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Abdominal pumping rate as a function of thoracic temperature in male and female A. plumipes at Ta=9˚C and Ta=21˚C (y=7.93+9.17x, r 2 =0.673).
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Summary 1. This study examines variation in thoracic temperatures, rates of pre-flight warm-up and heat loss in the solitary bee Anthophora plumipes(Hymenoptera; Anthophoridae). 2. Thoracic temperatures were measured both during free flight in the field and during tethered flight in the laboratory, over a range of ambient temperatures. These two te...
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... Males have good visual acuity and flying skills as they chase females in flight. Their activity is also highly dependent on ambient temperature, with flight activity starting at a minimum ambient temperature of 10-14°C and a thorax temperature of around 24°C (Stone 1993). Interestingly, thermoregulatory and flight abilitiesand therefore mating success -are highly dependent on body size, with larger males able to fly at lower temperatures and take prime position immediately after females (Stone et al. 1995). ...
... In fact, the bees were sampled along a gradient of only 5°C, smaller than the gradients studied by Ferrari et al. (2024b) and Tommasi et al. (2022) in Milan. Perhaps the small thermal gradient, together with the thermoregulatory ability of A. plumipes (Stone 1993), could explain why we did not see any changes in body mass following the urbanisation gradient. The second interpretation involves selective pressure acting specifically on males. ...
Urbanisation, leading to the reduction and fragmentation of green areas and an increase in temperature (urban heat island
effect), is known to be a strong driver of intraspecific phenotypic variation in wild bees. However, the effects of urbanisation on
many functionally relevant morphological traits are still unstudied or debated. Here, males of the ground-nesting, solitary bee
Anthophora plumipes were sampled at nine sites in the metropolitan city of Milan (Italy). The aim was to test variation in body
size, head width, compound eye size, ommatidia density, antenna length, median ocellus size, galea length (proxy for tongue
length), wing area, wing loading, wing aspect ratio, and wing fluctuating asymmetry along an urbanisation gradient. We found
some of these traits to significantly shift across the gradient. Bees in hotter (urban) areas had longer galea, agreeing with
previous community-level studies showing more long-tongued wild bee species in urban areas. This may suggest that
urbanisation filters for longer mouthparts at both species and individual level. Ocelli were larger in males from more urbanised
sites, perhaps improving navigation in more fragmented habitats. Finally, bees in greener (less urban) areas had also lower wing
fluctuating asymmetry, suggesting that urbanisation may act as an early-life stressor in A. plumipes. None of the other analysed
morphological traits varied with urbanisation, which contrasts (especially for body size and wing size) with several previous
studies on other bee species in urban contexts. Such patterns highlight how difficult is to draw generalisable trends regarding
the effects of urbanisation on wild bees. Nonetheless, this study provides the first evidence of such effects on rarely studied
morphological traits (mouthparts, ocelli) in male bees.
... In a Mediterranean montane plant community predominantly pollinated by bees (Herrera, 2020), Herrera et al. (2023) recently found that the seasonal activity of Andrena bees and their predominant role in the pollination of early-blooming plants can be parsimoniously explained by features of their thermal biology: null to weak endothermy, ability to forage at low body temperature, low upper tolerable limit of body temperature, weak thermoregulatory capacity, and high warming constant enhancing ectothermic warming. These results contrasted with those of previous work on the thermal biology of bees from other families, which had mostly documented strong endothermy and high body temperatures (Heinrich, 1993;May & Casey, 1983;Oyen et al., 2016;Roberts et al., 1998;Stone, 1993aStone, , 1993bStone & Willmer, 1989). These seemingly conflicting results, along with those of Stone (1994) and Bishop and Armbruster (1999), actually suggest a strong phylogenetic component in bee thermal biology, which in turn highlights the need of evaluating the diversity in thermal biology represented in taxonomically diverse bee pollinator assemblages and its potential ecological consequences in relation to the pollination of entire plant communities. ...
