Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki City, Nagasaki, 852-8521, Japan.
Division of Applied Entomology and Zoology, Graduate School of Agriculture, Tamagawa University, Machida, Tokyo, 194-8610, Japan.
Sci Rep. 2022 Sep 23;12(1):15874. doi: 10.1038/s41598-022-20389-z.
Some aphid species produce a soldier caste with enlarged forelegs and horns (weapons). It has been hypothesised that the evolution of morphological specialization by soldiers in social aphids is accelerated by high predation pressure, but this possibility has not been tested. Here, we investigated the relationship between local predator abundance and soldiers' weapon size and aggressiveness in a prey-predator system comprising a eusocial aphid, Ceratovacuna japonica, and its predators (larvae of the butterfly Taraka hamada and of the moth Atkinsonia ignipicta) in two populations with different predator abundances. We found that the soldiers in the predator-abundant population had larger weapons and were more aggressive than those in the population with lower predator abundance. Furthermore, the soldiers' defensive prowess (evaluated as the survival of aphids in the presence of predators) was greater in the predator-abundant population. These results provide the first evidence that a population of eusocial aphids experiencing high predation pressure has soldiers with pronounced defensive traits and defensive prowess.
一些蚜虫物种产生具有增大的前腿和角（武器）的兵虫。有人假设，社会蚜虫中兵虫形态特化的进化是由高捕食压力加速的，但这种可能性尚未得到检验。在这里，我们在包括社会性蚜虫 Ceratovacuna japonica 及其捕食者（蝴蝶 Taraka hamada 的幼虫和飞蛾 Atkinsonia ignipicta）的猎物-捕食者系统中，研究了两个具有不同捕食者丰度的种群中局部捕食者丰度与兵虫武器大小和攻击性之间的关系。我们发现，捕食者丰富种群中的兵虫具有更大的武器，并且比捕食者丰度较低的种群中的兵虫更具攻击性。此外，在捕食者丰富的种群中，兵虫的防御能力（评估为在存在捕食者的情况下蚜虫的存活率）更高。这些结果首次提供了证据，表明经历高捕食压力的社会性蚜虫种群具有明显的防御特征和防御能力。
