Aphidophagous ladybirds (Coleoptera: Coccinellidae) and climate change: a review

Abstract

1. I here review the potential effects of climate change on aphidophagous ladybirds and their future diversity. Aphidophagous ladybirds face challenges arising directly from climatic change and indirect challenges due to the effect of climate on their aphid prey and other organisms with which they interact.2. Ladybirds show at least some potential to respond to changes of climate through genetic change or phenotypic plasticity, notably through changes in colour pattern, dormancy and voltinism but also through thermal physiology and microhabitat or habitat plasticity.3. Phenological changes will likely occur in many aphidophagous species arising from relations with their prey. Changes in aphid abundance may lead to changes in ladybird prey associations over the season. The tendency to prey on multiple aphid species will insulate many ladybird predators from decline resulting from changes in the abundance of particular aphids.4. Like other insects, the geographic ranges of aphidophagous ladybird species will change as they track the climate. This is evidenced by the fossil record of ladybirds and by recent changes in ladybird biogeography. Such changes may be accompanied by a degree of thermal or phenological adaptation.5. It is likely that cold-adapted ladybirds and some island species will go extinct. Specialised species may also be threatened. A problem in assessing the threat to the latter is the minimal amount of research carried out on specialised species.6. In summary, aphidophagous ladybirds exhibit some potential resilience against climate change, but future climatic effects on their overall biodiversity are not fully clear.

Urbanization Negatively Affects the Species Composition of Native Ladybirds in Central Europe

“…The abundance of native coccinellids can be also negatively affected by the invasive Harmonia axyridis (Roy et al, 2012;Brown et al, 2015;Kenis et al, 2017;Masetti et al, 2018;Zaviezo et al, 2019). The extent of this negative effect depends on the species of native coccinellid (Honek et al, 2019a;Sloggett, 2021) and on the abundance of H. axyridis (Honek et al, 2018a(Honek et al, , 2019b. If the occurrence of H. axyridis and its effects on native species differ, this invasive species could significantly affect differences in the presence and abundance of native coccinellids.…”

“…An important factor threatening insects is urbanization (McGlynn et al, 2019), which increases the area of urban settlements at the expense of agricultural land, forest, and other land uses (Goddard et al, 2010;Jones and Leather, 2012;Rocha et al, 2018;Milanovic et al, 2021). The effect of urbanization has been well-studied on ladybirds (Coleoptera, Coccinellidae) (Honek et al, 2021;Sloggett, 2021). This family includes a number of predatory species feeding mainly on aphids (Hodek et al, 2012).…”

“…The aphidophagous species of coccinellids are easily identifiable (Jouveau et al, 2018), they can be picked up by sampling methods, which allows their research in the urban environment where they are assembled mainly on trees infested with aphid populations (Honek et al, 2017;Rocha et al, 2018). In addition to the availability of prey, coccinellids species are also affected by the microclimate, the possibility of immigration from source populations living in the city surroundings, and interactions with other species of the guild of aphid predators (Korányi et al, 2021;Sloggett, 2021). Therefore, coccinellids are a suitable subject for study into the effect of urbanization on insects.…”

“…Covering urban areas with impervious surfaces, such as buildings and paved or tarmac roads, has a negative effect on the quality of habitats: urban green spaces (where coccinellid prey and its host plants can persist) is fragmented into small discontinuous islands (Rocha et al, 2018;Sloggett, 2021). Urbanization of large areas can thus negatively affect the presence and abundance of coccinellids in the area by reducing the availability of breeding sites and increasing the need for migration abilities of coccinellids to enable displacement from undisturbed habitats of the city surroundings to the center or between green islands in urban areas (Sloggett, 2021). Fragmentation of green spaces may cause a shortage of food and extinction or emigration of the local population of coccinellids.…”

Warm Mesoclimate Advances the Seasonal Dynamics of Harmonia axyridis in Urban Habitats

“…An increase in body temperature above ambient temperature is realized by basking in the sunshine (Sloggett and Honek, 2012;Sloggett, 2021). The capacity to increase body temperature also exists in H. axyridis (Michie et al, 2010), but evidence of thermoregulation under natural conditions is indirect.…”