scholarly journals Generalism in Nature…The Great Misnomer: Aphids and Wasp Parasitoids as Examples

Insects ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 314 ◽  
Author(s):  
Hugh D. Loxdale ◽  
Adalbert Balog ◽  
Jeffrey A. Harvey
Keyword(s):  
Ecological Niche ◽  
Large Degree ◽  
Parasitoid Wasps ◽  
Pest Species ◽  
Entry And Exit ◽  
Relaxed Selection ◽  
Dietary Breadth ◽  
Trade Offs ◽  
Enemy Free Space ◽  
Living Organisms

In the present article we discuss why, in our view, the term ‘generalism’ to define the dietary breadth of a species is a misnomer and should be revised by entomologists/ecologists with the more exact title relating to the animal in question’s level of phagy—mono-, oligo, or polyphagy. We discard generalism as a concept because of the indisputable fact that all living organisms fill a unique ecological niche, and that entry and exit from such niches are the acknowledged routes and mechanisms driving ecological divergence and ultimately speciation. The term specialist is probably still useful and we support its continuing usage simply because all species and lower levels of evolutionary diverge are indeed specialists to a large degree. Using aphids and parasitoid wasps as examples, we provide evidence from the literature that even some apparently highly polyphagous agricultural aphid pest species and their wasp parasitoids are probably not as polyphagous as formerly assumed. We suggest that the shifting of plant hosts by herbivorous insects like aphids, whilst having positive benefits in reducing competition, and reducing antagonists by moving the target organism into ‘enemy free space’, produces trade-offs in survival, involving relaxed selection in the case of the manicured agro-ecosystem.

scholarly journals The evolutionary convergence of avian lifestyles and their constrained coevolution with species' ecological niche

2015 ◽  
Vol 282 (1821) ◽  
pp. 20151808 ◽  
Author(s):  
Paola Laiolo ◽  
Javier Seoane ◽  
Juan Carlos Illera ◽  
Giulia Bastianelli ◽  
Luis María Carrascal ◽  
...  
Keyword(s):  
Life Histories ◽  
Ecological Niche ◽  
Optimal Allocation ◽  
Reproductive Investment ◽  
Cost Of Reproduction ◽  
Phenotypic Evolution ◽  
Realized Niche ◽  
Trade Offs ◽  
The Cost ◽  
Species Variability

The fit between life histories and ecological niche is a paradigm of phenotypic evolution, also widely used to explain patterns of species co-occurrence. By analysing the lifestyles of a sympatric avian assemblage, we show that species' solutions to environmental problems are not unbound. We identify a life-history continuum structured on the cost of reproduction along a temperature gradient, as well as habitat-driven parental behaviour. However, environmental fit and trait convergence are limited by niche filling and by within-species variability of niche traits, which is greater than variability of life histories. Phylogeny, allometry and trade-offs are other important constraints: lifetime reproductive investment is tightly bound to body size, and the optimal allocation to reproduction for a given size is not established by niche characteristics but by trade-offs with survival. Life histories thus keep pace with habitat and climate, but under the limitations imposed by metabolism, trade-offs among traits and species' realized niche.

Positive association between resistance to Bacillus thuringiensis and overwintering survival of cabbage loopers, Trichoplusia ni (Lepidoptera: Noctuidae)

2008 ◽  
Vol 98 (3) ◽  
pp. 317-322 ◽  
Author(s):  
V. Caron ◽  
J.H. Myers
Keyword(s):  
Bacillus Thuringiensis ◽  
Trichoplusia Ni ◽  
Positive Association ◽  
Pest Species ◽  
Development Of Resistance ◽  
Trade Offs ◽  
Major Pest ◽  
Selection For ◽  
Overwintering Survival ◽  
Lepidoptera Noctuidae

AbstractDevelopment of resistance to insecticides has generally been associated with fitness costs that may be magnified under challenging conditions. Lepidopterans which are resistant to the biopesticide Bacillus thuringiensis subsp. kurstaki (Btk) have been shown to have reduced fitness, such as lower survival when subjected to overwintering stress. Recently, resistance to Btk has been found in some populations of Trichoplusia ni Hübner in greenhouses in British Columbia. This situation provides an opportunity to investigate potential trade-offs between overwintering survival and insecticide resistance in a major pest species. Here, we assess the survival and eventual fecundity of Btk resistant and susceptible T. ni pupae exposed to cool temperatures. Contrary to our expectations, resistant T. ni had higher overwintering survival than susceptible individuals. This is the first account of a potential advantage associated with Btk resistance. Resistant and susceptible moths had reduced fecundity and smaller progeny after cold exposure compared to controls, and this may counteract the survival advantage. Nevertheless, it seems unlikely that this is sufficient to select out the resistant phenotype in the presence of strong selection for resistance and in the absence of immigration of susceptible moths. The appearance of resistance without evidence of a trade-off in overwintering survival presents a major challenge to management in production greenhouses.

