Scientific illustration of Dolichoderus semiorbis ant - showing key identification features including head, thorax, and gaster.

Dolichoderus semiorbis

Monogynous Non-Parasitic Queen No Gamergate
Sci. Name
Dolichoderus semiorbis
Tribe
Dolichoderini
Subfamily
Dolichoderinae
Author
Shattuck & Marsden, 2013
Distribution
Found in 0 countries

Introduction

Dolichoderus semiorbis is a small ant species native to the coastal regions of Western Australia. Workers measure approximately 4-5mm in total length with a distinctive appearance featuring a strongly concave posterior face of the propodeum separated from the dorsal face by a clear ridge. They have a dark reddish-brown to black coloration with sparse or absent fine hairs on the abdomen and lack spines on the thorax. This species belongs to the scrobiculatus species group and was only described in 2013 . This species is part of a genus known for honeydew-collecting behavior. Like other Australian Dolichoderus species, D. semiorbis is diurnal and forages in columns, traveling along the ground and up into low vegetation to tend aphids and other honeydew-producing insects. They are generalist scavengers that will take a variety of food sources, making them relatively flexible in captivity. Their small size and relatively calm temperament make them an interesting species for antkeepers looking to branch out from more common genera .

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Status by country, from Kass et al. 2022 & Wong et al. 2023

Native Invasive Introduced (indoor) Intercepted Unknown
2000 - 2026

Quick Summary

  • Difficulty: Medium
  • Origin & Habitat: Western Australian coast, found in low shrubland on sand dunes along the coastline [1][3]
  • Colony Type: Colony structure is not directly documented for this species. Based on typical Dolichoderus genus patterns, likely single-queen colonies [2]
  • Size & Growth:
    • Queen: Size data unavailable, no queen measurements have been recorded for this species
    • Worker: Approximately 4-5mm total length, inferred from genus patterns [1]
    • Colony: Up to several hundred workers, estimated from related Dolichoderus species
    • Growth: Moderate
    • Development: Development time is unconfirmed for this specific species (Related Dolichoderus species typically develop in 6-10 weeks at warm temperatures, but this has not been studied in captivity.)
  • Antkeeping:
    • Temperature: Keep at 22-26°C. A gentle heat gradient allows workers to regulate their temperature. These ants are from coastal Western Australia and prefer warm but not extreme conditions.
    • Humidity: Moderate humidity around 50-60%. As coastal dune inhabitants, they tolerate somewhat drier conditions than rainforest species. Provide a moisture gradient with a damp section and a drier section in the outworld.
    • Diapause: Likely required, Western Australian temperate climate suggests a winter rest period. Reduce temperature to 15-18°C for 2-3 months during Australian winter (June-August in the Southern Hemisphere).
    • Nesting: Naturalistic setup works well, they nest in soil under rocks or in rotten wood in the wild. A Y-tong (AAC) nest or plaster nest with chambers scaled to their small size is appropriate. Provide soil areas and small rocks in the outworld for natural behavior [2].
  • Behavior: These ants are diurnal and relatively calm. Workers forage in columns both on the ground and in low vegetation, actively tending aphids for honeydew. They are not aggressive and lack a functional stinger, making them safe to handle. They are generalist scavengers and will accept various foods. Their small size means escape prevention should be taken seriously, they can slip through small gaps. Use fine mesh and tight-fitting lids [2].
  • Common Issues: small size makes escape likely without proper barriers, use fine mesh and check for gaps regularly, newly described species means captive husbandry is not well-established, be prepared to experiment, honeydew feeding behavior requires aphid colonies or sugar sources, live aphids may be needed for successful colony development, slow founding phase, queens may take time to produce first workers, patience is essential, coastal species may be sensitive to waterlogging, ensure drainage in naturalistic setups

Housing and Nest Setup

Dolichoderus semiorbis is a small ant that does well in a naturalistic or semi-naturalistic setup. In the wild, they nest in soil under rocks or in rotten wood, so providing these options in captivity encourages natural behavior. A Y-tong (AAC) nest with appropriately sized chambers works well, or you can use a plaster nest with a soil section. The key is providing a temperature gradient, place a heating cable on one side of the nest to create a warm zone around 26°C while leaving other areas cooler. For the outworld, include small rocks, pieces of bark, and a shallow water dish. These ants forage actively and will explore the entire outworld, so provide enough space for foraging. Escape prevention is important due to their small size, use fine mesh on all ventilation holes and ensure lids fit tightly. [2][3]

