Microclimatic variability buffers butterfly populations against increased mortality caused by phenological asynchrony between larvae and their host plants

Climate change affects insects in several ways, including phenological shifts that may cause asynchrony between herbivore insects and their host plants. Insect larvae typically have limited movement capacity and are consequently dependent on the microhabitat conditions of their immediate surroundings. Based on intensive field monitoring over two springs and on larger-scale metapopulation-level survey over the same years, we used Bayesian spatial regression modelling to study the effects of weather and microclimatic field conditions on the development and survival of post-diapause larvae of the Glanville fritillary butterfly Melitaea cinxia on its northern range edge. Moreover, we assessed whether the observed variation in growth and survival in a spring characterized by exceptionally warm weather early in the season translated into population dynamic effects on the metapopulation scale. While similar weather conditions enhanced larval survival and growth rate in the spring, microclimatic conditions affected survival and growth contrastingly due to the phenological asynchrony between larvae and their host plants in microclimates that supported fastest growth. In the warmest microclimates, larvae reached temperatures over 20 degrees C above ambient leading to increased feeding, which was not supported by the more slowly growing host plants. At the metapopulation level, population growth rate was highest in local populations with heterogeneous microhabitats. We demonstrate how exceptionally warm weather early in the spring caused a phenological asynchrony between butterfly larvae and their host plants. Choice of warmest microhabitats for oviposition is adaptive under predominant conditions, but it may become maladaptive if early spring temperatures rise. Such conditions may lead to larvae breaking diapause earlier without equally advancing host plant growth. Microclimatic variability within and among populations is likely to have a crucial buffering effect against climate change in many insects.peerReviewe

Species traits explain long-term population trends of Finnish cuckoo wasps (Hymenoptera: Chrysididae)

1. Kleptoparasitic and parasitoid insects are expected to be particularly sensitive to changes in habitat availability due to their high trophic position and small population sizes compared with their hosts, but there are only few quantitative studies on their population changes. 2. Here, we studied the distribution and abundance of 48 kleptoparasitic and parasitoid species of cuckoo wasps (Chrysididae) and eight selected host species recorded in Finland from 1840 to 2015 based on an extensive survey of entomological collections. Population trends were assessed by studying changes in occupancy in 10 9 10 km grid squares between two study periods, 1840-1967 and 1968-2015. 3. Statistically significant decreases in occurrence were found for 11 cuckoo wasp species and one host species, while significant increases were not observed for any species. Trends of cuckoo wasps and their hosts were positively correlated, and changes were generally stronger in cuckoo wasps than in their hosts. 4. In a comparative analysis of species traits, abundance, body size and nesting type of host were related to occurrence changes of cuckoo wasps. Scarce and small species that use above ground-nesting hosts declined more than abundant and large species that use ground-nesting hosts. 5. Cuckoo wasp species dependent on dead wood are more vulnerable to changes in the environment than species associated with open sandy habitats. While both groups of species have probably suffered from habitat loss, the emergence of secondary habitats may have benefitted species living in sandy areas and compensated for the negative impact of habitat destruction.Peer reviewe

Description of the female of Hyptioxesta magadanica, with notes on the occurrence of H. magadanica and H. penthima adults (Lepidoptera, Noctuidae)

The previously unknown female of the noctuid moth Hyptioxesta magadanica (Kononenko, 1981) is described and compared with other Hyptioxesta species. The H. magadanica female is brachypterous, unlike the females of the other two species included in the genus. The female genitalia of H. magadanica and the adults of all three species are illustrated. Notes on the flight behaviour of the adults of H. magadanica and H. penthima (Erschoff, 1870) are given and their habitats are illustrated

Maatalousympäristön päiväperhosseuranta 1999–2008

Tähän raporttiin on koottu vuonna 1999 alkaneen maatalousympäristön päiväperhosseurannan päätulokset vuosilta 1999–2008. Lisäksi kuvataan kattavasti seurannassa käytetyt menetelmät. Seurantaa koordinoi Suomen ympäristökeskus ja havaintojen keräämisestä vastaavat vapaaehtoiset perhosharrastajat. Seuranta tuottaa tietoa yleisten ja melko tavanomaisten lajien runsauksien muutoksista. Perhoshavainnot kerätään ns. linjalaskentamenetelmällä. Vuosittain tuotetaan  arvio yhteensä 51 päiväperhoslajin kannankehityksestä. Yksittäisten lajien indekseistä on koostettu myös päiväperhoslajistomme tilaa laaja-alaisemmin kuvastava seurantaindikaattori. Seurantajaksolla on kertynyt havaintoja yli 430 000 yksilöä kaikkiaan 80 päiväperhoslajista. Lisäksi laskennoissa on havaittu yli 78 000 yksilöä muita suurperhosia. Havaintoja on kerätty kaikkiaan 84 eri harrastajalinjalta, joiden määrä on vaihdellut vuosittain 30 ja 55 välillä. Viime vuosina seurannan laajuus on vakiintunut noin 50 harrastajalinjaan. Seurantaverkosto on kattavin Uudellamaalla ja Varsinais-Suomessa. Päiväperhosten kannalta kesät 2000, 2002 ja 2006 olivat keskimäärin seurantajakson parhaita, ja vastaavasti kesät 2004 ja 2008 heikoimpia. Seurantajakson aikana vähentyneitä lajeja (18) on ollut selvästi enemmän kuin runsastuneita (8). Tähän vaikuttaa kuitenkin osin se, että jakson viimeinen vuosi 2008 oli sääoloiltaan perhosille erityisen epäedullinen. Seurannan toiminta on vakiintunutta, ja tuloksia levitetään aktiivisesti sekä perhosharrastajien että median tietoon. Seuranta tuottaa säännöllistä runsaustietoa yli puolesta maamme vakituisista päiväperhoslajeista

