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Riparian forest fragments in rice fields under different management: differences on hymenopteran parasitoids
G S Silva1,2, S M Jahnke2, N F Johnson3
1Departamento de Fitosanidade, Faculdade de Agronomia, Universidade Federal do Rio Grande do Sul - UFRGS, Av. Bento Gonçalves, 7712, CEP 91540-000, Porto Alegre, RS, Brasil.
Summary
Habitat heterogeneity, including proximity to natural areas and organic farming, supports beneficial insect diversity in rice fields. Organic management and closer distances to natural vegetation increased parasitoid abundance, crucial for biological control.
Area of Science:
- Agroecology
- Biological Control
- Entomology
Background:
- Hymenopteran parasitoids are vital for biological control in agricultural systems.
- Habitat heterogeneity is known to enhance insect diversity.
- Understanding factors influencing parasitoid diversity is key for sustainable agriculture.
Purpose of the Study:
- To assess how distance from natural habitats, crop management type (organic vs. conventional), and crop stage affect parasitoid diversity in rice agroecosystems.
- To identify key drivers of parasitoid abundance and composition in irrigated rice fields.
Main Methods:
- Field study conducted in organic and conventional irrigated rice crops over two seasons.
- Parasitoids collected using Malaise traps at varying distances from native vegetation.
- Abundance and diversity compared across management types, distances, and rice phenological stages.
Main Results:
- Platygastridae, Mymaridae, Encyrtidae, Eulophidae, and Trichogrammatidae were the most abundant parasitoid families.
- Parasitoid abundance was significantly higher in organic management during the second season.
- A negative correlation between distance from native vegetation and parasitoid abundance was observed in conventional fields.
- Parasitoid community composition varied between the vegetative and reproductive stages of rice.
Conclusions:
- Organic management and proximity to native vegetation can enhance parasitoid abundance in rice agroecosystems.
- Crop phenology influences the composition of parasitoid communities.
- Habitat management strategies are crucial for maximizing biological control services in agriculture.
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