scholarly journals We Are What We Eat: A Stoichiometric and Ecometabolomic Study of Caterpillars Feeding on Two Pine Subspecies of Pinus sylvestris

2018 ◽  
Vol 20 (1) ◽  
pp. 59
Author(s):  
Albert Rivas-Ubach ◽  
Josep Peñuelas ◽  
José Hódar ◽  
Michal Oravec ◽  
Ljiljana Paša-Tolić ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Tissue Concentration ◽  
Trophic Levels ◽  
Food Sources ◽  
Thaumetopoea Pityocampa ◽  
Insect Herbivores ◽  
Plant Host ◽  
Total Variability ◽  
Specialist Insect ◽  
C:P Ratios

Many studies have addressed several plant-insect interaction topics at nutritional, molecular, physiological, and evolutionary levels. However, it is still unknown how flexible the metabolism and the nutritional content of specialist insect herbivores feeding on different closely related plants can be. We performed elemental, stoichiometric, and metabolomics analyses on leaves of two coexisting Pinus sylvestris subspecies and on their main insect herbivore; the caterpillar of the processionary moth (Thaumetopoea pityocampa). Caterpillars feeding on different pine subspecies had distinct overall metabolome structure, accounting for over 10% of the total variability. Although plants and insects have very divergent metabolomes, caterpillars showed certain resemblance to their plant-host metabolome. In addition, few plant-related secondary metabolites were found accumulated in caterpillar tissues which could potentially be used for self-defense. Caterpillars feeding on N and P richer needles had lower N and P tissue concentration and higher C:N and C:P ratios, suggesting that nutrient transfer is not necessarily linear through trophic levels and other plant-metabolic factors could be interfering. This exploratory study showed that little chemical differences between plant food sources can impact the overall metabolome of specialist insect herbivores. Significant nutritional shifts in herbivore tissues could lead to larger changes of the trophic web structure.

scholarly journals Do plant volatiles confuse rather than guide foraging behavior of the aphid hyperparasitoid Dendrocerus aphidum?

Chemoecology ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 315-325
Author(s):  
Jetske G. de Boer ◽  
Petra J. Hollander ◽  
Daan Heinen ◽  
Divya Jagger ◽  
Pim van Sliedregt ◽  
...  
Keyword(s):  
Foraging Behavior ◽  
Plant Volatiles ◽  
Sweet Pepper ◽  
Trophic Levels ◽  
Plant Host ◽  
Olfactory Responses ◽  
Clean Air ◽  
Series Of Experiments ◽  
Pepper Plants

Abstract Many species of parasitoid wasps use plant volatiles to locate their herbivorous hosts. These volatiles are reliable indicators of host presence when their emission in plants is induced by herbivory. Hyperparasitoids may also use information from lower trophic levels to locate their parasitoid hosts but little is known about the role of volatiles from the plant–host complex in the foraging behavior of hyperparasitoids. Here, we studied how Dendrocerus aphidum (Megaspilidae) responds to plant and host volatiles in a series of experiments. This hyperparasitoid uses aphid mummies as its host and hampers biological control of aphids by parasitoids in greenhouse horticulture. We found that D. aphidum females were strongly attracted to volatiles from mummy-infested sweet pepper plants, but only when clean air was offered as an alternative odor source in the Y-tube olfactometer. Hyperparasitoid females did not have a preference for mummy-infested plants when volatiles from aphid-infested or healthy pepper plants were presented as an alternative. These olfactory responses of D. aphidum were mostly independent of prior experience. Volatiles from the host itself were also highly attractive to D. aphidum, but again hyperparasitoid females only had a preference in the absence of plant volatiles. Our findings suggest that plant volatiles may confuse, rather than guide the foraging behavior of D. aphidum. Mummy hyperparasitoids, such as D. aphidum, can use a wide variety of mummies and are thus extreme generalists at the lower trophic levels, which may explain the limited role of (induced) plant volatiles in their host searching behavior.

