Biology and predation capacity of Parasitus bituberosus (Acari: Mesostigmata: Parasitidae) on Frankliniella occidentalis (Thysanoptera: Thripidae), and free-living nematodes as its complementary prey

BACKGROUND: Parasitus bituberosus is common in rose fields and nearby vegetation around Bogotá. In rearing units, it is often aggregated, feeding on Frankliniella occidentalis edaphic phases. Preliminary observations suggested predator immatures can not reach adulthood if isolated. The objectives were to evaluate the suitability of F. occidentalis as prey for P. bituberosus, to evaluate free-living nematodes as complementary food, and to confirm the aggregation effect on predator biology. Aggregation types: (1) isolated mites, (2) mites paired only as deutonymphs and early adulthood, and (3) mites always paired. Diets: thrips (T), nematodes (N) and thrips + nematodes (NT). RESULTS: Parasitus bituberosus juveniles did not feed on live F. occidentalis, but developed and oviposited on nematodes. Approximately 77% of the isolated mites died as immatures. Mortality was low (21–23%) when predators were paired at least in the deutonymph and the early adult phase. Female daily predation rates were comparable to other predators on F. occidentalis (≥2.5). Continuously paired mites had high biotic potential, especially when the diet included nematodes (r_m ≥ 0.33; R_o ≥ 33.90; daily oviposition rate ≥ 10.9). CONCLUSION: The results of this study warrant further investigation of this predator, to evaluate methods for its mass production, inclusion in conservation biocontrol programs and performance against the pest at a larger scale.