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Invasion of the coccinellid community associated with a tropical annual agroecosystem

Citation

Andow, David et al. (2022), Invasion of the coccinellid community associated with a tropical annual agroecosystem, Dryad, Dataset, https://doi.org/10.5061/dryad.1zcrjdfwb

Abstract

To examine the potential effect of an invasive coccinellid (Harmonia axyridis) on the resident community of coccinellids, we sampled predators and prey associated with organic Brassica oleracea production on 6 farms during 2 years in the Distrito Federal, Brasil and conducted a food acceptability trial to estimate niche breadth and overlap among the coccinellids. The data are in two files. The first is a community sample data set, with columns describing the sample characteristics (year, farm, sample period) and the summed counts of all macroinvertebrates found on 30 plants at each sample period, farm and year. There are 120 samples and 36 populations of macroinvertebrates in the data set. The second data set is the acceptability of 4 aphid prey species to 3 stages of 4 species of coccinellids. There are 15 replicates of the 48 treatments. The data also include the biomass of the predators at the end of the experiment. Farms have been de-identified, and the data can be used by anyone without any legal or ethical considerations. The authors request that anyone who reuses the data provide and acknowledgement of this in any publication as well as a citation to the originating study.

Methods

Brassica oleracea production fields at six organic vegetable farms in the Distrito Federal, Brazil were examined during 2017 and 2018: 15°39'06"S 48°06'33"W; 15°39'00"S 48°12'01"W; 15°36'43"S 48°04'43"W; 15°33'54"S 48°01'48"W; 15°44'18"S 47°39'13"W; and 15°45'44"S 47°38'29"W. Crops were grown according to recommendations for organic production. Within each field, an area of about 200 m2 was designated as the sample area. Invertebrates were sampled at each farm every two weeks during the dry season (May to September, 10 sample dates total per year), because aphid populations, which are important pests of brassicas, are higher during the dry season. Each sample comprised a count of all invertebrates on 30 plants by visual inspection. All invertebrates were identified in the field to the lowest feasible taxonomic level based on pictorial keys and experts in the field. When aphids were sparse, we counted all aphids, but when they reached very high numbers we estimated the total population by subsampling the plant. We sampled 30 plants/sample time x 10 sample times/farm x 6 farms/year x 2 years = 3600 plants. For each sample date for each farm in each year, the per plant mean of each taxon was calculated.

We determined the consumption of four species of aphids, Brevicoryne brassicae (L.), Lipaphis pseudobrassicae Davis, Myzus persicae (Sulzer) and Uroleucon ambrosiae (Thomas), by last instar larvae and adult males and females of four species of coccinellids, Hippodamia convergens (Guerin-Meneville), Eriopis connexa (Germar), Cycloneda sanguinea (L.), and the invasive Harmonia axyridis (Pallas). Previous research indicated that these aphids were consumed by all four coccinellids in agricultural habitats, including B. oleracea. Larvae were recently molted last instars, and adults were 5-10 days old. All coccinellids were reared on field-collected aphids. Based on preliminary experiments, we placed 20 apterous aphids of one aphid species in a 15 cm petri dish with a moistened filter paper and one individual that had been starved for 16-18 h of either a larva, adult male or adult female of one of the coccinellid species starting between 9 and 10 am. After 4 h, we counted the number of remaining aphids. This design ensured that some but not all aphids were consumed by the coccinellids in the allotted time. All experiments were conducted at 25oC and the weight of the coccinellid was measured immediately after the experiment was completed. There were 4 aphids x 4 coccinellids x 3 coccinellid stages = 48 treatments and 15 replicates of each treatment.

Usage Notes

All data files are csv files and the contents of each are described in the README.txt file.

Funding

Embrapa Recursos Genéticos e Biotecnologia, Award: SEG 12.13.12.005.00.00