Harmonia axyridis invasions: Deducing evolutionary causes and consequences

Abstract

I consider evolutionary approaches to deducing factors that have made the ladybird beetle Harmonia axyridis such a successful invader, and the contribution that studies of this species in its native range can make. Work aiming to demonstrate which (pre)adaptations have made the species so successful often fails to compare these putative characters with those of other ladybirds. This has led to a tendency for "argument by design"-type claims on characters widely shared by non-invasive coccinellids. There is good evidence from genetic studies that evolutionary change occurred in invasive populations, contributing to their success. There is some evidence for subsequent evolutionary change after the establishment of invasive H. axyridis, primarily in the native organisms with which the ladybird interacts. I show here that there appears to have been little adaptation in H. axyridis, over about 20 generations, to the alkaloids of one North American native intraguild prey, the ladybird Coleomegilla maculata. Studies of H. axyridis in its native range are important, as they provide a snapshot of the ancestral ladybird, unobscured by subsequent evolutionary change related to its invasiveness. They provide baseline data about phenomena such as interactions with natural enemies and intraguild predation, and they also can provide pointers as to how H. axyridis might further adapt in the regions it has colonized. Harmonia axyridis represents an ideal opportunity for greater international co-operation between scientists studying this species in its native range in Asia and scientists studying it in Europe, America and Africa, where it is an invasive exotic.

Harmonia axyridis (Coleoptera: Coccinellidae) as a host of the parasitic fungus Hesperomyces virescens (Ascomycota: Laboulbeniales, Laboulbeniaceae): A case report and short review

“…In addition, according to the so called evolution of increased competitive ability hypothesis, invaders can respond to a lack of natural enemies by reallocating resources from defense to growth and/or reproduction (Blossey & Nötzold, 1995). It is supposed that both these mechanisms may contribute to H. axyridis invasiveness (Roy et al, 2011a, b;Sloggett, 2012). However, as pointed out by Sloggett (2012), the initial benefit for the invader from the evolution of increased competitive ability may in a later phase of the invasion change into a disadvantage when the invader becomes more susceptible to native enemies.…”

“…It is supposed that both these mechanisms may contribute to H. axyridis invasiveness (Roy et al, 2011a, b;Sloggett, 2012). However, as pointed out by Sloggett (2012), the initial benefit for the invader from the evolution of increased competitive ability may in a later phase of the invasion change into a disadvantage when the invader becomes more susceptible to native enemies. This may partly explain the recent success of H. virescens in utilizing H. axyridis as a host.…”

Trophic induction of diapause in native and invasive populations of Harmonia axyridis (Coleoptera: Coccinellidae)

“…The fi rst aim was to compare the patterns in relatively independent trophic responses: the decrease in fecundity of ovipositing females, the termination of oogenesis, and the induction of reproductive diapause. However, H. axyridis is not only a convenient model insect it is also a biocontrol agent and a noxious invasive species (Koch & Galvan, 2008;Roy & Wajnberg, 2008;Lombaert et al, 2010;Brown et al, 2011;Sloggett, 2012;Roy et al, 2016). Recently, we demonstrated that photoperiod affects reproductive maturation of newly emerged females from native populations of H. axyridis much more strongly than those from invasive populations and suggested that the weak photoperiodic response could be compensated by a strong trophic response (Reznik et al, 2015).…”

“…Such a response, as well as oosorption during starvation and immediate start of ovarian development under favourable feeding conditions (Osawa, 2005) is probably an adaptation to fl uctuating prey abundance. In addition, this phenomenon, as well as a weak photoperiodic response (Reznik et al, 2015) and other manifestations of high individual variability (Sloggett, 2012;Roy et al, 2016) can be interpreted as a risk-spreading strategy (Hopper, 1999) that ensures the survival of at least some individuals of the invasive population under novel and unpredictable environmental conditions.…”

On the photoperiodic induction of diapause in first generation hybrids of Harmonia Axyridis (PALL.) (Coleoptera, Coccinellidae)

“…К настоящему времени инвазионные популяции H. axyridis найдены более чем в 40 странах Европы, Америки и Африки [12], в том числе и на тер-ритории России [18]. В качестве предпосылок этой инвазии рассматривали самые разные особенности биологии H. axyridis [12,14]. В частности, выя-снилось, что у представителей инвазионных популяций по сравнению с автох-тонными ослаблена фотопериодическая реакция, способствующая индукции зимней репродуктивной диапаузы при осеннем сокращении длины дня [11].…”