastorulus

Dolichoderus pastorulus is a tiny ant species from the cuspidatus group, known as 'herdsmen ants' for their mutualistic relationship with mealybugs. Workers measure just 4-5mm, making them one of the smallest species in their group alongside D. kinabaluensis and D. pilinomas. They have a distinctive steeply ascending propodeum that rises at least as high as it is long, overtopping the mesonotum by a significant margin. Coloration ranges from yellowish-brown to dark brown and black. This species is only known from lowland rainforest in Sabah, Northeast Borneo ^[1].

What makes D. pastorulus unique is its partnership with the mealybug Bolbococcus sabahanus, they tend these scale insects for their honeydew, just like other herdsmen ants. However, unlike most herdsmen species that form large colonies with extensive trail systems, D. pastorulus forms very small colonies with limited foraging trails. The queens are also unusual, they are ergatoid (wingless), which is rare in the Dolichoderus genus and correlates with their small colony sizes ^[1].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Lowland rainforest in Sabah, Northeast Borneo ^[1]. This species lives in a tropical rainforest environment with high humidity and stable warm temperatures year-round.
• Colony Type: Small colonies with ergatoid (wingless) queens. Unlike most ants, the queens of this species are born without wings and serve as replacement reproductives. Colonies are notably smaller than other herdsmen Dolichoderus species, with limited trail systems ^[1].
  • Colony: Monogyne
• Size & Growth:
  • Queen: 5.43-6.14 mm ^[1]
  • Worker: 4.18-5.08 mm ^[1]
  • Colony: Small colonies, exact maximum unknown but significantly smaller than other herdsmen species ^[1]
  • Growth: Moderate, small colony size suggests moderate growth rate
  • Development: Estimated 6-8 weeks based on typical Dolichoderus development patterns (Development timeline is not directly studied for this species. Estimates based on genus-level data for tropical Dolichoderus species.)
• Antkeeping:
  • Temperature: Keep at 24-28°C. This is a lowland tropical species from Borneo, so they need warm, stable temperatures. A heating cable on one side of the nest can create a gentle gradient if your room temperature is below this range.
  • Humidity: High humidity required, aim for 70-85%. These are rainforest ants from a tropical environment. Keep the nest substrate consistently moist but not waterlogged. Mist occasionally and provide a water tube.
  • Diapause: No, being a tropical lowland species from near the equator, they do not require hibernation or winter rest. Maintain warm conditions year-round.
  • Nesting: In the wild, they likely nest in rotting wood or under bark in the rainforest floor, similar to other Dolichoderus species. In captivity, a Y-tong (AAC) nest or plaster nest works well. The chambers should be appropriately scaled to their small worker size. Keep nesting material moist.
• Behavior: These are gentle, non-aggressive ants that focus on farming mealybugs for honeydew rather than defending territory aggressively. Workers are small and may be prone to escaping through small gaps. They form small, organized trails when foraging. They are not known to sting and pose no danger to keepers. Escape prevention should be good despite their small size, they are not strong climbers like some Dolichoderus species.
• Common Issues: small colony size means slower population growth, don't expect rapid expansion, tropical species requires consistent warmth, cold temperatures can weaken and kill colonies, high humidity needs can lead to mold if ventilation is poor, ergatoid queen system is unusual, don't expect dealate queens like most ant species, very limited distribution data means captive breeding information is scarce, success with this species is experimental

The Herdsmen Lifestyle

Dolichoderus pastorulus belongs to a special group of ants called 'herdsmen' or 'shepherds', species that tend scale insects (mealybugs) for their honeydew secretions. Specifically, this species partners with Bolbococcus sabahanus, a type of mealybug ^[1]. In captivity, you can simulate this relationship by offering sugar water, honey, or diluted syrup as a substitute for honeydew. However, they still need protein sources like small insects. The name 'pastorulus' literally means 'little herdsman' in Latin, a reference to their small size and their herding lifestyle with mealybugs ^[2]. This trophobiosis (food-sharing relationship) is a key part of their natural history and explains why they form smaller, more focused colonies compared to generalist ant species.

Housing and Nest Setup

Because of their small size and rainforest origins, these ants need appropriately scaled housing with high humidity. A Y-tong (AAC) nest or plaster formicarium works well, both hold moisture well and provide the dark, humid environment they prefer. The chambers should be sized appropriately for workers that are only 4-5mm. Keep the nest substrate consistently moist by adding water to a reservoir or misting occasionally. Place a water tube for drinking access. Avoid letting the nest dry out completely. Since they're from lowland Borneo rainforest, they need stable warm conditions, avoid cold drafts and consider a heating cable if your room temperature drops below 24°C. Outworld space can be simple since they don't form large colonies or extensive trail systems.

Feeding Your Colony

In the wild, D. pastorulus gets most of its carbohydrates from honeydew produced by the mealybugs they tend, plus they hunt small insects for protein. In captivity, offer sugar water, honey water, or diluted maple syrup as a constant carbohydrate source. For protein, small soft-bodied insects like fruit flies, pinhead crickets, or small mealworms work well. Feed protein prey 2-3 times per week, and keep sugar water available at all times. Remove uneaten prey after 24 hours to prevent mold. The small colony size means they won't consume large quantities of food, adjust portions accordingly. Their association with mealybugs suggests they may have a more specialized gut microbiome for processing sugary secretions, so sugar sources are particularly important for this species.

Understanding Their Unique Biology

This species has several unusual features that set it apart from most ants. First, the queens are ergatoid, meaning they are born wingless, unlike typical ant queens that have wings and fly to mate. Ergatoid queens serve as replacement reproductives within the colony, which explains why D. pastorulus colonies stay small, they don't have the massive nuptial flights that bring in many new queens ^[1]. Second, they form very small colonies compared to other herdsmen ants, which typically maintain large worker populations and extensive foraging trails. This species appears to live in more compact, focused groups. Third, their distribution is extremely limited, they're only known from a few locations in Sabah, Borneo, making them a rare and potentially difficult species to acquire for antkeeping.

Temperature and Seasonal Care

As a lowland tropical species from near the equator in Borneo, D. pastorulus does not experience cold winters or seasonal temperature changes in the wild. This means they do not require any diapause or hibernation period, maintain warm conditions year-round. Keep the nest area between 24-28°C consistently. Temperatures below 22°C can slow their metabolism and potentially cause health problems. If your room is cooler, use a heating cable placed on top of the nest (not underneath, to avoid drying out the substrate). Monitor colony activity, if workers become sluggish or cluster together excessively, they may be too cold. High humidity is equally important, so balance heating with maintaining moisture in the nest.

Frequently Asked Questions

References