Lipids that contain arsenic in the Mediterranean mussel, Mytilus galloprovincialis

2020 ◽  
Vol 17 (3) ◽  
pp. 289 ◽  
Author(s):  
Fabiana P. Freitas ◽  
Georg Raber ◽  
Kenneth B. Jensen ◽  
António J. A. Nogueira ◽  
Kevin A. Francesconi
Keyword(s):  
High Performance ◽  
Mytilus Galloprovincialis ◽  
Trophic Levels ◽  
Food Sources ◽  
Tissue Type ◽  
Unicellular Algae ◽  
Molecular Mass Spectrometry ◽  
Mediterranean Mussel ◽  
The Mediterranean ◽  
First Time

Environmental contextAlthough arsenic-containing lipids are widespread in marine environments, their origin remains unknown. We show that the arsenolipids in a filter-feeding bivalve mollusc closely match those found in marine food sources, including unicellular algae and bacteria. The results demonstrate the role of lower trophic levels in determining the forms of arsenic found in higher organisms. AbstractArsenic-containing lipids, arsenolipids, are widely found among marine organisms, but their origin and possible biochemical roles remain unknown This work describes the diversity and abundance of arsenolipids in the digestive gland and mantle of nine specimens of the Mediterranean mussel, Mytilus galloprovincialis. By using high performance liquid chromatography (HPLC) coupled to both elemental and high-resolution molecular mass spectrometry, we identified 36 arsenolipids including arsenic derivatives of fatty acids, hydrocarbons, sugar-phospholipids and sugar-phytol; 21 of these arsenolipids were identified for the first time and included a new group comprising ether-phospholipids. The arsenic compounds in the mussels show distinct profiles depending on the tissue type, which provide insight into the arsenolipid origin. The results suggest that the presence of some arsenolipids in the mussels is from direct uptake of the compounds, presumably from food, rather than biogenesis within the mussels.

Feeding and grazing in Lake George, Uganda

1973 ◽  
Vol 184 (1076) ◽  
pp. 299-319 ◽  
Keyword(s):  
Food Preference ◽  
Food Selection ◽  
Trophic Levels ◽  
Food Sources ◽  
Cyclopoid Copepod ◽  
Blue Green Algae ◽  
Tilapia Nilotica ◽  
Daily Ingestion ◽  
Herbivorous Species ◽  
Lake George

The fauna of Lake George is dominated by herbivores, in particular the fish Tilapia nilotica and Haplochromis nigripinnis , and the cyclopoid copepod Thermocyclops hyalinus . Digestion, and the assimilation of carbon from algae, by these herbivores were studied in detail. It was found that, contrary to previous observations reported in the literature, both fish and zooplankton were able to digest and assimilate blue-green algae. The diurnal feeding patterns of the herbivores were examined, and methods devised for assessing, in terms of carbon, the daily ingestion of algae. Hence, using biomass data, the total amount grazed by the herbivores was calculated. Estimates of carbon requirements at other trophic levels were made, as was an assessment of the required level of net production by the algae for comparison with figures for standing crop and net algal production measured by other means. Food selection by secondary and tertiary producers is discussed, and in several species age correlated changes in selectivity were examined. Both the major herbivorous species of fish adopt phytoplankton feeding after a period of carnivorous or omnivorous feeding as fry. Thermocyclops hyalinus is herbivorous all its life, but the size of particle taken changes with age. There are more species of carnivorous than herbivorous fish and these exploit a wider variety of food sources; the few species studied also show changes in food preference with age.

