Avoidance and locomotor behaviours of Armadillidium granulatum (Crustacea, Oniscidea) towards trace elements contaminated soils

ABSTRACT

Behavioral responses to trace metals (TM) in Armadillidium granulatum Brandt, 1833 collected from Sebkha El Ouafi were studied under controlled laboratory conditions. Avoidance test was conducted in individuals exposed to cadmium (Cd), lead (Pb) and zinc (Zn) during 48 hours. The locomotor activity was studied under entraining conditions (LD) and constant darkness (DD) in the control animals as well as those exposed to contaminated soil.

Whatever the tested metal, the animals did not show avoidance behavior. The determined efficient concentration (EC₅₀) was equal to 3.4 mg/L for Cd, 451 mg/L for Pb and 1043 mg/L for Zn. Furthermore, results revealed the existence of nocturnal behavior whatever the experimental conditions. Periodogram analysis showed the existence of ultradian and circadian periods. This last was globally longer for contaminated specimens than the control ones under entraining conditions as well as under constant darkness. Exposed animals to cadmium showed the most important activity time under DD (α_DD = 8h01 ± 3h27) contrary to that observed under nLD cycle (α_LD = 3h43 ± 2h36). In addition, control specimens and those exposed to Cd and Pb were characterized by a phase delay contrary to those exposed to Zn which showed a phase advance.

KEYWORDS:

• Sebkha
• cadmium
• lead
• zinc
• soil
• Armadillidium granulatum
• avoidance test
• locomotor behavior

Acknowledgments

The study was supported by the Research Laboratory of Diversity, Management and Conservation of Biological Systems, El Manar II, Tunis, Tunisia

Disclosure statement

No potential conflict of interest was reported by the authors.

Ethical approval

The present study did not involve human participants. All the applicable institutional guidelines for welfare, care and use of animals were followed.