| 1. |
- Amaya-Marquez, Marisol, et al.
(författare)
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Olfactory Learning in the Stingless Bee Melipona eburnea Friese (Apidae: Meliponini)
- 2019
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Ingår i: Insects. - : MDPI AG. - 2075-4450. ; 10:11
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Tidskriftsartikel (refereegranskat)abstract
- Olfactory learning and floral scents are co-adaptive traits in the plant-pollinator relationship. However, how scent relates to cognition and learning in the diverse group of Neotropical stingless bees is largely unknown. Here we evaluated the ability of Melipona eburnea to be conditioned to scent using the proboscis extension reflex (PER) protocol. Stingless bees did not show PER while harnessed but were able to be PER conditioned to scent when free-to-move in a mini-cage (fmPER). We evaluated the effect of: 1) unconditioned stimulus (US) reward, and 2) previous scent-reward associations on olfactory learning performance. When using unscented-US, PER-responses were low on day 1, but using scented-US reward the olfactory PER-response increased on day 1. On day 2 PER performance greatly increased in bees that previously had experienced the same odor and reward combination, while bees that experienced a different odor on day 2 showed poor olfactory learning. Bees showed higher olfactory PER conditioning to guava than to mango odor. The effect of the unconditioned stimulus reward was not a significant factor in the model on day 2. This indicates that olfactory learning performance can increase via either taste receptors or accumulated experience with the same odor. Our results have application in agriculture and pollination ecology.
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| 2. |
- Anderbrant, Olle, et al.
(författare)
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Article sex pheromone of the introduced pine sawfly, diprion similis, revisited to define a useful monitoring lure : Deviating chiral composition and behavioural responses compared to earlier reports
- 2021
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Ingår i: Insects. - : MDPI. - 2075-4450. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Extracts of Diprion similis females contained about 15 ng of the sex pheromone precursor 3,7‐dimethylpentadecan‐2‐ol per female. After derivatisation with (S)‐2‐acetoxypropanoyl chloride, we found that the major stereoisomer in the extract was (2S,3R,7R)‐3,7‐dimethylpentadecan‐2‐ol. Small amounts of other stereoisomers of 3,7‐dimethylpentadecan‐2‐ol were also identified in the extract, namely 1% of (2R,3S,7S), 0.3% (2R,3R,7R) and 0.4% of (2R,3R,7S). An unknown fifth substance showed a very similar spectrum to 3,7‐dimethylpentadecan‐2‐ol, both in SIM and full scan mode. None of the earlier suggested behavioural synergistic isomers ((2S,3S,7S), (2S,3S,7R) and (2S,3R,7S)) were detected in the extracts. In field tests in Ontario, Canada, the earlier identified main pheromone component, viz. the propanoate of (2S,3R,7R)‐3,7‐dimethylpentadecan‐2‐ol, was tested alone and in combination with other stereoisomers, earlier reported to be synergistic. No synergistic effects were detected and the threo four‐isomer blend was as attractive as the pure main compound. Thus, one of the few examples of a diprionid sawfly using more than one substance in its sex pheromone could not be confirmed. The results also suggest that monitoring programs can use the more easily synthesized threo‐blend without losing efficiency. Furthermore, the study suggests that other diprionid pheromones may benefit from a reinvestigation, to clarify possible synergistic effects of stereoisomers.
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| 3. |
- Andonov, Sreten
(författare)
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Evaluation of Suppressed Mite Reproduction (SMR) Reveals Potential for Varroa Resistance in European Honey Bees (Apis melliferaL.)
- 2020
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Ingår i: Insects. - : MDPI AG. - 2075-4450. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary The miteVarroa destructorrepresents a great threat to honey bees and the beekeeping industry. The opportunity to select and breed honey bees that are naturally able to fight the mite stands a sustainable solution. This can be achieved by evaluation of the failure of mite reproduction (SMR, suppressed mite reproduction). We conducted a large European experiment to assess the SMR trait in different populations of honey bees spread over 13 different countries, and representing different honey bee populations. The first goal was to standardize and validate the SMR evaluation method, and then to compare the SMR trait between the different populations. Our results indicate that it is necessary to examine at least 35 brood cells infested by a single mite to reliably estimate the SMR score of any given colony. Several colonies from our dataset display high SMR scores, indicating that this trait is present within the European honey bee populations. No major differences could be identified between countries for a given population, or between populations in different countries. This study shows the potential to increase selection efforts to breedV. destructorhoney bee resistant populations. In the fight against theVarroa destructormite, selective breeding of honey bee (Apis melliferaL.) populations that are resistant to the parasitic mite stands as a sustainable solution. Selection initiatives indicate that using the suppressed mite reproduction (SMR) trait as a selection criterion is a suitable tool to breed such resistant bee populations. We conducted a large European experiment to evaluate the SMR trait in different populations of honey bees spread over 13 different countries, and representing different honey bee genotypes with their local mite parasites. The first goal was to standardize and validate the SMR evaluation method, and then to compare the SMR trait between the different populations. Simulation results indicate that it is necessary to examine at least 35 single-infested cells to reliably estimate the SMR score of any given colony. Several colonies from our dataset display high SMR scores indicating that this trait is present within the European honey bee populations. The trait is highly variable between colonies and some countries, but no major differences could be identified between countries for a given genotype, or between genotypes in different countries. This study shows the potential to increase selective breeding efforts ofV. destructorresistant populations.
