Behavioral Ecotoxicology - Ecological Biomarkers: Indicators of Ecotoxicological Effects - page 253

10
Behavioral l Ecotoxicology
Claude Amiard-Triquet and Jean-Claude Amiard
CONTENTS
10.1 Introduction ........................................................................................................................ 253
10.2 Physiological Mechanisms Inducing Behavioral Impairments .................................. 254
10.2.1 Disruption of Sensory System Function ............................................................. 254
10.2.2 Neural and Hormonal Mechanisms of Behavior .............................................. 256
10.2.3 Energy Metabolism Impairments ........................................................................ 258
10.3 Behavioral Effects of Aquatic Pollutants ........................................................................ 259
10.4 Ecological Relevance of Behavioral Biomarkers ............................................................ 264
10.4.1 Environmental Realism of Behavioral Impairments ........................................ 264
10.4.2 From Individuals to Communities: Cascading Effects of Behavioral
Impairments ........................................................................................................... 266
10.5 Conclusions ......................................................................................................................... 269
References ..................................................................................................................................... 270
10.1 Introduction
In the present state of knowledge, most core biomarkers of defense or damage do not allow
the prediction of effects at higher levels of biological integration (Forbes et al. 2006), thus
hampering their use for the ecological risk assessment of chemically contaminated eco-
systems. However, for environmental toxicologists, it is intuitively evident that behavioral
changes can induce effects at population and community levels (Grue et al. in Dell'Omo
2002). For instance, a reduced swimming capability of fish may reduce their ability to cap-
ture prey and avoid predators, and may interfere with social and reproductive behavior
with a potential decrease in the fitness of wild populations (Weis et al. 2001; Vieira et al.
2009). On the other hand, behavioral disturbances have their origins in various biochemi-
cal and physiological impairments such as sensory system dysfunction, neurotoxicity,
endocrine disruption, or energy disturbances. Thus, behavior may be considered a key
link among cascading effects from infra- to supraorganismal responses. The relevance
of behavioral ecotoxicology is reinforced by numerous studies showing that behavioral
impairments occur at realistic doses in laboratory experiments, even after test organisms
have been exposed for their whole life in a contaminated environment (Amiard-Triquet
2009; Hellou et al. 2011). Owing to the large number of studies dealing with pesticides,
the relationships between acetylcholinesterase (AChE) inhibition (used as a biomarker of
exposure to organophosphate and carbamate pesticides) and behavioral impairments are
well documented for aquatic biota (see Table 4.1). In addition, recent studies dealing with
the ecological risk of emerging contaminants have shown that behavioral biomarkers are
253