Bdellovibrio and like organisms (BALOs) are obligate predatory bacteria commonly encountered in the environment. In dual predator–prey cultures, prey accessibility ensures optimal feeding and replication and rapid BALO population growth. However, the environmental prey landscape is complex, as it also incorporates non-prey cells and other particles. These may act as decoys, generating unproductive encounters which in turn may affect both predator and prey population dynamics. In this study, we hypothesized that increasing decoy:prey ratios would bring about increasing costs on the predator's reproductive fitness. We also tested the hypothesis that different BALOs and decoys would have different effects. To this end, we constructed prey landscapes including periplasmic or epibiotic predators including two types of decoy under a large range of initial decoy:prey ratio, and mixed cultures containing multiple predators and prey. We show that as decoy:prey ratios increase, the maximal predator population sizes is reduced and the time to reach it significantly increases. We found that BALOs spent less time handling non-prey (including superinfection-immune invaded prey) than prey cells, and did not differentiate between efficient and less efficient prey. This may explain why in multiple predator and prey cultures, less preferred prey appear to act as decoy.

中文翻译：

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猎物景观对细菌捕食者 Bdellovibrio 和类似生物体适应性的影响

Bdellovibrio 和类似生物 (BALO) 是环境中常见的专性捕食性细菌。在捕食者-猎物双重培养中，猎物可及性确保了最佳的摄食和复制以及 BALO 种群的快速增长。然而，环境猎物景观是复杂的，因为它还包含非猎物细胞和其他颗粒。这些可能充当诱饵，产生非生产性遭遇，进而可能影响捕食者和猎物种群动态。在这项研究中，我们假设增加诱饵：猎物的比例会增加捕食者的繁殖适应性成本。我们还检验了不同 BALO 和诱饵会产生不同效果的假设。为此，我们构建了包括周质或外生捕食者在内的猎物景观，包括在大范围的初始诱饵：猎物比率下的两种诱饵，以及包含多种捕食者和猎物的混合培养物。我们表明，随着诱饵：猎物比率的增加，最大捕食者种群规模减少，到达它的时间显着增加。我们发现，与猎物细胞相比，BALO 处理非猎物（包括重复感染免疫入侵的猎物）的时间更少，并且没有区分有效猎物和效率较低的猎物。这可以解释为什么在多种捕食者和猎物文化中，不太喜欢的猎物似乎充当诱饵。最大捕食者种群规模减少，达到它的时间显着增加。我们发现，与猎物细胞相比，BALO 处理非猎物（包括重复感染免疫入侵的猎物）的时间更少，并且没有区分有效猎物和效率较低的猎物。这可以解释为什么在多种捕食者和猎物文化中，不太喜欢的猎物似乎充当诱饵。最大捕食者种群规模减少，达到它的时间显着增加。我们发现，与猎物细胞相比，BALO 处理非猎物（包括重复感染免疫入侵的猎物）的时间更少，并且没有区分有效猎物和效率较低的猎物。这可以解释为什么在多种捕食者和猎物文化中，不太喜欢的猎物似乎充当诱饵。