DIFFERENTIAL VARIATION IN THE MEAN ISOTOPIC SIGNATURES OF SPIDER HUNTING STRATEGIES INFLUENCED BY LANDSCAPE FEATURES

Resumen

Spiders may play a crucial role as versatile predators within agroecosystems. Their diverse behavioral patterns, organized into different guilds, can significantly impact multitrophic interactions. Natural vegetation cover surrounding orchards can influence this predatory behavior, which in turn can impact the feeding patterns of different spider predatory guilds. This study aims to examine the differences among spider guilds actively foraging on apple orchards with different levels of surrounding natural vegetation density (SNVD). To achieve this, natural carbon and nitrogen isotope enrichment was used to assess the variations in isotopic signatures among spider guilds across a gradient of surrounding natural vegetation cover, categorized into three levels (low, medium, and high density), as an indicator of landscape complexity. The mean carbon and nitrogen isotopic signatures exhibited greater variability in diurnal aerial ambushers and orb-weaving spiders, particularly in landscapes with high complexity. Interestingly, similar variability was observed in samples from orchards surrounded primarily by agricultural land (with low SNVD). No significant differences in spider abundance were found across guilds or SNVD categories in apple orchards, suggesting that the spiders guilds identified in these orchards are not influenced by landscape categories. We further describe the guilds identified, which could potentially contribute to the biological control of pests in apple orchards.