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| 4. |
- Audusseau, Hélène, et al.
(författare)
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Ecology and Genetic Structure of the Parasitoid Phobocampe confusa (Hymenoptera: Ichneumonidae) in Relation to Its Hosts, Aglais Species (Lepidoptera: Nymphalidae)
- 2020
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Ingår i: Insects. - : MDPI AG. - 2075-4450. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- The biology of parasitoids in natural ecosystems remains very poorly studied, though they are key species for their functioning. Here we focused on Phobocampe confusa, a Nymphalini specialist, responsible for high mortality rates in charismatic butterfly species in Europe (genus Aglais). We studied its ecology and genetic structure in connection with those of its host butterflies in Sweden. To this aim, we gathered data from 428 P. confusa individuals reared from 6094 butterfly larvae (of A. urticae, A. io, and in two occasions of Araschnia levana) collected over two years (2017 and 2018) and across 19 sites distributed along a 500 km latitudinal gradient. We found that P. confusa is widely distributed along the latitudinal gradient. Its distribution seems constrained over time by the phenology of its hosts. The large variation in climatic conditions between sampling years explains the decrease in phenological overlap between P. confusa and its hosts in 2018 and the 33.5% decrease in the number of butterfly larvae infected. At least in this study, P. confusa seems to favour A. urticae as host. While it parasitized nests of A. urticae and A. io equally, the proportion of larvae parasitized is significantly higher for A. urticae. At the landscape scale, P. confusa is almost exclusively found in vegetated open land and near deciduous forests, whereas artificial habitats are negatively correlated with the likelihood of a nest to be parasitized. The genetic analyses on 89 adult P. confusa and 87 adult A. urticae using CO1 and AFLP markers reveal a low genetic diversity in P. confusa and a lack of genetic structure in both species, at the scale of our sampling. Further genetic studies using high-resolution genomics tools will be required to better understand the population genetic structure of P. confusa, its biotic interactions with its hosts, and ultimately the stability and the functioning of natural ecosystems.
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| 5. |
- Bohman, Björn
(författare)
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It Is Not All about Being Sweet: Differences in Floral Traits and Insect Visitation among Hybrid Carrot Cultivars
- 2020
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Ingår i: Insects. - : MDPI AG. - 2075-4450. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Cytoplasmically male-sterile (CMS) carrot cultivars suffer from low pollination rates. In this study, insect visitation varied more than eightfold between 17 CMS carrot cultivars in a field-based cultivar evaluation trial. The visitation rates of honey bees, nectar scarabs, muscoid flies, and wasps each significantly differed among these cultivars. No significant difference in visitation rates was observed among cultivars of different CMS type (brown-anther or petaloid) or flower colour, but cultivars of Berlicumer root type had significantly higher insect visitation rates than Nantes. Six cultivars were further compared in regard to selected umbel traits: as umbel diameter increased, so did the visitation of soldier beetles, while that of honey bees decreased. Finally, nectar of these six cultivars was analysed for sugar content, which revealed monosaccharides to be the most common sugars in all. There was high variation in the levels of sugars from individual umbellets but no significant difference in nectar sugar composition among cultivars, suggesting that nectar sugar composition is of minor importance regarding pollinator attraction to hybrid CMS carrot umbels.
