Geographic variation in the habitat preference of a scarce predatory insect: evolutionary and conservation perspectives

Abstract

1. While there has been considerable focus on prey occurrence as a factor determining the habitat preference of predators, the roles of other factors related to the habitat are less well characterised.2. In aphidophagous ladybird beetles (Coleoptera: Coccinellidae), a number of species are more restricted in the habitats in which they live than are their prey. A number of such ladybirds appear to show geographic variation in habitat preference.3. To better understand these phenomena, this study considered geographic variation in habitat preference in one such species, the 5-spot ladybird Coccinella quinquepunctata. Because of this ladybird's scarcity, a combination of over 20 years' observations, habitat surveys and online data was used to reach the study's conclusions.4. The data collected indicate that the ladybird is specialised in pioneer habitats close to water, but broadens its range to non-riverine pioneer habitats in north-west continental Europe, where it is likely that a damper (micro)climate allows it to do so. Thus, microclimatic factors appear to be important in determining the habitat of this and probably other predators that are not constrained by prey occurrence. 5. Although threatened by river management elsewhere, in north-western Europe, this species clearly benefits from human activity, which creates many of the disturbed habitats it colonises there. This finding provides further support for the contention that many ladybirds are net beneficiaries of human influence, although they are often characterised as threatened.

A roadmap for ladybird conservation and recovery

“…Also needed is improved understanding of the impacts of temperature fluctuations and extremes on ladybird survival and trophic ecology to assess the consequences of biological control in a warmer and more thermally unpredictable world (Bruno & Cardinale, 2008). Moisture and humidity regimes may also influence ladybird distribution and abundance (Sloggett & Zeilstra, 2020) and will be labile to climate change.…”

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

“…These behaviours apparently maintain the ladybird's association with humid habitats in a hotter, drier climate. They most likely arise due to plasticity, rather than local adaptation (Sloggett & Zeilstra, 2020). Certain aphidophagous species of ladybird do change their habitat preferences geographically (e.g., Sloggett & Majerus, 2000), although it remains to be seen how much of this variation is driven by climate and how effective habitat or microhabitat plasticity is as a buffer against climate change.…”

“…Certain aphidophagous species of ladybird do change their habitat preferences geographically (e.g., Sloggett & Majerus, 2000), although it remains to be seen how much of this variation is driven by climate and how effective habitat or microhabitat plasticity is as a buffer against climate change. In the case of C. quinquepunctata , suitable river habitats are generally scarce and a change to exclusively river habitats in north‐west Europe would still entail massive population losses (Sloggett & Zeilstra, 2020).…”

“…In China, at the hottest time of day, ladybirds moved into maize whorls in which the temperature was lower and the humidity higher (Pan et al ., 2020). In Western Europe, Coccinella quinquepunctata L., which is limited to humid sparsely vegetated pioneer habitats, is spread across a wider diversity of habitats in the north compared to the drier south, where it appears to be mainly limited to the vicinity of rivers (Sloggett & Zeilstra, 2020). The ladybird also pupates more frequently under stones in the south.…”