Food and Feeding Strategies of Water Mites of the Genus Hygrobates and the Impact of Their Predation On the Larval Population of the Chironomid Cladotanytarsus Mancus (Walker) in Lake Maarsseveen

1988 ◽  
Vol 39 (2) ◽  
pp. 246-263 ◽  
Author(s):  
Erik H. Ten Winkel ◽  
C. Davids ◽  
J.G. De Nobel
Keyword(s):  
Feeding Strategies ◽  
Water Mites ◽  
Larval Population ◽  
Food And Feeding ◽  
The Impact

An attempt to control ragwort in Australia with the cinnabar moth, Callimorpha jacobaeae (L.) (Arctiidae : Lepidoptera)

1966 ◽  
Vol 14 (2) ◽  
pp. 201 ◽  
Author(s):  
GF Bornemissza
Keyword(s):  
Fungal Infections ◽  
Virus Disease ◽  
Early Stage ◽  
Reproductive Rate ◽  
Reproductive Capacity ◽  
Weather Factors ◽  
Larval Population ◽  
Annual Fluctuation ◽  
Cinnabar Moth ◽  
The Impact

This paper describes research on the cinnabar moth, Callimorpha jacobaeae, introduced from England and Italy to Australia for the control of the poisonous weed, ragwort (Senecio jacobaea). Studies were conducted for six seasons in a high rainfall area of southern Gippsland, Vic., where the impact of ragwort infestation on dairy pastures was severe. Callimorpha has a univoltine life cycle with an obligatory pupal diapause during winter. The termination of this diapause in introduced stocks was successful to a limited extent only, and changes in its duration required for synchronization with the southern hemisphere seasons adversely affected the reproductive capacity of emerging females. The larval progeny of Italian stock failed to survive in the field, and disappeared completely within the first season, whereas those of English origin were reasonably successful. In view of the low reproductive rate of Callimorpha and because of its numerous insect enemies, breeding was carried out in the field using techniques designed to provide protection from the locally abundant predators. An attempt was also made to assess factors playing a role in its numerical regulation. The larvae were liable to heavy mortality in the field due to the combined effect of fungal infections, insect predators, and parasites, and also to a virus disease introduced in a latent state with the insect. At an early stage of this work (the second Australian generation), a nuclear polyhedral virus epizootic destroyed 90% of the larval population. The fifth Australian generation was the last to survive in the field. Of the larval predators, the mecopteran Harpobittacus nigriceps caused the most serious mortality. This predator, common in all ragwort-infested areas of Victoria, showed a zonal pattern in its density distribution; the high density zones often overlapped sites occupied by larval colonies of the cinnabar moth. The larvae of Callimorpha were more frequently taken by Harpobittacus than tipulid flies (Macromastix spp.) which are normally its principal prey; the abundance and distribution of these flies was also studied. The abundance of both Harpobittacus and Macromastix, was influenced by weather factors, resulting in a marked annual fluctuation in their numbers. At times of high Harpobittacus abundance, mortality in larval colonies of Callimorpha due to this predator averaged over 80%, with extremes of 90-100% being observed frequently. The larvae of Callimorpha were found to be potentially efficient in controlling ragwort. The viable seed production of severely attacked plants was reduced, following defoliation and destruction of the primary flowerheads, by an average of over 98%. However, taking all factors into account, it is unlikely that Callimorpha could exert useful control of ragwort in Australia. There seems little chance that high larval densities, necessary to suppress seeding by ragwort, could be maintained in face of heavy predation. As the data presented in this paper indicate, Harpobittacus alone would be capable of preventing the effective establishment of C. jacobaeae in this country.

