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Individual preferences and social interactions determine the aggregation of woodlice.

Devigne C, Broly P, Deneubourg JL - PLoS ONE (2011)

Bottom Line: Until now, no clear experimental demonstration was available about aggregation resulting from inter-attraction between conspecifics.Here we show for the first time that aggregation in woodlice implies a strong social component and results from a trade-off between individual preferences and inter-attraction between individuals.Moreover, our results reveal that the response to the heterogeneities affects only the location of the aggregates and not the level of aggregation, and demonstrate the strong inter-attraction between conspecifics which can outweigh individual preferences.

View Article: PubMed Central - PubMed

Affiliation: Université Lille Nord de France, Lille, France. cedric.devigne@icl-lille.fr

ABSTRACT

Background: The aggregation of woodlice in dark and moist places is considered an adaptation to land life and most studies are focused on its functionality or on the behavioural mechanisms related to the individual's response to abiotic factors. Until now, no clear experimental demonstration was available about aggregation resulting from inter-attraction between conspecifics.

Methodology/main findings: We present the dynamics of aggregation, not previously described in detail in literature, as being independent of the experimental conditions: homogeneous and heterogeneous environments with identical or different shelters. Indeed whatever these conditions, the aggregation is very quick. In less than 10 minutes more than 50% of woodlice were aggregated in several small groups in the homogeneous environment or under shelters in the heterogeneous environment. After this fast aggregation, woodlice progressively moved into a single aggregate or under one shelter.

Conclusions/significance: Here we show for the first time that aggregation in woodlice implies a strong social component and results from a trade-off between individual preferences and inter-attraction between individuals. Moreover, our results reveal that the response to the heterogeneities affects only the location of the aggregates and not the level of aggregation, and demonstrate the strong inter-attraction between conspecifics which can outweigh individual preferences. This inter-attraction can lead to situations that could seem sub-optimal.

Show MeSH
Distribution of woodlice in final aggregates in heterogeneous conditions D, E, and F.
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pone-0017389-g008: Distribution of woodlice in final aggregates in heterogeneous conditions D, E, and F.

Mentions: Similarly, whatever the experimental condition, the number of woodlice in the final aggregate under the “winning” shelter quickly increased to reach more than 50% of woodlice in 10 minutes. At the end of experiments, this aggregate consisted of 25–30 woodlice on average (Figure 8). Even if at the beginning of the experiments the dynamics were strongly similar, the number of woodlice in the final aggregate was significantly lower in condition F compared to conditions E after 17 minutes and D after 33 minutes (Figure 7b; Kruskal-Wallis test, KW >7.23, p<0.05 followed by Dunn's test, p<0.05 from 17 to 45 minutes and p<0.05 from 33 to 45 minutes, respectively).


Individual preferences and social interactions determine the aggregation of woodlice.

Devigne C, Broly P, Deneubourg JL - PLoS ONE (2011)

Distribution of woodlice in final aggregates in heterogeneous conditions D, E, and F.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3045452&req=5

pone-0017389-g008: Distribution of woodlice in final aggregates in heterogeneous conditions D, E, and F.
Mentions: Similarly, whatever the experimental condition, the number of woodlice in the final aggregate under the “winning” shelter quickly increased to reach more than 50% of woodlice in 10 minutes. At the end of experiments, this aggregate consisted of 25–30 woodlice on average (Figure 8). Even if at the beginning of the experiments the dynamics were strongly similar, the number of woodlice in the final aggregate was significantly lower in condition F compared to conditions E after 17 minutes and D after 33 minutes (Figure 7b; Kruskal-Wallis test, KW >7.23, p<0.05 followed by Dunn's test, p<0.05 from 17 to 45 minutes and p<0.05 from 33 to 45 minutes, respectively).

Bottom Line: Until now, no clear experimental demonstration was available about aggregation resulting from inter-attraction between conspecifics.Here we show for the first time that aggregation in woodlice implies a strong social component and results from a trade-off between individual preferences and inter-attraction between individuals.Moreover, our results reveal that the response to the heterogeneities affects only the location of the aggregates and not the level of aggregation, and demonstrate the strong inter-attraction between conspecifics which can outweigh individual preferences.

View Article: PubMed Central - PubMed

Affiliation: Université Lille Nord de France, Lille, France. cedric.devigne@icl-lille.fr

ABSTRACT

Background: The aggregation of woodlice in dark and moist places is considered an adaptation to land life and most studies are focused on its functionality or on the behavioural mechanisms related to the individual's response to abiotic factors. Until now, no clear experimental demonstration was available about aggregation resulting from inter-attraction between conspecifics.

Methodology/main findings: We present the dynamics of aggregation, not previously described in detail in literature, as being independent of the experimental conditions: homogeneous and heterogeneous environments with identical or different shelters. Indeed whatever these conditions, the aggregation is very quick. In less than 10 minutes more than 50% of woodlice were aggregated in several small groups in the homogeneous environment or under shelters in the heterogeneous environment. After this fast aggregation, woodlice progressively moved into a single aggregate or under one shelter.

Conclusions/significance: Here we show for the first time that aggregation in woodlice implies a strong social component and results from a trade-off between individual preferences and inter-attraction between individuals. Moreover, our results reveal that the response to the heterogeneities affects only the location of the aggregates and not the level of aggregation, and demonstrate the strong inter-attraction between conspecifics which can outweigh individual preferences. This inter-attraction can lead to situations that could seem sub-optimal.

Show MeSH