Climate change is an important driver of range shifts and community composition changes. Still, little is known about how the responses are influenced by the combination of land use, species interactions and species traits. We integrate climate and distributional data for 131 butterfly species in Sweden and Finland and show that cumulative species richness has increased with increasing temperature over the past 120 years. Average provincial species richness increased by 64% (range 15–229%), from 46 to 70. The rate and direction of range expansions have not matched the temperature changes, in part because colonisations have been modified by other climatic variables, land use and vary according to species characteristics representing ecological generalisation and species interactions. Results emphasise the role of a broad ecological filtering, whereby a mismatch between environmental conditions and species preferences limit the ability to disperse and establish populations in emerging climates and novel areas, with potentially widespread implications for ecosystem functioning.

This is the 49th consecutive annual report of new and interesting finds of Macrolepidopterain Sweden including a compilation of new provincial records, most of the new records are retrieved from the Swedish Species Observation System https://www.artportalen.se. The trend with warmer climate and thus longer vegetation periods continues to have a strong impact on faunal changes and the distribution of the Swedish Lepidopteran fauna. New species, mainly from south and east find their way almost yearly to our country. In 2021 three new species were observed for the first time in Sweden: Amata phegea, Mormo maura and Xylomoia graminea. The trend with expansion mainly northwards and inlands is still strong among species like: Zygaena minos, Pararge aegeria, Apatura ilia, Araschnia levana, Idaea ochrata, Mesoleuca albicillata, Hydrelia sylvata, Melanthia procellata, Eupithecia abbreviata, Cucullia scrophulariae, Cryphia algae, Hoplodrina ambigua, Atethmia centrago, Conisania luteago, Noctua interposita, Epilecta linogrisea, Meganola albula but also among many other species. A new and remarkable feature in the new climatic conditions is that species like Pararge aegeria, Watsonalla binaria and many others can produce full or partial second or even third generations in their just recently reached northernmost range limits. An impressive number of migrants found their way to Sweden, mostly from August to October. Among the more noteworthy are: Argynnis laodice, Acherontia atropos, Scopulani gropunctata, Orthonama obstipata, Horisme corticata, Narraga fasciolaria, Isturgia arenacearia, Rhyparia purpurata, Catocala elocata, Catocala electa, Chrysodeixis chalcites, Heliothis adaucta, Helicoverpa armigera, Caradrina kadenii, Mythimna vitellina, Peridromasaucium, Agrotis bigramma, Xestia ditrapezium, Nycteola asiatica. In northernmost Sweden Gazoryctra ganna was found for the third successive year, showing that the moth is resident in Sweden and presumably has been so during all the year it was not found. Also, one new, small population of Lycaena helle was found indicating that the species still lingers on 3-4 localities in Northernmost Sweden. In Skåne in southernmost Sweden the moths Lithostege farinata, Hadena filograna have been observed again after many years absence. They have been considered as nationally respectively regionally extinct, but hopefully new influx or some concealed unknown population may rescue the species survival in Skåne again. The number of macrolepidoptera found in Sweden is now 1130, of which 16 are introduced.

Ecosystem engineers affect other organisms by creating, maintaining or modifying habitats, potentially supporting species of conservation concern. However, it is important to consider these interactions alongside non-engineering trophic pathways. We investigated the relative importance of trophic and non-trophic effects of an ecosystem engineer, red deer, on a locally rare moth, the transparent burnet (Zygaena purpuralis). This species requires specific microhabitat conditions, including the foodplant, thyme, and bare soil for egg-laying. The relative importance of grazing (i.e., trophic effect of modifying microhabitat) and trampling (i.e., non-trophic effect of exposing bare soil) by red deer on transparent burnet abundance is unknown. We tested for these effects using a novel method of placing pheromone-baited funnel traps in the field. Imago abundance throughout the flight season was related to plant composition, diversity and structure at various scales around each trap. Indirect effects of red deer activity were accounted for by testing red deer pellet and trail presence against imago abundance. Imago abundance was positively associated with thyme and plant diversity, whilst negatively associated with velvet grass and heather species cover. The presence of red deer pellets and trails were positively associated with imago abundance. The use of these sites by red deer aids the transparent burnet population via appropriate levels of grazing and the provision of a key habitat condition, bare soil, in the form of deer trails. This study shows that understanding how both trophic and non-trophic interactions affect the abundance of a species provides valuable insights regarding conservation objectives.

