Skip header and navigation

Refine By

13 records – page 1 of 2.

Are the Antarctic dipteran, Eretmoptera murphyi, and Arctic collembolan, Megaphorura arctica, vulnerable to rising temperatures?

https://arctichealth.org/en/permalink/ahliterature261607
Source
Bull Entomol Res. 2014 Aug;104(4):494-503
Publication Type
Article
Date
Aug-2014
Author
M J Everatt
P. Convey
M R Worland
J S Bale
S A L Hayward
Source
Bull Entomol Res. 2014 Aug;104(4):494-503
Date
Aug-2014
Language
English
Publication Type
Article
Keywords
Acclimatization - physiology
Adaptation, Biological - physiology
Analysis of Variance
Animals
Antarctic Regions
Arctic Regions
Climate change
Ecosystem
Insects - physiology
Motor Activity - physiology
Statistics, nonparametric
Temperature
Abstract
Polar terrestrial invertebrates are suggested as being vulnerable to temperature change relative to lower latitude species, and hence possibly also to climate warming. Previous studies have shown Antarctic and Arctic Collembola and Acari to possess good heat tolerance and survive temperature exposures above 30 °C. To test this feature further, the heat tolerance and physiological plasticity of heat stress were explored in the Arctic collembolan, Megaphorura arctica, from Svalbard and the Antarctic midge, Eretmoptera murphyi, from Signy Island. The data obtained demonstrate considerable heat tolerance in both species, with upper lethal temperatures =35 °C (1 h exposures), and tolerance of exposure to 10 and 15 °C exceeding 56 days. This tolerance is far beyond that required in their current environment. Average microhabitat temperatures in August 2011 ranged between 5.1 and 8.1 °C, and rarely rose above 10 °C, in Ny-Ålesund, Svalbard. Summer soil microhabitat temperatures on Signy Island have previously been shown to range between 0 and 10 °C. There was also evidence to suggest that E. murphyi can recover from high-temperature exposure and that M. arctica is capable of rapid heat hardening. M. arctica and E. murphyi therefore have the physiological capacity to tolerate current environmental conditions, as well as future warming. If the features they express are characteristically more general, such polar terrestrial invertebrates will likely fare well under climate warming scenarios.
PubMed ID
24816280 View in PubMed
Less detail

Cold tolerance of Alpine, Arctic, and Antarctic Collembola and mites.

https://arctichealth.org/en/permalink/ahliterature12995
Source
Cryobiology. 1981 Apr;18(2):212-20
Publication Type
Article
Date
Apr-1981

Do birds see the forest for the trees? Scale-dependent effects of tree diversity on avian predation of artificial larvae.

https://arctichealth.org/en/permalink/ahliterature275256
Source
Oecologia. 2016 Mar;180(3):619-30
Publication Type
Article
Date
Mar-2016
Author
Evalyne W Muiruri
Kalle Rainio
Julia Koricheva
Source
Oecologia. 2016 Mar;180(3):619-30
Date
Mar-2016
Language
English
Publication Type
Article
Keywords
Animals
Biodiversity
Birds - physiology
Ecosystem
Finland
Food Preferences
Herbivory
Insects - physiology
Larva
Population Density
Predatory Behavior - physiology
Trees - physiology
Abstract
The enemies hypothesis states that reduced insect herbivory in mixed-species stands can be attributed to more effective top-down control by predators with increasing plant diversity. Although evidence for this mechanism exists for invertebrate predators, studies on avian predation are comparatively rare and have not explicitly tested the effects of diversity at different spatial scales, even though heterogeneity at macro- and micro-scales can influence bird foraging selection. We studied bird predation in an established forest diversity experiment in SW Finland, using artificial larvae installed on birch, alder and pine trees. Effects of tree species diversity and densities on bird predation were tested at two different scales: between plots and within the neighbourhood around focal trees. At the neighbourhood scale, birds preferentially foraged on focal trees surrounded by a higher diversity of neighbours. However, predation rates did not increase with tree species richness at the plot level and were instead negatively affected by tree height variation within the plot. The highest probability of predation was observed on pine, and rates of predation increased with the density of pine regardless of scale. Strong tree species preferences observed may be due to a combination of innate bird species preferences and opportunistic foraging on profitable-looking artificial prey. This study therefore finds partial support for the enemies hypothesis and highlights the importance of spatial scale and focal tree species in modifying trophic interactions between avian predators and insect herbivores in forest ecosystems.
PubMed ID
26201260 View in PubMed
Less detail

