Butterfly species respond differently to climate warming in the northern Alps

Local climate change velocities and evolutionary history explain multidirectional range shifts in a North American butterfly assemblage

Species are often expected to shift their distributions either poleward or upslope to evade warming climates and colonise new suitable climatic niches. However, from 18-years of fixed transect monitoring data on 88 species of butterfly in the midwestern United States, we show that butterflies are shifting their centroids in all directions, except towards regions that are warming the fastest (southeast). Butterflies shifted their centroids at a mean rate of 4.87 km year-1. The rate of centroid shift was significantly associated with local climate change velocity (temperature by precipitation interaction), but not with mean climate change velocity throughout the species' ranges. Species tended to shift their centroids at a faster rate towards regions that are warming at slower velocities but increasing in precipitation velocity. Surprisingly, species' thermal niche breadth (range of climates butterflies experience throughout their distribution) and wingspan (often used as metric for dispersal capability) were not correlated with the rate at which species shifted their ranges. We observed high phylogenetic signal in the direction species shifted their centroids. However, we found no phylogenetic signal in the rate species shifted their centroids, suggesting less conserved processes determine the rate of range shift than the direction species shift their ranges. This research shows important signatures of multidirectional range shifts (latitudinal and longitudinal) and uniquely shows that local climate change velocities are more important in driving range shifts than the mean climate change velocity throughout a species' entire range.

Upward and Poleward (but Not Phenological) Shifts in a Forest Tenebrionid Beetle in Response to Global Change in a Mediterranean Area

There is an increasing volume of literature on the impact of climate change on insects. However, there is an urgent need for more empirical research on underrepresented groups in key areas, including species for which the effects of climatic change may seem less evident. The present paper illustrates the results of a study on a common forest tenebrionid beetle, Accanthopus velikensis (Piller and Mitterpacher, 1783), at a regional scale within the Mediterranean basin. Using a large set of records from Latium (central Italy), changes in the median values of elevation, latitude, longitude, and phenology between two periods (1900-1980 vs. 1981-2022) were tested. Records of A. velikensis in the period 1981-2022 showed median values of elevation and latitude higher than those recorded in the first period. Thus, in response to rising temperatures, the species became more frequent at higher elevation and in northern places. By contrast, A. velikensis does not seem to have changed its activity pattern in response to increased temperatures, but this might be an artifact due to the inclusion of likely overwintering individuals. The results obtained for A. velikensis indicate that even thermally euryoecious species can show changes in their elevational and latitudinal distribution, and that poleward shifts can be apparent even within a small latitudinal gradient.

Active around the year: Butterflies and moths adapt their life cycles to a warming world

Living in a warming world requires adaptations to altered annual temperature regimes. In Europe, spring is starting earlier, and the vegetation period is ending later in the year. These climatic changes are leading not only to shifts in distribution ranges of flora and fauna, but also to phenological shifts. Using long-term observation data of butterflies and moths collected during the past decades across northern Austria, we test for phenological shifts over time and changes in the number of generations. On average, Lepidoptera adults emerged earlier in the year and tended to extend their flight periods in autumn. Many species increased the annual number of generations. These changes were more pronounced at lower altitudes than at higher altitudes, leading to an altered phenological zonation. Our findings indicate that climate change does not only affect community composition but also the life history of insects. Increased activity and reproductive periods might alter Lepidoptera-host plant associations and food webs.