In insects, lifetime fecundity, egg size, and female reproductive investment are key life-history traits that – within species – strongly relate to adult body size. How these reproductive traits scale with female body size at interspecific level, and whether they are affected by larval diet type, however, is yet poorly understood. In this study, we investigated these aspects by focussing on European butterflies and Erebidae moths, two speciose and ecologically distinct groups of Lepidoptera. Species were classified, according to their primary larval diet type, as either herb feeders, woody plant/grass feeders, or alternative feeders (i.e., species associated with other diets; only for Erebidae). By accounting for phylogenetic relationships, we found maximum fecundity to scale hyperallometrically with body size, while egg size and female reproductive investment scaled hypoallometrically. These scaling relationships were consistent across both lepidopteran groups and in no case affected by larval diet type. In butterflies, however, fecundity was higher for herb feeders than for woody plant/grass feeders, while the latter were found to lay, on average, larger eggs. Diet type effects on female reproductive investment, by contrast, were only present in Erebidae, where alternative feeders unveiled an overall lower reproductive investment than herb feeders. Our study highlights the profound reproductive advantages for species to become larger (especially regarding fecundity), demonstrates that diet type relates to variation in reproductive traits among species, and asks for further research to unveil the factors driving the inconsistent diet-type effects among lepidopteran clades.

Aim Phylogenetic diversity, structure and endemism of European Sterrhinae were investigated for the first time and interpreted in relation to species richness, latitude and mean annual temperature. Furthermore, ecological trait data for each species were analysed in a spatial context.Location Europe.Taxon Sterrhinae (Geometridae, Lepidoptera).Methods A phylogeny for European Sterrhinae was reconstructed using mitochondrial COI sequences and nuclear markers. Distribution data were digitized from taxonomic literature and extended with records from faunistic literature and GBIF. Phylogenetic diversity metrics were calculated using a grid-based approach with a spatial resolution of 50 & times; 50 km.Results Phylogenetic diversity (Faith's PD) was generally high in species rich regions, which are southwestern Europe and parts of the Balkans. However, additional areas such as the entire Mediterranean coast and adjacent areas of Southern Europe are hotspots of Faith's PD. Net relatedness index (NRI) and nearest taxon index (NTI) indicated that the species rich regions in Southern Europe host clusters of evolutionary older lineages, while recent phylogenetic clustering occurred mainly in Northern Europe. Hotspots of phylogenetic endemism (PE) were identified in the Iberian Peninsula, the Mediterranean Islands, southern France, southern Italy, and Greece. Diet breadth and restriction to a single generation per year increased with higher latitudes, likely due to harsher environments. Range size of European Sterrhinae was generally larger in higher latitudes.Main Conclusion Sterrhinae in Europe show slightly different spatial patterns of species richness and phylogenetic diversity; however, the Mediterranean region hosts the majority of species as well as phylogenetic lineages. Ecological traits are best explained by a latitudinal gradient, reflecting a general preference for xerothermic habitats in this subfamily.

ABSTRACT Aim Evaluating whether host plants can constrain the current distribution of host‐specialized butterflies as well as their ability to adapt ranges to climate change at cold and warm range margins. Location Continental Europe. Time Period Current to end of 21st century. Major Taxa Studied Butterflies. Methods We determined thermal niche margins of host‐specialized, Europe‐centred butterflies and their hosts from occurrence records and defined butterflies as potentially range‐limited by hosts if these limits differed by ≤ 0.1°C, ≤ 1°C or ≤ 2°C between the butterfly and its host collective. We used future temperatures under mild and pronounced climate change scenarios to evaluate whether a static host distribution could constrain butterflies' range adaptations at the cold margin or trigger co‐extinctions at the warm margin. Finally, we assessed relations between current host limitations and range size, mobility, phylogenetic host‐niche breadth, and red‐list status of the butterflies. Results Of the 118 butterfly species studied, 48/33 (cold/warm margin) were potentially host‐limited, when using the ≤ 2°C as criterion, 29/11 species under the ≤ 1°C criterion, but only 15/5 species using the ≤ 0.1°C criterion. Expansion at the cold margin was potentially hampered by host immobility in 22 and 59 species under mild and pronounced climate change, respectively, while we detected risk of co‐extinction at the warm range margin in 14 and 55 species. Current host limitation at the cold margin increased with larger butterfly ranges. No consistent relations with other variables were detected. Main Conclusions The distribution of several specialized Europe‐centred butterflies is at least co‐constrained by their hosts already today, and the impact of these constraints may intensify in the future. This is not only true at cold, but also at warm range limits, implying a risk of yet understudied future co‐extinctions. Understanding and prediction of climate‐change effects on insects thus need increased consideration of simultaneous host plant dynamics.

