scholarly journals Trait-Mediated Indirect Effects of Phorid Flies on Ants

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Hsun-Yi Hsieh ◽  
Ivette Perfecto
Keyword(s):  
Habitat Complexity ◽  
Ecological Impact ◽  
Trophic Levels ◽  
Foraging Activity ◽  
Ant Communities ◽  
Mediated Effects ◽  
Foraging Site ◽  
Phorid Flies ◽  
Average Size ◽  
Linear Nature

This paper provides a synthesis of the ecological impact of phorid fly parasitoids on ants. We find the most important impact of phorids on ants to be trait-mediated effects. Phorids diminish the foraging activity of ants, frequently reducing the number and average size of foragers and reducing the amount of food retrieved by a colony. However, ants' coping mechanisms include changing foraging site and time. Phorids can also affect competition, especially through changes in the ability of the host to win in exploitative competition. Factors such as microclimate, resource size, and habitat complexity interact with phorids to change their effect on competition. By being highly specific and attacking ants high in the competitive hierarchy, phorids can alter the linear nature of the competitive transitivity, and by reducing the number of foragers, they can change the discovery-dominance tradeoff that is observed in some ant communities. Trait-mediated effects of phorids also cascade to other trophic levels. As an example, we discuss the trait-mediated cascade of phorids on theAzteca instabilissystem in coffee. In this system, by reducing the foraging activity ofA. instabilis, phorids reduce the direct and indirect biological control impact of the ant in the coffee agroecosystem.

scholarly journals Micro plastics in soil ecosystem – A review of sources, fate, and ecological impact

2021 ◽  
Author(s):  
Jieru Yu ◽  
Samuel Adingo ◽  
Liu Xuelu ◽  
Xiaodan Li ◽  
Jing Sun ◽  
...  
Keyword(s):  
Management Practices ◽  
Ecological Impact ◽  
Chemical Properties ◽  
Scientific Basis ◽  
Trophic Levels ◽  
Control Measures ◽  
Ecological Environment ◽  
Future Research ◽  
Distribution Characteristics ◽  
Soil Ecosystem

In recent years, environmental experts and stakeholders have paid increased attention to the pollution of micro plastics in the soil. As persistent pollutants, micro plastics have a significant impact on the soil ecology, agricultural production, and the overall health of the ecological environment. Micro plastics can influence soil bio-physicochemical properties and the mobility of other contaminants in soil, with potentially significant implications on soil ecosystem functionality. Thus, functions including litter decomposition, soil aggregation or those related to nutrient cycling can be altered. Furthermore, micro plastics can influence soil biota at different trophic levels, and even threaten human health through food chains. Despite this potential negative interaction, there is limited research on micro plastics in the soil environment. The primary goals of this review are to summarise the sources, distribution characteristics, migration and degradation laws of micro plastics in the soil ecosystem, to summarise the combined effects of micro plastics and other pollutants in the soil ecosystem, to analyse the effects of micro plastics on soil physical and chemical properties, animals, plants, and microorganisms, and to reveal the effects of micro plastics on soil ecosystem and to according to the distribution characteristics of soil micro plastics, degradation, migration and ecological effects, propose pollution control measures. This current review will provide a comprehensive understanding of soil pollution by micro plastic and offer a scientific basis for the formulation of novel management practices that will protect and improve soils, and contribute to the sustainable development of the ecological environment and highlight important areas for future research.  

Foraging ecology of the thermophilic Australian desert ant, Melophorus bagoti

2005 ◽  
Vol 53 (5) ◽  
pp. 301 ◽  
Author(s):  
Barbara Muser ◽  
Stefan Sommer ◽  
Harald Wolf ◽  
Rüdiger Wehner
Keyword(s):  
Foraging Ecology ◽  
Soil Surface ◽  
Foraging Efficiency ◽  
Foraging Activity ◽  
Foraging Success ◽  
Success Rates ◽  
Desert Ant ◽  
Foraging Site ◽  
Intercolony Aggression ◽  
Melophorus Bagoti

