A neurotoxic pesticide changes the outcome of aggressive interactions between native and invasive ants

Abstract

Neurotoxic pesticides, such as neonicotinoids, negatively affect the cognitive capacity and fitness of non-target species, and could also modify interspecific interactions. We tested whether sublethal contamination with neonicotinoid could affect foraging, colony fitness and the outcome of behavioural interactions between a native (Monomorium antarcticum) and an invasive ant species (Linepithema humile). The foraging behaviour of both ants was not affected by neonicotinoid exposure. Colonies of the invasive species exposed to the neonicotinoid produced significantly fewer brood. In interspecific confrontations, individuals of the native species exposed to the neonicotinoid lowered their aggression towards the invasive species, although their survival probability was not affected. Exposed individuals of the invasive species interacting with non-exposed native ants displayed increased aggression and had their survival probability reduced. Nonexposed individuals of the invasive species were less aggressive but more likely to survive when interacting with exposed native ants. These results suggest that non-target exposure of invaders to neonicotinoids could either increase or decrease the probability of survival according to the exposure status of the native species. Given that, in any community, different species have different food preferences, and thus different exposure to pesticides, non-target exposure could potentially change the dynamics of communities and influence invasion success.

Ant assemblages (Hymenoptera: Formicidae) associated to environments of a rural property in the extreme western region of the state of Santa Catarina

“…If an environmental stress persists long enough to lead local populations to death -affecting their growth rates, reproduction, and preventing the re-colonization of the environment -, it is then able to affect the whole community structure (BARBIERI et al, 2013).…”

Parental sublethal insecticide exposure prolongs mating response and decreases reproductive output in offspring

“…Furthermore, we expected to find carry-over effects in the unexposed offspring, where surface profiles may still be changed and mating acceptance be reduced when parents were insecticideexposed compared to controls. Moreover, we predicted that aggression between females may be enhanced by insecticide exposure, as changed aggression has been found for ants in response to a neurotoxic pesticide (Barbieri et al, 2013). Finally, we hypothesized that K E Y W O R D S chemical signalling traits, insecticide, lambda-cyhalothrin, leaf beetle, pesticide, Phaedon cochleariae, pyrethroid, reproduction an insecticide exposure does not only impair the reproductive output of the exposed parental generation (Müller, Prosche, et al, 2017; Figure 1) but also reduces reproduction in the offspring.…”

“…Surprisingly few studies investigated pesticide impacts on mating behaviour, mostly revealing an impairment of mating success of exposed arthropods (Crawley et al, 2017;Tappert, Pokorny, Hofferberth, & Ruther, 2017;Tietjen, 2006; but see Wang, Lü, & He, 2018). Insecticide-dependent changes in aggression (Barbieri, Lester, Miller, & Ryan, 2013) or in the production or perception of (sexual) chemical signalling traits (Müller, 2018) might be mechanisms driving alterations in mating behaviour. Moreover, insects induce P450-dependent monooxygenases, esterases and glutathione S-transferases for detoxification of certain insecticides (Johnson et al, 2012;Kunce et al, 2017;Li, Schuler, & Berenbaum, 2007).…”

Different acute toxicity of fipronil baits on invasive Linepithema humile supercolonies and some non-target ground arthropods

“…However, since toxic chemicals such as insecticides can have broad adverse effects not only on target pests but also on non-target organisms, including beneficial species (Hayasaka et al 2012a;Hayasaka 2015), they pose problems when used in natural environments. Also, chemical control changes the natural community structure, as sensitive species are replaced by tolerant ones which develop a physiological and genetic adaptation to a given pollutant (Barbieri et al 2013;Rouco et al 2014). Information on intra-and inter-species variation in susceptibility and/or resistance to environmental stressors can help us understand how contaminants affect ecosystems (García-Muñoz et al 2010), and lead to the development of pest control and/or management strategies that include toxic chemicals in conjunction with biodiversity conservation.…”

“…The same applies probably in other countries around the world. Phenyl-pyrazole insecticides disrupt normal nerve function by blocking the gammaaminobutyric acid-gated chloride channels in the neuronal membranes, and are effective against insect target pests as well as non-target species (i.e., inter-species variation) either by direct contact or by ingestion (Cole et al 1993;Gant et al 1998;Scharf et al 2004;Gunasekara et al 2007;Hayasaka et al 2012b;Barbieri et al 2013).…”