Facilitation in an insect-pollinated herb with a floral display dimorphism.

https://arctichealth.org/en/permalink/ahliterature80919
Source
Ecology. 2006 Aug;87(8):2113-7
Publication Type
Article
Date
Aug-2006
Author
Toräng Per
Ehrlén Johan
Agren Jon
Author Affiliation
Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Villavägen 14, SE-752 36 Uppsala, Sweden. per.torang@ebc.uu.se
Source
Ecology. 2006 Aug;87(8):2113-7
Date
Aug-2006
Language
English
Publication Type
Article
Keywords
Animals
Flowers - anatomy & histology - growth & development
Fruit - growth & development
Insects - physiology
Pollen
Primula - anatomy & histology - growth & development - physiology
Reproduction
Seeds - growth & development
Sweden
Abstract
Population context should influence pollination success and selection on floral display in animal-pollinated plants because attraction of pollinators depends not only on the characteristics of individual plants, but also on the attractiveness of co-occurring conspecifics. The insect-pollinated herb Primula farinosa is polymorphic for inflorescence height. Natural populations may include both long-scaped plants, which present their flowers well above the soil surface, and short-scaped plants, with their flowers positioned close to the ground. We experimentally tested whether seed production in short-scaped P. farinosa varied with local morph frequency and surrounding vegetation height. In tall vegetation, short-scaped plants in polymorphic populations produced more fruit and tended to produce more seeds than short-scaped plants did in monomorphic populations. In low vegetation, population composition did not significantly affect fruit and seed output of short-scaped plants. The results suggest that long-scaped plants facilitate short-scaped plants in terms of pollinator attraction and that the facilitation effect is contingent on the height of the surrounding vegetation. The documented facilitation should contribute to the maintenance of the scape length polymorphism in ungrazed areas where litter accumulates and vegetation grows tall.
PubMed ID
16937650 View in PubMed
Less detail

How does climate warming affect plant-pollinator interactions?

https://arctichealth.org/en/permalink/ahliterature95469
Source
Ecol Lett. 2009 Feb;12(2):184-95
Publication Type
Article
Date
Feb-2009
Author
Hegland Stein Joar
Nielsen Anders
Lázaro Amparo
Bjerknes Anne-Line
Totland Ørjan
Author Affiliation
Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, PO Box 5003, N-1432 As, Norway. stein.hegland@umb.no
Source
Ecol Lett. 2009 Feb;12(2):184-95
Date
Feb-2009
Language
English
Publication Type
Article
Keywords
Animals
Evolution
Flowers - growth & development - physiology
Greenhouse Effect
Insects - physiology
Plants - growth & development
Pollination
Reproduction
Seasons
Temperature
Abstract
Climate warming affects the phenology, local abundance and large-scale distribution of plants and pollinators. Despite this, there is still limited knowledge of how elevated temperatures affect plant-pollinator mutualisms and how changed availability of mutualistic partners influences the persistence of interacting species. Here we review the evidence of climate warming effects on plants and pollinators and discuss how their interactions may be affected by increased temperatures. The onset of flowering in plants and first appearance dates of pollinators in several cases appear to advance linearly in response to recent temperature increases. Phenological responses to climate warming may therefore occur at parallel magnitudes in plants and pollinators, although considerable variation in responses across species should be expected. Despite the overall similarities in responses, a few studies have shown that climate warming may generate temporal mismatches among the mutualistic partners. Mismatches in pollination interactions are still rarely explored and their demographic consequences are largely unknown. Studies on multi-species plant-pollinator assemblages indicate that the overall structure of pollination networks probably are robust against perturbations caused by climate warming. We suggest potential ways of studying warming-caused mismatches and their consequences for plant-pollinator interactions, and highlight the strengths and limitations of such approaches.
PubMed ID
19049509 View in PubMed
Less detail