In protected areas, fragmentation and artificial light at night are usually present alongside changes in land type, from natural to agricultural or urban. We explored the intensity of edge effects on light trap responses of nocturnal insects at the margin of the floodplain forest in the Donau-Auen National Park in Central Europe, Austria. Specifically, we examined the abundance and biomass of nocturnal insects and characterized the community composition and diversity of moths with respect to the local habitat. In this study, 58 species were observed, with 21 unique records on the forest edge and nine in the interior. Traps in the forest interior harbored significantly higher nocturnal insect biomass. However, moth assemblages were more diverse at edge sites due to many singletons, attributed to individuals attracted from areas with open vegetation. Nine species (15.5% of total) were recorded later than expected given their summer flight periods, potentially reflecting the effects of ongoing climate change associated with warmer autumns. Overall, we observed higher moth species diversity at the forest edge, and insect biomass and moth abundance were higher within the forest. These findings underscore the urgent need to incorporate local anthropogenic landscape and climate change as synergically evolutionary drivers in future population and community-focused research.

Urbanization is a global phenomenon inducing rapid and permanent land-use changes. These transformations have significant impacts on biodiversity and ecosystem functioning, primarily through the filtering of specific functional and/or morphological traits. In animals, body size is a critical functional trait linked to ecosystem functioning because it affects metabolism, dispersal and trophic interactions. Moth communities are particularly sensitive to urbanization, often exhibiting reduced species diversity due to non-random species loss. However, body size responses to urbanization remain ambiguous, as contrasting eco-evolutionary processes may drive shifts in opposite directions. The Urban-Heat-Island effect (UHI) predicts a reduction in body size-following Atkinson's temperature-size rule-due to increased metabolic costs, whereas habitat fragmentation may favour larger individuals with greater dispersal ability. Here, to test these hypotheses, we sampled geometrid moths along an urbanization gradient in a tropical Andean city and analysed body size variation at both community and population levels in relation to UHI intensity. At the community level, our results revealed a reduction in body size at high levels of UHI, consistent with the temperature-size rule. However, at the population level, phenotypic changes were consistent with opposing pressures associated with urban warming and habitat fragmentation, depending on the species. Hence, our study suggests that urban environments can filter species idiosyncratically within communities and individuals within species, but through different mechanisms.

We tested how morphological traits and species diversity of Pyraloidea moth assemblages vary across an Andean rainforest elevational gradient in Ecuador, and how environmental conditions shape these patterns. We analyzed 4161 individuals representing 212 species from a larger dataset of 10,337 individuals and 749 morpho-species, using the latter for cross-validation, and related our findings to ambient temperature and vegetation cover. Our multivariate analysis at 22 sites from 1020 to 2700 m above sea level identified five species assemblage clusters, revealing a near-linear decrease in species diversity with cooler temperatures. Community-weighted means (CWMs) of forewing length, indicating body size, increased nearly linearly with dropping temperatures, contrasting with results found for Geometridae moths at the same sites. Forewing aspect ratio (AR) demonstrated a U-shaped relationship with temperature, while wing loading (WL) followed a hump-shaped trajectory. Around 2000 m, Pyraloidea assemblages exhibited the lowest AR and highest WL, indicating morphological adaptations to dense forests, in contrast to both the more open forests near the treeline and the tall rainforest found at lower elevations. Subfamily-level analyses revealed variable patterns: Acentropinae, with strictly aquatic larvae, showed larger sizes at cooler elevations but less wing shape variation, likely reflecting limited forest dependence on maneuverability. Musotiminae, with a larval diet of diverse ferns, exhibited wing morphologies more related to canopy openness than temperature, indicating adaptations to navigating different fern habitats along the gradient. Our observations reveal complex insect-environment interactions that challenge the applicability of just one common theoretical framework for explaining temperature-size relationships among different moth clades.

