Invasion success of a widespread invasive predator may be explained by a high predatory efficacy but may be influenced by pathogen infection

Abstract

Invasive alien species (IAS) can drive community change through ecological interactions. Parasites and pathogens can play an important role in community function including mitigating or enhancing IAS impacts. Despite this, the degree to which pathogen pressure influences IAS impacts remains poorly understood. We quantified the predatory behaviour of the highly invasive alien harlequin ladybird (Harmonia axyridis) and two UK native species, the 7-spot (Coccinella septempunctata) and 2-spot (Adalia bipunctata) ladybirds, using comparative functional response experiments. We investigated the impacts of pathogen infection on the predatory ability of the ladybirds by exposing individuals to Beauveria bassiana, a widespread entomopathogen. Invasive H. axyridis was a more efficient predator than both the native A. bipunctata and C. septempunctata, often having higher attack and/or lower prey handling time coefficients, whereas native A. bipunctata were the least efficient predators. These differences were found in both adult and larval life-stages. Beauveria bassiana infection significantly altered the predatory efficiency of adult and larval ladybird predators. The effects of pathogenic infection differed between species and life-stage but in many cases infection resulted in a reduced predatory ability. We suggest that the interactions between IAS and pathogens are integral to determining invasion success and impact.

Disturbance in invasion? Idiopathic necrotizing hepatopancreatitis in the signal crayfish Pacifastacus leniusculus (Dana, 1852) in Croatia

“…Emerging wildlife diseases usually occur due to movement of pathogens or ecosystem alterations of either anthropogenic or natural origin, and may threaten local biodiversity (Cunningham et al, 2012;Daszak et al, 2000;Schmeller et al, 2020). In the case of successful invaders like the signal crayfish, such diseases may also affect invasion success and even alleviate its negative effects on the ecosystem (Fincham et al, 2019;Thomas et al, 2020). In this study, we recorded the extensive manifestation of histopathological lesions in hepatopancreas of the majority of examined signal crayfish individuals along its entire invasion range in the Korana River.…”

“…These events may lead to population crashes of established populations of the invader, which has been recorded throughout Europe in the case of the signal crayfish (Aydin et al, 2014;Edsman et al, 2015). Thus, emerging diseases, which occur either due to movement of species and their pathogens or due to ecosystem alterations of either anthropogenic or natural origin, may modify the invasion success of the invader and mitigate its negative effects in the ecosystem (Chinchio et al, 2020;Fincham et al, 2019).…”

Revealing Fungal Communities in Alpine Wetlands through Species Diversity, Functional Diversity and Ecological Network Diversity

“…It is estimated that 92% of the plants on the earth can form a symbiotic relationship with mycorrhizal fungi, the symbiotic cooperation between mycorrhizal fungi and plants promotes the growth of plants and enhances plant resistance [20][21][22]; and at the same time, fixes the nutrient source obtained from plants to the soil, which improves soil nutritional conditions [23]. Pathogenic fungi assist in the decomposition of animals, plants and microorganisms and can even cause death [24][25][26][27][28]. The combination of these different trophic types of fungi will form a functional diversification of fungal communities in soil, which will affect the soil ecosystem process and is important for maintaining the health of the ecosystem [20].…”

Double Infections of the Invasive Ladybird Harmonia axyridis

“…Most of these natural enemies are generalists for coccinellid species or other insects. Part of H. axyridis' competitive success may be explained by its high resistance to such generalist enemies; H. axyridis has a relatively greater efficiency of its immune system, giving it robust and flexible defenses that surpass other competing ladybirds in the same region (Roy et al, , 2011bVilcinskas et al, 2013;Gegner et al, 2018;Fincham et al, 2019). The immune system of H. axyridis is two-layered-it combines constitutive chemical defenses effective against a variety of bacteria as well as a wide range of antimicrobial peptides that are a result of multiple gene duplication events after speciation (Vilcinskas et al, 2013).…”