Acetylcholinesterase inhibition and altered locomotor behavior in the carabid beetle Pterostichus cupreus. A linkage between biomarkers at two levels of biological complexity

Abstract

The establishment of cause–effect relationships is fundamental for the interpretation and the predictive value of biomarker responses measured at all levels of biological complexity. In the present study, the biochemical exposure biomarker acetylcholin‐esterase (AChE) inhibition was related to locomotor behavior, representing a general effect biomarker at the organismal level. Both sexes of the carabid beetle Pterostichus cupreus were intoxicated with three doses of the organophosphorous insecticide dimethoate. Five elements of their locomotor behavior were measured for 4 h employing computer‐aided video tracking, whereupon the whole body AChE activity was measured in the individual beetle. AChE inhibition was strongly correlated with dimethoate dose in both sexes. Alterations in the locomotor behavior were directly correlated with AChE inhibition in male beetles, which responded by reducing the time in locomotion, average velocity, and path length and by increasing the turning rate and frequency of stops. Females responded similarly at the two highest doses, whereas their locomotor behavior was not significantly different from the control group at the lowest dimethoate dose, suggesting a sex‐dependent difference in behavioral sensitivity to minor AChE depressions. The results demonstrate that automated measurements of locomotor behavior is at least as sensitive an endpoint to organophosphate poisoning as the AChE assay. Further, the correlation between the molecular and behavioral responses in individual beetles indicates a mechanistic relationship between the two biomarkers.

Folsomia candida (Collembola) locomotor activity pattern is changed by a neurotoxicant pesticide

“…We found in other unpublished experiments that the longer path length, the quicker the collembola F. candida run. Similar results have been found in studies with carabid beetles Pterostichus cupreus (Jensen 1997) and Scarites quadriceps (Prasifka et al 2008).…”

Effects of Wolf Spiders’ Captive Environment on Their Locomotor and Exploratory Behaviours

“…When introduced into a novel environment immediately after capture, my results show that adult P. saltans spiders developed in the wild exhibit high levels of locomotor and exploratory activity. Males are twice as active as females as previously observed in other studies with other invertebrate species [8][9][10][11]22]. Thus, males explore larger surfaces but contrary to our predictions they do not cover significantly longer distance than the females.…”

“…Sexual maturity causes a modification of the exploratory and locomotor activities of the majority of arthropod species and exploratory behaviours can then differ between adult males and females (spiders: [8]; myriapods and ground beetles: [9,10]; woodlouse: [11]). Generally, adult male arthropods move about more and this tendency can be explained by the fact that males, in addition to foraging, are looking for a sexual partner [12].…”

Whether warming magnifies the toxicity of a pesticide is strongly dependent on the concentration and the null model

“…Five physiological response variables were measured. Acetylcholinesterase (AChE), the target enzyme inhibited by organophosphates such as CPF (Domingues et al, 2010), was measured based on a modified protocol of Jensen et al (1997). Total fat content, the major long-term energy storage in insects (Azeez et al, 2014), was quantified based on a modified protocol of Marsh and Weinstein (1966).…”