... This set of parameters represents a rather minimalist subset of the possible thermal features that could have been considered. Aspects not considered include, for instance, endothermic and thermoregulatory ability, or the relationship between thoracic and operative temperatures, previously addressed in comparative studies of bee thermal biology (Bishop & Armbruster, 1999;Herrera, 1995;Herrera et al., 2023;Stone, 1993aStone, , 1993bStone & Willmer, 1989). Inclusion of these aspects might have produced a higher resolution picture of thermal biology diversity and their ecological correlates, but this improvement at resolution would come at the cost of reducing the number of taxa examined, since there was a compromise between number of taxa and the thoroughness of thermal information obtainable per taxon. ...
... Diversity of thermal biology had a strong taxonomic basis. The long-known relationships between body mass and thermal biology parameters in insects (e.g., Bishop & Armbruster, 1999;Digby, 1955;Herrera et al., 2023;May, 1976;Rodríguez et al., 2018;Stone, 1993aStone, , 1993bStone & Willmer, 1989;Unwin & Corbet, 1984) were also consistently found in this study. Body mass was inversely related to K and directly to T th and T exc (Table 1). ...
Community‐wide assembly of plant–pollinator systems depends on an intricate combination of biotic and abiotic factors, including heterogeneity among pollinators in thermal biology and responses to abiotic factors. Studies on the thermal biology of pollinators have mostly considered only one or a few species of plants or pollinators at a time, and the possible driving role of the diversity in thermal biology of pollinator asemblages at the plant community level remains largely unexplored. More specifically, it is unknown whether diversity in the thermal biology of bees, a major pollinator group worldwide, contributes to the assembly and maintenance of diverse bee communities; broadens the spectrum of possibilities available to bee‐pollinated plants; facilitates interspecific partitioning of ecological gradients across habitats, seasons, and time of day; and/or enhance plant pollination success through complementarity effects. The objectives of this study were to assess the diversity in thermal biology of the bee assemblage that pollinates plants in a Mediterranean montane area, evaluate its taxonomic and phylogenetic underpinnings, and elucidate whether there existed seasonal, daily, between‐habitat, or floral visitation correlates of bee thermal biology which could contribute to partition ecological gradients among plant and bee species. Thermal biology parameters were obtained in the laboratory (K, intrinsic warming constant) and the field (thoracic and ambient temperature at foraging site, Tth and Tair) on individual bees of a diverse sample (N = 204 bee species) comprising most bee pollinators of the regional plant community. Species‐specific thermal biology parameters were combined with quantitative field data on bee pollinators and flower visitation for the regional community of entomophilous plants (N = 292 plant species). Results revealed that the regional bee assemblage harbored considerable diversity in thermal biology features; that such diversity was mostly taxonomically, phylogenetically, and body‐size structured; and that the broad interspecific heterogeneity in thermal biology represented in the bee community as a whole eventually translated into daily, seasonal, among‐habitat, and flower visitation patterns at the plant community level. This lends support to the hypothesis that broad diversity in thermal biology of bees can enhance opportunities for bee coexistence, spatiotemporal partitioning of floral resources, and plant pollination success.
... All the species in this subfamily exhibit a unique brood parasitism behavior called kleptoparasitism, indicating that they usurp the host nests and lay their eggs in closed host cells through small circular openings (Danforth et al. 2019;Rozen & Ding 2012). All Melecta species are kleptoparasites of the tribe Anthophorini, mainly associated with the Anthophora (Lieftinck 1972), which is a large genus of robust, fast-flying, pollen-collecting bees occurring on every continent except Australia and South America (Michener 2007;Stone 1993). Melecta has a single generation per year and is active in either spring or summer, depending on the species (Amiet et al. 2007). ...
This study focused on a kleptoparasitic bee, Melecta chinensis , which is not well‐known in the Republic of Korea. We provided a detailed morphological illustration of the adult bees and their nesting biological characteristics with distributional data. Additionally, the complete mitochondrial genome of the species is presented for the first time, and its phylogenetic position within the family Apidae is estimated.