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| 6. |
- Bras, Audrey
(författare)
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Diapause Regulation in Newly Invaded Environments: Termination Timing Allows Matching Novel Climatic Constraints in the Box Tree Moth, Cydalima perspectalis (Lepidoptera: Crambidae)
- 2020
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Ingår i: Insects. - : MDPI AG. - 2075-4450. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Simple SummaryThe box tree moth, Cydalima perspectalis, is an Asian pest whose rapid invasion in Europe causes considerable economic and ecological impacts. Larvae enter a winter diapause induced by photoperiod in both native and invaded ranges, but factors that trigger the return to an active phase are still unknown. Yet, identifying them is crucial to understanding how diapause end synchronizes with the end of the winter stress encountered in Europe. We tested whether activity resumption is regulated by thermal and/or photoperiodic thresholds, two factors often involved in diapause termination, by exposing diapausing caterpillars from an invaded area to crossed treatments at the laboratory. The evolution of diapause rate was monitored over time and compared to that of nearby field sites invaded. A strong positive effect of increasing temperature was found on the rate and dynamics of diapause termination, whereas no compelling effect of photoperiod appeared. Resuming development directly when main stressors fade, not in response to indirect photoperiodic cues that could be mismatched outside native areas, likely contributes to the good match observed between diapause and the new climates encountered in the invaded range. This finding can improve phenological modelling of the overwintering generation and help better mitigate its damage.The association between indirect environmental cues that modulate insect diapause and the actual stressors is by no means granted when a species encounters new environments. The box tree moth, Cydalima perspectalis, is an Asian pest whose rapid invasion in Europe causes considerable economic and ecological impacts. Larvae enter a winter diapause induced by the photoperiod in both native and invaded ranges, but factors that trigger the return to an active phase are still unknown. Yet, identifying them is crucial to understand how diapause end synchronizes with the end of the winter stress encountered in Europe. To test whether activity resumption is regulated by thermal and/or photoperiodic thresholds, or additive effects between these factors often involved in diapause termination, diapausing caterpillars from an invaded area were exposed to crossed treatments at the laboratory. The evolution of diapause rate was monitored over time and compared to that of nearby field sites invaded. A strong positive effect of increasing temperature was found on the rate and dynamics of diapause termination, whereas no compelling effect of photoperiod appeared. Resuming development directly when main stressors fade, not in response to indirect photoperiodic cues that could be mismatched outside native areas, likely contributes to the good match observed between diapause and the new climates that this pest encountered in the invaded range.
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| 7. |
- Ceder, Mikaela M., et al.
(författare)
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The Fly Homologue of MFSD11 Is Possibly Linked to Nutrient Homeostasis and Has a Potential Role in Locomotion : A First Characterization of the Atypical Solute Carrier CG18549 in Drosophila Melanogaster
- 2021
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Ingår i: Insects. - : MDPI. - 2075-4450. ; 12:11
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Tidskriftsartikel (refereegranskat)abstract
- Cellular transport and function are dependent on substrate influx and efflux of various compounds. In humans, the largest superfamily of transporters is the SoLute Carriers (SLCs). Many transporters are orphans and little to nothing is known about their expression and/or function, yet they have been assigned to a cluster called atypical SLCs. One of these atypical SLCs is MFSD11. Here we present a first in-depth characterization of the MFSD11, CG18549. By gene expression and behavior analysis on ubiquitous and brain-specific knockdown flies. CG18549 knockdown flies were found to have altered adipokinetic hormone and adipokinteic hormone receptor expression as well as reduced vesicular monoamine transporter expression; to exhibit an altered locomotor behavior, and to have an altered reaction to stress stimuli. Furthermore, the gene expression of CG18549 in the brain was visualized and abundant expression in both the larvae and adult brain was observed, a result that is coherent with the FlyAtlas Anatomy microarray. The exact mechanism behind the observed behaviors is not fully understood, but this study provides new insights into the expression and function of CG18549. Clearly, these results provide a strong example as to why it is vital to fully characterize orphan transporters and through that gain knowledge about the body during normal condition and disease.
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| 8. |
- Cotes Ramal, Belén
(författare)
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Spider Communities and Biological Control in Native Habitats Surrounding Greenhouses
- 2018
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Ingår i: Insects. - : MDPI AG. - 2075-4450. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The promotion of native vegetation as a habitat for natural enemies, which could increase their abundance and fitness, is especially useful in highly simplified settings such as Mediterranean greenhouse landscapes. Spiders as generalist predators may also be involved in intra-guild predation. However, the niche complementarity provided by spiders as a group means that increased spider diversity may facilitate complementary control actions. In this study, the interactions between spiders, the two major horticultural pests, Bemisia tabaci and Frankliniella occidentalis, and their naturally occurring predators and parasitoids were evaluated in a mix of 21 newly planted shrubs selected for habitat management in a highly disturbed horticultural system. The effects of all factors were evaluated using redundancy analysis (RDA) and the generalized additive model (GAM) to assess the statistical significance of abundance of spiders and pests. The GAM showed that the abundance of both pests had a significant effect on hunter spider's abundance, whereas the abundance of B. tabaci, but not F. occidentalis, affected web-weavers' abundance. Ordination analysis showed that spider abundance closely correlated with that of B. tabaci but not with that of F. occidentalis, suggesting that complementarity occurs, and thereby probability of biocontrol, with respect to the targeted pest B. tabaci, although the temporal patterns of the spiders differed from those of F. occidentalis. Conservation strategies involving the establishment of these native plants around greenhouses could be an effective way to reduce pest populations outdoors.
