Aphaenogaster senilis

Introduction

Aphaenogaster senilis is a fascinating and highly specialized species native to the Western Mediterranean, particularly Spain, Portugal, and Southern France. Often called the "Mediterranean Funnel Ant," they are famous in the scientific community for their unique behaviors, including "colony fission" (where a colony splits into two rather than the queen flying) and their incredible ability to use tools. They are known to drop bits of debris into liquid food and then carry the soaked material back to the nest—a rare example of tool use in the insect world.

For the ant keeper, Aphaenogaster senilis offers a window into a very different type of social structure. They are long-legged, fast, and highly responsive to their environment. They lack the ability to perform trophallaxis (mouth-to-mouth food sharing), which is why they have evolved their ingenious tool-using methods for transporting liquids. This makes their feeding behavior some of the most interesting to watch in all of myrmecology.

Taxonomy & Classification

• Family: Formicidae
• Subfamily: Myrmicinae
• Genus: Aphaenogaster
• Species: Aphaenogaster senilis (Mayr, 1853)

The Aphaenogaster genus is diverse, but the senilis group is distinct for its lack of a traditional nuptial flight. Instead of winged queens flying to new locations, a queen will walk out of her mother's nest with a group of workers to start a new colony nearby. This has profound effects on their genetics and distribution.

Appearance & Morphology

Aphaenogaster senilis workers are monomorphic, usually measuring between 6mm and 8mm. The queen is slightly larger and more robust, around 10-12mm.

They have a slender, "spidery" appearance with very long legs and antennae, which they use to navigate rocky terrain. Their body is typically a matte greyish-black or dark brown. Their name "senilis" (meaning old/grey) likely refers to the fine, silvery-grey hairs that cover their bodies, giving them a slightly dusty or aged appearance under certain lighting conditions.

Natural Habitat & Distribution

This species thrives in the Mediterranean climate, preferring dry forests, shrublands, and sandy coastal areas. They are "funnel ants" because their nest entrances often feature a small, funnel-shaped depression in the sand or soil. They are primarily ground-nesters, creating simple but effective tunnels that reach down to cooler, moister layers. They are highly active during the day, especially in the spring and autumn.

Colony Structure & Life Cycle

Colonies are strictly monogynous. As mentioned, they reproduce by fission. In captivity, this means you usually start with a small colony rather than a single queen. They are very fast-growing once established. Because they cannot share food via trophallaxis, the workers are very individualistic in their foraging, and you will see many workers carrying "tools" or food items back to the nest simultaneously. A mature colony can have around 1,000 to 3,000 workers.

Dietary Requirements & Tool Use

Feeding Aphaenogaster senilis is a unique experience.

• Proteins: They are excellent hunters and will readily take small insects like crickets, roaches, and fruit flies. They use their long legs to keep their distance while they bite and pull at prey.
• Sugars & Tool Use: Since they cannot store liquid in their social stomachs, you should provide liquid food (honey-water/nectar) on a shallow dish. You will often see the ants dropping sand, coco-fiber, or even bits of paper into the liquid. Once the material is saturated, they pick it up and carry it into the nest for the queen and larvae to drink from.
• Seeds: They will occasionally take small seeds, although they are not as granivorous as Messor species.

Housing Conditions: Temperature & Humidity

They require a Mediterranean environment: warm summers and a cool, wet winter rest.