Marsh D M, Rand A S, Ryan M J
Department of Environmental Science and Policy and Center for Population Biology, Wickson Hall, One Shields Avenue, University of California, Davis, CA 95616, USA e-mail:
Smithsonian Tropical Research Institute, APO AA 34002-0948, USA, , , , , , US.
Oecologia. 2000 Mar;122(4):505-513. doi: 10.1007/s004420050973.
Habitat and resource distributions can influence the movement and aggregation of individuals and thus have important effects on breeding behavior and ecology. Though amphibians have been model systems for the study of breeding behavior and sexual selection, most studies have examined breeding behavior within a single pond. As a result, little is known about how inter-pond distance affects breeding amphibians. We studied the effects of inter-pond distance on the breeding ecology of the tungara frog, Physalaemus pustulosus, in replicated pond arrays in which distance was varied from 0 to 50 m. We predicted that male site fidelity and male aggregation within arrays would increase with inter-pond distance, and that the opportunity for mate choice and oviposition site selectivity by females would decrease with the distance between ponds. Male site fidelity did increase with inter-pond distance. However, male aggregation decreased with distance, such that males tended to be more evenly spaced among ponds when ponds were farther apart. The opportunity for mate choice by females, measured as the number of males within the phonotactic radius of females, also decreased with inter-pond distance. Each of these three responses was consistent with a threshold effect between 5 m and 10 m in inter-pond distance. This threshold corresponded to the maximum distance at which females in laboratory choice experiments exhibited phonotaxis toward the "whine" call of a tungara male, suggesting that phonotactic limits may play an important role in tungara movements and spacing patterns. The distribution of egg masses among ponds, a potential correlate of oviposition site selectivity, did not vary with inter-pond distance. Multiple egg masses deposited on the same night were significantly overdispersed in all distance treatments, implying that females may select oviposition sites to avoid conspecific egg masses over distances of at least 50 m. Collectively, these results demonstrate that inter-pond distance may indeed affect amphibian breeding and movement behavior, and that consideration of multiple habitat patches and their spatial distributions can provide new insights into even the most well-understood mating systems.
栖息地和资源分布会影响个体的移动和聚集，进而对繁殖行为和生态产生重要影响。尽管两栖动物一直是研究繁殖行为和性选择的模式生物，但大多数研究都局限于单个池塘内的繁殖行为。因此，对于池塘间距离如何影响繁殖两栖动物，我们知之甚少。我们在重复设置的池塘阵列中研究了池塘间距离对泡蟾（Physalaemus pustulosus）繁殖生态的影响，其中池塘间距离从0米到50米不等。我们预测，阵列内雄性的地点忠诚度和雄性聚集程度会随着池塘间距离的增加而上升，而雌性的择偶机会和产卵地点选择性会随着池塘间距离的增加而减少。雄性的地点忠诚度确实随着池塘间距离的增加而上升。然而，雄性聚集程度却随着距离的增加而下降，以至于当池塘距离更远时，雄性在各池塘间的分布往往更加均匀。以处于雌性趋声半径内的雄性数量来衡量，雌性的择偶机会也随着池塘间距离的增加而减少。这三种反应均与池塘间距离在5米至10米之间的阈值效应一致。这个阈值对应于实验室选择实验中雌性对泡蟾雄性“呜呜”叫声表现出趋声行为的最大距离，这表明趋声限制可能在泡蟾的移动和分布模式中发挥重要作用。各池塘间卵块的分布情况，作为产卵地点选择性的一个潜在关联因素，并未随池塘间距离而变化。在所有距离处理中，同一晚产下的多个卵块都显著呈过度分散分布，这意味着雌性可能会选择产卵地点，以在至少50米的距离内避免同种卵块。总体而言，这些结果表明池塘间距离确实可能影响两栖动物的繁殖和移动行为，并且考虑多个栖息地斑块及其空间分布能够为即使是最广为人知的交配系统提供新的见解。