As a result, we could suggest a full redescription of M. chinenesis for identification and a newly reported potential flower host for it. In addition, the mitochondrial DNA (mtDNA) of M. chinensis is revealed as 15,489 base pairs (bp) long, with 35 eukaryotic mitochondrial genes (13PCGs, 2 rRNAs, and 20 tRNAs) and a 706 bp AT‐rich region. The overall base composition is 75.82% AT and 24.18% GC. The 13 protein‐coding genes (PCGs) started with a typical ATN codon (ATA in nine genes and ATG in four genes) and terminated with TNN (TAN in 10 genes and TTT in one gene) or ANN (AAC in one gene and ATT in one gene). The phylogenetic results based on 13 PCGs showed that M. chinensis is distantly positioned to bumble bees ( Bombus ) and honey bees ( Apis ) but closely related to a stingless bee, Frieseomelitta varia , within the family.
... Regardless of time of year, bees with low K and high Tth and Texc tended to 553 prevail shortly after sunrise, the daytime period with the lowest incident solar irradiance and 554 ambient temperature. This group of early-morning bees typically included species of large-sized 555 Apidae in the genera Bombus and Anthophora, both of which are well known for their 556 thermoregulatory abilities and strong endothermy (Heinrich 1993, Stone 1993a,b, 1994 and Armbruster 1999). Bees with progressively higher K and lower Tth and Texc entered the bee (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. ...
Community-wide assembly of plant-pollinator systems depends on an intricate combination of biotic and abiotic factors, including heterogeneity among pollinators in thermal biology and responses to abiotic environmental gradients. Studies on the thermal biology of pollinators, however, have mostly considered only one or a few species of plants or pollinators at a time, and the possible driving role of the diversity in thermal biology of pollinator asemblages at the plant community level thus remains largely unexplored. More specifically, it is unknown whether expected diversity in the thermal biology of bees, a major, species-rich pollinator group worldwide, contributes to the assembly and maintenance of diverse bee communities, broadens the spectrum of possibilities available to bee-pollinated plants, facilitate interspecific partitioning of ecological gradients across habitats, seasons and time of day, and/or enhance plant pollination success through complementarity effects. The objectives of this study were to evaluate the diversity in thermal biology of the bee assemblage pollinating the community of entomophilous plants from a Mediterranean montane area, and to elucidate whether there existed seasonal, daily, between-habitat or floral visitation correlates of bee thermal biology which could contribute to partition ecological gradients among plant and bee species. Thermal biology parameters were obtained in the laboratory ( K , intrinsic warming constant) and the field (thoracic and ambient temperature at foraging site, T th and T air) on individual bees of a diverse sample ( N = 204 bee species) comprising most bee pollinators of the regional plant community. Species-specific thermal biology parameters were combined with quantitative field data on bee pollinators and flower visitation for the regional community of entomophilous plants ( N = 292 plant species). Results revealed that the regional bee assemblage harbored considerable diversity in thermal biology features, that such diversity was mostly taxonomically and body-size structured, and that the broad interspecific heterogeneity in thermal biology represented in the bee community as a whole eventually translated into daily, seasonal, among-habitat and flower visitation patterns at the plant community level. This lends support to the hypothesis that broad diversity in thermal biology of bees can act enhancing opportunities for bee coexistence, spatio-temporal partitioning of floral resources, and plant pollination success.
O pen research statement
All data and metadata will be deposited at figshare upon manuscript acceptance.
... In moths and bumblebees, other featuresincluding a coat of insulating 'fur'participates in the process as well by limiting heat dissipation by convection at the thoracic cuticle. This allows some species to fly at very low T a (Heinrich, 1972(Heinrich, , 1987Heinrich and Mommsen, 1985;Stone, 1993). Interestingly, other species such as Operophtera bruceata can take off with a T th close to 0°C and do not produce heat endogenously (Heinrich and Mommsen, 1985). ...
