Ground beetles in city forests: does urbanization predict a personality trait?

Abstract

BackgroundUrbanization leads to substantial changes in natural habitats with profound effects on wildlife. Understanding behavioural responses to such environmental change is essential for identifying which organisms may adapt, as behaviour is often the first response to altered conditions. Individuals in more urbanized habitats may be expected to be more exploratory and bolder than their conspecifics in less urbanized habitats as they may be better able to cope with novel challenges.MethodsIn a two-year field study we tested ground beetles from differently urbanized forests for their exploratory behaviour (in a novel environment) and their risk-taking (death-feigning). In total, we tested ca. 3,000 individuals of four forest-dwelling ground beetle species from eight within-city forest patches. In the second year, we also transferred ca. 800 tested individuals of two species to the laboratory to test for consistent behavioural differences (i.e. personality differences) under standardised conditions.ResultsIndividuals were generally more exploratory in more urbanized than in less urbanized areas but only in one year of the study. Exploratory behaviour was not predicted by population density but increased with temperature or showed a temperature optimum. Exploration was consistent over time and individuals that were more exploratory also took higher risks.DiscussionWe demonstrated that species which are generally less directly exposed to human activities (e.g., most invertebrates) show behavioural responses to urbanization. Effects of urbanization were year-dependent, suggesting that other environmental conditions interacted with effects of urbanization on beetle behaviour. Furthermore, our results indicate that different personality compositions might cause behavioural differences among populations living in differently urbanized habitats.

Are There Personality Differences between Rural vs. Urban-Living Individuals of a Specialist Ground Beetle, Carabus convexus?

“…The results obtained in the present study, however, are not likely to have been influenced by these characteristics, since all individuals were of the same cohort (overwintered beetles in their first breeding season) and sexes were distinguished. Although a few previous studies on beetles showed no differences in behavior between sexes [47,61,62], ours and other findings [33] on ground beetles, however, reveal the existence of sex-dependent behavioral differences.…”

“…For example, species with wide tolerance limits (habitat generalists [ 31 ]) or with traits that increase tolerance to urbanization-generated conditions [ 32 ] are clearly beneficial. Some behavioral traits, such as high exploration and high risk-taking, can be beneficial to cope with urban environmental conditions and/or for colonizing these habitats [ 11 , 33 ]. The only urban study on behavioral traits of ground beetles [ 33 ], however, raised questions about the consistency of individual behavior.…”

“…Some behavioral traits, such as high exploration and high risk-taking, can be beneficial to cope with urban environmental conditions and/or for colonizing these habitats [ 11 , 33 ]. The only urban study on behavioral traits of ground beetles [ 33 ], however, raised questions about the consistency of individual behavior. Different species and even the same species in different localities could show different responses to urbanization, preventing to draw generalizations for ground beetles.…”

An experimental test of changed personality in butterflies from anthropogenic landscapes

“…Evidence for personality differences among rural and urban populations is accumulating in animals (e.g. Miranda et al 2013;Charmantier et al 2017;Lapiedra et al 2017;Senar et al 2017;Schuett et al 2018;Baxter-Gilbert et al 2019). However, most studies on urban-rural behavioural differences focused on wild individuals.…”

“…Comparatively few studies investigated whether similar shifts also occur in invertebrate taxa (Schuett et al 2018). In this regard, the Speckled wood (Pararge aegeria L.) is an interesting study system for exploring changes in personality traits linked to anthropogenic activities.…”