Body size is one of the most characteristic traits of every animal species and strongly influences its ecological niche. Identifying life-history traits that are associated with body size and investigating possible causalities behind such contingencies is thus a central topic in evolutionary ecology. In this study, we examined whether adult body size in Lepidoptera relates with resource type used at larval stage, larval dietary specialisation, voltinism, or adult diel activity. Based on previous findings, we hypothesised that species associated with woody plants are overall larger than those feeding on herbaceous plants or alternative food sources (e.g., lichens, detritus etc.). We further hypothesised that larger body sizes are associated with a lower degree of dietary specialisation, a univoltine life style, and nocturnal activity in adults. To test our hypotheses, we focussed on more than 220 species of European Erebidae moths, one of the taxonomically and ecologically most diverse Lepidoptera families worldwide. Increasing availability of molecular data for this group, coupled with advances in phylogenetic comparative methods, allowed us to study these trait relationships by accounting for shared evolutionary history among species, and– in addition to that– investigate potential causalities driving the detected patterns. We found adult body size to be positively linked with woody plant feeding and a univoltine life cycle, supporting the respective hypothesis. Our results further indicated that resource type affects the evolution of body size, while the latter strongly determines voltinism. Contrary to expectation, body size was neither related with larval dietary specialisation nor with adult diel activity. In conclusion, our study suggests that smaller body sizes, frequently associated with feeding on herbaceous plants or alternative food sources, are of evolutionary advantage as they facilitate the realisation of multiple generations per year and thus allow for faster adaptations to changing environmental conditions.

Diet breadth is one of the fundamental species traits of an herbivorous insect as it strongly determines its ecological niche and, at the same time, its ability to cope with changing environmental conditions. To what extent this trait is associated with other characteristics that may influence a species' ability to respond to environmental changes, however, is yet poorly understood. Using European butterflies as a model group of holometabolous insect herbivores, we here tested whether larval diet breadth is positively related with latitudinal range size (i.e. north–south extent of global distribution), voltinism and adult body size. We further investigated whether range size, voltinism, and body size are associated with each other. In order to test for these relationships, we based our analyses on a solid, time‐calibrated butterfly phylogeny as well as on an updated host plant database that reflects interactions between butterfly larvae and their food plants in a yet unparalleled breadth and depth. We further calculated two measures to reflect the fundamental dietary niche of a species: taxonomic diet breadth and phylogenetic diet breadth. Irrespective of diet breadth measure, we found that diet breadth increases with latitudinal range size. We further found an overall higher diet breadth for species that are capable to realise multiple broods per year (i.e. multivoltine species) compared to obligatorily univoltine species. Contrary to expectation, our results indicated a negative relationship between larval diet breadth and adult body size. Regarding our explorative analyses, we observed a positive link between voltinism and latitudinal range size, while neither one of these variables was associated with body size. Taken together, our study shows that larval diet breadth, latitudinal range size and voltinism are positively linked in European butterflies, and we argue that these interrelationships are important in determining a species' overall potential to cope with changing environmental conditions.

1. DNA metabarcoding has developed into a commonly used tool for biodiversity assessment and monitoring. How results from DNA metabarcoding are compared with studies based on 'classic', in most cases morphological species identification, is still unclear. Studies investigating species detection against a known baseline are virtually non-existent.2. In this study, we used light trap samples collected in eastern Austria to investigate the concordance between morphological species lists and results obtained from COI metabarcoding using the Illumina MiSeq platform. Two primer combinations of different lengths (313 and 205 bp) were compared to assess the influence of amplicon length.3. Species detection rates ranged between 0.38 and 0.69; the shorter amplicon had on average higher species detection rates compared with the longer amplicon. Singleton species were less likely to be detected through metabarcoding.4. The major determinant for a species to be detected was its biomass, viz. smaller species had a lower chance to be detected. However, there is also evidence of taxonomic bias on the level of superfamilies. While the influence of biomass is to be expected, the presence of taxonomic bias gives reason for concern and requires further studies. Such a bias can be of significance when metabarcoding is used to determine conservation measures. Ordination analyses of all sampling sites showed that as far as community ecology is concerned, the overall pattern obtained from the full species list was mostly preserved in our metabarcoding results.

