Trait life history

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. 

Of the examples considered above, two are of phenotypic diversity in a life-history trait where the life-history trait under consideration is clearly a facultative phenomenon. That is, for developmental route in S. ratti and for arrested development, there are distinct, mutually exclusive developmental routes. Thus, diversity in these traits between different parasite lines is relatively easy to observe, as is the response to selection. Both these traits are, in part, affected by environmental conditions and so are phenotypically plastic. For S. ratti, variation in the sensitivity of this plasticity can also be seen. Although environmental sensitivity of arrested development is as yet uninvestigated, by analogy with S. ratti it is likely to vary. 

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... 

Koivisto, S. and M. Ketola. 1995. Effects of copper on life-history traits of Daphnia pulex and Bosmina longirostris. Aquat. Toxicol. 32 255-269. 

Stored-product arthropods can be grouped in different ways based on taxonomy, feeding preference, and life history traits. To provide an... 

Leonardo, T. E. and Mondor, E. B. 2006. Symbiont modifies host life history traits that affect gene flow. Proceedings of the Royal Society B-Biological Sciences, 273(1590) 1079-1084. 

There are many important life-history traits of parasitic flatworms that determine their success, as measured either as numbers, biomass,... 

Trouve, S., Morand, S. and Gabrion, C. (2003) Asexual multiplication of larval parasitic worms a predictor of adult life-history traits in Taeniidae Parasitology Research 89, 81-88. 

Linke-Gamenick I, Forbes VE, Sibly RM. 1999. Density-dependent effects of a toxicant on life-history traits and population dynamics of a capitellid polychaete. Mar Ecol Prog Ser 184 139-148. 

Postma JF, van Kleunen A, Admiraal W. 1995b. Alterations in life-history traits of Chrironomus riparius (Diptera) obtained from metal contaminated rivers. Arch Environ Contain Toxicol 29 469-475. 

Despite this plethora of information regarding the physiological ecology of Phaeocystis, fundamental interactions between life history traits and system ecology are poorly understood. Research summarized here, and described in the various papers in this special issue, derives from a central question how do physical (light, temperature, particle distributions, hydrodynamics), chemical (nutrient resources, infochemistry,... 

TABLE 1 Factor analysis of a correlation matrix among life history traits from Charlesworth (1990), generated on the assumption that all variation is due to trade-offs among traits... 

TABLE 3 Loadings of life-history traits on the first eigenvector in the data of Tatar et al (1996). mx is adult fecundity on day x, and lx is the probability of survival from day x-1 to x. 

Houle D, Hughes KA, Hoffmaster DK et al 1994 The effects of spontaneous mutation on quantitative traits. I. Variance and covariance of life history traits. Genetics 138 773-785 Houle D, Morikawa B, Lynch M 1996 Comparing mutational variabilities. Genetics 143 1467— 1483... 

Price T, Schluter D 1991 On the low heritability of life history traits. Evolution 45 853-861 Rowe L, Houle D 1996 The lek paradox and the capture of genetic variance by condition dependent traits. Proc R Soc Lond B Biol Sci 263 1415—1421 Taylor PD, Williams GC 1982 The lek paradox is not resolved. Theor Pop Biol 22 392—409 Wilkinson GS, Reillo 1994 Female choice response to artificial selection on an exaggerated male trait in a stalk-eyed fly. Proc R Soc Lond B Biol Sci 255 1—6... 

Even though the Baltic is a young ecosystem, species-poor and vulnerable to the threat of invasive marine and exotic species, both the strong gradient and the rapid change in salinity conditions especially in the southern Baltic inhibit an unhindered colonization. As a result, the Baltic benthic fauna is still largely characterized by species with obvious opportunistic life history traits (Rumohr et al., 1996). 

H.J. De Lange, E. Van Donk (1997). Effects of UVB-irradiated algae on life history traits of Daphnia pulex. Freshwat. Biol, 38, 711-720. 

Comparing recovery time interval to generation time, we find that exposure to the EEC of acephate resulted in a delay of >1 generation time interval only for the oriental fruit fly (Table 5.2). Therefore, results of this exercise show that these 3 closely related species exhibited differences in life history traits and susceptibility to acephate, which resulted in very different outcomes at the population level. The quotient method correctly indicated that acephate posed a hazard only to the oriental fruit fly. However, sublethal effects were not considered in this model and the range of effects (7-week recovery) versus no delay in the Mediterranean fly could not be predicted by the quotient method. 

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