scholarly journals Comprehensive Transcriptome of the Maize Stalk Borer, Busseola fusca, from Multiple Tissue Types, Developmental Stages, and Parasitoid Wasp Exposures

2020 ◽  
Vol 12 (12) ◽  
pp. 2554-2560
Author(s):  
Keyword(s):  
Target Genes ◽  
Developmental Stages ◽  
Management Strategies ◽  
Busseola Fusca ◽  
Parasitoid Wasp ◽  
Sub Saharan Africa ◽  
Biological Research ◽  
Parasitoid Wasps ◽  
Pest Species ◽  
Stalk Borer

Abstract Busseola fusca (Fuller) (Lepidoptera: Noctuidae), the maize stalk borer, is a widespread crop pest in sub-Saharan Africa that has been the focus of biological research and intensive management strategies. Here, we present a comprehensive annotated transcriptome of B. fusca (originally collected in the Western Province of Kenya) based on ten pooled libraries including a wide array of developmental stages, tissue types, and exposures to parasitoid wasps. Parasitoid wasps have been used as a form of biocontrol to try and reduce crop losses with variable success, in part due to differential infectivities and immune responses among wasps and hosts. We identified a number of loci of interest for pest management, including genes potentially involved in chemoreception, immunity, and response to insecticides. The comprehensive sampling design used expands our current understanding of the transcriptome of this species and deepens the list of potential target genes for future crop loss mitigation, in addition to highlighting candidate loci for differential expression and functional genetic analyses in this important pest species.

scholarly journals Can Top-Down Controls Expand the Ecological Niche of Marine N2 Fixers?

2021 ◽  
Vol 12 ◽  
Author(s):  
Angela Landolfi ◽  
A. E. Friederike Prowe ◽  
Markus Pahlow ◽  
Christopher J. Somes ◽  
Chia-Te Chien ◽  
...  
Keyword(s):  
Ecological Niche ◽  
Ecological Niches ◽  
Ecological Interactions ◽  
Top Down ◽  
Viral Lysis ◽  
Controlled Systems ◽  
Trade Offs ◽  
Limiting Nutrient ◽  
Resource Levels ◽  
Critical Process

The ability of marine diazotrophs to fix dinitrogen gas (N2) is one of the most influential yet enigmatic processes in the ocean. With their activity diazotrophs support biological production by fixing about 100–200 Tg N/year and turning otherwise unavailable dinitrogen into bioavailable nitrogen (N), an essential limiting nutrient. Despite their important role, the factors that control the distribution of diazotrophs and their ability to fix N2 are not fully elucidated. We discuss insights that can be gained from the emerging picture of a wide geographical distribution of marine diazotrophs and provide a critical assessment of environmental (bottom-up) versus trophic (top-down) controls. We expand a simplified theoretical framework to understand how top-down control affects competition for resources that determine ecological niches. Selective mortality, mediated by grazing or viral-lysis, on non-fixing phytoplankton is identified as a critical process that can broaden the ability of diazotrophs to compete for resources in top-down controlled systems and explain an expanded ecological niche for diazotrophs. Our simplified analysis predicts a larger importance of top-down control on competition patterns as resource levels increase. As grazing controls the faster growing phytoplankton, coexistence of the slower growing diazotrophs can be established. However, these predictions require corroboration by experimental and field data, together with the identification of specific traits of organisms and associated trade-offs related to selective top-down control. Elucidation of these factors could greatly improve our predictive capability for patterns and rates of marine N2 fixation. The susceptibility of this key biogeochemical process to future changes may not only be determined by changes in environmental conditions but also via changes in the ecological interactions.

scholarly journals Phosphatidic acid – a simple phospholipid with multiple faces

2018 ◽  
Vol 65 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Jolanta Zegarlinska ◽  
Magda Piaścik ◽  
Aleksander F Sikorski ◽  
Aleksander Czogalla
Keyword(s):  
Phosphatidic Acid ◽  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Gene Expression Regulation ◽  
Large Degree ◽  
Cellular Lipids ◽  
Living Organisms ◽  
Protein Recruitment ◽  
Membrane Shape

