Chemical pollutants are one of the main threats against biodiversity and chemicals affecting non-target organisms are of great environmental concern. The herbicide triclopyr is commonly used to keep weeds under control and is believed to be weakly toxic to animals and only lethal in high doses. However, the knowledge of possible sub-lethal behavior effects in low doses is scarce. This study investigates whether the wood ant (family Formica) show behavioral changes when exposed to sub-lethal doses of triclopyr. The main hypotheses tested were; i) ants behaving normally show a preference for dark surfaces (i.e. scototaxis); and ii) triclopyr affect this behavior trait among ants. The hypotheses were tested by exposing ants to diets containing 1, 10 and 100 mg/L triclopyr for 24 hours (acute) and 7 days (chronic). To what extent ants preferred the white surface (proportion of frames with the ant visible), their activity (proportion of speed above 1 mm/s) their exploration (proportion area covered) and their average velocities was measured using a newly developed tracking software (ToxTrac). The results clearly show that ants have preference for dark surfaces and thus, that the first hypothesis is valid. However, the second hypothesis appear invalid as the different exposures to triclopyr did not affect the examined behaviors. Based on the results, triclopyr appear to not affect non-target organism such as ants, although possible behavioral effects in other organisms and other behavioral traits cannot be excluded.

A recent theory within behavioural ecology suggests that some animal behaviour traits are consistent over time and over different contexts as part of an animals’ “personality”. Animal personality has generally been accepted within vertebrates, but the idea of invertebrates expressing personality has long been meet with scepticism. In this study, I investigate if red wood ants (Formica rufa) show exploratory and bold behaviours that fulfil the personality criteria. Moreover, I test if this species prefers dark surfaces instead of white surfaces (scototaxis). My experiment included tests of 30 ants and two different behaviour trials targeting exploration and boldness that repeated over three different time periods. My results shows that the exploratory behaviours were correlated between trials conducted at different times and therefore, that this behaviour was repeatable. It was also clear that the red wood ant consistently showed large between individuals, indicating difference in personality. However, the studied ants did not show preferences for dark surfaces and the performance in the scototaxis trial did not correlate with any other measurable behaviour. The result of this study suggests that Formica rufa show behaviours that match the animal personality criteria for exploratory behaviour, but my result could not validate that bold behaviours were repeatable across time and context.

Animal behavior has become a frequently used tool in modern ecology and ecotoxicology, where laboratory behavioral traits are recognized as sensitive endpoints for assessing natural behavior or non-lethal effects of pollutants on animals. Within these research fields, behavioral traits measured in laboratory environments have been used to formulate predictions of ecological consequences that accompany specific behavior. However, the predictive power of behavioral traits measured in simplified laboratory environments for complex natural aquatic ecosystems has been questioned. In this study, I have examined to what extent behavioral changes, noted in laboratory settings in response to chemical stressors (an anxiolytic drug) or visual cues of black and white bottom substrates, are also expressed in the wild. In my first experiment, I scrutinized whether reduced social behavior previously shown to occur in the lab for European perch (Perca fluvatilis) in response to oxazepam also occurs within a natural lake subjected to oxazepam. The in situ behavior was measured using high temporal resolution (3 sec) acoustic telemetry. In my second experiment, I assessed if the Atlantic salmon’s (Salmo salar) preference for black bottom substrates (scototaxis) in laboratory assays could be utilized for guiding migrating Atlantic salmon in situ. I show that: i) Oxazepam does not affect the social (association) behavior or the social network structure of perch in natural settings, in contrast to laboratory-based predictions; ii) Atlantic salmon show a preference for black bottom substrates both in laboratory- and natural environments. My study with oxazepam underlines that abiotic environmental factors and collective decision making in-situ, can override the anti-social behavioral effects of oxazepam on perch in a natural Lake. However, there seems to be potential in using laboratory behavioral assays to predict behavior in the wild, given that there is a tendency for migrating salmon to follow black bottom substrates both in laboratory environments and in streams.