The feeding selectivity of an herbivorous amphipod Ampithoe valida on three dominant macroalgal species of Yundang Lagoon
- 环境生态－已发表论文 
在室内开展了强壮藻钩虾对筼筜湖3种优势大型海藻,即石莼(ulVA lACTuCA)、根枝藻(rHIzOClOnIuM SP.)和细基江蓠繁枝变种(grACIlArIA TEnuISTIPITATA VAr.lIuI)的摄食实验研究,并以海藻的干湿比、总有机碳、总有机氮、碳氮比和蛋白质含量为指标,分析了大型海藻的营养价值对强壮藻钩虾的摄食选择性产生的影响。无选择性摄食实验的结果显示,强壮藻钩虾摄食率与3种海藻的干湿比和鲜海藻总有机碳含量呈显著负相关关系,表明该端足类存在着明显的“补偿性摄食“行为。选择性摄食实验的结果显示,强壮藻钩虾对石莼和根枝藻有明显的摄食偏好,其摄食率与鲜海藻的总有机碳和蛋白质含量呈显著的负相关关系,与海藻的总氮含量则无明显的相关关系,表明海藻的营养价值对强壮藻钩虾的摄食选择性并未产生可以预见的影响。Marine algae vary considerably in their nutritional,chemical,and structural composition,thus providing a heterogeneous and variable food resource for marine herbivores.However,Due to seasonal fluctuation in species composition and abundance of marine algae,herbivores usually encounter the environments with little tasty,highly nutritional food.Because herbivores eat foods that are much lower in nutrients than their own tissues,they display a diversity of behavioral and physiological adaptations to cope with the low nutritional value of their foods.Selective feeding on more nutritious plants,increasing consumption of lower quality foods( compensatory feeding) have all been proposed as important behaviors allowing herbivores to obtain adequate nourishment.Amphipods were common benthic species in macroalgal-based communities.They may regulate the macroalgal community structure by their selective feeding behavior.This study investigated the feeding of amphipod Ampithoe valida on three dominant macroalgae( Ulva lactuca,Gracilaria tenuistipitata var.liui and Rhizoclonium sp.) of Yundang Lagoon, and analyzed how the nutritional quality in terms of dry mass / wet mass( DM / FM),total organic carbon( TOC),total nitrogen( TN),C / N ratio and protein level may affect the food selectivity in the amphipod.The results showed that there was negative correlation between the feeding rates and the DM / FM,or TOC / FM of the macroalgae when macroalgae was separately offered to A.valida,indicating compensatory feeding behavior in the amphipod,that is,A.valida can use quantity to compensate quality when nutritional value of macroalgae was low.A.valida preferentially fed on U.lactuca and Rhizoclonium sp.,and their feeding rates negatively correlated to the TOC concentrations or protein levels in the macroalgae.However,no relationship was found between the feeding rates and TN.These results suggest there are no predictable effects of the nutritional quality on the feeding selectivity of amphipods.However,although A.valida have strong preference to green algae,Yundang Lagoon doesn' t structure a macroalgal community dominated by red algae G.tenuistipitata var.liui.