Although diurnality is widespread across Lepidoptera and has evolved many times independently, its causes and ecological implications are yet poorly understood. The "Salient Aroma Hypothesis" (SAH) postulates that diurnal insect herbivores are overall more specialized in dietary breadth than species active at night. It is furthermore assumed that diurnality evolved more frequently in species that live in cooler environments. Using European geometrid moths as a model group, we tested whether diurnal activity in adults is associated with an increased larval dietary breadth as predicted by the SAH. We further investigated whether species that exclusively occur in colder regions or whose flight period is restricted to cool seasons are more likely to exhibit a diurnal flight activity. Contrary to expectation, we found no consistent differences in larval dietary breadth between diurnal and nocturnal species, and thus no support for the SAH. Diurnal activity occurred more frequently in species restricted to cold regions but not in species restricted to cool seasons. We conclude that diurnality could serve as an advantageous adaptation in cold environments, depending on further factors such as resource availability or predation pressure, but has no immediate consequences for larval dietary breadth.

In mutualistic associations, lycaenid butterfly caterpillars trade nectar secretions against protective services by ants. Eversions of paired abdominal tentacle organs (TO) have been suggested to honestly signal nectar secretion capacity of caterpillars to their ant visitors. Using data from 1561 staged encounters between larvae of nine West Palaearctic Polyommatinae species and worker ants of three species, I show that within experimental series, significantly positive correlations between TO eversion and nectar secretion rate emerged only sporadically (12 of 50 series). In a meta-analysis integrating over all tested species combinations and experimental conditions, the relationship between nectar secretion and TO eversion rate was weak (r2 = 6.6%), though significantly positive. This association between myrmecophilous behaviours was not stronger in experiments with feeding mature larvae than in prepupal non-feeding larvae; however, the latter delivered distinctly more nectar. Relationships between nectar secretions and TO eversions were independent of the density of ant partners available and did not vary consistently between lycaenid species showing different levels of myrmecophily. When mean values of nectar secretions per experimental series were related to the respective mean TO eversion rates, a clear positive relationship only emerged among intimately ant-associated species. In moderate myrmecophiles average tentacle activity was unrelated to mean nectar delivery. Overall, these experiments yielded only weak support for the reliable-signalling hypothesis. I propose that TO eversions rather serve as complementary dimension of multimodal communication between partners. ‘Apparent honesty’ may then emerge if caterpillars achieve optimal ant attendance by concomitantly increasing nectar secretion and TO eversion rates.

Due to agriculture and logging, Costa Rica has lost many primary forests, making reforestation an important task. To judge the progress of reforestation, it is important to follow the reassembly of organismal communities within restored habitats. The COBIGA project near La Gamba, in the Golfo Dulce region of Costa Rica, aims at reforestation of lowland sites with native tree species. Ants, as ubiquitous and highly abundant terrestrial organisms, have a substantial influence on tropical ecosystems. The multiple roles include scavenging, predation, herbivory, and mutualistic interactions. We examined ant community responses to reveal the status of community regeneration and functional integrity. We compared the composition and diversity of the ant assemblages at three different age reforestation sites (2, 8, and 10 years old) with those at an old-growth forest as a reference site. By offering canned tuna fish at ground level along replicated transects, we observed 43 ant species representing six functional groups during the 2 months of sampling. Most of the observed ant species were omnivorous, but old-growth forests harbored a substantial number of other functional groups, such as generalized predators, arboreal predators, and arboreal omnivores. In contrast, the youngest reforestation site harbored a severely impoverished ant assemblage comprising mostly generalized polygynous and polydomous ant species from lower trophic levels. The within-site heterogeneity of the ant assemblages increased from the youngest to the oldest forest. In addition, our results show the importance of monitoring the progress of forest recovery to avoid the spread of invasive species into primary habitats.

Large pulses of tree mortality have ushered in a major reorganization of Europe’s forest ecosystems. To initiate a robust next generation of trees, the species that are planted today need to be climatically suitable throughout the entire twenty-first century. Here we developed species distribution models for 69 European tree species based on occurrence data from 238,080 plot locations to investigate the option space for current forest management in Europe. We show that the average pool of tree species continuously suitable throughout the century is smaller than that under current and end-of-century climate conditions, creating a tree species bottleneck for current management. If the need for continuous climate suitability throughout the lifespan of a tree planted today is considered, climate change shrinks the tree species pool available to management by between 33% and 49% of its current values (40% and 54% of potential end-of-century values), under moderate (Representative Concentration Pathway 2.6) and severe (Representative Concentration Pathway 8.5) climate change, respectively. This bottleneck could have strong negative impacts on timber production, carbon storage and biodiversity conservation, as only 3.18, 3.53 and 2.56 species of high potential for providing these functions remain suitable throughout the century on average per square kilometre in Europe. Our results indicate that the option space for silviculture is narrowing substantially because of climate change and that an important adaptation strategy in forestry—creating mixed forests—might be curtailed by widespread losses of climatically suitable tree species. Species distribution modelling for 69 European tree species under current climate conditions and projected conditions to 2100 (in decadal steps) demonstrates that, for climate suitability to be maintained throughout a tree’s lifespan, many fewer tree species are available to forest managers than are currently used.

