Dolichoderus semirugosus

Dolichoderus semirugosus

Dolichoderus semirugosus is a medium-sized tropical ant found across Southeast Asia, including Borneo, Peninsular Malaysia, and Thailand. Workers measure around 5-7mm and have a distinctive appearance: they are dark brown to black with a matt (non-shiny) finish, and their most striking feature is the very coarse surface sculpturing, their head, alitrunk (middle body section), and petiolus (the narrow waist segment) are deeply wrinkled and roughened, giving them a distinctive texture. This coarse sculpturing sets them apart from other Dolichoderus species in the sulcaticeps group, making them relatively easy to identify. As members of this group, they likely have a mutualistic relationship with mealybugs, tending them for honeydew just like their relatives ^[1][2].

This species is part of the Dolichoderus genus, which contains ants known for their association with sap-sucking insects and their ability to form moderate-sized colonies. While not as commonly kept as some other genera, they offer an interesting alternative for antkeepers looking to work with less frequently kept Southeast Asian species.

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Southeast Asia, found in Borneo (Sarawak), Peninsular Malaysia, and Thailand (Khao Yai). They inhabit tropical forest environments in the Indomalaya region ^[2][1].
• Colony Type: Likely single-queen (monogyne) colonies based on typical Dolichoderus patterns. Colony size is not well documented in scientific literature, but related species in the genus typically reach several hundred workers.
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Approximately 6-8mm (estimated based on genus patterns)
  • Worker: Approximately 5-7mm ^[1]
  • Colony: Unknown, estimated several hundred workers based on related species
  • Growth: Moderate, typical for tropical Dolichoderus
  • Development: Estimated 6-8 weeks at tropical temperatures (25-28°C) based on genus-level data for related species (Development time is estimated from typical Dolichoderus patterns, specific timing for this species has not been directly studied)
• Antkeeping:
  • Temperature: Keep at 24-28°C. As a tropical Southeast Asian species, they prefer warm, stable conditions. A heating cable on one side of the nest can create a gentle gradient if room temperature is below this range.
  • Humidity: Moderate to high humidity (60-80%). These forest-dwelling ants prefer damp substrate but not waterlogged conditions. Keep the nest substrate consistently moist but allow some drying between waterings.
  • Diapause: No, being a tropical species, they do not require hibernation. However, they may slow down slightly during cooler periods.
  • Nesting: In captivity, they do well in Y-tong (AAC) nests, plaster nests, or naturalistic setups with damp substrate. They prefer enclosed nests with chambers scaled to their size. Avoid very dry conditions.
• Behavior: Dolichoderus semirugosus workers are relatively active and alert. They are not particularly aggressive toward keepers but will defend their nest if threatened. Like other Dolichoderus ants, they may have a defensive secretion that gives them a distinctive odor when disturbed. They are moderate escape artists, ensure their enclosure has secure barriers, but they are not as prone to escaping as some tiny species. Workers likely forage for honeydew from mealybugs and may hunt small insects.
• Common Issues: tropical species requires warm conditions, temperatures below 20°C for extended periods can weaken or kill colonies, humidity must be maintained, too-dry conditions will cause colony decline, wild-caught colonies may carry parasites or diseases that can wipe out captive colonies, slow founding means patience is required, queens may take months to raise first workers, escape prevention should be maintained even though they are not tiny, they are agile and will explore gaps

Housing and Nest Setup

For Dolichoderus semirugosus, use a nest that maintains humidity while providing adequate ventilation. Y-tong (AAC) nests work well because they hold moisture without becoming waterlogged. Plaster nests are another good option, simply keep the water reservoir filled to maintain moderate humidity inside the chambers. Naturalistic setups with a dirt chamber also work, but monitor moisture levels carefully. The nest should have chambers scaled to the ant size, these are medium-sized ants, so passages and chambers should be appropriately proportioned. Connect the nest to an outworld (foraging area) that is escape-proof. Use a test tube setup for the founding queen, and transition to a larger nest once the colony reaches 30-50 workers. ^[1]

Feeding and Diet

In the wild, Dolichoderus semirugosus likely tends mealybugs and other sap-sucking insects for honeydew, while also hunting small insects for protein. In captivity, offer a varied diet: sugar water or honey should be available constantly for energy. For protein, offer small insects like fruit flies, small crickets, or mealworms. You can also experiment with commercial ant foods, but live prey is always appreciated. Feed protein sources 2-3 times per week, and remove any uneaten prey after 24 hours to prevent mold. The mealybug association suggests they prefer sweet liquids, a cotton ball soaked in diluted honey or sugar water makes an excellent supplementary food source.

Temperature and Humidity

As a tropical species from Southeast Asia, Dolichoderus semirugosus needs warm conditions. Keep the nest area at 24-28°C. Room temperature may be sufficient in warm climates, but in cooler environments, use a heating cable placed on top of the nest (never underneath, as it can dry out the nest too quickly). For humidity, aim for 60-80% relative humidity inside the nest. The substrate should feel damp to the touch but not have standing water. Rehydrate by adding water to the nest's reservoir or misting the substrate when it begins to dry out, check every few days rather than on a fixed schedule. Good ventilation is important to prevent mold while maintaining humidity. ^[2]

Colony Development and Growth

A newly mated queen will seal herself into a small chamber and lay eggs. She will not leave to forage, she lives entirely on her stored fat reserves while raising the first brood. This is called claustral founding and is typical for Dolichoderus ants. The first workers (called nanitics) are usually smaller than normal workers and emerge within 6-8 weeks under warm conditions. After the nanitics hatch, the queen stops caring for the brood directly and focuses on laying more eggs. The colony then grows as workers forage for food to feed more larvae. Growth is moderate, expect several months to reach 50 workers, and potentially a year or more to reach several hundred. Patience is key with this species.

Behavior and Temperament

Dolichoderus semirugosus workers are active foragers and will explore their outworld in search of food. When threatened, they may release a defensive secretion that produces a distinctive odor, this is a characteristic shared by many Dolichoderus ants. They are not particularly aggressive toward humans and rarely sting, making them manageable for antkeepers. Workers are moderately alert and will investigate disturbances. They are good climbers and may attempt to explore any gaps in their enclosure, so check that lid connections and barrier edges are secure. Their dark coloration and coarse sculpturing make them visually distinctive in the ant collection. ^[1]

Frequently Asked Questions

References