Invasive Mediterranean ants establish supercolonies in Hesse with 45 confirmed finds

Influx of reports across Hesse

Public reports of the invasive ant species Tapinoma magnum have increased across Hesse, with authorities recording 45 confirmed sightings from more than 300 suspected cases within a span of several months. The submissions followed the activation of a specialized online identification service introduced in February by the Hessian State Agency for Nature Conservation, Environment and Geology (HLNUG). Data handled through regional offices in Darmstadt and Giessen indicate that the species is establishing territory in multiple residential districts. HLNUG officials stated that municipalities should anticipate further expansion across the state as nesting networks continue to develop.

Origins and commercial transmission routes

Tapinoma magnum, commonly known in German as the Große Drüsenameise, is native to the Mediterranean region and has been spreading across Germany over a span of several years. According to records maintained by the Federal Environment Agency, the invasive ant was first documented on German territory in 2009. The commercial horticulture and plant trade serves as the primary vector for introducing the species into northern regions. Fertile queens and worker ants are routinely transported across state and national borders embedded within the soil of imported Mediterranean potted plants sold at garden centers.

It is to be expected that the species will spread further in Hesse.

Infrastructure damage and supercolony behavior

Infestations of Tapinoma magnum present severe risks to municipal infrastructure, residential buildings, and public paved areas. The species reproduces with a multitude of fertile queens, constructing vast subterranean supercolonies that can populate several square kilometers. Because the ants preferentially establish their extensive branch nests within populated settlement areas, infestations typically become apparent when paving stones, sidewalk slabs, and structural foundations begin to undermine and subside. At nest entrance holes, the insects eject visible mounds of excavated sand and soil onto surrounding surfaces. If left unmanaged, foraging worker ants enter homes and commercial buildings in search of warmth and food supplies, causing damage to external wall facades and electrical wiring systems while generating substantial pest control expenses.

It is almost impossible to completely eradicate an already established supercolony, which can colonize several square kilometers.

Ecological disruption and pest behavior

Beyond urban damage, the establishment of Tapinoma magnum supercolonies causes severe ecological harm by eradicating native ant populations across occupied terrain. Environmental authorities observe that native ants are almost entirely absent wherever the invasive colonies take root. Worker ants eliminate competing native species through a combination of powerful biting mouthparts and the spraying of a toxic defensive secretion. The feeding habits of the species also disrupt local food webs. Adult ants sustain themselves primarily on honeydew, a sugar-rich excretion produced by aphids, while feeding captured small insects to their developing brood. By fiercely guarding aphid colonies against natural predators, the ants impair beneficial insects, such as ladybugs, that normally control garden pests.

Where colonies of the large gland ant are located, one generally finds no other ant species.