Ambient temperature (Ta) is a critical abiotic factor for insects that cannot maintain a constant body temperature (Tb). Interestingly, Ta varies during the day, between seasons and habitats; insects must constantly cope with these variations to avoid reaching the deleterious effects of thermal stress. To minimize these risks, insects have evolved a set of physiological and behavioral thermoregulatory processes as well as molecular responses that allow them to survive and perform under various thermal conditions. These strategies range from actively seeking an adequate environment, to cooling down through the evaporation of body fluids and synthesizing heat shock proteins to prevent damage at the cellular level after heat exposure. In contrast, endothermy may allow an insect to fight parasitic infections, fly within a large range of Ta and facilitate nest defense. Since May (1979), Casey (1988) and Heinrich (1993) reviewed the literature on insect thermoregulation, hundreds of scientific articles have been published on the subject and new insights in several insect groups have emerged. In particular, technical advancements have provided a better understanding of the mechanisms underlying thermoregulatory processes. This present Review aims to provide an overview of these findings with a focus on various insect groups, including blood-feeding arthropods, as well as to explore the impact of thermoregulation and heat exposure on insect immunity and pathogen development. Finally, it provides insights into current knowledge gaps in the field and discusses insect thermoregulation in the context of climate change.
... One of these studies showed that pollination of the early-flowering daffodil Narcissus longispathus was facilitated by the thermal biology of Andrena bicolor, its main pollinator, which flies at low body temperature and has a low upper thermal tolerance limit in comparison to other bees (Herrera, 1995). It remains unknown, however, whether these distinctive thermal features apply to the genus Andrena as a whole, as knowledge on bee thermal biology largely refers to a few lineages of extremely endothermic bees in the family Apidae (Chappell, 1982;Heinrich, 1993;Inouye, 1975;May & Casey, 1983;Oyen et al., 2016;Roberts et al., 1998;Stone, 1993;Stone & Willmer, 1989). The thermal biology of Andrena bees remains essentially unexplored (Danforth et al., 2019; but see Bishop & Armbruster, 1999;Herrera, 1995;Schmaranzer et al., 1997), which represents a remarkable gap in our knowledge given their extraordinary biological diversity, broad geographical distribution, high seasonal abundance, and importance as pollinators of many cultivated and wild plants. ...
Understanding the factors that drive community‐wide assembly of plant‐pollinator systems along environmental gradients has considerable evolutionary, ecological, and applied significance. Variation in thermal environments combined with intrinsic differences among pollinators in thermal biology have been proposed as drivers of community‐wide pollinator gradients, but this suggestion remains largely speculative. We test the hypothesis that seasonality in bee pollinator composition in Mediterranean montane habitats of southeastern Spain, which largely reflects the prevalence during the early flowering season of mining bees (Andrena), is a consequence of the latter's thermal biology. Quantitative information on seasonality of Andrena bees in the whole plant community (275 plant species) and their thermal microenvironment was combined with field and laboratory data on key aspects of the thermal biology of 30 species of Andrena (endothermic ability, warming constant, relationships of body temperature with ambient and operative temperatures). Andrena bees were a conspicuous, albeit strongly seasonal component of the pollinator assemblage of the regional plant community, visiting flowers of 153 different plant species (57% of total). The proportion of Andrena relative to all bees reached a maximum among plant species which flowered in late winter and early spring, and declined precipitously from May onward. Andrena were recorded only during the cooler segment of the annual range of air temperatures experienced at flowers by the whole bee assemblage. These patterns can be explained by features of Andrena's thermal biology: null to weak endothermy; ability to forage at much lower body temperature than strongly endothermic bees (difference ~ 10°C); low upper tolerable limit of body temperature, beyond which thermal stress presumably precluded foraging at the warmest period of year; weak thermoregulatory capacity; and high warming constant enhancing ectothermic warming. Our results demonstrate the importance of lineage‐specific pollinator traits as drivers of seasonality in community‐wide pollinator composition; show that exploitation of cooler microclimates by bees does not require strong endothermy; and suggest that intense endothermy and precise thermoregulation probably apply to a minority of bees. Medium‐ and large‐sized bees with low upper thermal limits and weak thermoregulatory ability can actually be more adversely affected by climate warming than large, hot‐blooded, extremely endothermic species.
