Kaczmarski Mikołaj, Tryjanowski Piotr, Kubicka Anna Maria
Department of Zoology, Poznań University of Life Sciences, Poznań, Wielkopolska, Poland.
PeerJ. 2019 Jan 30;7:e6337. doi: 10.7717/peerj.6337. eCollection 2019.
The main aim of the study was to analyse the influence of fleshy fruits (plums) on the post-metamorphic growth and feeding behaviour of the green toad . We tested the following two hypotheses: (1) juveniles of the green toad are characterised by faster growth in conditions involving fallen plums due to the associated presence of more varied food such as invertebrates; (2) green toads exhibit more active feeding behaviour in the presence of fleshy fruits.
A total of 120 fresh metamorphs of the green toad were randomly assigned to one of four groups: two experimental groups with fleshy plums and two other groups as controls (without fruits). Each group was kept in an enclosure to which wild invertebrates had free access. Each individual toad was measured for snout-vent length (mm) and body mass (g) every other day for 30 days. In order to determine whether fallen plums influence the feeding behaviour of toads, the number of active and hidden (under an artificial shelter) individuals was also noted.
The results showed that green toads from both enclosures with plums were characterised by more rapid growth than individuals from the control treatments. Simultaneously, in the enclosure with fleshy fruits, greater species richness of wild invertebrates was observed. No differences in active feeding behaviour were noted between control groups and groups with plums.
Fleshy fruits, upon falling, attract many types of invertebrates; thus they may represent good dietary supplements for fresh amphibian metamorphs. Therefore, the presence of fruit trees close to a breeding site might influences the post-metamorphic growth of amphibians, but not their feeding behaviour. The presence of insects associated with fallen fruit seems to favour the occurrence of amphibian populations, which is particularly important, since, due to political and social pressure, numbers of fruit trees are currently being reduced. To our knowledge, no previous study has investigated the potential influence of the presence of fruit trees on the growth and behaviour of anurans.
本研究的主要目的是分析肉质果实（李子）对绿蟾蜍变态后生长和摄食行为的影响。我们检验了以下两个假设：（1）绿蟾蜍幼体在有掉落李子的环境中生长更快，这是因为存在更多样化的食物，如无脊椎动物；（2）绿蟾蜍在有肉质果实的情况下表现出更活跃的摄食行为。
总共120只刚变态的绿蟾蜍被随机分配到四组中的一组：两组为有肉质李子的实验组，另外两组为对照组（无果实）。每组蟾蜍被饲养在一个野生无脊椎动物可以自由进入的围栏中。每隔一天测量每只蟾蜍的吻肛长度（毫米）和体重（克），持续30天。为了确定掉落的李子是否影响蟾蜍的摄食行为，还记录了活跃个体和隐藏在人工遮蔽物下的个体数量。
结果表明，两个有李子的围栏中的绿蟾蜍比对照组的个体生长更快。同时，在有肉质果实的围栏中，观察到野生无脊椎动物的物种丰富度更高。对照组和有李子的组在活跃摄食行为上没有差异。
肉质果实掉落时会吸引多种无脊椎动物；因此，它们可能是刚变态的两栖动物的良好饮食补充。因此，靠近繁殖地的果树的存在可能会影响两栖动物变态后的生长，但不会影响它们的摄食行为。与掉落果实相关的昆虫的存在似乎有利于两栖动物种群的出现，这一点尤为重要，因为由于政治和社会压力，目前果树的数量正在减少。据我们所知，以前没有研究调查过果树的存在对无尾两栖动物生长和行为的潜在影响。