Enhancing ecosystem service provision by floral biodiversity in long-term set-asides

Species richness of pollinators increased throughout the four-year experiment in all treatments. Pollinator species richness and abundance were highest during the whole experiment in the seed mixture containing meadow plants but the difference to the other seed mixtures decreased during the last two years. The experiment showed that the benefits of applying alternative seed mixtures vary between ecosystem services. This suggests that the promotion of each ecosystem service requires specific management

Linking pollinator occurrence in field margins to pollinator visitation to a mass-flowering crop

Uncultivated field margins are important refugia for pollinating insects in agricultural landscapes. However, the spill-over of pollination services from field margins to adjacent crops is poorly understood. This study (i) examined the effects of landscape heterogeneity on pollinator occurrence in permanent field margins and pollinator visitation to adjacent mass-flowering turnip rape (Brassica rapa ssp. oleifera) in boreal agricultural landscapes, and (ii) tested whether pollinator abundance and species richness in field margins predict abundance and species richness of crop visitors. Pollinators visiting the crop were more affected by landscape heterogeneity than pollinators in adjacent margins. Species richness, total abundance, and the abundance of syrphid flies visiting the crop increased with increasing landscape heterogeneity, whereas, in field margins, landscape heterogeneity had little effect on pollinators. In field-dominated homogeneous landscapes, wild pollinators rarely visited the crop even if they occurred in adjacent margins, whereas in heterogeneous landscapes, differences between the two habitats were smaller. Total pollinator abundance and species richness in field margins were poor predictors of pollinator visitation to adjacent crop. However, high abundances of honeybees and bumblebees in margins were related to high numbers of crop visitors from these taxa. Our results suggest that, while uncultivated field margins help pollinators persist in boreal agricultural landscapes, they do not always result in enhanced pollinator visitation to the adjacent crop. More studies quantifying pollination service delivery from semi-natural habitats to crops in different landscape settings will help develop management approaches to support crop pollination.Peer reviewe

Bryodema tuberculata and Psophus stridulus in southwestern Finland (Saltatoria, Acrididae)

Bryodema tuberculata (Fabricius) was discovered as a species new to Finland at St: Säkylä, Säkylänharju, where it occurred sparsely together with Psophus stridulus (Linnaeus). The habitat on a SW-facing esker slope is described, and the spatial distribution of the two species is examined. Preliminarily estimates of the population density, aggregation and vagility are calculated for P. stridulus. The biogeography and conservation biology of the species are discussed

Attraction of Melitaea cinxia butterflies to previously-attacked hosts : a likely complement to known Allee effects?

Clumped distributions of herbivorous insect eggs often result from independent assess- ments of individual plants by different ovipositing females. Here we ask whether, in addition, plants might be rendered more or less attractive to ovipositing Melitaea cinxia butter ies by presence of conspeci c eggs and/or by prior larval attack. Both eggs and larval damage rendered Veronica spicata plants signi cantly more accept- able; the effect of eggs was particularly strong. Larval damage caused a marginally signi cant increase in acceptability of Plantago lanceolata, but there was no trend for an effect of eggs on this host. Variable oviposition preferences of Melitaeine butter ies are known to drive their metapopulation dynamics by affecting rates of emigration and patch colonization. Therefore variable host acceptability, as documented here, should do likewise, reducing emigration rates at high population densities where V. spicata is present in the landscape and complementing Allee effects that are already known in this system.Peer reviewe

Incorporating landscape heterogeneity into multi-objective spatial planning improves biodiversity conservation of semi-natural grasslands

Recent actions to mitigate biodiversity loss in agricultural environments appear insufficient despite the considerable efforts channeled via the European Union’s Common Agricultural Policy. One likely reason for this failure is the limited attention paid to the regional and landscape level ecological characteristics in farmland conservation planning. We demonstrate how to obtain conservation prioritization solutions that would address simultaneously three goals, including two landscape level targets: minimizing local habitat quality loss, maximizing habitat connectivity, and incorporating landscape heterogeneity. As these goals may be contradictory, we investigate the potential trade-offs between them. We used the Zonation prioritization tool to examine how our three goals could be implemented in the agricultural landscapes of southwest Finland. We used measures of (i) biodiversity value of grasslands, (ii) connectivity between grasslands, and (iii) landscape heterogeneity which comprised of (land cover type based) compositional heterogeneity and (field margin based) configurational heterogeneity. Integration of landscape heterogeneity measures and habitat connectivity resulted in some tradeoffs with local habitat quality, the most prominent observation being that landscape heterogeneity co-varied with grassland connectivity. Among the two landscape heterogeneity parameters, inclusion of compositional heterogeneity resulted in more clustered prioritization solutions than configurational heterogeneity, which had a spatially more balanced impact. Concordance among landscape scale factors implies high potential for reconstruction of a functioning network of semi-natural grasslands in areas under intensive agricultural use. Broader scale multi-objective planning approaches can thus importantly support targeting biodiversity conservation planning and mediating the implementation of Common Agricultural Policy objectives.peerReviewe

Ecosystem service provision by establishing temporal habitats in agricultural environments

Ecosystem services can be promoted by establishing temporal habitats. The most beneficial management varies between ecosystem services. Area of temporal habitats supported by AES should be increased in agricultural landscape