| 1. |
- Salido, Angela, et al.
(författare)
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Context-dependent insect predation pressure on an avian ectoparasite
- 2023
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Ingår i: Insect science. - : Wiley. - 1672-9609 .- 1744-7917. ; 30:6, s. 1784-1797
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Tidskriftsartikel (refereegranskat)abstract
- Context dependence arises when ecological relationships vary with the conditions under which they are observed. Context dependence of interactions involving parasites is poorly known, even if it is key to understanding host–parasite relationships and food web dynamics. This paper investigates to which extent predation pressure on an avian ectoparasite (Carnus hemapterus) is context-dependent. Based on a predator-exclusion experiment, predation pressure on C. hemapterus pupae in the host's nest for 3 years, and its variation between habitat types are quantified. Variation in precipitation and normalized difference vegetation index (NDVI) is also explored as a likely cause of context dependency. We hypothesize that predation pressure should fluctuate with such surrogates of food availability, so that inter-annual and intra-annual differences may emerge. The number of nests with significant reduction of pupae varied widely among years ranging from 24% to 75%. However, average pupae reduction in nests where a significant reduction occurred did not vary between years. No differences in predation rates between habitat types were detected. Precipitation and NDVI varied widely between years and NDVI was consistently lower around nests on cliffs than around nests on trees and farmhouses. Parallels were found between variation in predation pressure and precipitation/NDVI at a wide scale (highest predation the driest year, and much lower the 2 rainier ones), but not at the nest scale. This paper shows clear context-dependent insect predation pressure on an ectoparasite under natural conditions, and that such interaction changes in signs rather than magnitude between years. The causes for these variations require longer-term studies and/or well-designed, large-scale experiments.
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| 2. |
- Gamberale-Stille, Gabriella, et al.
(författare)
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Host plant choice in the comma butterfly-larval choosiness may ameliorate effects of indiscriminate oviposition
- 2014
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 21:4, s. 499-506
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Tidskriftsartikel (refereegranskat)abstract
- In most phytophagous insects, the larval diet strongly affects future fitness and in species that do not feed on plant parts as adults, larval diet is the main source of nitrogen. In many of these insect host plant systems, the immature larvae are considered to be fully dependent on the choice of the mothers, who, in turn, possess a highly developed host recognition system. This circumstance allows for a potential mother-offspring conflict, resulting in the female maximizing her fecundity at the expense of larval performance on suboptimal hosts. In two experiments, we aimed to investigate this relationship in the polyphagous comma butterfly, Polygonia c-album, by comparing the relative acceptance of low- and medium-ranked hosts between females and neonate larvae both within individuals between life stages, and between mothers and their offspring. The study shows a variation between females in oviposition acceptance of low-ranked hosts, and that the degree of acceptance in the mothers correlates with the probability of acceptance of the same host in the larvae. We also found a negative relationship between stages within individuals as there was a higher acceptance of lower ranked hosts in females who had abandoned said host as a larva. Notably, however, neonate larvae of the comma butterfly did not unconditionally accept to feed from the least favorable host species even when it was the only food source. Our results suggest the possibility that the disadvantages associated with a generalist oviposition strategy can be decreased by larval participation in host plant choice.
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| 3. |
- Kozlov, Mikhail, V, et al.
(författare)
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Climate shapes the spatiotemporal variation in color morph diversity and composition across the distribution range of Chrysomela lapponica leaf beetle
- 2022
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Ingår i: Insect Science. - : John Wiley & Sons. - 1672-9609 .- 1744-7917. ; 29:3, s. 942-955
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Tidskriftsartikel (refereegranskat)abstract
- Color polymorphism offers rich opportunities for studying the eco-evolutionary mechanisms that drive the adaptations of local populations to heterogeneous and changing environments. We explored the color morph diversity and composition in a Chrysomela lapponica leaf beetle across its entire distribution range to test the hypothesis that environmental and climatic variables shape spatiotemporal variation in the phenotypic structure of a polymorphic species. We obtained information on 13 617 specimens of this beetle from museums, private collections, and websites. These specimens (collected from 1830-2020) originated from 959 localities spanning 33 degrees latitude, 178 degrees longitude, and 4200 m altitude. We classified the beetles into five color morphs and searched for environmental factors that could explain the variation in the level of polymorphism (quantified by the Shannon diversity index) and in the relative frequencies of individual color morphs. The highest level of polymorphism was found at high latitudes and altitudes. The color morphs differed in their climatic requirements; composition of colour morphs was independent of the geographic distance that separated populations but changed with collection year, longitude, mean July temperature and between-year temperature fluctuations. The proportion of melanic beetles, in line with the thermal melanism hypothesis, increased with increasing latitude and altitude and decreased with increasing climate seasonality. Melanic morph frequencies also declined during the past century, but only at high latitudes and altitudes where recent climate warming was especially strong. The observed patterns suggest that color polymorphism is especially advantageous for populations inhabiting unpredictable environments, presumably due to the different climatic requirements of coexisting color morphs.
