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Love thy neighbour: group properties of gaping behaviour in mussel aggregations.

Nicastro KR, Zardi GI, McQuaid CD, Pearson GA, Serrão EA - PLoS ONE (2012)

Bottom Line: Although made up of individual members, an aggregation often displays novel effects that do not manifest at the level of the individual organism.P. perna gaping behaviour had no effect on body temperatures of isolated individuals, while it led to increased humidity and decreased temperatures in dense groups (beds).Gaping resulted in cooler body temperatures for P. perna than M. galloprovincialis when in aggregations, while solitary individuals exhibited the highest temperatures.

View Article: PubMed Central - PubMed

Affiliation: CCMAR-CIMAR Laboratório Associado, Universidade do Algarve, Faro, Portugal.

ABSTRACT
By associating closely with others to form a group, an animal can benefit from a number of advantages including reduced risk of predation, amelioration of environmental conditions, and increased reproductive success, but at the price of reduced resources. Although made up of individual members, an aggregation often displays novel effects that do not manifest at the level of the individual organism. Here we show that very simple behaviour in intertidal mussels shows new effects in dense aggregations but not in isolated individuals. Perna perna and Mytilus galloprovincialis are gaping (periodic valve movement during emersion) and non-gaping mussels respectively. P. perna gaping behaviour had no effect on body temperatures of isolated individuals, while it led to increased humidity and decreased temperatures in dense groups (beds). Gaping resulted in cooler body temperatures for P. perna than M. galloprovincialis when in aggregations, while solitary individuals exhibited the highest temperatures. Gradients of increasing body temperature were detected from the center to edges of beds, but M. galloprovincialis at the edge had the same temperature as isolated individuals. Furthermore, a field study showed that during periods of severe heat stress, mortality rates of mussels within beds of the gaping P. perna were lower than those of isolated individuals or within beds of M. galloprovincialis, highlighting the determinant role of gaping on fitness and group functioning. We demonstrate that new effects of very simple individual behaviour lead to amelioration of abiotic conditions at the aggregation level and that these effects increase mussel resistance to thermal stress.

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Results of group gaping laboratory experiments (trials pooled).(a) Average and (b) maximum value of humidity; (c) average and (d) maximum value of ambient temperature; (e) average and (f) maximum robomussel temperature. Post hoc results are included in the figure.
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pone-0047382-g003: Results of group gaping laboratory experiments (trials pooled).(a) Average and (b) maximum value of humidity; (c) average and (d) maximum value of ambient temperature; (e) average and (f) maximum robomussel temperature. Post hoc results are included in the figure.

Mentions: ANOVA and SNK tests showed that minimum and average humidity declined significantly in the order P. perna beds>M. galloprovincialis beds but with no significant difference between M. galloprovincialis and solitary mussels. (Fig. 3a, b; p<0.05; Table S3, Table S4). A significant difference in minimum humidity between trials was detected [Trial (Treatment); p<0.05].


Love thy neighbour: group properties of gaping behaviour in mussel aggregations.

Nicastro KR, Zardi GI, McQuaid CD, Pearson GA, Serrão EA - PLoS ONE (2012)

Results of group gaping laboratory experiments (trials pooled).(a) Average and (b) maximum value of humidity; (c) average and (d) maximum value of ambient temperature; (e) average and (f) maximum robomussel temperature. Post hoc results are included in the figure.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3472978&req=5

pone-0047382-g003: Results of group gaping laboratory experiments (trials pooled).(a) Average and (b) maximum value of humidity; (c) average and (d) maximum value of ambient temperature; (e) average and (f) maximum robomussel temperature. Post hoc results are included in the figure.
Mentions: ANOVA and SNK tests showed that minimum and average humidity declined significantly in the order P. perna beds>M. galloprovincialis beds but with no significant difference between M. galloprovincialis and solitary mussels. (Fig. 3a, b; p<0.05; Table S3, Table S4). A significant difference in minimum humidity between trials was detected [Trial (Treatment); p<0.05].

Bottom Line: Although made up of individual members, an aggregation often displays novel effects that do not manifest at the level of the individual organism.P. perna gaping behaviour had no effect on body temperatures of isolated individuals, while it led to increased humidity and decreased temperatures in dense groups (beds).Gaping resulted in cooler body temperatures for P. perna than M. galloprovincialis when in aggregations, while solitary individuals exhibited the highest temperatures.

View Article: PubMed Central - PubMed

Affiliation: CCMAR-CIMAR Laboratório Associado, Universidade do Algarve, Faro, Portugal.

ABSTRACT
By associating closely with others to form a group, an animal can benefit from a number of advantages including reduced risk of predation, amelioration of environmental conditions, and increased reproductive success, but at the price of reduced resources. Although made up of individual members, an aggregation often displays novel effects that do not manifest at the level of the individual organism. Here we show that very simple behaviour in intertidal mussels shows new effects in dense aggregations but not in isolated individuals. Perna perna and Mytilus galloprovincialis are gaping (periodic valve movement during emersion) and non-gaping mussels respectively. P. perna gaping behaviour had no effect on body temperatures of isolated individuals, while it led to increased humidity and decreased temperatures in dense groups (beds). Gaping resulted in cooler body temperatures for P. perna than M. galloprovincialis when in aggregations, while solitary individuals exhibited the highest temperatures. Gradients of increasing body temperature were detected from the center to edges of beds, but M. galloprovincialis at the edge had the same temperature as isolated individuals. Furthermore, a field study showed that during periods of severe heat stress, mortality rates of mussels within beds of the gaping P. perna were lower than those of isolated individuals or within beds of M. galloprovincialis, highlighting the determinant role of gaping on fitness and group functioning. We demonstrate that new effects of very simple individual behaviour lead to amelioration of abiotic conditions at the aggregation level and that these effects increase mussel resistance to thermal stress.

Show MeSH
Related in: MedlinePlus