Ceutorhynchinae Gistel are a diverse weevil subfamily of almost worldwide distribution and considerable economic importance. Nevertheless, the classification of Ceutorhynchinae and their phylogenetic relationships are not yet fully resolved. Here, we sequenced the mitogenomes of 54 ceutorhynchine species. Phylogenetic analyses by maximum likelihood and Bayesian inference were performed on a dataset of 13 protein-coding and two ribosomal genes. All analyses recovered three well supported clades A-C. A principal component analysis shows that codon usage differs considerably between these clades, indicating a compositional asymmetry in ceutorhynchine mitogenomes. This increased the challenge of resolving the early relationships among the three clades. The resolution of the later diversification was more robust, and the resulting topologies were largely compatible with each other and with the current taxonomic classification. Exceptions are the genera Micrelus Thomson, which is transferred from the tribe Ceutorhynchini to Egriini Pajni and Kohli (new position) and Amalus Schoenherr, which is transferred to Phytobiini Gistel (new position). Amalini Wagner 1936 is a junior synonym of Phytobiini Gistel 1848 (syn. n.). Coeliodini Lacordaire (new status), a tribe previously regarded as junior synonym of Ceutorhynchini, is re-established. Our analyses also clarified the difficult assignments of taxa to the tribes Scleropterini Schultze and Phytobiini. All taxa with the ability to jump as adult beetles belong to clade B, which comprises the tribes Cnemogonini Colonnelli, Hypurini Schultze, Mecysmoderini Wagner and Phytobiini. With dense taxon sampling and appropriate analytical methods, mitogenome data provide a phylogeny well suited to improve the traditional classification of this neglected and species-rich taxon. Fifty-four newly sequenced mitochondrial genomes of Ceutorhynchinae weevils First comprehensive molecular dataset to infer phylogenetic relationships of Ceutorhynchinae Inference of a compositional asymmetry in ceutorhynchine mitogenomes image

Land use change, as a result of many local-scale decisions scaling up to large spatial extents, is considered the main threat to European butterflies. The impact of large-scale pressures, such as atmospheric nitrogen deposition or climate change, is less understood or less documented, respectively. However, it is acknowledged that they might reinforce the pressure on already threatened species. To evaluate the additional threat exerted by these pressures we compared their geographical pattern to those of threatened butterflies across Europe. We therefore derived range maps of 383 butterfly species and used two species-specific threat assessments derived from national and European Red Lists. We then used Spearman rank-correlations and beta-regressions to compare two metrics of species threat per 10 x 10 km raster cells with geographical patterns of cumulative nitrogen depositions from 1980 to 2015, as well as the magnitude of change in precipitation sums and temperature means between the decades 1979-1988 and 2004-2013. We found that threatened species tend to concentrate in areas with high nitrogen depositions and pronounced summer temperature changes. In particular, parts of central and eastern Europe were both hotspots of threatened butterflies and hotspots of climatic pressure. This spatial coincidence of the distribution of threatened butterfly species with large-scale patterns of nitrogen depositions and recent climate warming indicates an already considerable risk of regional to continental extinctions that will likely increase further in the future as climate change will most likely intensify. Consequences for area-based conservation measures are discussed.

We used European geometrid moths (>630 species) as a model group to investigate how life history traits linked to larval host plant use (i.e., diet breadth and host-plant growth form) and seasonal life cycle (i.e., voltinism, overwintering stage and caterpillar phenology) are related to adult body size in holometabolous insect herbivores. To do so, we applied phylogenetic comparative methods to account for shared evolutionary history among herbivore species. We further categorized larval diet breadth based on the phylogenetic structure of utilized host plant genera. Our results indicate that species associated with woody plants are, on average, larger than herb feeders and increase in size with increasing diet breadth. Obligatorily univoltine species are larger than multivoltine species, and attain larger sizes when their larvae occur exclusively in the early season. Furthermore, the adult body size is significantly smaller in species that overwinter in the pupal stage compared to those that overwinter as eggs or caterpillars. In summary, our results indicate that the ecological niche of holometabolous insect herbivores is strongly interrelated with body size at maturity.