... HYMENOPTERA Anthophora plumipes Stone (1993) Apis mellifera Roberts and Harrison (1999), Cooper et al. (1985) A. mellifera Heinrich (1980), Stevenson and Woods (1997) B. vagans Heinrich (1972a) B. vosnesenskii Heinrich (1976) Centris pallida , Chappell (1984b) C. caesalpiniae Johnson et al. (2022) Euglossa imperialis Borrell and Medeiros (2004) Melipona subnitida Souza-Junior et al. (2020) Sphecius grandis Coelho et al. (2007) Vespula germanica Coelho and Ross (1996) V. maculifrons Coelho and Ross (1996) Xylocopa capitata Nicolson and Louw (1982) X. californica Chappell (1982) X. frontalis de Farias-Silva and Freitas (2021) X. varipuncta Heinrich and Buchmann (1986) X. virginica Baird (1986) COLEOPTERA Sarcophaga subvicina Willmer (1982) S. carnaria Willmer (1982) LEPIDOPTERA Hyles lineata Casey (1976b) Manduca sexta Hegel and Casey (1982), Heinrich and Bartholomew (1971) Zenithoptera lanei Guillermo-Ferreira and Gorb (2021) Within each category, a red, upsloping triangle indicates that the parameter increases when air temperature rises, a blue downsloping triangle indicates a decrease when air temperature rises, a gray box indicates no change when air temperature rises, and a white box indicates that the parameter was not measured. MR, metabolic rate (a decrease as air temperature rises contributes to thermoregulation); EW, evaporative water loss (an increase as air temperature rises contributes to thermoregulation); R ab , abdominal excess temperature ratio (an increase as air temperature rises often indicates transfer of warm blood from thorax to abdomen, aiding convective and radiative heat loss and thermoregulation; a decrease may indicate evaporative water loss from the abdomen), R h , head excess temperature ratio (a decrease as air temperature rises is often interpreted as evidence of evaporative water loss for thermoregulation). ...
... MR, metabolic rate (a decrease as air temperature rises contributes to thermoregulation); EW, evaporative water loss (an increase as air temperature rises contributes to thermoregulation); R ab , abdominal excess temperature ratio (an increase as air temperature rises often indicates transfer of warm blood from thorax to abdomen, aiding convective and radiative heat loss and thermoregulation; a decrease may indicate evaporative water loss from the abdomen), R h , head excess temperature ratio (a decrease as air temperature rises is often interpreted as evidence of evaporative water loss for thermoregulation). Stone (1993), Roberts and Harrison (1999), Cooper et al. (1985), Heinrich (1980), Stevenson and Woods (1997), Joos et al. (1991), Joos et al. (1991), Unwin and Corbet (1984), Unwin and Corbet (1984), Unwin and Corbet (1984), Heinrich (1972a), Heinrich (1976), Coelho and Ross (1996), Coelho and Ross (1996), Nicolson and Louw (1982), Chappell (1982), de Farias-Silva and Freitas (2021), Heinrich and Buchmann (1986), Baird (1986), Verdú et al. (2012), Verdú et al. (2012), Gomes et al. (2018), Willmer (1982), Willmer (1982), Casey (1976b), Hegel and Casey (1982); Heinrich and Bartholomew (1971), Guillermo-Ferreira and Gorb (2021). mechanism of heat transfer (Centris spp., Bombus ephippiatus, Eulaema spp.), to ten for Apis mellifera, which cannot use this mechanism (Dyer and Seeley, 1987;Wille, 1958). ...
