When the adaptive value of intraguild predation between an indigenous and an invasive ladybeetle is altered by an insecticide

Autor: Paula Cabrera, Éric Lucas, Vanessa Cruz, Marianne Bessette, Daniel Cormier
Rok vydání: 2021
Předmět:
Zdroj: Journal of Pest Science. 95:797-810
ISSN: 1612-4766
1612-4758
DOI: 10.1007/s10340-021-01404-0
Popis: The multicolored Asian ladybeetle, Harmonia axyridis Pallas (Col, Coccinellidae), is recognized as one of the most invasive insects in the world. It has reduced the native coccinellids populations in several areas, and it is considered a threat for biodiversity at large. A significant trait, favoring its invasiveness and its dominance over indigenous ladybeetles, is intraguild predation (IGP). IGP has advantageous adaptive value for individuals: removing competitors and potential predators, and providing an alternative nutritive resource when main resources are scarce. IGP can be affected by several factors, but little is known about the effect of pesticides on this behavior. Previous research demonstrated that the invasive Asian ladybeetle is highly susceptible to the reduced-risk insecticide novaluron, a chitin synthesis inhibitor, whereas the North American indigenous competitor, Coleomegilla maculata DeGeer (Col, Coccinellidae), is not. Our study explores the adaptive value of IGP for each of the two coccinellids after preying on each other’s larvae, which were previously treated with insecticide. Our first hypothesis is that the invasive ladybeetle, susceptible to the insecticide, should lose the adaptive value of IGP. Our second hypothesis is that the adaptive value of IGP for the invasive predator will recover over time, because of neutralization of the insecticide by the intraguild prey. The results confirm both hypotheses and show that an insecticide can completely remove the adaptive value of IGP for the invader, while the adaptive value of IGP does not change for the indigenous ladybeetle. Moreover, the study demonstrates that if the intraguild prey (non-susceptible to the insecticide) undergoes molt after being exposed to the insecticide, the adaptive value for the intraguild predator is restored.
Databáze: OpenAIRE
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