Aim:The breadth of ecological niches and dispersal abilities have long been discussed as important determinants of species' range sizes. However, studies directly comparing the relative effects of both factors are rare, taxonomically biased and revealed inconsistent results. Location:Europe. Time Period:Cenozoic. Major Taxa:Butterflies, Lepidoptera. Methods:We relate climate, diet and habitat niche breadth and two indicators of dispersal ability, wingspan and a dispersal tendency index, to the global range size of 369 European-centred butterfly species. The relative effects of these five predictors and their variation across the butterfly phylogeny were assessed by means of phylogenetic generalized least squares models and phylogenetically weighted regressions respectively. Results:Climate niche breadth was the most important single predictor, followed by habitat and diet niche breadth, while dispersal tendency and wingspan showed no relation to species' range size. All predictors together explained 59% of the variation in butterfly range size. However, the effects of each predictor varied considerably across families and genera. Main Conclusions:Range sizes of European-centred butterflies are strongly correlated with ecological niche breadth but apparently independent of dispersal ability. The magnitude of range size-niche breadth relationships is not stationary across the phylogeny and is often negatively correlated across the different dimensions of the ecological niche. This variation limits the generalizability of range size-trait relationships across broad taxonomic groups.

Analysing the effects of environmental variation on species assemblages is a key topic in community ecology. However, the outcome may strongly depend on the focal species group. Moths have often been used as the target in ecological studies due to their fast response to environmental change. Yet, some moth subgroups might be more sensitive than others to reflect environmental differences, depending on their functional and physiological characteristics. We investigated which moth subsets are especially suitable to mirror responses to subtle variation in vegetation. We analysed the susceptibility of different subsets to local weather conditions and inter‐annual fluctuations. Finally, we checked for the importance of including abundance information. We analysed moth communities (392 species, 23.870 individuals) at 60 sites within two Mediterranean forest reserves and investigated relationships between community composition and environment of (1) all moths (with and without taking abundances into account), and of subsets comprising only (2) small‐sized species, (3) host‐plant specialists, (4) moss, lichen and detritus feeding species, (5) ‘microlepidoptera’, (6) ‘macro‐moths’ and (7) random subsets of 50, 100 and 200 species. Incidence data performed similarly to abundance data in matrix regression models. Host plant specialists responded especially sensitive to small‐scaled variation in vegetation composition. Macro‐moth samples in contrast were highly prone to local weather conditions and to inter‐annual abundance fluctuations. Accordingly, a focus on host‐specialists and micro‐moths is the best way to analyse relationships between shallow environmental gradients and insect communities.

Aim Latitudinal clines in dietary specialization and range size are used to explain biodiversity distributions at large spatial scales, such as the latitudinal diversity gradient. The aim of this study was to test whether dietary breadth (as a dimension of niche breadth) and range size decrease towards lower latitudes in a species-rich clade of herbivorous insects as predicted by the latitude-niche breadth hypothesis and Rapoport's rule, respectively. We also aimed to study whether these species characteristics are positively linked with each other as stated by the niche breadth-range size hypothesis. Location Europe (35-71 degrees N). Time period Present-day. Major taxa Geometrid moths (Lepidoptera: Geometridae). Methods For every species, we compiled information on latitudinal distribution and host-plant use based on available literature and online sources. We estimated the level of fundamental dietary specialization of each species while accounting for phylogenetic relationships among the host plants used. We also reconstructed a phylogeny including all studied moth taxa, in order to control for phylogenetic dependence in species characteristics. Phylogenetic least squares (PGLS) analyses were used to test each of our hypotheses. Results We analysed 631 species of geometrids (85.2% of taxa within the biogeographical region) and found strong support for the latitude-niche breadth hypothesis and for Rapoport's rule. Fundamental dietary breadth was also found to be positively related to latitudinal range size, which supports the niche breadth-range size hypothesis. These results were retained when the subfamilies Ennominae and Larentiinae were analysed separately. Main conclusions Our findings indicate that latitudinal clines in range size and fundamental dietary breadth covary in European geometrid moths and are likely to be drivers of increased species richness towards lower latitudes. This supports the idea that both characteristics should be studied simultaneously in order to unveil mechanisms structuring biodiversity patterns at the macroecological scale.