The feeding and foraging behaviour of three ladybird beetles on Phenacoccus solenopsis (Hem.: Pseudococcidae) at different temperatures

Ladybird beetles Scymnus nubilus Mulsant, Scymnus interruptus (Goeze), and Hippodamia convergens Guérin-Méneville are key contributors to biological control of some pests including Phenacoccus solenopsis Tinsley. This study explores their feeding preferences, functional response, and interference in controlled laboratory conditions. Feeding experiments, including both no-choice and free-choice tests, were conducted at temperatures ranging from 15 to 35°C fed on different developmental stages of P. solenopsis. The study analyzed the functional response with Holling's disc equation and assessed mutual interference among predators using the Hassell and Varley model. In the no-choice feeding tests, H. convergens adults exhibited the highest consumption at 26°C, with values of 46.0 1st instar nymphs, 40.9 2nd instar nymphs, and 34.9 adult females of P. solenopsis, followed by S. interruptus. Free-choice feeding tests also showed a preference for 26°C, with H. convergens consistently consuming the most prey at all stages, followed by S. interruptus. Functional response analysis revealed a type II functional response for three predators. Hippodamia convergens exhibited a significantly higher attack rate (1.0250 h−1) and a shorter handling time (0.0449 h) compared to the other species. Interference among predators was observed, with a progressive decline in prey consumption as predator density increased. Mutual interference constants (m) were calculated as 1.70, 1.74, and 1.77 for S. nubilus, S. interruptus, and H. convergens, respectively. As predator densities increased, searching efficiency declined. This suggest that H. convergens and S. interruptus adults at 26°C with a prey density of 40 can effectively contribute to sustainable P. solenopsis management.