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| 4. |
- Ngernsiri, Lertluk, et al.
(författare)
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Ten-a overexpression causes abnormal pattern in the Drosophila compound eye
- 2006
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Ingår i: Insect science. - : Wiley. - 1672-9609 .- 1744-7917. ; 13:5, s. 355-364
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Ten-a is one of the two Drosophila proteins that belong to the Ten M protein family. This protein is a type II transmembrane protein and is expressed mainly in the embryonic CNS, in the larval eye imaginal disc and in the compound eye of the pupa. Here, we investigate the role of ten-a during development of the compound eye by using the Gal4/UAS system to induce ten-a overexpression in the developing eye. We found that overexpression of ten-a can perturb eye development during all stages examined. In an early stage, overexpression of ten-a in eye primordial cells caused small and rough eyes and interfered with photoreceptor cell recruitment, resulting in some ommatidia having fewer or extra photoreceptor cells. Conversely, ten-a overexpression during ommatidial formation caused severe eye defects due to absence of many cellular components. Interestingly, overexpression of ten-a in the late stage developing ommatidial cluster affected the number of pigment cells, caused cone cells proliferation in many ommatidia, and caused some photoreceptor cell defects. These results suggest that ten-a may be a novel gene required for normal eye morphogenesis.
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| 5. |
- Norkute, Milda, et al.
(författare)
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Aphids-induced plant volatiles affect diel foraging behavior of a ladybird beetle Coccinella septempunctata
- 2020
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 27, s. 1266-1275
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Tidskriftsartikel (refereegranskat)abstract
- The ladybird beetle Coccinella septempunctata (L.) is an important biocontrol agent of pests such as various aphid species. Despite being one of the most studied coccinellid species, many aspects of its foraging behavior are still not completely understood. This study focuses on the diel foraging behavior of C. septempunctata, investigating their olfactory orientation toward aphid-infested plants, walking activity on plants and on the soil, and feeding rates. In the scotophase the ladybird beetles were significantly more attracted to the odor of aphid-infested plants, on which they also showed considerably higher walking activity then on uninfested controls. Females were more prone to utilize olfactory cues when searching for prey and fed at higher rates than males; this shows that they are better adapted to nocturnal activity, as they require higher food intake. Coccinella septempunctata have the same feeding rate during the scotophase as in the photophase. Our study shows that C. septempunctata has the potential to forage in the scotophase if prey is abundant. The results support the hypothesis that volatiles of aphid-infested plants can attract or arrest foraging adult ladybird beetles, even in the darkness, which makes a considerable contribution to efficient prey search and enhances feeding capacity.
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| 6. |
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| 7. |
- Swiergiel, Weronika, et al.
(författare)
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Soil application of Beauveria bassiana GHA against apple sawfly, Hoplocampa testudinea (Hymenoptera: Tenthredinidae): Field mortality and fungal persistence
- 2016
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 23, s. 854-868
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Tidskriftsartikel (refereegranskat)abstract
- Low impact alternatives to synthetic insecticides for the control of apple sawfly (Hoplocampa testudinea Klug) are scarce encumbering pest management in organic apple orchards. We investigated the soil persistence and field efficacy of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (BotaniGard) against apple sawfly under common organic orchard practices. We also assessed the efficacy of B. bassiana GHA and Metarhizium brunneum Petch (indigenous strain) against sawfly in the laboratory. Larvae treated with either fungus in the laboratory died faster than control larvae and displayed 49.4%-68.4% mycosis. In the field, B. bassiana density remained high in the week after application, during larval descent to the soil. Fungal density decreased to 25% at 49 d after application and to 0.4% after 55 weeks. Molecular markers revealed that the majority of fungal isolates recovered comprised the applied B. bassiana strain GHA. Larvae pupating in soil cages in the orchard for 49 d displayed 17% mycosis. The high efficacy under laboratory conditions was not seen in the field. B. bassiana application resulted in densities above the upper natural background level during the growing season, but reversion to background levels occurred within a year. It remains to be investigated whether this has a detrimental effect on nontarget organisms. Additional work is needed to bridge the knowledge gap between laboratory and field efficacy in orchards.