Phosphatidic acid (PA) is the simplest glycerophospholipid naturally occurring in living organisms, and even though its content among other cellular lipids is minor, it is drawing more and more attention due to its multiple biological functions. PA is a precursor for other phospholipids, acts as a lipid second messenger and, due to its structural properties, is also a modulator of membrane shape. Although much is known about interaction of PA with its effectors, the molecular mechanisms remain unresolved to a large degree. Throughout many of the well-characterized PA cellular sensors, no conserved binding domain can be recognized. Moreover, not much is known about the cellular dynamics of PA and how it is distributed among subcellular compartments. Remarkably, PA can play distinct roles within each of these compartments. For example, in the nucleus it behaves as a mitogen, influencing gene expression regulation, and in the Golgi membrane it plays a role in membrane trafficking. Here we discuss how a biophysical experimental approach enabled PA behavior to be described in the context of a lipid bilayer and to what extent various physicochemical conditions may modulate the functional properties of the lipid. Understanding these aspects would help to unravel specific mechanisms of PA-driven membrane transformation and protein recruitment and thus would lead to a clearer picture of the biological role of PA.

scholarly journals Life History Trade-Offs and Relaxed Selection Can Decrease Bacterial Virulence in Environmental Reservoirs

PLoS ONE ◽  
2012 ◽  
Vol 7 (8) ◽  
pp. e43801 ◽  
Author(s):  
Lauri Mikonranta ◽  
Ville-Petri Friman ◽  
Jouni Laakso
Keyword(s):  
Life History ◽  
Bacterial Virulence ◽  
Relaxed Selection ◽  
Trade Offs

scholarly journals Using parasitoid wasps in Integrated Pest Management in museums against biscuit beetle (Stegobium paniceum) and webbing clothes moth (Tineola bisselliella)

2011 ◽  
Vol 43 (2) ◽  
pp. 169 ◽  
Author(s):  
Pascal Querner ◽  
Stephan Biebl
Keyword(s):  
Integrated Pest Management ◽  
Pest Management ◽  
Parasitoid Wasps ◽  
Pest Species ◽  
Trichogramma Evanescens ◽  
Biological Pest Control ◽  
Moth Population ◽  
Lariophagus Distinguendus ◽  
Stegobium Paniceum ◽  
Tineola Bisselliella

Biscuit beetle (<em>Stegobium paniceum</em>) and webbing clothes moth (<em>Tineola bisselliella</em>) cause much damage to museum objects. Some objects and materials are very attractive to these two pest species and objects are often re-infested after treatment. For some years parasitoid wasps have been used in biological pest control to treat and reduce infestations of stored product pests in food processing facilities. Their application in museums is still new and in a research stage. Results from five different museums in Germany and Austria and their application are presented. <em>Lariophagus distinguendus</em> wasps were released against <em>Stegobium paniceum</em> in the municipal library Augsburger Stadtarchiv (Germany), the Ethnological Museum in Berlin (Germany) and the Picture Gallery in the Kunsthistorisches Museum in Vienna (Austria). <em>Trichogramma evanescens </em>were released against <em>Tineola bisselliella </em>in the Technisches Museum in Vienna (Austria) and in the Deutsches Museum Verkehrszentrum in Munich (Germany). Results show that for active biscuit beetle infestations good results can be expected using the <em>Lariophagus distinguendus </em>in museums. Active clothes moth infestations are harder to treat but with a very regular and long-term exposure to the wasps, the clothes moth population can be reduced over the years. We see the application of parasitoid wasps as part of an Integrated Pest Management concept that should be used besides regular insect monitoring and other preventive measures. Difficulties, limitations and research needs in the application of parasitoid wasps in museums are discussed.

Trade-offs underlying polyphagy in a facultative ant-tended florivorous butterfly: the role of host plant quality and enemy-free space

Oecologia ◽  
2010 ◽  
Vol 163 (3) ◽  
pp. 719-728 ◽  
Author(s):  
Daniela Rodrigues ◽  
Lucas A. Kaminski ◽  
André V. L. Freitas ◽  
Paulo S. Oliveira
Keyword(s):  
Host Plant ◽  
Free Space ◽  
Plant Quality ◽  
Host Plant Quality ◽  
Trade Offs ◽  
Enemy Free Space

scholarly journals Next Generation dsRNA-Based Insect Control: Success So Far and Challenges

2021 ◽  
Vol 12 ◽  
Author(s):  
Rahul B. Nitnavare ◽  
Joorie Bhattacharya ◽  
Satnam Singh ◽  
Amardeep Kour ◽  
Malcolm J. Hawkesford ◽  
...  
Keyword(s):  
Endosomal Escape ◽  
Pest Species ◽  
New Techniques ◽  
Environment Friendly ◽  
Safe Delivery ◽  
Rnai Efficiency ◽  
Important Pest ◽  
Living Organisms ◽  
Underlying Mechanisms ◽  
Interfering Rna

