Fecundity

Abamectin is also used to control the imported red fine ant Soknopsis invicta. For this use abamectin is formulated as a bait together with soybean oil and com grits. Worker ants transport the bait to the colony, the queen becomes sterile, and the colony is eliminated after 12 to 21 weeks. Similar effects on the fecundity of other female insects at nonlethal doses have been reported (16,17). 

A second focus for chemical engineers in agriculture is the improvement of veterinary pharmaceuticals (e.g., peptide hormones that promise to stimulate growth, fecundity, and feed efficiency in farm animals) and vaccines. The prospects for improvement of these compounds parallel the bright prospects for human pharmaceuticals and vaccines, and the requirements for chemical engineering expertise are similar. 

Sheepshead minnow (Cyprinodon variegatus) DBTC 191-day NOEC (survival, growth, and fecundity) 0.45 0.45 Elf Atochem NA (1992)... 

In predicting the effects of a pollutant on population growth rate, the effects of the chemical on the values of t, I, and n are of central interest. Chemical residue data and biomarker assays that provide measures of toxic effects are relevant here because they can, in concept, be used to relate the effects of a chemical upon the individual organism to a population parameter such as survivorship or fecundity (Figures 4.5 and 4.6). Examples of this are discussed in the second part of the text, including the reduction of survivorship of sparrow hawks caused by dieldrin (Chapter 5), the... 

Here we illustrate that the population-level impacts of exposure to EDCs cannot easily be extrapolated from bioassays on individuals. Even when total fecundity is... 

For nonequilibrium statistical mechanics, the present development of a phase space probability distribution that properly accounts for exchange with a reservoir, thermal or otherwise, is a significant advance. In the linear limit the probability distribution yielded the Green-Kubo theory. From the computational point of view, the nonequilibrium phase space probability distribution provided the basis for the first nonequilibrium Monte Carlo algorithm, and this proved to be not just feasible but actually efficient. Monte Carlo procedures are inherently more mathematically flexible than molecular dynamics, and the development of such a nonequilibrium algorithm opens up many, previously intractable, systems for study. The transition probabilities that form part of the theory likewise include the influence of the reservoir, and they should provide a fecund basis for future theoretical research. The application of the theory to molecular-level problems answers one of the two questions posed in the first paragraph of this conclusion the nonequilibrium Second Law does indeed provide a quantitative basis for the detailed analysis of nonequilibrium problems. 

There is good evidence, for a number of helminth species, that different parasite lines vary in their infection characteristics in hosts, much of which is reviewed by Read and Viney (1996). For example, different isolates of Trichinella spiralis vary in the kinetics of their primary infection in the same mouse strain. Crucially, these differences are removed when mice are immunosuppressed (Bolas-Fernandez and Wakelin, 1989). Analogous observations have been made for Trichuris muris in mice. Different isolates differed in the kinetics of infection and expulsion. However, in immunosuppressed mice, all isolates had similar fecundity (Bellaby et al., 1995). Combined, these observations show immune-dependent variation between parasite lines in their infection kinetics. 

Taken as a whole, these observations show that parasite lines differ in an immune-dependent manner in their infection/expulsion kinetics. Furthermore, there is heritable variation in survival and fecundity in previously exposed hosts and quantitative variation in the immune response that selected parasite lines elicit. Again, taken as a whole, these observations have the necessary corollary that variation in these traits exists not only in laboratory-maintained isolates but also in helminth species in nature. The phenotypes under consideration here (infection/expulsion kinetics, survival, fecundity) are multifactorial life-history traits. Understanding the basis of variation in the components and interplay of these complex, immune-responsive phenotypes must be of crucial relevance to understanding the immunology of infections of parasitic nematodes. This is of particular relevance in view of current attempts to develop immunological methods of nematode control. 

The third example considered the interaction of life-history traits (survival rates, fecundity, immunogenicity) with an environmental factor specific to parasites, namely the host immune system. Here phenotypic diversity in response to environmental conditions (host immunity) is not so readily apparent. To observe phenotypic diversity, different parasite lines need to be compared in their kinetics of infection and, to show immune-dependence, these must be complemented by control experiments in immunosuppressed hosts. Experiments seeking to select on this diversity... 

Other contributions to this book have taken a molecular view of parasitic nematodes, yet molecules make only a rather brief appearance here. This chapter has tried to show that parasitic nematodes are fascinatingly and tantalizingly diverse at a phenotypic level. It has focused particularly on diversity in phenotypes that are apparent in response to environmental conditions within or outside a host. The interaction of parasites with within-host factors is a major current research effort. However, helminth immunology is particularly notable for its inattention to diversity, especially when compared with the immunology of parasitic protozoa (Read and Viney, 1996). Observations of the interaction of host immunity with subsequent development in S. ratti show the potential power of such interactions. It is also clear that a principal mechanism of the action of host immune responses is against nematode fecundity (Stear et al., 1997). This is likely to be a molecularly complex interaction. Understanding this interaction, as well as variation in the interaction is interesting, but could also form the basis of control by transmission-reduction rather than eradication per se. 

Pritchard, D.I., Quinnell, R.J. and Walsh, E.A. (1995) Immunity in humans to Necator americanus. IgE, parasite weight, and fecundity. Parasite Immunology 17, 71-75. 

Vanamail, P., Ramaiah, K.D., Pani, S.P., Das, P.K., Grenfell, B.T. and Bundy, D.A.P. (1996) Estimation of the fecund life-span of Wuchereria bancrofti in an endemic area. Transactions of the Royal Society of Tropical Medicine and HygieneQO, 119—121. 

Most social insects are found in the order Hymenoptera. Sociality in insects is defined by the presence of one or more of the following traits (1) individuals of the same species cooperate in caring for the young (2) there is a reproductive division of labor, with usually sterile individuals working on behalf of fecund individuals and (3) there is an overlap of at least two generations in life... 

The queen is usually reproductively dominant within the colony and uses chemical cues as both primer and releaser pheromones to suppress the production or fecundity of other sexuals, inhibit reproduction by worker castes, modulate reproductive behaviors (e.g., inhibit swarming and orient swarms), attract males, regulate worker tasks and worker ontogeny, and produce host repellents in slave-making species. Considering the importance of queen semiochemicals in social hymenoptera, few queen pheromones have been chemically identified. The queens of most social hymenopteran colonies are attractive to workers, allowing them to be properly tended as well as to facilitate the dissemination of other pheromone cues. However, the retinue pheromone has been chemically identified in very few species. In the 1980s, queen pheromone components were identified in the fire ant, Solenopsis invicta [91,92], and in the Pharaoh s ant, Monomoriumpharaonis [93]. 

Benejam L, Benito J, Garcia-Berthou E (2009) Decreases in condition and fecundity of freshwater fishes in a highly polluted reservoir. Water Air Soil Pollut. doi 10.1007/sll270-009-0245-z... 

This section of the Ebro River is under the direct impact of the Flix chlor-alkali plant and of its residue sediments. Contamination of Hg and OCs is maximal in these sediments, and there is evidence that it leaks downstream as far as at least to Xerta, 37 km away Flix ([8, 9], Fig. 4a, d). Fish populations in Flix show poorer condition and fecundity than their counterparts sampled in Riba-roja or the Delta [38]. In addition, HSI and CF in carps showed good correlation (positive and negative, respectively) with OC burden (Fig. 4c). These data indicate that the pollution by Flix residues and, specifically, by OCs, affects the growth and health status of fish from the low Ebro River. 

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