... One of these studies showed that pollination of the early-103 flowering daffodil Narcissus longispathus was facilitated by the thermal biology of Andrena 104 bicolor, its main pollinator, which flies at low body temperature and has a low upper thermal 105 tolerance limit in comparison to other bees (Herrera 1995). It remains unknown, however, 106 whether these distinctive thermal features apply to the genus Andrena as a whole, as knowledge 107 on bee thermal biology largely refers to a few lineages of endothermic bees in the family Apidae 108 (Inouye 1975, Chappell 1982, May and Casey 1983, Stone and Willmer 1989, Stone 1993 . CC-BY-NC-ND 4.0 International license available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. ...
Understanding the factors that drive community-wide assembly of plant-pollinator systems along environmental gradients has considerable evolutionary, ecological and applied significance. Variation in thermal environments combined with intrinsic differences among pollinators in thermal biology (tolerance limits, thermal optima, thermoregulatory ability) have been proposed as drivers of community-wide pollinator gradients, but this suggestion remains largely speculative. We test the hypothesis that seasonality in bee pollinator composition in montane habitats of southeastern Spain, which largely reflects the prevalence during the early flowering season of mining bees (Andrena), is a consequence of the latter's thermal biology. Quantitative information on seasonality of Andrena bees in the whole plant community (275 plant species) was combined with field and laboratory data on key aspects of the thermal biology of 30 species of Andrena (endothermic ability, warming constant, relationships of body temperature with ambient and operative temperatures). Andrena bees were a conspicuous, albeit strongly seasonal component of the pollinator assemblage of the regional plant community, visiting flowers of 153 different plant species (57% of total). Proportion of Andrena relative to all bees reached a maximum among plant species which flowered in late winter and early spring, and declined precipitously from May onwards. Andrena were recorded only during the cooler segment of the annual range of air temperatures experienced at flowers by the whole bee assemblage. These patterns can be explained by features of Andrena's thermal biology: null or negligible endothermy; ability to forage at much lower body temperature than endothermic bees (difference ~10 C); low upper tolerable limit of body temperature, beyond which thermal stress presumably precluded foraging at the warmest period of year; weak thermoregulatory capacity; and high warming constant enhancing ectothermic warming. Our results demonstrate the importance of lineage-specific pollinator traits as drivers of seasonality in community-wide pollinator composition; show that exploitation of cooler microclimates by bees does not require endothermy; falsify the frequent assumption that endothermy and thermoregulation apply to all bees; and suggest that medium- and large-sized ectothermic bees with low upper thermal limits and weak thermoregulatory ability can actually be more adversely affected by climate warming than large endothermic species.
... Large bodies are assumed to be advantageous in colder climates because the body surface-to-volume ratio decreases with size. This means that larger species can raise their body temperature above the ambient temperature because of the slower loss of heat gained by solar radiation through the body surface ('heat conservation hypothesis; ' Stone 1993, Zamora-Camacho et al. 2014. Furthermore, ectotherms develop faster in warm regions but tend to reach a smaller adult body size than in colder regions ('temperature size rule', Atkinson and Sibly 1997). ...
Previous macroecological studies have suggested that larger and darker insects are favored in cold environments and that the importance of body size and color for the absorption of solar radiation is not limited to diurnal insects. However, whether these effects hold true for local communities and are consistent across taxonomic groups and sampling years remains unexplored. This study examined the variations in body size and color lightness of the two major families of nocturnal moths, Geometridae and Noctuidae, along an elevational gradient of 700 m in Southern Germany. An assemblage‐based analysis was performed using community‐weighted means and a fourth‐corner analysis to test for variations in color and body size among communities as a function of elevation. This was followed by a species‐level analysis to test whether species occurrence and abundance along an elevation gradient were related to these traits, after controlling for host plant availability. In both 2007 and 2016, noctuid moth assemblages became larger and darker with increasing elevation, whereas geometrids showed an opposite trend in terms of color lightness and no clear trend in body size. In single species models, the abundance of geometrids, but not of noctuids, was driven by habitat availability. In turn, the abundance of dark‐colored noctuids, but not geometrids increased with elevation. While body size and color lightness affect insect physiology and the ability to cope with harsh conditions, divergent trait–environment relationships between both families underline that findings of coarse‐scale studies are not necessarily transferable to finer scales. Local abundance and occurrence of noctuids are shaped by morphological traits, whereas that of geometrids are rather shaped by local habitat availability, which can modify their trait–environment‐relationship. We discuss potential explanations such as taxon‐specific flight characteristics and the effect of microclimatic conditions.