Board Invited Review: Management and feeding strategies to ameliorate the impact of removing antibiotic growth promoters from diets fed to weanling pigs

2010 ◽  
Vol 90 (4) ◽  
pp. 447-460 ◽  
Author(s):  
D.Y. Kil ◽  
H.H. Stein
Keyword(s):  
Feeding Strategies ◽  
Growth Promoters ◽  
Weanling Pigs ◽  
Liquid Form ◽  
Review Management ◽  
Antibiotic Growth Promoters ◽  
Negative Impacts ◽  
Hind Gut ◽  
Ad Libitum Intake ◽  
The Impact

A review of the literature was conducted with the objective of identifying management and feeding strategies for weanling pigs that are effective in reducing the negative impacts of discontinued use of antibiotic growth promoters (AGP) in diets fed to weanling pigs. If no AGP are used, dietary crude protein concentrations should be reduced to less than 18% in diets fed to pigs during the immediate post-weaning period. Diets should be fed in a liquid form if possible, preferably as fermented liquid feed. Feed intake should be restricted to 75% of ad libitum intake during the initial 2 wk post-weaning to reduce the amount of substrates available to pathogens in the hind gut. The profit from pig production will be maximized if pigs are weaned between 21 and 28 d of age. All-in all-out production should be practiced and pigs should always be weaned into an empty, clean, and disinfected room, preferably at a location separated from the sow farm. Disease pressure and mortality do not necessarily have to increase if no AGP are used, but profits will likely be reduced because costs of preventing diseases in pigs fed diets containing no AGP often are greater than the cost of AGP.

scholarly journals The impact of selective logging on sympatric civet species in Borneo

Oryx ◽  
1996 ◽  
Vol 30 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Matthew J. Heydon ◽  
Pullin Bulloh
Keyword(s):  
East Asia ◽  
Marked Reduction ◽  
Selective Logging ◽  
Primary Forest ◽  
Feeding Strategies ◽  
Food Chains ◽  
South East Asia ◽  
Logged Forest ◽  
Disturbed Forest ◽  
The Impact

Selective logging is the predominant method of commercial timber exploitation in South East Asia. Its effects upon mammalian carnivores have seldom been addressed, despite the vulnerability of these animals at the top of many food chains. The authors investigated the effects of logging by comparing the abundance of sympatric civet species, which display feeding strategies ranging from strict carnivory tofrugivory, in primary and selectively logged rainforest in the Malaysian state ofSabah in northern Borneo. All species occurred in disturbed forest, but the overall density of civets in logged forest (6.4 individuals per sq km) was found to be significantly lower than in primary forest (31.5 individuals per sq km). This reflected a marked reduction in the abundance of civets from the predominantly carnivorous subfamilies Viverrinae and Hemigalinae.

Enhancing the vitamin content of meat and eggs: Implications for the human diet

2006 ◽  
Vol 86 (2) ◽  
pp. 181-195 ◽  
Author(s):  
A. Sahlin ◽  
J. D. House
Keyword(s):  
Well Being ◽  
Feeding Strategies ◽  
Human Diet ◽  
Vitamin Content ◽  
Vitamin Intake ◽  
Optimal Health ◽  
Definition Of ◽  
The Impact ◽  
And Storage ◽  
Meat And Eggs

Enhancing the vitamin content of meat and eggs provides an opportunity to increase the levels of key nutrients-especially those deemed to be at marginal or insufficient levels-in the human diet for optimal health and well-being. In general, enhancement efforts have focussed on developing feeding strategies to achieve optimal vitamin levels in meat and eggs. The definition of an optimal strategy is influenced by factors such as: (1) the efficiency of vitamin transfer into the final product, (2) the impact on animal performance or health, (3) the impact on the quality characteristics of the final product and (4) economic considerations. Vitamins are an extremely diverse class of nutrients in terms of their chemical and physical properties. Each vitamin differs with respect to stability during processing, susceptibility to bioconversion within the intestinal tract, digestibility, transport and storage in tissues. It follows that the development of vitamin-enriched meat and eggs will be highly dependent on the interaction of multiple factors. Ultimately, the success of such strategies must be judged against the contributions that the enriched products make to the human diet in terms of vitamin intake and consumer acceptance of the products. Key words: Meat, eggs, vitamin enhancement, bioavailability, dietary reference intakes

scholarly journals Trace metal accumulation in decapods and its use in monitoring the marine environment

