By Daniel Webster (dWeb.News Publisher) With the UK’s native ladybirds declining, many have blamed the harlequin. However, a new study from the Game & Wildlife Conservation Trust, (GWCT), suggests that the situation may not be as straightforward as people think.
Scientists discovered that aggressive interactions between ladybirds from the same species were more common than between them when they were compared to conflict between them. These instances were more likely to occur when there were more aphids. The GWCT research also revealed a marked difference in their foraging behavior. Two-spot ladybirds found their aphid prey in a narrow area, while harlequins searched a larger area and consumed 3-4 times as many aphids as their native counterparts.
The study published in Bulletin of Entomological Research indicates that harlequins may be an indirect competitor to two-spots and not an aggressive predator. This is similar to Japan’s experience with two-spots. They were introduced in Japan as a pest control measure for 1993. Low levels of aggressive interaction have been observed.
Harlequins were introduced to Europe from Asia in order to control aphid populations. They have been called ‘the UK’s fastest-invading species’, and are responsible for native declines. Research has shown that two-spot ladybirds have been declining for nearly 40years. This suggests that the harlequin ladybirds’ continued presence could actually be contributing to the problems faced by two-spot ladybirds.
In the natural environment, many factors like habitat and climate change can lead to the decline or increase in species. This study does not indicate that harlequin ladies pose a threat to two-spot ladybirds. However, further research is required in other contexts to better understand their relationship.
The full paper is available at https://www.cambridge.org/core/journals/bulletin-of-entomological-research/article/abs/does-the-nonnative-harlequin-ladybird-disrupt-the-feeding-behaviour-of-the-native-twospot-ladybird/BE59847225D56E672480A1886679D194.
Press release distributed by Pressat for Game & Wildlife Conservation Trust on Wednesday 15 Sept, 2021.. For more information subscribe and follow https://pressat.co.uk/
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