Healy S D, Clayton N S, Krebs J R
Department of Psychology, University of Newcastle, Newcastle upon Tyne, UK.
Behav Brain Res. 1994 Mar 31;61(1):23-8. doi: 10.1016/0166-4328(94)90004-3.
Food storing birds have been shown to have a larger hippocampus, relative to the rest of the telencephalon, than do non-storers. A previous study reported that this difference in relative hippocampal volume is not apparent in a comparison of nestling birds, but emerges after birds have fledged. This conclusion was based on a comparison of a storing and a non-storing species in the corvid family. The present study compared another storer/non-storer pair of species in order to test whether the results of the previous study can be replicated in another family of birds. The volumes of the hippocampal region and remainder of the telencephalon were measured and estimates of neuron size, density and total number in the hippocampal region were made for nestlings and adults of the food-storing marsh tit Parus palustris and non-storing blue tit Parus caeruleus. Relative hippocampal volume did not differ between nestlings of the two species, whilst the relative hippocampal volume of adult marsh tits was greater than that of blue tits. The difference between adults arose because in marsh tits but not blue tits, adults had a significantly larger relative hippocampal volume than did nestlings. Neuron density was significantly higher in both species in nestlings than in adults and adult blue tits had fewer neurons than did adult marsh tits. The results of this study are largely consistent with the earlier study comparing a storing and non-storing species of corvid, suggesting that the observed patterns may reflect a general difference between storers and non-storers in the development of the hippocampal region.
与非储食性鸟类相比，储食性鸟类的海马体相对于端脑的其他部分更大。此前有研究报告称，在雏鸟的比较中，相对海马体体积的这种差异并不明显，但在鸟类羽翼丰满后才会出现。这一结论是基于对鸦科中一个储食性物种和一个非储食性物种的比较得出的。本研究比较了另一对储食性/非储食性物种，以测试先前研究的结果是否能在另一鸟类家族中得到重复验证。对储食性沼泽山雀（Parus palustris）和非储食性蓝山雀（Parus caeruleus）的雏鸟和成年鸟，测量了海马体区域和端脑其余部分的体积，并对海马体区域的神经元大小、密度和总数进行了估计。两种雏鸟的相对海马体体积没有差异，而成年沼泽山雀的相对海马体体积大于蓝山雀。成年鸟之间的差异是因为，对于沼泽山雀而非蓝山雀来说，成年鸟的相对海马体体积显著大于雏鸟。两种雏鸟的神经元密度均显著高于成年鸟，成年蓝山雀的神经元数量少于成年沼泽山雀。本研究的结果在很大程度上与早期比较一个储食性和一个非储食性鸦科物种的研究一致，表明观察到的模式可能反映了储食性鸟类和非储食性鸟类在海马体区域发育上的普遍差异。
