The negative effect of wood ant presence on tick abundance

Abstract

BackgroundTicks and tick-borne pathogens are a global problem for the health of humans and their livestock. Wood ants are important ecosystem engineers in forests worldwide. Although both taxa are well studied, little is known about their interactions under natural conditions. The purpose of the present field study was to test whether European red wood ants (Formica polyctena) influence the abundance of Ixodes tick populations in temperate forests.MethodsData collection took place in 130 sampling plots located at 26 ant nest sites paired with 26 control sites in northwestern Switzerland. At each sampling plot, tick abundance, ant abundance, ant nest volume and habitat variables (describing litter, vegetation and microclimate) were measured. We used linear mixed-effect models to analyze the abundance of questing ticks as a function of ant abundance and habitat variables.ResultsAnt nest volume, rather than the presence of ants, had a significant negative effect on tick abundance. The number of ticks decreased from 11.2 to 3.5 per 100 m2 if the volume of the adjacent ant nest increased from 0.1 m3 to 0.5 m3. Additionally, high vegetation cover and litter depth had negative and positive relationships with tick abundance, respectively.ConclusionsWe showed that the number of questing ticks was negatively correlated with the size of red wood ant nests. Further studies are needed to identify the mechanisms that drive the relationship. Possible mechanisms include the repellent effect of ant formic acid, and the predatory behavior of wood ants. The present field study suggests that red wood ants provide a new ecosystem service by reducing the local abundance of Ixodes ticks.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-2712-0) contains supplementary material, which is available to authorized users.

Interactions between sympatric invasive European fire ants (Myrmica rubra) and blacklegged ticks (Ixodes scapularis)

“…Contrary to previous studies that have demonstrated negative associations between the presence of the invasive ants Solenopsis invicta and Formica polyctena and the abundance of hard-bodied tick species [28,29], our field studies suggest that M. rubra presence is positively associated with I. scapularis nymph abundance. Positive correlation between nymph abundance and ant presence could be attributed to similar preferred habitat.…”

“…Ants have been cited as predators of ticks more than any other arthropod group in laboratory and field studies [27]. Multiple field studies indicate that the density of nymphs (DON) may be suppressed by the presence and/or density of nests of two invasive ant species, the imported fire ant, Solenopsis invicta, and the European red wood ant, Formica polyctena [28,29]. Although M. rubra is omnivorous [30][31][32], it may have similar impacts on I. scapularis populations.…”

Nest Survival and Transplantation Success of Formica rufa (Hymenoptera: Formicidae) Ants in Southern Turkey: A Predictive Approach

“…Several studies have shown that naturally occurring or transplanted ants can reduce the numbers of forest pest insects during outbreaks, such as pine processionary moths Thaumetopoea pityocampa and T. wilkinsoni (Lepidoptera: Notodontidae), pine sawfly Neodiprion sertifer (Diptera: Diprionidae), spruce budworms Choristoneura spp. (Lepidoptera: Tortricidae), and great spruce bark beetle Dendroctonus micans (Coleoptera: Curculionidae), by predation or harassment [6,[10][11][12][13][14] (for possible disadvantages, see [15,16]).…”

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“…[61] Few wood ant species are also natural enemies of ticks and feed on tick larvae. [62] Similarly, Bacillus thuringiensis, Beauveria bassiana, and M. anisopliae are widely employed agents to control Acarid species, Dermanyssus gallinae and Psoroptes sp. [Table 1].…”