Institut für Zoologie, Tierärztliche Hochschule Hannover, Germany.
Institut für Biometrie, Epidemiologie und Informationsverarbeitung, Tierärztliche Hochschule Hannover, Germany.
Oecologia. 2001 Dec;129(4):534-542. doi: 10.1007/s004420100751. Epub 2001 Jul 10.
In many species with a resource-based mating system, males defend resources to increase their attractiveness to females. In the strawberry poison frog, Dendrobates pumilio, suitable tadpole-rearing sites appear to be a limited resource for females. Territorial males have been suggested to defend tadpole-rearing sites to increase their access to females. In this study we investigate the spatial association between tadpole-rearing sites and the sexes as well as the spatial association of males and females. If strawberry poison frogs have resource defense polygyny, we expect males and females to be associated with tadpole-rearing sites and that females will deposit their offspring in tadpole-rearing sites inside the territories of their mates. To test this hypothesis, home range and core area sizes were calculated for both sexes and the association patterns were compared in two areas that differed in their abundance of tadpole-rearing sites. Home ranges and core areas of females were much larger than male home ranges. Females showed a clumped distribution in the vicinity of tadpole-rearing sites. Males were not clumped and were less associated with tadpole-rearing sites. Females generally did not use tadpole-rearing sites in the territory of their mates and we therefore conclude that males did not defend tadpole-rearing sites for females. Our data are consistent with the general assumption that female distribution is influenced by resource distribution and that male distribution depends on female distribution. Nevertheless, the distribution of D. pumilio females was also influenced by male spacing patterns. Males probably initially establish their core areas where female density is high and then females move among territories to sample males. Males compete vigorously for places with high female density, the defense of which is likely important for enhancing their mating success. In general, the spacing patterns did not differ between populations but the sex ratio was strongly female biased in the habitat with more tadpole-rearing sites, reflecting the direct reliance of females on these resources.
在许多基于资源的交配系统的物种中，雄性通过保护资源来提高对雌性的吸引力。在草莓毒蛙（Dendrobates pumilio）中，适宜的蝌蚪繁殖地似乎是雌性的有限资源。有研究表明，有领地的雄性会保护蝌蚪繁殖地，以增加与雌性接触的机会。在这项研究中，我们调查了蝌蚪繁殖地与性别之间的空间关联，以及雄性和雌性之间的空间关联。如果草莓毒蛙存在资源防御性多配偶制，我们预计雄性和雌性将与蝌蚪繁殖地相关联，并且雌性将在其配偶的领地内将其后代产在蝌蚪繁殖地中。为了检验这一假设，我们计算了两性的活动范围和核心区域大小，并在两个蝌蚪繁殖地数量不同的区域比较了它们的关联模式。雌性的活动范围和核心区域明显大于雄性。雌性在蝌蚪繁殖地附近呈聚集分布。雄性不聚集，与蝌蚪繁殖地的关联性较小。雌性通常不在其配偶的领地内使用蝌蚪繁殖地，因此我们得出结论，雄性并没有为雌性保护蝌蚪繁殖地。我们的数据与一般假设一致，即雌性的分布受资源分布的影响，而雄性的分布则取决于雌性的分布。然而，D. pumilio 雌性的分布也受到雄性间隔模式的影响。雄性可能最初在雌性密度高的地方建立核心区域，然后雌性在领地之间移动以对雄性进行采样。雄性会为具有高雌性密度的地方进行激烈的竞争，这些地方的防御对提高其交配成功率可能很重要。一般来说，不同种群之间的间隔模式没有差异，但在有更多蝌蚪繁殖地的栖息地中，性别比例严重偏向雌性，这反映了雌性对这些资源的直接依赖。
