External marking of terrestrial isopods (Isopoda, Oniscidea): efficiency of materials and influence on feeding behavior

Diego Costa Kenne,Geraldo Luiz Gonçalves Soares,Paula Beatriz Araujo

doi:10.1590/2358-2936e2019018

Diego Costa Kenne, Geraldo Luiz Gonçalves Soares + Show 1 more

Open Access

https://doi.org/10.1590/2358-2936e2019018

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Journal: Nauplius	Publication Date: Jan 1, 2019
Citations: 2	License type: CC BY 4.0

Affiliation: Universidade Federal do Rio Grande do Sul

Abstract

Abstract Many monitoring studies use marking techniques to obtain dispersal data on individuals. Marking procedures may influence the vital activities of the terrestrial isopods, such as feeding behavior. The objective of this study was to identify the efficiency of different materials for external marking of woodlice and the influence on their feeding performance. Cyanoacrylate glue + glitter and nail polish were used as separate marking materials on three species: Balloniscus glaber, Benthana picta and Armadillidium vulgare. The material efficiency was compared using Kaplan-Meier curves and Log-Rank analysis. Individuals were fed with leaf discs of Machaerium stipitatum for feeding performance trials, and consumption rates were compared using ANOVA (α<0.05). There was no difference in durability between the materials used for external markings, except between marked and unmarked Benthana specimens when the observation period exceeded 15 days (Log-Rank=8.446, p=0.015). Nail polish was considered more suitable for feeding experiments. Statistical differences in consumption rates were observed only between the marked individual treatments of Benthana (ANOVA, F=7.5440, p=0.0002). These results indicate that external marking does not affect the feeding habits of the animals and suggest that this technique can be used to monitor dispersal of terrestrial isopods in field conditions for approximately 15 days.

Highlights

Animal marking techniques are widely used in monitoring research, such as in density and population size studies, through the recognition of marked individuals in recapture events (Suzuki et al, 2010; Drag et al, 2011)
At least until the 15th day of observation all species showed more than 50% survival of total individuals with the marks, and this fact indicates that the animals can tolerate three external marking events on a weekly frequency (Figs. 2–4)
The following events were observed during the experiment: lost mark, lost mark on exuvia, natural death, death during ecdysis, cannibalism and presumed drowning

Summary

Introduction

Animal marking techniques are widely used in monitoring research, such as in density and population size studies, through the recognition of marked individuals in recapture events (Suzuki et al, 2010; Drag et al, 2011). This method is used in animal dispersal observations, via periodic inspections of hotspots or by active searching for marked individuals in natural environments (Nazni et al, 2005; Hamer et al, 2014). The mark can be removed by the animal itself, due to chemical constituents of the cuticle (Lok et al, 1975), abrasion with elements present in the environment (Tuf et al, 2013), grooming behavior (Wojcik et al, 2000), or even by simple loss through the molting process (Willows, 1987)

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