... Large bodies are assumed to be advantageous in colder climates because the body surface-to-volume ratio decreases with size. This means that larger species can raise their body temperature above the ambient temperature because of the slower loss of heat gained by solar radiation of the body surface ("heat conservation hypothesis;" Stone , 1993;Zamora-Camacho et al., 2014). Furthermore, ectotherms develop faster in warm regions but reach a smaller adult body size than in colder regions ("temperature size rule", Atkinson and Sibly ,1997). ...
How diversity of life is generated, maintained, and distributed across space and time is the central question of community ecology. Communities are shaped by three assembly processes: (I) dispersal, (II) environ-mental, and (III) interaction filtering. Heterogeneity in environmental conditions can alter these filtering processes, as it increases the available niche space, spatially partitions the resources, but also reduces the effective area available for individual species. Ultimately, heterogeneity thus shapes diversity. However, it is still unclear under which conditions heterogeneity has positive effects on diversity and under which condi-tions it has negative or no effects at all. In my thesis, I investigate how environmental heterogeneity affects the assembly and diversity of diverse species groups and whether these effects are mediated by species traits. In Chapter II, I first examine how much functional traits might inform about environmental filtering pro-cesses. Specifically, I examine to which extent body size and colour lightness, both of which are thought to reflect the species thermal preference, shape the distribution and abundance of two moth families along elevation. The results show, that assemblages of noctuid moths are more strongly driven by abiotic filters (elevation) and thus form distinct patterns in colour lightness and body size, while geometrid moths are driven by biotic filters (habitat availability), and show no decline in body size nor colour lightness along elevation. Thus, one and the same functional trait can have quite different effects on community assembly even between closely related taxonomic groups. In Chapter III, I elucidate how traits shift the relative importance of dispersal and environmental filtering in determining beta diversity between forests. Environmental filtering via forest heterogeneity had on aver-age higher independent effects than dispersal filtering within and among regions, suggesting that forest heterogeneity determines species turnover even at country-wide extents. However, the relative importance of dispersal filtering increased with decreasing dispersal ability of the species group. From the aspects of forest heterogeneity covered, variations in herb or tree species composition had overall stronger influence on the turnover of species than forest physiognomy. Again, this ratio was influenced by species traits, namely trophic position, and body size, which highlights the importance of ecological properties of a taxo-nomic group in community assembly. In Chapter IV, I assess whether such ecological properties ultimately determine the level of heterogeneity which maximizes species richness. Here, I considered several facets of heterogeneity in forests. Though the single facets of heterogeneity affected diverse species groups both in positive and negative ways, we could not identify any generalizable mechanism based on dispersal nor the trophic position of the species group which would dissolve these complex relationships. In Chapter V, I examine the effect of environmental heterogeneity of the diversity of traits itself to evalu-ate, whether the effects of environmental heterogeneity on species richness are truly based on increases in the number of niches. The results revealed that positive effects of heterogeneity on species richness are not necessarily based on an increased number of niches alone, but proposedly also on a spatially partition of resources or sheltering effects. While ecological diversity increased overall, there were also negative trends which indicate filtering effects via heterogeneity. In Chapter VI, I present novel methods in measuring plot-wise heterogeneity of forests across continental scales via Satellites. The study compares the performance of Sentinel-1 and LiDar-derived measurements in depicting forest structures and heterogeneity and to their predictive power in modelling diversity. Senti-nel-1 could match the performance of Lidar and shows high potential to assess free yet detailed infor-mation about forest structures in temporal resolutions for modelling the diversity of species. Overall, my thesis supports the notion that heterogeneity in environmental conditions is an important driv-er of beta-diversity, species richness, and ecological diversity. However, I could not identify any general-izable mechanism which direction and form this effect will have.
