scholarly journals The evolution of symmetrical snapping in termite soldiers need not lead to reduced chemical defence

2015 ◽  
Vol 115 (4) ◽  
pp. 818-825 ◽  
Author(s):  
Pavlína Kyjaková ◽  
Klára Dolejšová ◽  
Jana Krasulová ◽  
Lucie Bednárová ◽  
Romana Hadravová ◽  
...  
Keyword(s):  
Chemical Defence ◽  
Termite Soldiers

scholarly journals Toxins and Other Bioactive Metabolites in Deep Chlorophyll Layers Containing the Cyanobacteria Planktothrix cf. isothrix in Two Georgian Bay Embayments, Lake Huron

Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 445
Author(s):  
Arthur Zastepa ◽  
Todd R. Miller ◽  
L. Cynthia Watson ◽  
Hedy Kling ◽  
Susan B. Watson
Keyword(s):  
Thermal Stratification ◽  
Chemical Defence ◽  
Euphotic Zone ◽  
Lake Huron ◽  
Metabolic Inhibitors ◽  
Bioactive Metabolites ◽  
Total Biomass ◽  
Key Factors ◽  
Georgian Bay ◽  
And Function

The understanding of deep chlorophyll layers (DCLs) in the Great Lakes—largely reported as a mix of picoplankton and mixotrophic nanoflagellates—is predominantly based on studies of deep (>30 m), offshore locations. Here, we document and characterize nearshore DCLs from two meso-oligotrophic embayments, Twelve Mile Bay (TMB) and South Bay (SB), along eastern Georgian Bay, Lake Huron (Ontario, Canada) in 2014, 2015, and 2018. Both embayments showed the annual formation of DCLs, present as dense, thin, metalimnetic plates dominated by the large, potentially toxic, and bloom-forming cyanobacteria Planktothrix cf. isothrix. The contribution of P. cf. isothrix to the deep-living total biomass (TB) increased as thermal stratification progressed over the ice-free season, reaching 40% in TMB (0.6 mg/L at 9.5 m) and 65% in South Bay (3.5 mg/L at 7.5 m) in 2015. The euphotic zone in each embayment extended down past the mixed layer, into the nutrient-enriched hypoxic hypolimnia, consistent with other studies of similar systems with DCLs. The co-occurrence of the metal-oxidizing bacteria Leptothrix spp. and bactivorous flagellates within the metalimnetic DCLs suggests that the microbial loop plays an important role in recycling nutrients within these layers, particularly phosphate (PO4) and iron (Fe). Samples taken through the water column in both embayments showed measurable concentrations of the cyanobacterial toxins microcystins (max. 0.4 µg/L) and the other bioactive metabolites anabaenopeptins (max. ~7 µg/L) and cyanopeptolins (max. 1 ng/L), along with the corresponding genes (max. in 2018). These oligopeptides are known to act as metabolic inhibitors (e.g., in chemical defence against grazers, parasites) and allow a competitive advantage. In TMB, the 2018 peaks in these oligopeptides and genes coincided with the P. cf. isothrix DCLs, suggesting this species as the main source. Our data indicate that intersecting physicochemical gradients of light and nutrient-enriched hypoxic hypolimnia are key factors in supporting DCLs in TMB and SB. Microbial activity and allelopathy may also influence DCL community structure and function, and require further investigation, particularly related to the dominance of potentially toxigenic species such as P. cf. isothrix.

scholarly journals Growing up aspen: ontogeny and trade-offs shape growth, defence and reproduction in a foundation species

2020 ◽  
Author(s):  
Christopher T Cole ◽  
Clay J Morrow ◽  
Hilary L Barker ◽  
Kennedy F Rubert-Nason ◽  
Jennifer F L Riehl ◽  
...  
Keyword(s):  
Intraspecific Variation ◽  
Genotypic Variation ◽  
Chemical Defence ◽  
Extrafloral Nectaries ◽  
Foundation Species ◽  
Community Genetics ◽  
Indirect Defence ◽  
Juvenile Period ◽  
Trade Offs ◽  
Sex Marker