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| 8. |
- Walker, William
(författare)
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Identification and localization of two sensory neuron membrane proteins from Spodoptera litura (Lepidoptera: Noctuidae)
- 2015
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 22, s. 399-408
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Tidskriftsartikel (refereegranskat)abstract
- Sensory neuron membrane proteins (SNMPs), which are located on the dendritic membrane of olfactory sensory neurons (OSNs), are proposed to be associated with odor reception in insects. Recent studies have demonstrated that SNMP1 is essential for electrophysiological responses of OSNs to the sex pheromone, cis-vaccenyl acetate (cVA) in Drosophila melanogaster. To investigate the function of Lepidoptera SNMPs, we cloned two SNMP genes, SlituSNMP1 and SltiuSNMP2, from Spodoptera litura (Lepidoptera: Noctuidae). Sequence alignment and phylogenetic analysis showed that both genes bear the general characteristics of SNMPs, including six conserved cysteine residues and two transmembrane domains. Further expression profile experiments showed that SlituSNMP1 is mainly expressed in the antenna, while SlituSNMP2 is broadly expressed in various tissues. By in situ hybridization experiments, it was found that SlituSNMP1 expressing cells are surrounded by the SlituSNMP2 expressing cells in the pheromone sensitive sensilla, suggesting different functions of the two SNMPs in insect olfaction.
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| 9. |
- Yañez, Orlando, et al.
(författare)
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Distribution and variability of deformed wing virus of honeybees (Apis mellifera L.) in the Middle East and North Africa
- 2017
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 24, s. 103-113
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Tidskriftsartikel (refereegranskat)abstract
- Three hundred and eleven honeybee samples from 12 countries in the Middle East and North Africa (MENA) (Jordan, Lebanon, Syria, Iraq, Egypt, Libya, Tunisia, Algeria, Morocco, Yemen, Palestine, and Sudan) were analyzed for the presence of deformed wing virus (DWV). The prevalence of DWV throughout the MENA region was pervasive, but variable. The highest prevalence was found in Lebanon and Syria, with prevalence dropping in Palestine, Jordan, and Egypt before increasing slightly moving westwards to Algeria and Morocco Phylogenetic analysis of a 194 nucleotide section of the DWV Lp gene did not identify any significant phylogenetic resolution among the samples, although the sequences did show consistent regional clustering, including an interesting geographic gradient from Morocco through North Africa to Jordan and Syria. The sequences revealed several clear variability hotspots in the deduced amino acid sequence, which furthermore showed some patterns of regional identity. Furthermore, the sequence variants from the Middle East and North Africa appear more numerous and diverse than those from Europe.
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| 10. |
- Zmihorski, Michal
(författare)
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Changes in the speed of ants as a result of aggressive interactions
- 2017
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 24, s. 842-852
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Tidskriftsartikel (refereegranskat)abstract
- Subordinate ant species utilize different tactics to reduce competition with the stronger, larger and more aggressive individuals of a dominant species. In our experimental study, we assessed the behavioral response of individual workers of 4 subordinate ant species during their co-occurrence with workers of a single dominant species. Contrary to most classical experiments focused on aggressive interactions, we assessed workers' speed as a crucial factor in the outcome of co-occurrence. Generally, there was a large intraspecific variation in the speed of the studied specieseach had slow and fast individuals. Workers of all studied species moved faster just after interaction, suggesting that contact between 2 hostile workers is a stressful stimulus, generating a behavioral reaction of increasing speed. Also, the number of aggressive contacts experienced by a given individual positively affected its speed. Moreover, workers which were fast when exploring territory were also fast after interspecific interactions. The duration of aggression was significantly reduced by the speed and body size of a subordinate species workerthe more quickly a worker reacted and bigger it was, the shorter was the time of cumulative aggression. To our knowledge, this is the first study of this type to be conducted on ants and we conclude that speed is an overlooked and important characteristic of species and also individuals, therefore it should be considered as a driver of patterns of co-occurrence in ant assemblages.
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| 11. |
- Berggren, Åsa
(författare)
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Testing the effect of individual color morphology on immune response in bush-crickets
- 2010
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 17, s. 400-405
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Tidskriftsartikel (refereegranskat)abstract
- Despite the growing interest in how an individual's immune response is correlated to morphological and ecological factors, little empirical data has been available from wild insect populations. Many insects have different color morphs and exhibit differences in immune responses. Links are expected to exist between body colors and immune function in insects, because the same biochemical precursors involved in the immune response are responsible for melanin-based color markings. In this study, I assay the immune response of two different color morphs of 377 wild-caught bush-crickets, Metrioptera roeseli, from 20 populations by measuring individual encapsulation responses to a surgically implanted nylon monofilament. There was no difference between green and brown bush-cricket morphs (low melanin vs high melanin investment in cuticula color respectively) and their ability to mount an immune response to the implant. Further study is needed on the relationship between color morphology and immune response in wild insects, and whether trade-offs occur between factors during an insect's development phase and long-term health.