RNA interference (RNAi) is a method of gene silencing where dsRNA is digested into small interfering RNA (siRNA) in the presence of enzymes. These siRNAs then target homologous mRNA sequences aided by the RNA-induced silencing complex (RISC). The mechanism of dsRNA uptake has been well studied and established across many living organisms including insects. In insects, RNAi is a novel and potential tool to develop future pest management means targeting various classes of insects including dipterans, coleopterans, hemipterans, lepidopterans, hymenopterans and isopterans. However, the extent of RNAi in individual class varies due to underlying mechanisms. The present review focuses on three major insect classes viz hemipterans, lepidopterans and coleopterans and the rationale behind this lies in the fact that studies pertaining to RNAi has been extensively performed in these groups. Additionally, these classes harbour major agriculturally important pest species which require due attention. Interestingly, all the three classes exhibit varying levels of RNAi efficiencies with the coleopterans exhibiting maximum response, while hemipterans are relatively inefficient. Lepidopterans on the other hand, show minimum response to RNAi. This has been attributed to many facts and few important being endosomal escape, high activity dsRNA-specific nucleases, and highly alkaline gut environment which renders the dsRNA unstable. Various methods have been established to ensure safe delivery of dsRNA into the biological system of the insect. The most common method for dsRNA administration is supplementing the diet of insects via spraying onto leaves and other commonly eaten parts of the plant. This method is environment-friendly and superior to the hazardous effects of pesticides. Another method involves submergence of root systems in dsRNA solutions and subsequent uptake by the phloem. Additionally, more recent techniques are nanoparticle- and Agrobacterium-mediated delivery systems. However, due to the novelty of these biotechnological methods and recalcitrant nature of certain crops, further optimization is required. This review emphasizes on RNAi developments in agriculturally important insect species and the major hurdles for efficient RNAi in these groups. The review also discusses in detail the development of new techniques to enhance RNAi efficiency using liposomes and nanoparticles, transplastomics, microbial-mediated delivery and chemical methods.

scholarly journals Effects of Prohydrojasmon on the Number of Infesting Herbivores and Biomass of Field-Grown Japanese Radish Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Kengo Yoshida ◽  
Masayoshi Uefune ◽  
Rika Ozawa ◽  
Hiroshi Abe ◽  
Yuka Okemoto ◽  
...  
Keyword(s):  
Crop Production ◽  
Insect Pests ◽  
Insect Pest ◽  
Parasitoid Wasps ◽  
Pest Species ◽  
Water Control ◽  
Aphid Parasitoid ◽  
Commercial Formulation ◽  
Indirect Defenses ◽  
Japanese Radish

Prohydrojasmon (PDJ), an analog of jasmonic acid (JA), was found to induce direct and indirect defenses against herbivores in non-infested plants. To test whether PDJ can be used for pest control in crop production, we conducted experiments in pesticide-free Japanese radish fields from October 4 to December 12 in 2015. Twenty-four Japanese radish plants in three plots were treated with a 100 times-diluted commercial formulation (5%) of PDJ (treated plants), and 24 plants in three different plots were treated with water (control plants) until November 29 every week. Throughout the observation period, the number of aphids, leaf-mining fly larvae, vegetable weevils, and thrips was significantly lower on the treated plants than on the control plants. In contrast, the number of lepidopteran larvae was not significantly different between the treated and control plants throughout the study period. Parasitized aphids (mummies) were also observed in both plots. Poisson regression analyses showed that a significantly higher number of mummies was recorded on the treated plants as compared to that on the control plants when the number of aphids increased. This suggested that PDJ application to Japanese radish plants attracted more parasitoid wasps on the treated plants than on the control plants. We also identified eight terpenoids and methyl salicylate as the PDJ-induced plant volatiles in the headspace of the treated plants. Some of these volatiles might be responsible for attracting aphid-parasitoid wasps in the field. However, for other insect pests, we did not find any natural enemies. Interestingly, the genes of the JA and salicylic acid signaling pathways were differentially upregulated in the treated plants. We also observed that the PDJ treatments induced the expression of the genes related to glucosinolate biosynthesis and the subsequent isothiocyanate formation. Additionally, the weights of both the aboveground and belowground parts of the treated plants were significantly lower than those of the respective parts of the control plants. These results indicated that the treatment of Japanese radish plants with a 100 times-diluted commercial formulation of PDJ induced their direct and indirect defenses against several insect pest species to reduce their numbers, and negatively affected their biomass.

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