Abstract Background and Aims Intraspecific variation in foundation species of forest ecosystems can shape community and ecosystem properties, particularly when that variation has a genetic basis. Traits mediating interactions with other species are predicted by simple allocation models to follow ontogenetic patterns that are rarely studied in trees. The aim of this research was to identify the roles of genotype, ontogeny and genotypic trade-offs shaping growth, defence and reproduction in aspen. Methods We established a common garden replicating >500 aspen genets in Wisconsin, USA. Trees were measured through the juvenile period into the onset of reproduction, for growth, defence chemistry (phenolic glycosides and condensed tannins), nitrogen, extrafloral nectaries, leaf morphology (specific leaf area), flower production and foliar herbivory and disease. We also assayed the TOZ19 sex marker and heterozygosity at ten microsatellite loci. Key Results We found high levels of genotypic variation for all traits, and high heritabilities for both the traits and their ontogenetic trajectories. Ontogeny strongly shaped intraspecific variation, and trade-offs among growth, defence and reproduction supported some predictions while contradicting others. Both direct resistance (chemical defence) and indirect defence (extrafloral nectaries) declined during the juvenile stage, prior to the onset of reproduction. Reproduction was higher in trees that were larger, male and had higher individual heterozygosity. Growth was diminished by genotypic allocation to both direct and indirect defence as well as to reproduction, but we found no evidence of trade-offs between defence and reproduction. Conclusions Key traits affecting the ecological communities of aspen have high levels of genotypic variation and heritability, strong patterns of ontogeny and clear trade-offs among growth, defence and reproduction. The architecture of aspen’s community genetics – its ontogeny, trade-offs and especially its great variability – is shaped by both its broad range and the diverse community of associates, and in turn further fosters that diversity.

scholarly journals Brightly coloured tissues in limid bivalves chemically deter predators

2019 ◽  
Vol 6 (10) ◽  
pp. 191298
Author(s):  
Lindsey F. Dougherty ◽  
Alexandria K. Niebergall ◽  
Corey D. Broeckling ◽  
Kevin L. Schauer ◽  
Jingchun Li
Keyword(s):  
Mass Spectrometry ◽  
Chemical Defence ◽  
Chemical Compositions ◽  
Marine Bivalve ◽  
Metabolomic Analysis ◽  
Defence Mechanism ◽  
Defensive Compounds ◽  
Mantis Shrimp ◽  
Metabolite Profiles ◽  
Bivalve Tissues

Members of the marine bivalve family Limidae are known for their bright appearance. In this study, their colourful tissues were examined as a defence mechanism towards predators. We showed that when attacked by the peacock mantis shrimp ( Odontodactylus scyllarus ), the ‘disco’ clam, Ctenoides ales , opened wide to expose brightly coloured tissues to the predator. The predator also significantly preferred to consume the internal, non-colourful clam tissues than the external, colourful tissues. Mass spectrometry-based metabolomic analysis confirmed that colourful tissues had significantly different chemical compositions than the non-colourful ones. The internal, non-colourful tissues had metabolite profiles more similar to an outgroup bivalve than to the species' own colourful external tissues. A number of the compounds that differentiated the colourful tissues from the non-colourful tissues appeared to be peptide-like, which potentially serve as the underlying defensive compounds. This is the first study demonstrating that colourful bivalve tissues are used for chemical defence.

scholarly journals Chemical defence in chrysomelid eggs and neonate larvae

1986 ◽  
Vol 11 (1) ◽  
pp. 29-37 ◽  
Author(s):  
J. M. PASTEELS ◽  
D. DALOZE ◽  
M. ROWELL-RAHIER
Keyword(s):  
Chemical Defence ◽  
Neonate Larvae

scholarly journals Chemical defence responses of Norway spruce to two fungal pathogens

2020 ◽  
Vol 50 (6) ◽  
Author(s):  
Karolin Axelsson ◽  
Amene Zendegi‐Shiraz ◽  
Gunilla Swedjemark ◽  
Anna‐Karin Borg‐Karlson ◽  
Tao Zhao
Keyword(s):  
Norway Spruce ◽  
Fungal Pathogens ◽  
Chemical Defence ◽  
Defence Responses

Chemical defense by termite soldiers

1979 ◽  
Vol 5 (3) ◽  
pp. 459-480 ◽  
Author(s):  
Glenn D. Prestwich
Keyword(s):  
Chemical Defense ◽  
Termite Soldiers