Inferring the effects of potential dispersal routes on the metacommunity structure of stream insects: as the crow flies, as the fish swims or as the fox runs?

https://arctichealth.org/en/permalink/ahliterature273932
Source
J Anim Ecol. 2015 Sep;84(5):1342-53
Publication Type
Article
Date
Sep-2015
Author
Olli-Matti Kärnä
Mira Grönroos
Harri Antikainen
Jan Hjort
Jari Ilmonen
Lauri Paasivirta
Jani Heino
Source
J Anim Ecol. 2015 Sep;84(5):1342-53
Date
Sep-2015
Language
English
Publication Type
Article
Keywords
Animal Distribution
Animals
Biodiversity
Energy Metabolism
Finland
Geography
Insects - physiology
Rivers
Abstract
1. Metacommunity research relies largely on proxies for inferring the effect of dispersal on local community structure. Overland and watercourse distances have been typically used as such proxies. A good proxy for dispersal should, however, take into account more complex landscape features that can affect an organism's movement and dispersal. The cost distance approach does just that, allowing determining the path of least resistance across a landscape. 2. Here, we examined the distance decay of assemblage similarity within a subarctic stream insect metacommunity. We tested whether overland, watercourse and cumulative cost distances performed differently as correlates of dissimilarity in assemblage composition between sites. We also investigated the effect of body size and dispersal mode on metacommunity organization. 3. We found that dissimilarities in assemblage composition correlated more strongly with environmental than physical distances between sites. Overland and watercourse distances showed similar correlations to assemblage dissimilarity between sites, being sometimes significantly correlated with biological variation of entire insect communities. In metacommunities deconstructed by body size or dispersal mode, contrary to our expectation, passive dispersers showed a slightly stronger correlation than active dispersers to environmental differences between sites, although passive dispersers also showed a stronger correlation than active dispersers to physical distances between sites. The strength of correlation between environmental distance and biological dissimilarity also varied slightly among the body size classes. 4. After controlling for environmental differences between sites, cumulative cost distances were slightly better correlates of biological dissimilarities than overland or watercourse distances between sites. However, quantitative differences in correlation coefficients were small between different physical distances. 5. Although environmental differences typically override physical distances as determinants of the composition of stream insect assemblages, correlations between environmental distances and biological dissimilarities are typically rather weak. This undetermined variation may be attributable to dispersal processes, which may be captured using better proxies for the process. We suggest that further modifying the measurement of cost distances may be a fruitful avenue, especially if complemented by more direct natural history information on insect dispersal behaviour and distances travelled by them.
PubMed ID
25981411 View in PubMed
Less detail

Insect emergence in relation to floods in wet meadows and swamps in the River Dalälven floodplain.