We examined the distribution of sesiid species in the triangle Upper-, Lower Austria and the Czech Republic between 2015 and 2020, and registered the occurrence of 19 species. So far, only four species have been known on the Austrian side of the mountains. We discovered ten other species in this area,and a total of 14 species are now known on the Austrian side. Ten species were previously known on the Czech side of the mountains, and we newly registered eight more. Because Synanthedon andrenaeformis (Laspeyres 1801) is among the 14 known species in Austria, but it is not yet found on the Czech side of the border, we have recorded a total of 19 species in the study area.

Wir haben im Dreieck Ober-, Niederösterreich und Tschechien in den Jahren 2015 bis 2020 dieVerbreitung der Sesiidae untersucht undinsgesamt 19 Arten festgestellt. Bisherwaren auf der österreichischen Seite desGebirges nur vier Arten bekannt. Beiunseren Untersuchungen haben wirzehn weitere entdeckt. Insgesamt sindjetzt auf österreichischer Seite 14 Artenbekannt. Auf der tschechischen Seite desGebirges waren bisher zehn (Špatenka2015) bekannt, jetzt kamen noch achtweitere dazu. Unter den in Österreich14 bekannten Arten war auch Synanthedon andrenaeformis (Laspeyres 1801),welche bisher auf der tschechischenSeite des untersuchten Gebietes nichtbekannt war, damit erhöht sich im untersuchten Gebiet die Zahl auf 19 nachgewiesene Spezies.

This is the 48th annual report of new and interesting finds of Macrolepidoptera in Sweden with a compilation of new provincial records. This season was warm compared with what was previously average in Sweden, except for the north-easternmost parts of the country and some areas in the Swedish mountains, which partly experienced cool and wet weather. However, the summer temperatures were much less extreme than in 2018, with some cool spells as well. The presence of Gazoryctra ganna as a native species was confirmed by additional observations on the same site as in previous year, plus the discovery of new location further north in the Torne valley. A large number of species continues to expand northwards and inlands like Idaea emarginata, Apeira syringaria, Cryphia algae, Apameaepomidion, Cirrhia ocellaris, Atethmia centrago, Agrotis puta, Apamea scolopacina; and some also are rounding the Gulf of Bothnia from the east like Globia sparganii and Noctua comes. Many migrant species were found in periods with S-SE winds like Agriusconvolvuli, Acherontia atropos, Macroglossum stellatarum, Hyles euphorbiae, Orthonamaobstipata, Hypena lividalis, Eublemma purpurina, Heliothis peltigera, Heliothis adaucta, Heli-coverpa armigera, Spodoptera exigua, Fabula zollikoferi, Mythimna vitellina, Agrotisbigramma, Xestia ditrapezium and Nycteola asiatica. The globally widespread moth Utetheisapulchella was recorded for the first time in Sweden on the Baltic islands Öland and Gotland. The butterfly Melitaea britomartis (CR) could not be rediscovered for the second year and must now be considered as extinct in Sweden. In addition, the butterfly Plebejus argyrognomon(EN) was not found this year and appears to have gone extinct. Both these butterfly specieshave almost unique subspecies in Sweden which makes this loss very serious. 