The paper describes the foraging ecology of the Australian desert ant, Melophorus bagoti, a thermophilic, diurnal scavenger with ground-nesting colonies. Overlapping foraging ranges, low foraging success rates, and intercolony aggression suggest intense competition for food between colonies. Daily foraging starts when soil surface temperatures approach 50°C. Workers search individually and collect predominantly dead insects. Occasionally, they consume plant secretions. Foraging activity peaks on mid-summer days. On cloudy days the onset of foraging is delayed, and the foraging activity is low. Ants do not forage on rainy days. Typically, workers start their above-ground activities with a few short exploration runs. On average, they perform one foraging run on the first day of their outdoor lives. With age they gradually increase foraging site fidelity and daily foraging effort. Individual foraging efficiency is low at the beginning but grows with experience. However, due to a high mortality rate and, hence, high forager turnover, average rates of foraging success for a colony remain rather low. The outdoor activity gradually decreases towards the end of summer and appears to stop completely during the winter months.

scholarly journals Viral lysis modifies seasonal phytoplankton dynamics and carbon flow in the Southern Ocean

2021 ◽  
Author(s):  
Tristan E. G. Biggs ◽  
Jef Huisman ◽  
Corina P. D. Brussaard
Keyword(s):  
Microbial Community ◽  
Southern Ocean ◽  
Temporal Dynamics ◽  
Ecological Impact ◽  
Carbon Flow ◽  
Trophic Levels ◽  
Viral Lysis ◽  
Carbon Export ◽  
Community Interactions ◽  
Phytoplankton Communities

AbstractPhytoplankton form the base of marine food webs and are a primary means for carbon export in the Southern Ocean, a key area for global pCO2 drawdown. Viral lysis and grazing have very different effects on microbial community dynamics and carbon export, yet, very little is known about the relative magnitude and ecological impact of viral lysis on natural phytoplankton communities, especially in Antarctic waters. Here, we report on the temporal dynamics and relative importance of viral lysis rates, in comparison to grazing, for Antarctic nano- and pico-sized phytoplankton of varied taxonomy and size over a full productive season. Our results show that viral lysis was a major loss factor throughout the season, responsible for roughly half (58%) of seasonal phytoplankton carbon losses. Viral lysis appeared critically important for explaining temporal dynamics and for obtaining a complete seasonal mass balance of Antarctic phytoplankton. Group-specific responses indicated a negative correlation between grazing and viral losses in Phaeocystis and picoeukaryotes, while for other phytoplankton groups losses were more evenly spread throughout the season. Cryptophyte mortality was dominated by viral lysis, whereas small diatoms were mostly grazed. Larger diatoms dominated algal carbon flow and a single ‘lysis event’ directed >100% of daily carbon production away from higher trophic levels. This study highlights the need to consider viral lysis of key Antarctic phytoplankton for a better understanding of microbial community interactions and more accurate predictions of organic matter flux in this climate-sensitive region.

scholarly journals Interaction complexity matters: disentangling services and disservices of ant communities driving yield in tropical agroecosystems

2014 ◽  
Vol 281 (1775) ◽  
pp. 20132144 ◽  
Author(s):  
Arno Wielgoss ◽  
Teja Tscharntke ◽  
Alfianus Rumede ◽  
Brigitte Fiala ◽  
Hannes Seidel ◽  
...  
Keyword(s):  
Dominant Species ◽  
Species Traits ◽  
Trophic Levels ◽  
Species Density ◽  
Similar Species ◽  
Ant Communities ◽  
Ant Community ◽  
Pest Damage ◽  
Non Invasive ◽  
Tropical Agroecosystems

Owing to complex direct and indirect effects, impacts of higher trophic levels on plants is poorly understood. In tropical agroecosystems, ants interact with crop mutualists and antagonists, but little is known about how this integrates into the final ecosystem service, crop yield. We combined ant exclusion and introduction of invasive and native-dominant species in cacao agroecosystems to test whether (i) ant exclusion reduces yield, (ii) dominant species maximize certain intermediate ecosystem services (e.g. control of specific pests) rather than yield, which depends on several, cascading intermediate services and (iii) even, species-rich ant communities result in highest yields. Ants provided services, including reduced leaf herbivory and fruit pest damage and indirect pollination facilitation, but also disservices, such as increased mealybug density, phytopathogen dissemination and indirect pest damage enhancement. Yields were highest with unmanipulated, species-rich, even communities, whereas ant exclusion decreased yield by 27%. Introduction of an invasive-dominant ant decreased species density and evenness and resulted in 34% lower yields, whereas introduction of a non-invasive-dominant species resulted in similar species density and yields as in the unmanipulated control. Species traits and ant community structure affect services and disservices for agriculture in surprisingly complex ways, with species-rich and even communities promoting highest yield.

