Spatiotemporal dynamics of active flying Diptera predators among different farmland habitats

Abstract

1 Farmland habitats comprise an arrangement of cropped, uncropped and natural vegetation among the farms. Despite the differences in these habitats' features, generalist highly mobile predators are more likely to explore them in time and space. 2 We investigated the spatiotemporal dynamics of the species of Dolichopodidae (Diptera) in organic vegetable farms because they are one of the most abundant generalist highly mobile predators in Brazilian agroecosystems. 3 We simultaneously sampled the abundance of Condylostylus Bigot and Chrysotus Loew adults (both Dolichopodidae) in the crop, fallow areas, agroforests and forest fragments within five organic farms for 2 years. 4 Predators preferred open-field habitats to agroforests and forest fragments. Probably, open-field habitats present more opportunities to prey foraging, resulting in higher population densities. 5 To the extent that abiotic conditions become more restrictive during the dry season, agroforests and forests act as breeding sites and shelter, thereby maintaining the predators' populations in the overall farmland habitat. 6 Both predatory genera occupy habitats with distinct features across time, forming a dynamic and contiguous population unit within the farm. Therefore, conservation biological control strategies in organic crops should consider the role of agroforests and forest fragments in species conservation beyond the plot level.

Natural habitat connectivity and organic management modulate pest dispersal, gene flow, and natural enemy communities

“…These favorable conditions are further provided by surrounding natural habitat patches, explaining why NE abundance and richness increased with the amount of natural vegetation on smaller scales. The presence of NEs is conditioned to the amount of close and accessible prey in the crop (Harterreiten‐Souza et al, 2021; Nicholls et al, 2001), and NEs will be more abundant and active near habitat interfaces. Furthermore, such habitats can sustain NE populations during disturbances and ensure crop recolonization afterward (Togni, Venzon, Souza, Sousa, et al, 2019).…”

Beyond Carbon: The Contributions of South American Tropical Humid and Subhumid Forests to Ecosystem Services

“…Forest and agroforest areas are important to natural pest enemies when abiotic conditions become more restrictive, such as during the Cerrado's dry season. They act as breeding sites and shelters, thereby maintaining the predator populations in the nearby farmland habitat (Harterreiten‐Souza et al., 2021).…”

Phenology of the black bean aphid, Aphis fabae, on organic crops and effect of parasitoid communities

“…The food web of herbivorous insects and their natural enemies, as well as the structure of these communities, might be affected by agricultural landscape and practices (Andrade et al, 2015; Birkhofer et al, 2011; Dong et al, 2019; Harterreiten‐Souza et al, 2021). Depending on the type of activities in agricultural ecosystems, an increase or decrease in habitats can be occasioned, thus affecting the phenology of herbivorous insects and consequently the abundance of their natural enemies (Kross et al, 2020; Perez‐Alvarez et al, 2021).…”

“…The food web of herbivorous insects and their natural enemies, as well as the structure of these communities, might be affected by agricultural landscape and practices (Andrade et al, 2015;Birkhofer et al, 2011;Dong et al, 2019;Harterreiten-Souza et al, 2021).…”