Urban moth communities suggest that life in the city favours thermophilic multi-dimensional generalists

Abstract

Biodiversity is challenged worldwide by exploitation, global warming, changes in land use and increasing urbanization. It is hypothesized that communities in urban areas should consist primarily of generalist species with broad niches that are able to cope with novel, variable, fragmented, warmer and unpredictable environments shaped by human pressures. We surveyed moth communities in three cities in northern Europe and compared them with neighbouring moth assemblages constituting species pools of potential colonizers. We found that urban moth communities consisted of multi-dimensional generalist species that had larger distribution ranges, more variable colour patterns, longer reproductive seasons, broader diets, were more likely to overwinter as an egg, more thermophilic, and occupied more habitat types compared with moth communities in surrounding areas. When body size was analysed separately, results indicated that city occupancy was associated with larger size, but this effect disappeared when body size was analysed together with the other traits. Our findings indicate that urbanization imposes a spatial filtering process in favour of thermophilic species characterized by high intraspecific diversity and multi-dimensional generalist lifestyles over specialized species with narrow niches.

A window to the world of global insect declines: Moth biodiversity trends are complex and heterogeneous

“…The proportion of moth declines due to other aspects of urbanization is difficult to estimate, but a number of studies have documented that urbanization has large negative effects on moth diversity and abundance (e.g., ref. 63) and favors thermophilic and generalist species (64). Other stressors mentioned here may be intensified in urban areas; thus, species that are already at risk are more likely to decline in urban areas (65).…”

United colours of the city: A review about urbanisation impact on animal colours

“…For example, Franzén et al . (2020) suggested that polymorphic moths may have an advantage in urban environments with visual heterogeneity created by light pollution and non‐native plants (see also Galeotti et al . 2003).…”

“…Studies analysing moths (Franzén et al . 2020) and birds (Leveau 2019) found that polymorphic species were more frequent and dominant, respectively, in urban areas than in non‐urban areas. Both studies were conducted in three cities of northern Europe (Franzén et al .…”

“…Both studies were conducted in three cities of northern Europe (Franzén et al . 2020) and central Argentina (Leveau 2019), but the former analysed species presence/absence data, whereas the latter took into account the relative abundance of species.…”

Airborne environmental DNA metabarcoding for the monitoring of terrestrial insects - a proof of concept

“…We collected aerosol samples at three locations in southern Sweden, two of which in parallel to two insect surveys, a Moth monitoring scheme and a Pollinator survey (called “Moth site” and “Pollinator site” henceforth). The Moth monitoring scheme was part of a systematic monitoring of Swedish moth species that has been ongoing for more than a decade (Franzén et al 2020). The project monitors moths using an automatic light trap (Robinson type) with a 250 W mercury vapour lamp (Leinonen et al 1998).…”