Habitat-contingent responses to disturbance: impacts of cattle grazing on ant communities vary with habitat complexity

2018 ◽  
Vol 28 (7) ◽  
pp. 1808-1817 ◽  
Author(s):  
Gabriela B. Arcoverde ◽  
Alan N. Andersen ◽  
Inara R. Leal ◽  
Samantha A. Setterfield
Keyword(s):  
Habitat Complexity ◽  
Cattle Grazing ◽  
Ant Communities

scholarly journals Predicting global killer whale population collapse from PCB pollution

Science ◽  
2018 ◽  
Vol 361 (6409) ◽  
pp. 1373-1376 ◽  
Author(s):  
Jean-Pierre Desforges ◽  
Ailsa Hall ◽  
Bernie McConnell ◽  
Aqqalu Rosing-Asvid ◽  
Jonathan L. Barber ◽  
...  
Keyword(s):  
Polychlorinated Biphenyl ◽  
Killer Whale ◽  
Trophic Levels ◽  
Orcinus Orca ◽  
Killer Whales ◽  
Model Framework ◽  
Population Collapse ◽  
Mediated Effects ◽  
Chemical Class

Killer whales (Orcinus orca) are among the most highly polychlorinated biphenyl (PCB)–contaminated mammals in the world, raising concern about the health consequences of current PCB exposures. Using an individual-based model framework and globally available data on PCB concentrations in killer whale tissues, we show that PCB-mediated effects on reproduction and immune function threaten the long-term viability of >50% of the world’s killer whale populations. PCB-mediated effects over the coming 100 years predicted that killer whale populations near industrialized regions, and those feeding at high trophic levels regardless of location, are at high risk of population collapse. Despite a near-global ban of PCBs more than 30 years ago, the world’s killer whales illustrate the troubling persistence of this chemical class.

scholarly journals Disentangling factors that assemble New Zealand's ant communities

2021 ◽  
Author(s):  
◽  
Rafael Forti Barbieri
Keyword(s):  
Small Groups ◽  
Community Assembly ◽  
Survival Probability ◽  
Pesticide Exposure ◽  
Foraging Activity ◽  
Invasive Ant ◽  
Ant Communities ◽  
Defensive Reaction ◽  
Occurrence Patterns ◽  
Forest Habitats

