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3 Brown, P.M.J. & Roy, H.E. (2017) Native ladybird decline caused by the invasive harlequin ladybird Harmonia axyridis: evidence from a long-term field study. Thus, I decline in percentage abundance does not necessarily indicate a negative effect of the invader on the abundance of the native species i , as is often claimed (Alyokhin & Sewell, 2004; Grez I et al i ., 2016; Brown & Roy, 2017, etc.). It is seductive to say that an invader in reducing the abundance of native predators lowers the biocontrol potential of the whole guild (Soares I et al i ., 2008; Brown I et al i ., 2011; Roy I et al i ., 2012). [Extracted from the article]

1. Dynamic models of optimal foraging predict that an animal's decision to accept or reject a patch depends not only on the environment and patch quality, but also on its internal state. Previous experiments have shown that the two-spot ladybird beetle,Adalia bipunctata(L.), is reluctant to lay eggs in a patch of prey contaminated by the oviposition-deterring pheromone produced by conspecific larvae.2. An experiment was conducted to test whether the internal state of anA. bipunctatafemale affects its oviposition response to oviposition-deterring pheromone. Firstly, the oviposition response to oviposition-deterring pheromone of young and old females was compared. Secondly, the oviposition response to oviposition-deterring pheromone of females previously exposed continuously to oviposition-deterring pheromone was compared with that of females of the same age but with no previous experience of oviposition-deterring pheromone.3. Old females and females with previous experience of oviposition-deterring pheromone were less reluctant to lay eggs in the presence of oviposition-deterring pheromone than young and naive females. These results are consistent with the predictions of optimal foraging theory. [ABSTRACT FROM AUTHOR]