Relationship between spider traits and individual-based trophic networks attributes of Neoscona oaxacensis (Araneidae) webs in Mexican maize crops

Spiders are common generalist predators in agroecosystems, contributing to natural pest control through diverse trophic interactions. However, their trophic role depends on how individual traits influence prey selection and network structure. Using standardised transect walks, direct observation, and prey collection from webs, we investigated individual-based trophic networks of the orb-weaving spider Neoscona oaxacensis (Keyserling, 1864) (Araneae: Araneidae) in maize fields in Mexico, focusing on the influence of body size and web position on trophic structure. Spiders consumed a wide range of prey spanning nine orders and 65 taxa, with Coleoptera and Orthoptera dominating the diet. Notably, N. oaxacensis frequently preyed on Sphenarium purpurascens Charpentier, 1842 (Orthoptera: Pyrgomorphidae), a major maize pest, highlighting its potential agricultural importance. The interaction networks were sparsely connected, highly modular, and lacked nestedness, suggesting heterogeneous prey use among individuals, with groups of spiders focusing on small subsets of prey. Larger spiders had higher betweenness centrality, acting as more central nodes in the metaweb; whereas web height was linked to dietary specialisation, spiders from higher strata preyed upon fewer species, yet these prey were commonly shared across individuals, indicating a generalist feeding pattern. Overall, N. oaxacensis exhibited marked individual trophic heterogeneity, driven by morphological and spatial traits. The combination of low network connectivity, strong modularity, and trait-dependent prey use suggests that individual differentiation probably enhances the stability and functional resilience of trophic networks in agricultural landscapes.

蜘蛛是农业生态系统中常见的广食性捕食者，通过多样的营养级相互作用参与自然害虫防控。然而，其营养级功能取决于个体性状对猎物选择与网络结构的调控作用。本研究采用标准化样带行走、直接观测以及蛛网猎物采集的方法，针对墨西哥玉米田中墨西哥园蛛（*Neoscona oaxacensis* (Keyserling, 1864)，蜘蛛目：园蛛科）构建了基于个体的营养级网络，重点探究体型大小与蛛网位置对营养级结构的影响。

该蜘蛛的捕食猎物涵盖9个目共65个分类单元，其中鞘翅目与直翅目构成了饮食组成的主体。值得注意的是，墨西哥园蛛常捕食主要玉米害虫紫翅锥头蝗（*Sphenarium purpurascens* Charpentier, 1842，直翅目：锥头蝗科），凸显了其潜在的农业生态价值。

其营养相互作用网络连接稀疏、模块化程度高且缺乏嵌套性（nestedness），这表明个体间的猎物利用存在异质性，部分蜘蛛类群仅聚焦于少量特定猎物。体型更大的蜘蛛具有更高的介数中心性（betweenness centrality），在总食物网（metaweb）中处于更核心的节点位置；而蛛网高度与食性特化程度相关：处于更高空间层级的蜘蛛捕食的猎物种类更少，但这些猎物多为个体间共享的类群，表明其整体仍属于广食性取食模式。

总体而言，墨西哥园蛛表现出显著的个体营养级异质性，这种异质性由形态与空间特征共同驱动。低网络连接度、高模块化程度以及依赖性状的猎物利用模式三者结合表明，个体间的功能分化可能提升了农业景观中营养级网络的稳定性与功能恢复力。