Climate and land use change can alter the incidence and strength of biotic interactions, with important effects on the distribution, abundance and function of species. To assess the importance of these effects and their dynamics, studies quantifying how biotic interactions change in space and time are needed. We studied interactions between nettle-feeding butterflies and their shared natural enemies (parasitoids) locally and across 500 km latitudinal gradient in Sweden. We also examined the potential impact of the range-expansion of the butterfly Araschnia levana on resident butterflies via shared parasitoids, by studying how parasitism in resident butterflies covaries with the presence or absence of the newly-established species. We collected 6777 larvae of four nettle-feeding butterfly species (Aglais urticae, Aglais io, Ar. levana and Vanessa atalanta), over two years, at 19 sites distributed along the gradient. We documented the parasitoid complex for each butterfly species and measured their overlap, and analysed how parasitism rates were affected by butterfly species assemblage, variations in abundance, time, and the arrival of Ar. levana. Parasitoids caused high mortality, with substantial overlap in the complex of parasitoids associated with the four host butterflies. Levels of parasitism differed significantly among butterflies and were influenced by the local butterfly species assemblage. Our results also suggest that parasitism in resident butterflies is elevated at sites where Ar. levana has been established for a longer period. In our study system, variations in butterfly species assemblages were associated in a predictable way with substantial variations in rates of parasitism. This relationship is likely to affect the dynamics of the butterfly host species, and potentially cascade to the larger number of species with which they interact. These results highlight the importance of indirect interactions and their potential to reorganise ecological communities, especially in the context of shifts in species distributions in a warmer world.

Burnet moths (Zygaena spp.) are day-flying Lepidoptera considered indicative of species-rich grasslands. In the present study, our aim was to clarify whether clear-cuts are habitat, supporting habitat or matrix for three species of Zygaena. We did so by sampling these species with sex pheromones on 48 clear-cuts, varying in amount of host and nectar plants, in southern Sweden. To compare the efficiency of such sampling, we also conducted transect walks on these clearcuts. Overall, host-plants on clear-cuts best explained the abundance of Zygaena spp. recorded, better than nectar-plants or connectivity with nearby grasslands. These results indicate that clear-cuts with an abundance of host plants are used as a fully functional habitat, and not a supporting habitat in the sense of only providing nectar. There is no support in these results for considering clear-cuts as an inert matrix. With about half the work-effort, pheromone traps recorded 100 times more Zygaena spp. as transect walks. The poor correspondence between observations during transects walks and pheromone trap catches suggest Zygaena spp. being difficult to monitor by transect walks. In contrast to grasslands, clear-cuts are short-term in nature requiring repeated recolonization, indicating the importance of permanent grasslands. However, clear-cuts are important temporary insect habitats due to their great acreage, and suitable management can increase the time they remain a habitat.

Whittleia retiella (Newman, 1847) is a threatened salt marsh species of the bagworm moth family Psychidae. For its preservation it is necessary to develop efficient tools to survey its distribution and habitat requirements in order to use appropriate conservation methods. Such tools may be pheromone-based monitoring systems, which have documented efficacy in establishing the occurrence of cryptic insect species in nature. By using gas chromatography combined with electroantennographic detection (GC-EAD), we found two compounds in female W. retiella headspace samples and whole-body extracts that elicited electrophysiological activity in male antennae. Gas chromatograpy coupled with mass spectrometry (GC-MS) operating in electron impact (EI) mode and comparison of the analytical data with those of synthetic reference compounds showed the chemical structures of these putative pheromone components to be (1S)-1-methylpropyl (5Z)-dec-5-enoate and 1-methylethyl (5Z)-dec-5-enoate. Field assays using baits loaded with synthetic compounds revealed that conspecific males were attracted to (1S)-1-methylpropyl (5Z)-dec-5-enoate alone or in combination with 1-methylethyl (5Z)-dec-5-enoate, whereas 1-methylethyl (5Z)-dec-5-enoate neither attracted nor repelled males in the field assays when tested alone. This study shows the potential of using (1S)-1-methylpropyl (5Z)-dec-5-enoate for monitoring W. retiella to gather more detailed information about the geographic distribution and habitat needs of this rare moth.