Effects of simulated herbivory on growth and reproduction of two beach annuals, Cakile edentula and Corispermum hyssopifolium

1992 ◽  
Vol 70 (12) ◽  
pp. 2467-2475 ◽  
Author(s):  
Kevin E. Gedge ◽  
M. A. Maun
Keyword(s):  
Reproductive Output ◽  
Natural Habitat ◽  
Critical Time ◽  
Insect Herbivores ◽  
Compensatory Response ◽  
Large Numbers ◽  
Cakile Edentula ◽  
Specialist Insect ◽  
Heavy Damage ◽  
Growth And Reproduction

Cakile edentula var. lucustris (sea rocket) and Corispermum hyssopifolium (bugseed) are two annual flowering plants that grow on the sandy shores of the Great Lakes. This habitat is extremely unpredictable and plants are subject to grazing by a number of insect herbivores as well as browsing by white-tailed deer. The objectives of these studies were to estimate the extent of herbivore damage under natural conditions, to determine the most vulnerable stage of damage, and to examine the compensatory ability of each species to tolerate herbivory. Greenhouse experiments showed that both species were able to compensate for low to moderate levels of artificial defoliation. However, high levels near the time of anthesis reduced the growth and reproductive output of both species. Similar experiments in the field revealed that although the critical time of damage was still the same, the plants were less able to tolerate herbivory. Cakile edentula plants exposed to natural herbivory in an unsprayed cabbage field were quickly attacked by large numbers of specialist insect herbivores and completely defoliated in 11 days. The fact that such damage does not occur in its natural habitat suggests that Cakile edentula escapes heavy damage because insects are unable to locate these populations along the shoreline. Key words: white-tailed deer, defoliation intensity, defoliation stage, compensatory response, indeterminate growth.

scholarly journals Phytoplankton Fuel Fish Food Webs in a Low-Turbidity Temperate Coastal Embayment: A Stable Isotope Approach

2021 ◽  
Vol 8 ◽  
Author(s):  
Goutam Kumar Kundu ◽  
Changseong Kim ◽  
Dongyoung Kim ◽  
Riaz Bibi ◽  
Heeyong Kim ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Food Webs ◽  
Trophic Levels ◽  
Food Sources ◽  
Estuarine Fish ◽  
Multiple Sources ◽  
Terrestrial Organic Matter ◽  
Fish Food ◽  
High Productivity

Trophic contributions of diverse OM sources to estuarine and coastal food webs differ substantially across systems around the world, particularly for nekton (fish, cephalopods, and crustaceans), which utilize basal resources from multiple sources over space and time because of their mobility and feeding behaviors at multiple trophic levels. We investigated the contributions of putative OM sources to fish food webs and assessed the spatiotemporal patterns, structures, and trophic connectivity in fish food webs across four seasons from three closely spaced (10–15 km) sites: an estuarine channel (EC), a deep bay (DB), and an offshore (OS) region in Gwangyang Bay, a high-productivity, low-turbidity estuarine embayment off the Republic of Korea. While nearly all previous studies have focused on few representative species, we examined δ13C and δ15N values of whole nekton communities along with dominant benthic macro-invertebrates, zooplankton, and their putative primary food sources. The δ13C and δ15N values coupled with MixSIAR, a Bayesian mixing model, revealed that these communities utilized multiple primary producers, but phytoplankton comprised the primary trophic contributor (46.6–69.1%). Microphytobenthos (15.8–20.4%) and the seagrass Zostera marina (8.6–19.8%) made substantial contributions, but the role of river-borne terrestrial organic matter was negligible. Spatially different species composition and stable isotope values, but higher utilization of coastal phytoplankton by estuarine fish, indicated disparate food webs structures between the EC and DB/OS coastal areas, with considerable trophic connectivity. Greater overlaps in fish and cephalopod isotopic niches than among other consumers and a higher estimated carbon trophic enrichment factor for EC nekton confirmed feeding migration-mediated biological transport of coastal OM sources to the estuary. Further, the seasonally consistent structures and resource utilization patterns indicate that fish food webs are resilient to changes at lower trophic levels. Our results contrast with those for other highly turbid coastal systems depending highly on diversified basal sources, including exported terrestrial and wetland detritus alongside autochthonous phytoplankton. Finally, this study provides a novel perspective on the role of OM sources in such low turbidity and highly productive coastal embayments and enhances our understanding of marine ecosystems.

scholarly journals Meta-Analysis Suggests Differing Indirect Effects of Viral, Bacterial, and Fungal Plant Pathogens on the Natural Enemies of Insect Herbivores

Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 765
Author(s):  
Ussawit Srisakrapikoop ◽  
Tara J. Pirie ◽  
Mark D. E. Fellowes
Keyword(s):  
Natural Enemies ◽  
Indirect Effects ◽  
Plant Pathogens ◽  
Meta Analysis ◽  
Trophic Levels ◽  
Plant Diseases ◽  
Plant Quality ◽  
Insect Herbivore ◽  
Insect Herbivores ◽  
Fungal Plant Pathogens

Indirect effects are ubiquitous in nature, and have received much attention in terrestrial plant–insect herbivore–enemy systems. In such tritrophic systems, changes in plant quality can have consequential effects on the behavior and abundance of insect predators and parasitoids. Plant quality as perceived by insect herbivores may vary for a range of reasons, including because of infection by plant pathogens. However, plant diseases vary in their origin (viral, bacterial or fungal) and as a result may have differing effects on plant physiology. To investigate if the main groups of plant pathogens differ in their indirect effects on higher trophic levels, we performed a meta-analysis using 216 measured responses from 29 primary studies. There was no overall effect of plant pathogens on natural enemy traits as differences between pathogen types masked their effects. Infection by fungal plant pathogens showed indirect negative effects on the performance and preference of natural enemies via both chewing and piercing-sucking insect herbivore feeding guilds. Infection by bacterial plant pathogens had a positive effect on the natural enemies (parasitoids) of chewing herbivores. Infection by viral plant pathogens showed no clear effect, although parasitoid preference may be positively affected by their presence. It is important to note that given the limited volume of studies to date on such systems, this work should be considered exploratory. Plant pathogens are very common in nature, and tritrophic systems provide an elegant means to examine the consequences of indirect interactions in ecology. We suggest that further studies examining how plant pathogens affect higher trophic levels would be of considerable value.

Trophic studies in a high-latitude fjord ecosystem — a comparison of stable isotope analyses (δ13C and δ15N) and trophic-level estimates from a mass-balance model

2008 ◽  
Vol 65 (12) ◽  
pp. 2791-2806 ◽  
Author(s):  
Marianne Nilsen ◽  
Torstein Pedersen ◽  
Einar Magnus Nilssen ◽  
Stein Fredriksen
Keyword(s):  
Food Web ◽  
Mass Balance ◽  
High Latitude ◽  
Carbon Sources ◽  
Trophic Levels ◽  
Food Sources ◽  
Balance Model ◽  
Ecological Groups ◽  
Mass Balance Model ◽  
Δ13c And Δ15n

Stable isotopes of δ13C and δ15N were used to examine food sources and trophic structure of 65 taxa, representing 19 ecological groups, in a high-latitude ecosystem. Discrimination was made between pelagic and benthic carbon sources, where feeding in most cases reflected the habitat. Trophic levels from these analyses, TLN, were compared with corresponding levels estimated by an Ecopath mass-balance model, TLE, constructed independently of the isotope data. The good correlation between the two methods (r2 = 0.72) supports the diet composition and the grouping of taxa into ecological groups in the model. However, when estimates diverged, this was often explained by the analyses of few taxa, taxa that were not the most representative for the group, or the analyses of specimens from a limited size range. Some assumed detrivores were assigned high TLN in favour of an abundant microbial community in the sediments. High TLN estimates for many invertebrate taxa, combined with relatively low TLN for fishes, suggest that parts of the benthic food web are decoupled from the classical food web.