Two‐tier morpho‐chemical defence tactic in Aethionema via fruit morph plasticity and glucosinolates allocation in diaspores

2018 ◽  
Vol 42 (4) ◽  
pp. 1381-1392 ◽  
Author(s):  
Samik Bhattacharya ◽  
Sara Mayland‐Quellhorst ◽  
Caroline Müller ◽  
Klaus Mummenhoff
Keyword(s):  
Chemical Defence

scholarly journals Spectral properties, gas exchange, and water potential of leaves of glandular and non-glandular trichome types in Datura wrightii (Solanaceae)

2004 ◽  
Vol 31 (3) ◽  
pp. 267 ◽  
Author(s):  
James L. Smith II ◽  
J. Daniel Hare
Keyword(s):  
Gas Exchange ◽  
Spectral Properties ◽  
Glandular Trichomes ◽  
Chemical Defence ◽  
Geographic Location ◽  
Glandular Trichome ◽  
Datura Wrightii ◽  
Significant Difference ◽  
Sticky Plants ◽  
Trichome Types

Plant trichomes commonly serve a role in mechanical and chemical defence against herbivores, but may also have the potential to alter physiology by reducing the amount of light absorbed by leaves, lowering temperatures, and reducing water loss. Populations of Datura wrightii Regel in southern California produce 'sticky' plants with glandular trichomes and 'velvety' plants bearing non-glandular trichomes. Because stickiness is inherited as a dominant Mendelian trait, and the proportions of sticky plants vary among populations with the moisture availability of their environment, there may be some ecophysiological differences between trichome types that contribute to their ability to survive in a particular geographic location. To examine the possible physiological significance of trichome variation, we measured the spectral properties, midday gas-exchange rates, and water potentials of D. wrightii leaves from sticky and velvety plants growing in a field experiment. The differences in leaf reflectance (0.9%) and absorptance (1.3%) of photosynthetically active radiation (PAR) between trichome types are too small to have any direct physiologically significant effect. Simulations of leaf temperatures based on the difference in leaf absorptances reveal that leaf temperature would be no more than 1°C lower in velvety compared to sticky plants. Gas-exchange measurements revealed no significant difference between types in their transpiration rates or stomatal conductances. In this case, trichome variation may be more important to plant defenses than to physiology.

The gastropod Arion fuscus prefers cyanobacterial to green algal parts of the tripartite lichen Nephroma arcticum due to low chemical defence

2009 ◽  
Vol 42 (1) ◽  
pp. 113-117 ◽  
Author(s):  
Johan ASPLUND ◽  
Yngvar GAUSLAA
Keyword(s):  
Usnic Acid ◽  
Chemical Defence ◽  
Secondary Compounds ◽  
Distribution Limit ◽  
Green Algal ◽  
Defensive Role ◽  
N Starvation ◽  
And Control ◽  
Terricolous Lichen ◽  
Acetone Rinsing

AbstractAlthough the tripartite terricolous lichen Nephroma arcticum is easily accessible to lichen-feeding gastropods, grazing marks are mainly restricted to localized cephalodia with N-fixing Nostoc. We tested if this gastropod preference for cephalodia can be explained by differences in carbon based secondary compounds (CBSCs) in cyanobacterial versus green-algal tissues. CBSCs were non-destructively removed from air-dry thalli by 100% acetone. Compound deficient and control thallus parts were offered to the slug Arion fuscus and grazing preferences were quantified by area measurements in ArcGIS™. The concentrations of CBSCs (phenarctin, usnic acid, nephroarctin and methyl gyrophorate) in thallus parts with and without cephalodia were quantified with HPLC. Compared to purely green-algal parts, cephalodial parts with adjoining fungal tissues contained less defensive compounds, and were preferred by A. fuscus. The cephalodia themselves do not contain any CBSCs. After acetone rinsing, A. fuscus did not discriminate between green-algal and cyanobacterial parts. The results were consistent with the hypothesis that CBSCs in green-algal parts of N. arcticum play a herbivore-defensive role. It is further hypothesized that grazing of cephalodia may lead to N-starvation and reduced growth of N. arcticum thalli in southern portions of its range where lichenivorous gastropods are more abundant. This may play a role in shaping the southern distribution limit of this arctic-boreal lichen species.

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