Detta är den 47:e årliga rapporten i Entomologisk Tidskrift som behandlar intressanta storfjärilsfynd i Sverige. I texten tas arter upp som författarna och granskare bedömt som intressanta ur främst ett riksperspektiv. Det kan till exempel gälla tillfälligt förekommande arter, arter som expanderar och sprider sig i landet, arter som minskar i antal eller vars utbredning är ofullständigt känd. I arbetet med ”Rödlistan över fjärilar” (se nedan) är alla rapporter viktiga bidrag till att förstå arternas nuvarande status. En del arter har en mer omfattande text och dessa bygger ofta på rapportörernas egna erfarenheter. Från Artportalen är endast fynd som har kunnat valideras medtagna och dessa är markerade med AP. Det kanske mest anmärkningsvärda storfjärilsfyndet detta år är silverbandad rotfjäril, Gazoryctra ganna (Hübner, 1808), som återfunnits i en population i Norrbotten, Tornedalen. Det är 172 år sedan arten för första och fram tills nu enda gången noterats i landet. Även ytterligare en observation av mörkbrämat ängsfly, Mniotype bathensis (Lutzau, 1901), från 2015, denna gång från Jämtland, är överraskande. Fem migrerande arter rapporteras nya för landet. Dessa är Isturgia arenacearia (Denis & Schiffermüller, 1775), Ascotis selenaria (Denis & Schiffermüller, 1775), Eublemma purpurina (Denis & Schiffermüller, 1775), Caradrina kadenii (Freyer, 1836) och Leucania loreyi (Duponchel, 1827). Andra intressanta migrerande arter som rapporterats är Agrius convolvuli (Linnaeus, 1758), Macroglossum stellatarum (Linnaeus, 1758), Hyles livornica (Esper, 1779), Thaumetopoea processionea (Linnaeus, 1758), Eilema griseolum (Hübner, 1803), Grammodes stolida (Fabricius, 1775), Catocala fulminea (Scopoli, 1763), C. adultera Menetries, 1856, C. elocata (Esper, 1788), Helicoverpa armigera (Hübner, 1808), Autographa mandarina (Freyer, 1846), Spodoptera exigua (Hübner, 1808), Blepharita amica (Treitschke, 1825), Mythimna vitellina (Hübner, 1808), Peridroma saucium (Hübner, 1808), Xestia ditrapezium (Denis & Schiffermüller, 1775), och Nycteola asiatica (Krulikowsky, 1904). Totalt detta år är 145 nya landskaps- och lappmarksfynd rapporterade.

This is the 47th consecutive annual report of new and interesting finds of Macrolepidoptera in Sweden, and also a compilation of new provincial records. This summer was also warmer than average, with periods of favourable S-SE winds, which brought many migrating Lepidoptera to Sweden. Five species were for the first time recorded in Sweden. These are: Isturgia arenacearia, Ascotis selenaria, Eublemma purpurina, Caradrina kadenii and Leucania loreyi. Many other migrant moths like Agrius convolvuli, Macroglossum stellatarum, Hyles livornica, Thaumetopoea processionea, Eilema griseolum, Grammodes stolida, Catocala fulminea, C. adultera, C. elocata, Helicoverpa armigera, Autographa mandarina, Spodoptera exigua, Blepharita amica, Mythimna vittelina, Peridroma saucium, Xestia ditrapezium, and Nycteola asiatica were also recorded. This report also gives numerous examples of native butterflies and moths expanding northwards in the country due to the climate change. The number of Macrolepidoptera species found in Sweden are now 1126, of which 16 are introduced. Possibly the most remarkable observation this year is the rediscovery of Gazoryctra ganna, in northernmost Sweden, 172 year after the last and only time the species has been found in the country. In addition, a second find of the enigmatic species Mniotype bathensis from 2015 in Jämtland is also extraordinary. This observation further supports the view that the species is resident in the southern Scandinavian mountain region. Unfortunately, the situation for the endangered butterfly Melitaea britomartis is becoming extremely critical. No observations at all could be done this year in the two remaining habitats in Småland and Västmanland (Artportalen).