Relative hippocampal volume in relation to food-storing behavior in four species of woodpeckers.
Relative hippocampal volume in relation to food-storing behavior in four species of woodpeckers.
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DOI：
10.1159/000112985
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
Susan F. Volman;Thomas C. Grubb;Kristofor C. Schuett
中科院分区：
文献类型：
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作者：
Susan F. Volman;Thomas C. Grubb;Kristofor C. Schuett
先前的研究已经表明，雀形目中那些能记住食物储藏位置的鸟类，其海马复合体比那些不储存食物的雀形目鸟类要大。啄木鸟构成了一个不同的鸟类目（Piciformes），其中也包括一些食物储存物种。我们比较了四种具有不同缓存行为的啄木鸟的海马体积，相对于端脑其余部分的体积。红腹啄木鸟（Melanerpes carolinus）是“分散囤积者”。在秋季和冬季，它们在一大片领土上的分散地点储存橡子或山毛榉果。红头啄木鸟（Melanerpes erythrocephalus）也储存坚果，但在它们激烈捍卫的小领土的中央“储藏室”。在有毛啄木鸟（Picoides villosus）和绒毛啄木鸟（Picoides pubescens）中，贮藏是不存在的或大大减少的，这两种啄木鸟都在冬季的大范围内以各种食物为食。分散囤积者海马复合体的相对体积大于贮藏室囤积者，这表明红腹啄木鸟，像雀形目分散囤积者，依靠记忆来恢复缓存。令人惊讶的是，在两个非存储Picoides啄木鸟的相对海马体积是最相似的分散囤积的其他属。在雀形目鸟类中，海马体积和端脑体积在储存物种中高度相关，但在非储存物种中则不相关。我们发现，这两个大脑区域的体积在两个Melanerpes物种中高度相关，在毛茸茸的啄木鸟中不相关，而在绒毛啄木鸟中相关性较弱。Picoides物种中出乎意料的大海马复合体表明，它们可能参与了一些行为，而不是食物储存，选择这种特征。相反，我们的研究结果有关海马和端脑体积之间的关系可能表明，弱相关性与一个不太专业的海马，独立于其相对体积。
Previous studies have shown that those food-storing birds of the order Passeriformes that remember the locations of their caches have relatively larger hippocampal complexes than do non-storing passerines. Woodpeckers constitute a different avian order (Piciformes), which also includes some food-storing species. We compared hippocampal volume, relative to the volume of the rest of the telencephalon, across four species of woodpeckers with disparate caching behavior. Red-bellied woodpeckers (Melanerpes carolinus) are "scatter hoarders'. During the fall and winter they cache acorns or beechnuts in dispersed sites throughout a large territory. Red-headed woodpeckers (Melanerpes erythrocephalus) also store nuts but in central "larders' on their small territories which they fiercely defend. Caching is absent or much reduced in hairy woodpeckers (Picoides villosus) and downy woodpeckers (Picoides pubescens), both of which forage on a variety of foods within large winter home ranges. The relative volume of the hippocampal complex in the scatter hoarder was larger than in the larder hoarder, suggesting that red-bellied woodpeckers, like passerine scatter hoarders, rely on memory to recover their caches. Surprisingly, the relative hippocampal volumes in the two non-storing Picoides woodpeckers were most similar to the scatter hoarder of the other genus. In passerine birds, hippocampal volume and telencephalon volume are highly correlated in storing species but not in non-storers. We found that the volumes of these two brain areas were highly correlated in both Melanerpes species, uncorrelated in the hairy woodpeckers, and more weakly correlated in the downy woodpeckers. The unexpectedly large hippocampal complexes in the Picoides species suggests they may engage in some behavior, other than food-storing, that selects for this trait. Conversely, our results concerning the relationship between hippocampal and telencephalon volumes may indicate that a weak correlation is associated with a less specialized hippocampus, independent of its relative volume.