Entomology and Arachnology Laboratory (Laboratorio de Aracnología y Entomología), Conservation and Environmental Planning Program (Programa de Planeación Ambiental y Conservación), Northwest Biological Research Center (Centro de Investigaciones Biológicas del Noroeste), La Paz, Baja California Sur, México.
PLoS One. 2019 Nov 21;14(11):e0225266. doi: 10.1371/journal.pone.0225266. eCollection 2019.
Species within the same trophic level show different strategies to avoid competition. Among these mechanisms, differences in body size, spatio-temporal segregation, and diet preference often leads to a niche partitioning. Nonetheless, little attention on coexisting predatory insects and their network interactions has been paid. In this study, we analyzed the strategies to avoid competition among three sympatric mud-daubing wasps of the genus Trypoxylon (Hymenoptera: Crabronidae) in oases and their surrounding xeric area from the Baja California peninsula, Mexico. We compared the prey richness, composition and proportion of spider guilds that were captured by the wasps. We tested whether the differences in wasp body size explained the niche breadth, niche overlap and the size of spider prey. We assessed the spider-wasp interactions through a network analysis. With the use of trap-nests, we collected 52 spider species captured by the wasps. Both the guild and species composition of preyed spiders was different between the three wasp species. Differential proportions in the capture of spider guilds and a little diet overlap were found among the wasp species. We found that the wasp body size was positively correlated with prey size, but it was not a proxy of niche breadth. Moreover, the largest wasp species was able to nest in both mesic and xeric habitats, while the two smaller species were restricted to the oases. This study reveals that the diversity of spiders in oases of Baja California peninsula is crucial to maintain highly specialized oasis-dependent wasp species. The niche partitioning between mud-daubing wasps can be shaped by their inherent body size limitations and hunting strategies through foraging specialization for specific spider guilds. Food selection and slight differences in body size reduce competition and allow the coexistence of sympatric wasps. Our study is the first approach exploring the interaction networks between mud-daubing wasps and their spider preys, highlighting new insights into the morphological and ecological factors that shape antagonistic interactions, and allow the coexistence of predators in deserts.
同一营养级内的物种表现出不同的策略来避免竞争。在这些机制中，体型差异、时空隔离和饮食偏好等差异往往导致生态位分化。然而，对于共存的捕食性昆虫及其网络相互作用，人们关注甚少。在这项研究中，我们分析了三种共生的泥蜂（Trypoxylon 属，膜翅目：泥蜂科）在墨西哥下加利福尼亚半岛绿洲及其周围干旱地区避免竞争的策略。我们比较了泥蜂捕获的猎物丰富度、组成和蜘蛛类群的比例。我们测试了体型差异是否解释了生态位宽度、生态位重叠和蜘蛛猎物的大小。我们通过网络分析评估了蜘蛛-泥蜂的相互作用。使用陷阱巢，我们收集了 52 种被泥蜂捕获的蜘蛛。被三种泥蜂捕食的蜘蛛类群和物种组成均存在差异。在捕食蜘蛛类群方面存在差异比例，而且种间存在一定程度的饮食重叠。我们发现，泥蜂的体型与猎物的大小呈正相关，但体型并不是生态位宽度的代理。此外，最大的泥蜂物种能够在湿润和干旱生境中筑巢，而两种较小的物种则局限于绿洲。本研究表明，下加利福尼亚半岛绿洲的蜘蛛多样性对于维持高度专业化的依赖绿洲的泥蜂物种至关重要。泥蜂之间的生态位分化可以通过其固有的体型限制和觅食策略来塑造，这些策略包括针对特定蜘蛛类群的觅食专业化。食物选择和体型的细微差异减少了竞争，允许共生的泥蜂共存。我们的研究首次探索了泥蜂和它们的蜘蛛猎物之间的相互作用网络，强调了形态和生态因素在塑造对抗性相互作用以及允许捕食者在沙漠中共存方面的新见解。