2021 ◽  
Author(s):  
◽  
Annie Graham
Keyword(s):  
Trace Metals ◽  
Trace Metal ◽  
Spatial Variation ◽  
Marine Environment ◽  
Metal Accumulation ◽  
Environmental Indicators ◽  
Trophic Levels ◽  
Geochemical Data ◽  
Feeding Strategies ◽  
The Impact

<p>Coastal habitats are susceptible to severe contamination due to their exposure to both marine and terrestrial inputs, many of which contain toxic heavy metals. Trace metals in the marine environment can have severe impacts on the health of coastal ecosystems, as even those with essential functions can be toxic at high concentrations, and non-essential elements can cause impairment of biological functions even at low levels.  It is important to understand the chemistry of New Zealand’s marine environment, in order to successfully monitor any changes to the chemical profile of the environment from anthropogenic pollutants. Biological indicators are a useful tool for monitoring ecosystem health, and the impact of human activity on the environment. Crustaceans fulfil all the criteria of being good environmental indicators, as well as having a range of feeding strategies, and being present at multiple trophic levels. The aim of this research was to 1) investigate spatial variation and the effect of urbanisation in trace metal concentration in two native decapod species, Heterozius rotundifrons and Petrolisthes elongatus, which co-occur but feed at different trophic levels; and 2) examine how essential and non-essential trace metals are accumulated into different body tissues of the decapod Jasus edwardsii, a significant cultural and fishery species.  To assess spatial variation and trophic level differences between decapods, baseline data of the concentrations of thirty trace metals was collected and analysed from both species at three sites in the Wellington region. Little variation was found between the sites, despite their differences in proximity to urban development, but significant differences were found between species, with the consumer H. rotundifrons having higher concentrations of most trace metals than the filter feeder P. elongatus.  To assess trace metal accumulation into tissues of J. edwardsii, an experiment was run exposing juveniles to water doped with an elevated copper and neodymium treatment. Copper was preferentially accumulated into the organ tissue, as was expected for an essential element. Neodymium was accumulated differentially into organ and exoskeleton tissue depending on the treatment, with specimens in the elevated treatment taking it up into the shell rather than the organs. A second experiment was also run to investigate whether moulted exoskeletons would passively absorb copper from their environment, which was shown to be the case.  This research aids in understanding the importance of multiple species monitoring, as trace element accumulation was shown to be highly variable depending on species and metals, and contributes valuable geochemical data on native New Zealand species, which have been little studied in this context.</p>

scholarly journals Water mites (Acari, Hydrachnidia) of riparian springs in a small lowland river valley: what are the key factors for species distribution?

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4797 ◽  
Author(s):  
Andrzej Zawal ◽  
Robert Stryjecki ◽  
Edyta Buczyńska ◽  
Paweł Buczyński ◽  
Joanna Pakulnicka ◽  
...  
Keyword(s):  
Positive Impact ◽  
Mite Species ◽  
River Valley ◽  
Conservation Strategies ◽  
Lowland River ◽  
Water Mites ◽  
Water Mite ◽  
Anthropogenic Transformation ◽  
River Valleys ◽  
The Impact

This paper examines the impact of disturbance factors—flooding and intermittency—on the distribution of water mites in the riparian springs situated in the valley of a small lowland river, the Krąpiel. The landscape factors and physicochemical parameters of the water were analysed in order to gain an understanding of the pattern of water mite assemblages in the riparian springs. Three limnological types of springs were examined (helocrenes, limnocrenes and rheocrenes) along the whole course of the river and a total of 35 water mite species were found. Our study shows that flooding influences spring assemblages, causing a decrease in crenobiontic water mites in flooded springs. The impact of intermittency resulted in a high percentage of species typical of temporary water bodies. Surprisingly, the study revealed the positive impact of the anthropogenic transformation of the river valley: preventing the riparian springs from flooding enhances the diversity of crenobiontic species in non-flooded springs. In the conclusion, our study revealed that further conservation strategies for the protection of the riparian springs along large rivers would take into account ongoing climatic changes and possible the positive impact of the anthropogenic transformation of river valleys.

