Tropical forests, including the biodiverse Brazilian Atlantic Forest, are crucial for global climate regulation and biodiversity conservation. Conservation efforts seek to regenerate these forests, although herbivory can pose a threat to these secondary succession forests. Previous work suggests that plant diversity can influence herbivore communities, which can influence plant condition and performance. This paper explores the impact of plant neighborhood diversity on herbivory rates and arthropod communities in experimental early-successional tropical forests in Sao Paulo, Brazil. Pioneer plant community assembly experiments conducted in deforested areas adjacent to fragments of Brazilian Atlantic Forests reveal that higher plant neighborhood diversity correlates with lower herbivory rates and greater arthropod species richness, although plant diversity had no impact on arthropod abundance. This research contributes to a deeper understanding of how biotic interactions between plants, herbivores, and arthropod assemblages are shaped by plant neighborhood diversity, and therefore of community assembly processes.