https://arctichealth.org/en/permalink/ahliterature261633
Source
Bull Entomol Res. 2014 Aug;104(4):453-61
Publication Type
Article
Date
Aug-2014
Author
T Z Persson Vinnersten
Ö. Östman
M L Schäfer
J O Lundström
Source
Bull Entomol Res. 2014 Aug;104(4):453-61
Date
Aug-2014
Language
English
Publication Type
Article
Keywords
Animals
Floods
Insects - physiology
Life Cycle Stages - physiology
Linear Models
Population Dynamics
Rivers
Species Specificity
Sweden
Wetlands
Abstract
Annual variation in flood frequency and hydroperiod during the vegetation season has ecological impacts on the floodplain biota. Although many insect groups may have a lower emergence during a flood event, it is poorly known how annual emergence of insects in temporary wetlands is related to the variation in hydrology. Between May and September, we studied the weekly emergence of 18 insect taxa over six consecutive years, 2002-2007, in six temporary flooded wetlands (four wet meadows and two forest swamps) in the River Dalälven floodplains, Central Sweden. We used emergence traps to collect emerging insects from terrestrial and aquatic parts of wet meadows and swamp forests. In all wetlands, the insect fauna was numerically dominated by the orders Diptera, Hymenoptera, Coleoptera and Homoptera. On a weekly basis, 9 out of the 18 insect taxa had lower emergence in weeks with flood than in weeks with no flood, whereas no taxon had a higher emergence in weeks with flood. Over the seasons, we related insect emergence to seasonal flood frequency and length of hydroperiod. The emergence of most studied taxa decreased with increasing hydroperiod, which suggests that emergence after floods do not compensate for the reduced emergence during floods. Only Culicidae and the aquatic Chironomidae sub-families Tanypodinae and Chironominae showed an increase in emergence with increasing hydroperiod, whereas Staphylinidae peaked at intermediate hydroperiod. We conclude that a hydroperiod covering up to 40% of the vegetation season has a significant negative effect on the emergence of most taxa and that only a few taxa occurring in the temporary wetlands are actually favoured by a flood regime with recurrent and unpredictable floods.
PubMed ID
24521711 View in PubMed
Less detail

Insect overwintering in a changing climate.

https://arctichealth.org/en/permalink/ahliterature97871
Source
J Exp Biol. 2010 Mar 15;213(6):980-94
Publication Type
Article
Date
Mar-15-2010
Author
J S Bale
S A L Hayward
Author Affiliation
School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK. j.s.bale@bham.ac.uk
Source
J Exp Biol. 2010 Mar 15;213(6):980-94
Date
Mar-15-2010
Language
English
Publication Type
Article
Keywords
Acclimatization - physiology
Animals
Climate change
Cold Climate
Environment
Insects - physiology
Photoperiod
Seasons
Temperature
Trees
Tropical Climate
Abstract
Insects are highly successful animals inhabiting marine, freshwater and terrestrial habitats from the equator to the poles. As a group, insects have limited ability to regulate their body temperature and have thus required a range of strategies to support life in thermally stressful environments, including behavioural avoidance through migration and seasonal changes in cold tolerance. With respect to overwintering strategies, insects have traditionally been divided into two main groups: freeze tolerant and freeze avoiding, although this simple classification is underpinned by a complex of interacting processes, i.e. synthesis of ice nucleating agents, cryoprotectants, antifreeze proteins and changes in membrane lipid composition. Also, in temperate and colder climates, the overwintering ability of many species is closely linked to the diapause state, which often increases cold tolerance ahead of temperature-induced seasonal acclimatisation. Importantly, even though most species can invoke one or both of these responses, the majority of insects die from the effects of cold rather than freezing. Most studies on the effects of a changing climate on insects have focused on processes that occur predominantly in summer (development, reproduction) and on changes in distributions rather than winter survival per se. For species that routinely experience cold stress, a general hypothesis would be that predicted temperature increases of 1 degree C to 5 degrees C over the next 50-100 years would increase winter survival in some climatic zones. However, this is unlikely to be a universal effect. Negative impacts may occur if climate warming leads to a reduction or loss of winter snow cover in polar and sub-polar areas, resulting in exposure to more severe air temperatures, increasing frequency of freeze-thaw cycles and risks of ice encasement. Likewise, whilst the dominant diapause-inducing cue (photoperiod) will be unaffected by global climate change, higher temperatures may modify normal rates of development, leading to a decoupling of synchrony between diapause-sensitive life-cycle stages and critical photoperiods for diapause induction. In terms of climate warming and potential heat stress, the most recent predictions of summer temperatures in Europe of 40 degrees C or higher in 50-75 years, are close to the current upper lethal limit of some insects. Long-term data sets on insect distributions and the timing of annual migrations provide strong evidence for 'positive' responses to higher winter temperatures over timescales of the past 20-50 years in North America, Europe and Asia.
PubMed ID
20190123 View in PubMed
Less detail

