Variable colour patterns indicate multidimensional, intraspecific trait variation and ecological generalization in moths

Abstract

Animal colour patterns long have provided information about key processes that drive the ecological and evolutionary dynamics of biological diversity. Theory and empirical evidence indicate that variation in colour patterns and other traits among individuals generally improves the performance of populations and species, for example by reducing predation risk, increasing establishment success, improving resilience to environmental change, and decreasing risk of extinction. However, little is known about whether and how variation in colour pattern among species is associated with variation in other phenotypic dimensions. To address this issue, we analysed associations of colour pattern with morphological, behavioural and life‐history traits on the basis of data for nearly 400 species of noctuid moths. We found that moths with more variable colour patterns had longer flight activity periods, more diverse habitats and a greater number of host plant species than species with less variable colour patterns. Variable coloration in adult noctuid moths therefore can be considered as indicative of broader niches and generalist diets. Colour pattern variability was not significantly associated with overwintering stage or body size (wing span), and it was independent of whether the colour pattern of the larvae was non‐variable, variable or highly variable. Colour pattern variation during the larval stage tended to increase as the duration of the flight activity period increased, but was independent of the length of the larval period, diet breadth and habitat use. The realization that information on colour pattern variation in adult moths, and possibly other organisms, offers a proxy for niche breadth and dietary generalization can inform management and conservation biology.

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

“…That species with large geographical range distributions were overrepresented in the cities was expected, as they occur across larger regions, including urban areas and cities, compared to species with restricted ranges [17,61]. That species with a high colour pattern variation were overrepresented in cities is consistent with previous evidence that more variable colour patterns in moths is associated with larger intraspecific trait variation also in other (morphological, behavioural, and life history) phenotypic dimensions [62], and with increased colonization success, more stable population dynamics, and decreased extinction risk [42,43,45]. Moreover, light pollution [63] and non-native plant species [5] might create more heterogeneous and novel visual backgrounds in cities that are more suitable for species with variable colour patterns [64].…”

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

“…Other traits shared by declining moths include univoltinism, short flight seasons, low dispersal ability, and overwintering in the egg stage (21,67,68,70,71,74). Moths with canalized phenotypes are declining faster than those that are polytypic (69,75).…”

Positive shifts in species richness and abundance of moths over five decades coincide with community-wide phenotypic trait homogenisation

“…Long-term persistence and successful establishments in new areas require suitable environmental conditions (Parmesan and Yohe 2003;Pöyry et al 2016). Previous studies of moths suggest that, in general, species that occupy large geographic ranges and are characterised by a generalist lifestyle, high mobility, and highly variable colour patterns are better able to cope with changing environments, colonise new habitats, and avoid local extinction (Forsman et al 2020;Franzen and Johannesson 2007;Nilsson et al 2008). Conversely, specialised species are generally believed to suffer most from environmental change.…”