The diet of amphioxus in subtropical Hong Kong as indicated by fatty acid and stable isotopic analyses

2008 ◽  
Vol 88 (7) ◽  
pp. 1487-1491 ◽  
Author(s):  
Y. Chen ◽  
S.G. Cheung ◽  
P.K.S. Shin
Keyword(s):  
Hong Kong ◽  
Fatty Acid ◽  
Stable Isotope ◽  
Trophic Levels ◽  
Food Sources ◽  
Filter Feeder ◽  
Total Particulate Matter ◽  
Isotopic Analyses ◽  
Wide Range ◽  
Hong Kong Waters

Fatty acid profiles and carbon (δ13C) and nitrogen (δ15N) stable isotope markers were used to identify the diet of amphioxus in subtropical Hong Kong waters, and to evaluate the role of co-occurring Branchiostoma belcheri and B. malayanum in trophic transfer, in coastal ecosystems. The present results showed that while amphioxus is generally regarded as a filter feeder, total particulate matter in the water column might not be the main food supply. The diet of amphioxus could be traced to comprise a wide range of food sources, from microbes and microplankton to microalgae, based on the stable isotope analysis. Results of fatty acid profile analysis also revealed contributions from dinoflagellates, zooplankton, detritus and bacteria, and minor contribution from diatoms and fungi in the diet of amphioxus in Hong Kong waters. The use of fatty acid and stable isotope analyses further proved that amphioxus can, not only capture and partition such a different size-range of food particles during their feeding, but also assimilate most of them into their body tissue. The present findings suggested that amphioxus may play an important role in marine food webs by transferring microbial production to higher trophic levels through utilizing microbes in seawater as food.

scholarly journals What Is the Carcass-Usage Mode of the Collembola? A Case Study of Entomobrya proxima in the Laboratory

Insects ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 67 ◽  
Author(s):  
Lichao Feng ◽  
Liang Chang ◽  
Shaoqing Zhang ◽  
Xinyu Zhu ◽  
Sina Adl ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Food Preference ◽  
Feeding Habits ◽  
Food Resource ◽  
Food Preferences ◽  
Trophic Levels ◽  
Food Sources ◽  
Body Parts ◽  
Animal Food ◽  
Rhizopus Sp

Collembola display a variety of feeding habits, and prey on many types of food at different trophic levels in the soil. In most cases, their feeding selections are widely varied. In the interest of the food preferences of E. proxima, we attempted to confirm how the Collembola utilize food when feeding on carrion (unusual sources). Four different soil animals (with different stable isotope values and increasing trophic levels) were used to examine whether collembolans can use dead insects as a food resource in specific manners, depending on food preference. Our results demonstrated that the food preference of a collembolan changed significantly after feeding on insects with different feeding habits for 60 days. We found that stable isotope values (δ13C) of Entomobrya proxima approached those of the food sources. A large proportion of the diet (more than 50%) should directly consist of insect body parts, with the remainder consisting of indirectly used, mixed microorganisms naturally growing on animal food, such as fungi (Rhizopus sp., Alternaria sp., Penicillium sp., and Aspergillus sp.) and bacteria (Bacillus sp1. and Bacillus sp2.). Based on this research, the food preference of collembolans is more focused on carcasses (dead insect bodies) than microorganisms during the animal-food decomposition process.

scholarly journals Fresh and Dry Weight Relations Are Predictors of Cycas micronesica Seed Age

Horticulturae ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 29
Author(s):  
Thomas E. Marler ◽  
Christopher A. Shaw
Keyword(s):  
Dry Weight ◽  
Insect Herbivores ◽  
Seed Traits ◽  
Fresh Weight ◽  
Historical Source ◽  
Absolute Value ◽  
Seed Age ◽  
Specialist Insect ◽  
Total Seed ◽  
Substantial Change

Cycas micronesica is a foundation species in several Micronesian islands and its seeds have been a historical source of starch for the island residents. The species has become endangered by invasive specialist insect herbivores and conservationists struggle with the inability to estimate the age of observed seeds. To inform this agenda, we evaluated numerous Cycas micronesica seed traits to determine if any exhibited a relationship with age and a substantial change in absolute value. Of the 30 direct and derived seed traits that we evaluated, most of them were non-linear and exhibited minimal change after about 12 months in age. The only traits that emerged as unambiguous estimators of age were the quotients derived as gametophyte fresh weight/total seed fresh weight and sarcotesta dry weight/sclerotesta dry weight. These two simple metrics can be used to accurately estimate seed age for this arborescent cycad species.

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