Nutrient fluxes from insect herbivory increase during ecosystem retrogression in boreal forest.

https://arctichealth.org/en/permalink/ahliterature271945
Source
Ecology. 2016 Jan;97(1):124-32
Publication Type
Article
Date
Jan-2016
Author
Daniel B Metcalfe
Gregory M Crutsinger
Bright B Kumordzi
David A Wardle
Source
Ecology. 2016 Jan;97(1):124-32
Date
Jan-2016
Language
English
Publication Type
Article
Keywords
Animals
Environmental monitoring
Forests
Herbivory - physiology
Insects - physiology
Islands
Nitrogen - chemistry - metabolism
Phosphorus - chemistry - metabolism
Sweden
Abstract
Ecological theory, developed largely from ungulates and grassland systems, predicts that herbivory accelerates nutrient cycling more in productive than unproductive systems. This prediction may be important for understanding patterns of ecosystem change over time and space, but its applicability to other ecosystems and types of herbivore remain uncertain. We estimated fluxes of nitrogen (N) and phosphorus (P) from herbivory of a common tree species (Betula pubescens) by a common species of herbivorous insect along a -5000-yr boreal chronosequence. Contrary to established theory, fluxes of N and P via herbivory increased along the chronosequence despite a decline in plant productivity. The herbivore-mediated N and P fluxes to the soil are comparable to the main alternative pathway for these nutrients via tree leaf litterfall. We conclude that insect herbivores can make large contributions to nutrient cycling even in unproductive systems, and influence the rate and pattern of ecosystem development, particularly in systems with low external nutrient inputs.
PubMed ID
27008782 View in PubMed
Less detail

Selective photoreceptor damage in four species of insects induced by experimental exposures to UV-irradiation.

https://arctichealth.org/en/permalink/ahliterature50814
Source
Micron. 2002;33(1):23-31
Publication Type
Article
Date
2002
Author
V B Meyer-Rochow
T. Kashiwagi
E. Eguchi
Author Affiliation
Department of Biology, University of Oulu, SF-90570, Oulu, Finland. vmr@cc.oulu.fi
Source
Micron. 2002;33(1):23-31
Date
2002
Language
English
Publication Type
Article
Keywords
Animals
Bees - radiation effects
Butterflies - radiation effects
Eye - radiation effects - ultrastructure
Gryllidae - radiation effects
Insects - physiology - radiation effects
Photoreceptors, Invertebrate - radiation effects - ultrastructure
Ultraviolet Rays
Abstract
Damage to photoreceptive cells of insect compound eyes exposed to abnormally high doses of UV-radiation of 350nm peak wavelength manifests itself in at least two different ways. In the butterflies Papilio xuthus and Pieris napi from Japan and northern Finland, respectively, only the cell bodies of retinula cells 1 and 2, (identified as short wavelength receptors), but not their corresponding rhabdomeres, exhibit damage with apoptotic features. In the eye of UV-irradiated adult crickets, however, cell bodies and cytoplasm remain normal, while the rhabdomeres of cells 7 and 8 exhibit signs of severe membrane disruptions. No signs of damage whatsoever occurred in the eyes of northern Finnish bumblebees exposed to UV. It is suggested that metabolic shortfalls in the UV-sensitive cells of the butterfly eyes result in cellular shut-down, but that in the cricket receptors UV-induced changes of the membrane lipids dominate, leading to membrane instability without concomittant cell death. The strong resistance of the bumblebee eye to UV-induced damage requires further investigation, but since preconditioning to light can reduce photic damage in the rat eye, the 24h daylight experienced by northern Finnish bumblebees during the summer season could be involved.
PubMed ID
11473811 View in PubMed
Less detail

13 records – page 1 of 2.