Tamboia Teri, Cipollini Martin L, Levey Douglas J
Department of Botany, University of Florida, 32601, Gainesville, FL, USA.
Oecologia. 1996 Sep;107(4):522-532. doi: 10.1007/BF00333944.
We examined the ecological relevance of bird versus mammal dispersal syndromes in four species of Solanum, S. americanum Type A, S. americanum Type B, S. ptychanthum, and S. sarrachoides. These plants were selected because their morphological characteristics, such as fruit color, mass, and persistence, resembled those typically associated with classically-defined bird and mammal dispersal syndromes. We monitored persistence of tagged fruits, compared physical and chemical chaacteristics, performed fruit preference trials with northern bobwhite quail (Colinus virginianus), deer mice (Peromyscus maniculatus), and American robins (Turdus migratorius), and assessed differences in use of olfactory cues by foraging deer mice. We predicted that principal components analysis of physical and chemical characteristics would place fruits of these species along a clear gradient from bird to mammal dispersal syndromes (S. americanum Type A, S. americanum Type B, S. ptychanthum, and S. sarrachoides). However, physical and chemical characteristics did not consistently follow the gradient. Also, contrary to expectations, both birds and mammals demonstrated a preference for S. americanum Types A and B, both "bird" fruits. Deer mice and bobwhite quail showed much less discrimination among fruit types than did American robins. While the relatively strong odor of the green-fruited S. sarrachoides suggested a mammalian attractant, deer mice discovered the relatively odorless S. americanum Type A significantly more quickly. We conclude that in Solanum, suites of morphological characteristics resembling bird and mammal dispersal syndromes are not good predictors of fruit choice by birds and mammals. We note, however, that this conclusion is based on a sample of three animal species. Alternative explanations for fruit character suites should be considered. For example, the adaptive significance for an association of green coloration of ripe fruit with impersistence (dropping when ripe), as in S. sarrachoides and some S. ptychanthum, may relate more to photosynthesis and carbon balance in detached fruits than to disperser attraction.
我们研究了茄属四种植物，即美洲龙葵A型、美洲龙葵B型、普蒂龙葵和刺萼龙葵中，鸟类与哺乳动物传播综合征的生态相关性。选择这些植物是因为它们的形态特征，如果实颜色、质量和持久性，类似于那些通常与经典定义的鸟类和哺乳动物传播综合征相关的特征。我们监测了标记果实的持久性，比较了物理和化学特征，用北部 bobwhite 鹌鹑（Colinus virginianus）、鹿鼠（Peromyscus maniculatus）和美洲知更鸟（Turdus migratorius）进行了果实偏好试验，并评估了觅食鹿鼠对嗅觉线索的使用差异。我们预测，对物理和化学特征进行主成分分析会将这些物种的果实沿着从鸟类到哺乳动物传播综合征的清晰梯度排列（美洲龙葵A型、美洲龙葵B型、普蒂龙葵和刺萼龙葵）。然而，物理和化学特征并没有始终如一地遵循这个梯度。此外，与预期相反，鸟类和哺乳动物都表现出对美洲龙葵A型和B型这两种“鸟类”果实的偏好。鹿鼠和 bobwhite 鹌鹑对果实类型的区分远不如美洲知更鸟。虽然绿色果实的刺萼龙葵相对较强的气味表明它是一种吸引哺乳动物的物质，但鹿鼠发现相对无味的美洲龙葵A型的速度要快得多。我们得出结论，在茄属植物中，类似于鸟类和哺乳动物传播综合征的一系列形态特征并不能很好地预测鸟类和哺乳动物对果实的选择。然而，我们注意到这个结论是基于三种动物物种的样本得出的。应该考虑对果实特征组合的其他解释。例如，成熟果实的绿色与不持久（成熟时掉落）相关联的适应性意义，就像在刺萼龙葵和一些普蒂龙葵中那样，可能更多地与脱离果实中的光合作用和碳平衡有关，而不是与吸引传播者有关。
