Insecticides usually present in low concentrations in streams are known to impair behaviour and development of non-target freshwater invertebrates. Moreover, there is growing awareness that the presence of natural stressors, such as predation risk may magnify the negative effects of pesticides. This is because perception of predation risk can by itself lead to changes on behaviour and physiology of prey species. To evaluate the potential combined effects of both stressors on freshwater detritivores we studied the behavioural and developmental responses of Chironomus riparius to chlorantraniliprole (CAP) exposure under predation risk. Also, we tested whether the presence of a shredder species would alter collector responses under stress. Trials were conducted using a simplified trophic chain: Alnus glutinosa leaves as food resource, the shredder Sericostoma vittatum and the collector C. riparius. CAP toxicity was thus tested under two conditions, presence/absence of the dragonfly predator Cordulegaster boltonii. CAP exposure decreased leaf decomposition. Despite the lack of significance for interactive effects, predation risk marginally modified shredder effect on leaf decomposition, decreasing this ecosystem process. Shredders presence increased leaf decomposition, but impaired chironomids performance, suggesting interspecific competition rather than facilitation. C. riparius growth rate was decreased independently by CAP exposure, presence of predator and shredder species. A marginal interaction between CAP and predation risk was observed regarding chironomids development. To better understand the effects of chemical pollution to natural freshwater populations, natural stressors and species interactions must be taken into consideration, since both vertical and horizontal species interactions play their role on response to stress.

• Keywords
• Chlorantraniliprole, Detritivore invertebrates, Leaf decomposition, Predation risk,
• MeSH
• Chironomidae drug effects   growth & development   physiology   MeSH
• Insecta drug effects   growth & development   physiology   MeSH
• Insecticides toxicity   MeSH
• Larva drug effects   growth & development   physiology   MeSH
• Plant Leaves MeSH
• Nymph drug effects   growth & development   physiology   MeSH
• Alnus MeSH
• ortho-Aminobenzoates toxicity   MeSH
• Food Chain * MeSH
• Predatory Behavior * MeSH
• Feeding Behavior drug effects   MeSH
• Odonata growth & development   physiology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• chlorantranilipole MeSH Browser
• Insecticides MeSH
• ortho-Aminobenzoates MeSH