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| 9. |
- Coulson, Stephen
(författare)
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Changing microarthropod communities in front of a receding glacier in the High Arctic
- 2020
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Ingår i: Insects. - : MDPI AG. - 2075-4450. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- This study was carried out at Ny-angstrom lesund on Spitsbergen in Svalbard (High Arctic). Eight study sites were established along a transect from the fjord to the snout of the glacier. The sites differed from each other by the type of vegetation cover and soil characteristics. Soil samples were collected and placed in Tullgren funnels. Extracted arthropods were represented by two groups of mites (Mesostigmata and Oribatida) and springtails (Collembola). The pioneer species that occurred first after retreat of the glacier were representatives of the Collembola (Agrenia bidenticulata and Hypogastrura concolor). Later, other springtails appeared including Folsomia alpha, Folsomia quadrioculata, Hypogastrura concolor, Isotoma anglicana, Sminthurinus concolor and the first species of oribatid mites; Camisia foveolata and Tectocepheus velatus velatus. Arthropod communities recorded along the transect were characterized by large variations in both species composition and abundance of individuals. The greater the distance from the glacier snout, the greater the species richness (2 to 22 species). The mean number of species per sample was the lowest at site 8 (1 +/- 0.71) (the closest to the glacier) and greatest at site 1 (14 +/- 1.41) (furthest from the glacier). The Simpson's diversity index (D) was distinctly greater at sites 1 (4.61 +/- 0.06) and 3 (3.94 +/- 0.11) than at other sites, especially site 8 (1.07 +/- 0.06). Densities were least in the samples closest to the glacier (30 to 101 individuals; density 3000-10,100 individuals/m2). At the other locations, abundance was highly variable (905 to 7432 individuals; density 90,500-743,200 individuals/m2). The mean abundances were greatest at sites 2 and 3. The great variations in total abundances observed were often due to the presence or absence of one or more dominant species exhibiting extreme abundance variability between sites. The microarthropod community of the High Arctic is composed of heterogeneous circumpolar species, yet on a landscape scale is extremely dependent on local environmental conditions which may be subject to rapid change.
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| 10. |
- Davydenko, Kateryna, et al.
(författare)
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Fungal Communities Vectored by Ips sexdentatus in Declining Pinus sylvestris in Ukraine: Focus on Occurrence and Pathogenicity of Ophiostomatoid Species
- 2021
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Ingår i: Insects. - : MDPI AG. - 2075-4450. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary Bark beetles serve as vectors to numerous tree pathogens, the most conspicuous guild of which are ophiostomatoid fungi. Most of these fungi are known to cause blue-stain discoloration of wood, and some of them are pathogenic to trees, in certain cases able to kill them. Over the last years, drought-induced stress and attacks by bark beetle Ips sexdentatus resulted in a massive dieback of Pinus sylvestris in Ukraine. Limited and fragmented knowledge is available as to which ophiostomatoid fungi in this geographic area are vectored by Ips sexdentatus, and their roles in tree dieback. It is known, though, that in different parts of Europe those fungal communities might significantly differ. This study represents the first and so far, the most extensive analysis of fungal associates of I. sexdentatus in eastern Europe accomplished combining different methods, using insect, plant, and fungal material, and reports a number of previously unknown insect-vectored pathogens of P. sylvestris. Increasing climate change-related disturbances to forests put reported findings in a broader geographical context. Drought-induced stress and attacks by bark beetle Ips sexdentatus currently result in a massive dieback of Pinus sylvestris in eastern Ukraine. Limited and fragmented knowledge is available on fungi vectored by the beetle and their roles in tree dieback. The aim was to investigate the fungal community vectored by I. sexdentatus and to test the pathogenicity of potentially aggressive species to P. sylvestris. Analysis of the fungal community was accomplished by combining different methods using insect, plant, and fungal material. The material consisted of 576 beetles and 96 infested wood samples collected from six sample plots within a 300 km radius in eastern Ukraine and subjected to fungal isolations and (beetles only) direct sequencing of ITS rDNA. Pathogenicity tests were undertaken by artificially inoculating three-to-four-year-old pine saplings with fungi. For the vector test, pine logs were exposed to pre-inoculated beetles. In all, 56 fungal taxa were detected, 8 exclusively by isolation, and 13 exclusively by direct sequencing. Those included nine ophiostomatoids, five of which are newly reported as I. sexdentatus associates. Two ophiostomatoid fungi, which exhibited the highest pathogenicity, causing 100% dieback and mortality, represented genera Graphium and Leptographium. Exposure of logs to beetles resulted in ophiostomatoid infections. In conclusion, the study revealed numerous I. sexdentatus-vectored fungi, several of which include aggressive tree pathogens.
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