IMPACT OF BEAUVERIA BASSIANA ON THE COTTONWOOD BORER, PLECTRODERA SCALATOR (COLEOPTERA: CERAMBYCIDAE), IN A COMMERCIAL COTTONWOOD NURSERY.

1989 ◽  
Vol 24 (2) ◽  
pp. 186-190 ◽  
Author(s):  
B. T. Forschler ◽  
G. L. Nordin
Keyword(s):  
Beauveria Bassiana ◽  
Populus Deltoides ◽  
Adult Population ◽  
Control Treatment ◽  
High Dose ◽  
Flight Period ◽  
Treatment Area ◽  
Larval Population ◽  
The Mean ◽  
The Impact

A commercial Beauveria bassiana (Balsamo) Vuillemin conidial formulation, AGB 6178, was applied as a soil drench against the cottonwood borer, Plectrodera scalator (F.), in a commercial eastern cottonwood, Populus deltoides, nursery. Doses of 0, 2 × 109, 2 × 1010 and 1 × 1011 conidia/m2 were applied in June 1986. The adult population was monitored throughout its flight period (June–August) for B. bassiana infection. Greater than 60% of the adults collected in the treatment area post-treatment were infected with B. bassiana. The impact of the fungal application on the larval population was assessed 8 months later by the removal and dissection of the treated rootstocks. Though no differences were detected in the number of second-year larvae recovered, the mean number of first-year larvae found at the high dose (1 × 1011 CFU's/m2) was significantly less (LSD, alpha 0.05) than the mean number of larvae found in the control treatment (0 CFU's/m2), 5.0 and 9.4 larvae/10 rootstocks, respectively.

SIMULATION MODEL FOR THE POPULATION DYNAMICS OF THE CARROT WEEVIL, LISTRONOTUS OREGONENSIS (LECONTE) (COLEOPTERA: CURCULIONIDAE)

1991 ◽  
Vol 123 (1) ◽  
pp. 63-76 ◽  
Author(s):  
D.X. Zhao ◽  
G. Boivin ◽  
R.K. Stewart
Keyword(s):  
Population Dynamics ◽  
Simulation Model ◽  
Mortality Rates ◽  
Egg Parasitoid ◽  
Adult Density ◽  
Larval Population ◽  
Listronotus Oregonensis ◽  
The Mean ◽  
Carrot Weevil ◽  
The Impact

AbstractA simulation model was developed for the population dynamics of a carrot weevil, Listronotus oregonensis (LeConte), population on muck-grown carrots. The model includes mortality rates of eggs, larvae, and pupae for different sowing dates of carrots. It also incorporates the overwintered adult density, the temperature-dependent growth rates of the above-mentioned life stages, the age-, temperature-, and phenology-dependent oviposition rates, and the impact of an egg parasitoid, Anaphes sordidatus (Girault), on egg mortality rates. Model output was evaluated by comparing simulated results with observed results on the seasonal totals and time of population peaks of the egg and larval populations. The mean percentage differences between the simulated and observed seasonal egg totals were 3.1 ± 0.66 (SE) in 1987 and 1988, and 4.2 ± 0.05 in 1989. They were not statistically different. The mean percentage differences between the simulated and observed seasonal larval totals were 10 ± 3.33 in 1987 and 1988 and 29.8 ± 0.66 in 1989. Independent data sets (i.e. field data in 1989) showed a significant increase in the simulation error of the larval population. Sensitivity analysis indicated that A. sordidatus had a large influence on the population dynamics of L. oregonensis.

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