Feeding and Nutrition

Like other Dolichoderus species, D. semiorbis is a generalist scavenger with a strong preference for honeydew. In captivity, you should offer a varied diet: sugar water or honey water as a constant energy source, and protein-rich foods like small insects regularly. They are particularly fond of tending aphids, so establishing a small aphid colony in the outworld can provide ongoing honeydew. Live prey is preferred for the founding queen and growing colonies. Feed small insects 2-3 times per week for established colonies, and remove any uneaten prey after 24 hours to prevent mold. Sugar water should always be available, changed every 2-3 days. [2]

Temperature and Seasonal Care

As a species from the Western Australian coast, D. semiorbis prefers warm conditions but not extreme heat. Maintain temperatures between 22-26°C in the nest area, with a slight gradient allowing workers to move between warmer and cooler zones. A heating cable placed on top of the nest works well to maintain stable temperatures. During the Australian winter (June-August), you should provide a diapause period by reducing temperatures to 15-18°C. This mimics their natural seasonal cycle and helps maintain colony health long-term. Do not feed during diapause, the colony will be less active and metabolic processes slow down. Resume normal feeding and temperatures gradually when spring arrives. [1][3]

Colony Development and Growth

D. semiorbis was only described in 2013, so there is limited captive data on colony development. The queen seals herself in a chamber and raises the first brood alone without foraging. This founding phase typically takes several weeks at optimal temperatures. The first workers will be smaller than mature workers and may take several more weeks to reach full size. Colonies grow moderately, expect several months to reach 50 workers, and potentially a year or more to reach several hundred. Patience is essential with this species. [1]

Behavior and Foraging

One of the most interesting aspects of keeping Dolichoderus semiorbis is observing their foraging behavior. Workers are strictly diurnal, becoming active during daylight hours and resting at night. They forage in characteristic columns, with workers following pheromone trails between the nest and food sources. In the wild, they forage both on the ground and in low vegetation, climbing plants to access aphids and other honeydew-producing insects. In captivity, you may observe workers climbing on decorations and plants in the outworld as they search for food. They are not aggressive toward keepers and lack a painful sting, making them safe to observe up close. [2]

Frequently Asked Questions

How long does it take for Dolichoderus semiorbis to produce first workers?

Development time is unconfirmed for this species. Based on typical Dolichoderus patterns, expect several weeks from egg to first worker at optimal temperatures. This species has not been studied in captivity, so times may vary.

What do Dolichoderus semiorbis ants eat?

They are generalist scavengers that primarily feed on honeydew in the wild. In captivity, offer sugar water or honey water as a constant energy source, plus small insects for protein. They will readily accept these foods and are active foragers.

What temperature do Dolichoderus semiorbis need?

Keep them at 22-26°C in the nest area. A gentle heat gradient is ideal, use a heating cable on one side of the nest to create warm and cool zones.

Do Dolichoderus semiorbis need hibernation?

Yes, they likely require a diapause period. As Western Australian coastal ants, they experience cooler winters. Reduce temperatures to 15-18°C for 2-3 months, typically during June-August (Southern Hemisphere winter). Do not feed during this period.

How big do Dolichoderus semiorbis colonies get?

Based on related species, colonies likely reach several hundred workers over several years. This is a relatively new species in the hobby with limited captive data, so exact maximum sizes are not well documented.

Can I keep multiple Dolichoderus semiorbis queens together?

Colony structure is unconfirmed for this species. Based on typical genus behavior, single-queen colonies are likely. Combining unrelated queens is not recommended as they may fight.

What size formicarium is best for Dolichoderus semiorbis?

Use a nest with small, appropriately scaled chambers, these are tiny ants. A Y-tong (AAC) nest or plaster nest works well. Provide a naturalistic outworld with soil areas and small rocks to mimic their natural nesting under rocks in soil.

Why are my Dolichoderus semiorbis dying?

Common causes include: temperature extremes (too hot or too cold), improper humidity (too wet or too dry), insufficient food (especially protein), or escape-related losses. Their small size makes escape a common issue, check your barriers. Also ensure you are not overfeeding, as mold from decaying food can be fatal.

Are Dolichoderus semiorbis good for beginners?

This species is rated as medium difficulty. While not aggressive and relatively easy to feed, they are a newly described species with limited captive husbandry information. They require specific temperature ranges and escape prevention. Beginners may want to start with more established species before trying D. semiorbis.

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References

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