<p>Several biotic and abiotic stressors can influence community assembly. The negative co-occurrence patterns observed within many communities, for example, may derive either from behavioural similarities (e.g. species displaying high aggression levels towards each other) or habitat preference. I evaluated the role of several stressors that may shape New Zealand’s ant communities. First, I investigated (in chapter 2) the co-occurrence patterns of two native ant communities located within transitional grassland-forest habitats. I also monitored the temperature variation in these habitats over a one-year period. I found that grasslands are exposed to higher temperature variation than forest habitats. I also found that some ants are mostly associated with forest habitats and others with grasslands. Using null models to examine these communities, I found evidence that two ant species (Monomorium antarcticum and Prolasius advenus) exhibit negative co-occurrence patterns. In the reminder of my thesis I developed a series of laboratory-based experiments to examine the processes that could explain the co-occurrence patterns that I observed in these ant communities.  In chapter 3, I subjected heterospecific groups of ants to interactions in controlled conditions. I asked if interspecific aggression predict the survival probability and co-occurrence patterns described in chapter 2. My results demonstrated that aggression predicted the survival probability of interacting ant species and their co-occurrence patterns. I argued that aggressive behaviour might reflect the risks imposed by competitors. Differences in aggression may thus be a key factor influencing sympatric and allopatric co-occurrence patterns of these ant communities.  In chapter 4, I tested the hypotheses that arrival sequence and diet influence the strength of interactions between colonies of two species that exhibited negative co-occurrence patterns (P. advenus and M. antarcticum). When arriving first, P. advenus displayed increased aggression and M. antarcticum a defensive reaction. The adoption of a defensive reaction by M. antarcticum increased their colony survival probability. Changes in carbohydrate and protein availability modulated colony activity rates of both species. These results indicate that arrival sequence can modulate the territorial behaviour displayed by interacting species in situations of conflict. Also, I showed that these ant species adjust their foraging activity rates in according to their diet, but different species do so differently.  In chapter 5, I expanded the scope of chapter 4 and asked if aggression and foraging behaviour of P. advenus and M. antarcticum change in different conditions of temperature, diet and group size. For both ant species, changes in temperature had stronger effects on small than large colonies. Small groups of M. antarcticum displayed higher foraging activity at lower temperatures. Conversely, small groups of P. advenus displayed higher foraging activity at high temperatures. Also, small M. antarcticum colonies displayed increased aggression and significantly reduced the size of large P. advenus colonies, regardless of temperature and diet. These results suggest that P. advenus and M. antarcticum perform differently at different temperatures. Furthermore, I demonstrated that the persistence of these small colonies might be related to their ability to modulate foraging activities and interspecific aggression according to the environment.  I also investigated (in chapter 6) the effects of a neurotoxic pesticide (neonicotinoid) on a native (M. antarcticum) and an invasive ant (Linepithema humile). I tested whether sublethal contamination with a neonicotinoid affects foraging, fitness and the outcome of interspecific interactions between these ants. Overall, pesticide exposure increased aggression of the invasive ant and reduced the aggression of the native species. Importantly, non-exposed individuals of the invasive species subjected to interactions against exposed natives were less aggressive, but more likely to survive. These results suggest that the modification of the physicochemical environment by pesticide contamination could change the dynamics of communities and influence invasion success.  Overall, this thesis highlights that synergistic effects between several biotic and abiotic factors influence community assembly. My results suggest that non-random allopatric patterns of niche occupancy observed in these ant communities are better explained by high levels of aggression displayed between pairs of species that seldom co-occur, though I was unable to falsify the hypothesis that habitat preference also plays a role in determining their distribution and co-occurrence patterns. The modification of behaviour by external factors – either natural (e.g. temperature) or human mediated (e.g. pesticide exposure) – likely has broad effects on population and community dynamics and on patterns of species co-existence.</p>

Early herbivore alert matters: plant-mediated effects of egg deposition on higher trophic levels benefit plant fitness

2015 ◽  
Vol 18 (9) ◽  
pp. 927-936 ◽  
Author(s):  
Foteini G. Pashalidou ◽  
Enric Frago ◽  
Eddie Griese ◽  
Erik H. Poelman ◽  
Joop J. A. van Loon ◽  
...  
Keyword(s):  
Trophic Levels ◽  
Plant Fitness ◽  
Mediated Effects ◽  
Egg Deposition

scholarly journals Prey selection by North Sea herring (Clupea harengus), with special reference to fish eggs

2006 ◽  
Vol 64 (1) ◽  
pp. 60-68 ◽  
Author(s):  
F. H. I. D. Segers ◽  
M. Dickey-Collas ◽  
A. D. Rijnsdorp
Keyword(s):  
Special Reference ◽  
North Sea ◽  
Prey Selection ◽  
Ecological Impact ◽  
Clupea Harengus ◽  
Trophic Levels ◽  
Trawl Survey ◽  
Fish Eggs ◽  
The North ◽  
The North Sea

Abstract Segers, F. H. I. D, Dickey-Collas, M., and Rijnsdorp, A. D. 2007. Prey selection by North Sea herring (Clupea harengus), with special reference to fish eggs. ICES Journal of Marine Science, 64: 60–68. he herring stock in the North Sea in recent years has recovered to a relatively high biomass, and here we investigate prey selection of individual North Sea herring when population numbers are high. The diet composition, and specifically pelagic fish eggs, was investigated in February 2004. Samples of herring from the International Bottom Trawl Survey were used for stomach analysis, and ichthyoplankton samples from the southern North Sea were used to investigate selection. Crustaceans were the main diet component. The average diameter of the fish eggs recovered from the stomachs was significantly larger than that of the eggs collected in the field. In addition, the frequency at which the latest developmental stages occurred in the herring stomachs was significantly different from the frequency at which these stages were found in the field. This shows selective foraging. There was a relationship between the amount of food and the number of eggs in a herring stomach: the fullest stomachs tended to contain fewer fish eggs. This suggests that herring forage on eggs when other prey are not available. Hence, it is likely that the dynamics of multiple trophic levels influence the ecological impact of a large herring stock on the North Sea ecosystem.

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