Brain size and weight vary tremendously in the animal kingdom. It has been suggested that brain structural develop- ment must evolve balanced between the advantages of dealing with greater social challenges mad the en...Brain size and weight vary tremendously in the animal kingdom. It has been suggested that brain structural develop- ment must evolve balanced between the advantages of dealing with greater social challenges mad the energetic costs of maintain- ing and developing larger brains. Here we ask if interspecific differences in cooperative behaviour （i.e. cleaning behaviour） are related to brain weight variations in four close-related species of Labrid fish： two are obligatory cleanerfish throughout their en- tire life （Labroides dimidiatus and L. bicolor）, one facultative cleaner fish Labropsis australis and one last species that never en- gage in cleaning Labrichthys unilineatus. We first search for the link between the rate of species＇ cooperation and its relative brain weight, and finally, if the degree of social complexity and cooperation are reflected in the weight of its major brain sub- structures. Overall, no differences were found in relative brain weight （in relation to body weight） across species. Fine-scale dif- ferences were solely demonstrated for the facultative cleaner L. australis, at the brainstem level. Furthermore, data visual exami- nation indicates that the average cerebellum and brainstem weights appear to be larger for L. dimidiatus. Because variation was solely found at specific brain areas （such as cerebellum and brainstem） and not for the whole brain weight values, it suggests that species social-ecological and cognitive demands may be directly contributing to a selective investment in relevant brain areas. This study provides first preliminary evidence that links potential differences in cognitive ability in cooperative behaviour to how these may mediate the evolution of brain structural development in non-mammal vertebrate groups .展开更多
The extraction of large boulders from coastal reefs for construction of harbours and coastal protection has led to habitat degradation for local fish populations through the destruction of cavernous reefs and changes ...The extraction of large boulders from coastal reefs for construction of harbours and coastal protection has led to habitat degradation for local fish populations through the destruction of cavernous reefs and changes in macroalgal cover resulting from a loss of substrate. The temperate reef at L?s? Trindel in Kattegat, Denmark, has now been re-established with the aim of restoring the reef’s historical structure and function. The effects of the restoration on the local fish community are reported here. Fishing surveys using gillnets and fyke nets were conducted before the restoration (2007) and four years after the restoration of the reef (2012). Species of the family Labridae, which have a high affinity for rocky reefs, dominated both before and after the restoration. Commercially important species such as cod Gadus morhua, and saithe Pollachius virens, occurred infrequently in the catches in 2007 but were significantly more abundant in the catches in 2012. Cods were especially attracted to the shallow part of the reef that was restored by adding stones. For some species, such as ballan wrasse Labrus bergylta, and cod, the proportion of larger individuals increased after the restoration. The findings highlight the importance of reef habitats for fish communities and the need for their protection.展开更多
文摘Brain size and weight vary tremendously in the animal kingdom. It has been suggested that brain structural develop- ment must evolve balanced between the advantages of dealing with greater social challenges mad the energetic costs of maintain- ing and developing larger brains. Here we ask if interspecific differences in cooperative behaviour （i.e. cleaning behaviour） are related to brain weight variations in four close-related species of Labrid fish： two are obligatory cleanerfish throughout their en- tire life （Labroides dimidiatus and L. bicolor）, one facultative cleaner fish Labropsis australis and one last species that never en- gage in cleaning Labrichthys unilineatus. We first search for the link between the rate of species＇ cooperation and its relative brain weight, and finally, if the degree of social complexity and cooperation are reflected in the weight of its major brain sub- structures. Overall, no differences were found in relative brain weight （in relation to body weight） across species. Fine-scale dif- ferences were solely demonstrated for the facultative cleaner L. australis, at the brainstem level. Furthermore, data visual exami- nation indicates that the average cerebellum and brainstem weights appear to be larger for L. dimidiatus. Because variation was solely found at specific brain areas （such as cerebellum and brainstem） and not for the whole brain weight values, it suggests that species social-ecological and cognitive demands may be directly contributing to a selective investment in relevant brain areas. This study provides first preliminary evidence that links potential differences in cognitive ability in cooperative behaviour to how these may mediate the evolution of brain structural development in non-mammal vertebrate groups .
基金funded by the EU LIFE project“Rebuilding of Marine Cavernous Boulder Reefs in Kattegat(Blue Reef)”.LIFE06 NAT/DK/000159by the National Program for Coastal Recreational Fisheries“marinfiskepleje”.
文摘The extraction of large boulders from coastal reefs for construction of harbours and coastal protection has led to habitat degradation for local fish populations through the destruction of cavernous reefs and changes in macroalgal cover resulting from a loss of substrate. The temperate reef at L?s? Trindel in Kattegat, Denmark, has now been re-established with the aim of restoring the reef’s historical structure and function. The effects of the restoration on the local fish community are reported here. Fishing surveys using gillnets and fyke nets were conducted before the restoration (2007) and four years after the restoration of the reef (2012). Species of the family Labridae, which have a high affinity for rocky reefs, dominated both before and after the restoration. Commercially important species such as cod Gadus morhua, and saithe Pollachius virens, occurred infrequently in the catches in 2007 but were significantly more abundant in the catches in 2012. Cods were especially attracted to the shallow part of the reef that was restored by adding stones. For some species, such as ballan wrasse Labrus bergylta, and cod, the proportion of larger individuals increased after the restoration. The findings highlight the importance of reef habitats for fish communities and the need for their protection.