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| 12. |
- Bonet, James, et al.
(författare)
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Species richness estimations of the megadiverse scuttle fly genus Megaselia (Diptera Phoridae) in a wildfire-affected hemiboreal forest
- 2011
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 18:3, s. 325-348
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Tidskriftsartikel (refereegranskat)abstract
- The species richness of the scuttle fly (Diptera: Phoridae) genus Megaselia was estimated by various non-parametric estimators from EstimateS, Species Prediction And Diversity Estimation (SPADE) and Ws2m, based on material from a Swedish hemiboreal forest area recently affected by major wildfires, Tyresta National Park and Nature Reserve (TNPNR), south of Stockholm. A total of 21 249 individuals were collected in Malaise traps, of which males constituted 16 976 and females 4 273. The analysed dataset represents 37 samples containing 18 549 specimens sorted into 330 species (184 described, 146 are either undescribed or of unsettled taxonomic status). It was not possible to estimate the total species richness using all samples due to heterogeneity caused by inclusion of different communities and temporal incoherencies between samples within and between years. Even with material obtained from a sampling program that was not designed for species richness estimates, it was possible to obtain reliable results when sample heterogeneity was minimized. By dividing the data into community-specific datasets - for bog, forest and wildfire - it was possible to obtain asymptotic curves for the smaller of the two wildfire datasets. A total estimate of 357-439 (95% CI) was attained by using the smaller wildfire dataset and adding the 85 unique species from the samples not included in the estimation analysis. TNPNR has one of the richest known scuttle fly communities in Europe, consisting of almost 50% of the currently named Megaselia species; 48 of these species are reported as new records for Sweden in this study.
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| 13. |
- Dalin, Peter
(författare)
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Diapause induction and termination in a commonly univoltine leaf beetle (Phratora vulgatissima)
- 2011
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 18, s. 443-450
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Tidskriftsartikel (refereegranskat)abstract
- The leaf beetle Phratora vulgatissima (Linnaeus 1758) is commonly univoltine in south-central Sweden but may sometimes initiate a partial second generation. The current study was set out to investigate under what abiotic conditions the beetles initiate a second generation. Using climate chamber experiments, the beetles were shown to have a facultative reproductive diapause induced by declining day-length. The critical day-length (CDL) for diapause induction was estimated to be 18 h and 10 min. In the field, first-generation beetles developing to adulthood before August in 2009 became reproductively active and produced a second generation, but most individuals emerged later and were in reproductive diapause. P. vulgatissima overwinter as adults and diapause was shown to be maintained until mid-winter in 2008/2009. The cumulative temperature requirement for oviposition after diapause termination was estimated to be 222 day-degrees with a 5.5 degrees C temperature threshold. Three different day-degree models that were developed to predict the phenology of female oviposition in the spring were validated by comparing model results with field data on the timing of oviposition in previous years. The study suggests that P. vulgatissima may initiate a second generation in Sweden if development of the first generation is completed before August. Warmer spring and summer temperatures due to ongoing climate change may cause advanced insect phenology and faster completion of insect life-cycles at northern latitudes, which will affect the proportion of insects that initiate a second generation.
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| 14. |
- Dalin, Peter
(författare)
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Geographic variation in photoperiodic diapause induction and diapause intensity in Sericinus montelus (Lepidoptera: Papilionidae)
- 2012
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 19, s. 295-302
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Tidskriftsartikel (refereegranskat)abstract
- Due to the risk of extinction and ornamental value of the swallowtail butterfly, Sericinus montelus Gray (Lepidoptera: Papilionidae) in China, knowledge about local adaptations is important for the conservation and economical utilization of the species. In the present study, photoperiodic diapause induction and diapause intensity of S. montelus populations from Jiamusi (46 degrees 37'N), Beijing (40 degrees 15'N), Zibo (36 degrees 48'N), Fangxian (32 degrees 36'N), Wuhan (30 degrees 33'N) and Huaihua (27 degrees 33'N) were characterized at 25 degrees C. Logistic regression analysis revealed a significant population x hours of light interaction, confirming that photoperiodic responses varied among populations. The critical photoperiod was positively correlated with latitude and increased toward the north at a rate of about 1 h for each 6.67 degrees of latitude. Survival analyses indicated that survival time of diapausing pupae before adult eclosion differed significantly among populations at 25 degrees C and 16 : 8 L : D h. The mean duration of pupal diapause was also positively correlated with latitude. Our study reveals geographic variation in the critical photoperiod for diapause induction and in diapause intensity of S. montelus. These results provide useful information for our general understanding about seasonal adaptation in insects and may also be used to predict how geographic populations respond to climate warming.
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| 15. |
- Johansson, Karin C, et al.
(författare)
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Pefabloc : A sulfonyl fluoride serine protease inhibitor blocks induction of Diptericin in Drosophila l(2)mbn cells
- 2012
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 19:4, s. 472-476
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Tidskriftsartikel (refereegranskat)abstract
- Insects protect themselves against microbial infection by an efficient innate immune system that is activated by recognition of invariant microbial surface molecules. In the fruit fly Drosophila melanogaster the presence of bacteria is associated with expression of antimicrobial peptides in host immune-competent tissues. Host receptors detect infection and relay the signal to mount the appropriate immune response. In Drosophila hemocyte-like l(2)mbn cells pre-infection treatment with Pefabloc, a commonly used serine protease inhibitor, induced two major effects: it blocked expression of the antibacterial peptide Diptericin in response to live Gram-negative bacteria and bacterial surface molecules (crude lipopolysaccharide contaminated by peptidoglycans) and it induced morphological changes.
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| 16. |
- Stenberg, Johan A
(författare)
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Effects of local vegetation and plantation age for the parasitoid Asecodes mento- a biocontrol agent in organic strawberry fields
- 2012
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Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 19, s. 604-608
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Tidskriftsartikel (refereegranskat)abstract
- The parasitoid Asecodes mento (Walker, 1839) (Hymenoptera: Eulophidae) is the most important biocontrol agent of the strawberry leaf beetle Galerucella tenella (L.) (Coleoptera: Chrysomelidae) in northern Europe. Here, I investigated whether natural parasitism in organic strawberry plantations was affected by the presence of the alternative host plant meadowsweet (Filipendula ulmaria), and whether parasitism rates differed between plantations of different ages (6 to 79 years). I also investigated whether parasitoid brood size, body size and sex ratio differed between the two host plants in the field. Parasitism was very low (0%) in newly established plantations and increased to a plateau (similar to 40%) in fields where strawberries had been grown for approximately 20 years or longer. Such an extended colonization process is unacceptable for commercial growers. It would thus be desirable to find a method to catalyze parasitoid population buildup in young plantations. Parasitoid brood sizes were larger in beetles collected from meadowsweet, while body size and sex ratio did not differ between parasitoids collected from the two plants. These findings suggest that meadowsweet can export parasitoids to neighboring strawberry fields. Although this is a possibility, I did not find any significant differences in parasitism rates between isolated strawberry fields and fields adjacent to meadowsweet stands, indicating that effects of local vegetation are small on parasitism rates. Releasing parasitoids in newly established strawberry plantations may be a better strategy for quickly obtaining high parasitism than intercropping with meadowsweet.
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| 17. |
- Hou, Xiao Qing, et al.
(författare)
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Odorant receptor orthologues from moths display conserved responses to cis-jasmone
- 2023
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Ingår i: Insect science. - 1672-9609.
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Tidskriftsartikel (refereegranskat)abstract
- In insects, the odorant receptor (OR) multigene family evolves by the birth-and-death evolutionary model, according to which the OR repertoire of each species has undergone specific gene gains and losses depending on their chemical environment, resulting in taxon-specific OR lineage radiations with different sizes in the phylogenetic trees. Despite the general divergence in the gene family across different insect orders, the ORs in moths seem to be genetically conserved across species, clustered into 23 major clades containing multiple orthologous groups with single-copy gene from each species. We hypothesized that ORs in these orthologous groups are tuned to ecologically important compounds and functionally conserved. cis-Jasmone is one of the compounds that not only primes the plant defense of neighboring receiver plants, but also functions as a behavior regulator to various insects. To test our hypothesis, using Xenopus oocyte recordings, we functionally assayed the orthologues of BmorOR56, which has been characterized as a specific receptor for cis-jasmone. Our results showed highly conserved response specificity of the BmorOR56 orthologues, with all receptors within this group exclusively responding to cis-jasmone. This is supported by the dN/dS analysis, showing that strong purifying selection is acting on this group. Moreover, molecular docking showed that the ligand binding pockets of BmorOR56 orthologues to cis-jasmone are similar. Taken together, our results suggest the high conservation of OR for ecologically important compounds across Heterocera.
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