Does the presence of a human tracker affect the behaviour of radio‐tagged wood mice Apodemus sylvaticus?

1. While the effect on animals of handling them and fitting them with radio tags has been investigated, little work has been reported testing the effect of the presence of a human observer tracking an animal. 2. The activity of wood mice fitted with radio collars and confined to a semifield pen was measured in the presence and the absence of a human observer. Free‐ranging wood mice were radio tracked by using two protocols: ‘fixes’ taken periodically, and periods of continuous tracking. 3. There was no significant difference in any quantified aspect of the animals’ behaviour. This suggests that the presence of a human tracker has a negligible effect on the behaviour of wood mice.     

Linguistic Diversity in the South: Changing Codes, Practices, and Ideology

Linguistic Diversity in the South: Changing Codes, Practices, and Ideology . Margaret Bender, ed. Athens: University of Georgia Press, 2004. 141 pp.     

Competitor avoidance drives within‐host feeding site selection in a passively dispersed herbivore

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Evolution of life history traits in Leporidae: a test of nest predation and seasonality hypotheses

Recently, it has been proposed that adult mortality schedules may be responsible for latitudinal patterns of life history variation in passerine birds, whereas nest predation only could explain within latitude patterns. Unfortunately, no independent test has been performed regarding the importance of nest predation with different taxa. In the present study, seasonality and nest predation hypotheses explaining variations in gestation time and litter size in 17 lagomorph species were tested. Among latitude patterns were analysed using the phylogenetic independent contrast method of Felsenstein and within latitude patterns were analysed by the pairwise comparative method. The results obtained indicate that latitudinal patterns observed in both variables are explained by different factors: seasonality for litter size and nest predation for gestation time. Litter size variations within latitudes are also explained by differences in nest predation, supporting previous hypotheses. In conclusion, the present study suggests that, when compared among latitudes, different life history traits (e.g. litter size and gestation time) may be shaped by different selective forces and that the effects of nest predation may be high both within and between latitudes.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 603–610.     

CONSUMER ATTITUDES AND OPINIONS TOWARD FUNCTIONAL FOODS: A FOCUS GROUP STUDY

Acceptance of foods with specific health characteristics depends largely on the consumers' opinion. The objective of this work was to investigate Spanish consumers' opinions, attitudes and beliefs regarding functional foods in general, and one of the most popular foods, yogurt, in particular. Six consumer focus group interviews were conducted, involving a total of 59 participants. Each group profile was chosen to either complement or contrast the other groups according to previously established criteria (gender, age and educational level). The youngest consumers (18–30 years old) proved, in general, to have a fairly negative attitude toward these types of products, although this attitude varied according to the type of food. For the consumers participating in this study, the most acceptable functional foods were low-fat foods and some fermented dairy products. Purchase and consumption of yogurt were more dependent on its sensorial qualities and its price than on the nutritional information printed on the label.

PRACTICAL APPLICATIONS

The influence of attitudes, beliefs and opinions on food choice and purchase is specially important in the acceptance of some types of foods (organic or ecological, genetically modified or functional) that are presented to the consumer as a possible alternative to the conventional foods. The application of focus groups can help not only in explaining consumer behavior, but also in designing more effective nutritional education rules and products that satisfy consumer needs and expectations.     

Body mass and habitat correlates of song structure in a primitive group of birds

We assessed relationships between acoustic frequency, body mass, and habitat in tinamous. This monophyletic group of primitive birds comprises c. 47 ground dwelling species whose habitats range from dense humid forest to open grasslands. The relationship between frequency and body mass was found to be negative, while the songs of open-habitat species exhibited higher frequencies and a wider bandwidth than the closed-habitat ones. Residual variation in song frequency, after controlling for the effect of body mass and phylogeny, tends to differ among habitats. However, a statistical test of this pattern was not possible because of the existence of only five pairs of sister species differing in habitat. In spite of this, positive contrasts of bandwidth were associated with positive contrasts of habitat, confirming that songs of open-habitat species have a wider bandwidth than those of their more closed habitat relatives.  © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77 , 423–430.     

Isolation of MTX-resistant Cell Line NP-19 of Nicotiana plumbaginifolia: Phenotypic, Genetic and Biochemical Study

Several cell lines of Nicotiana plumbaginifolia resistant tomethotrexate (MTX) were isolated upon gradual elevation of theMTX concentration in the growth medium. One of the MTX-resistantcell lines, NP-19, acquired resistance to 10 mmol m^–3MTX, that is, at least 50-fold higher than the lethal dose forthe wild-type cell suspension. Its resistance was stably maintainedupon prolonged withdrawal of the drug. The acquisition of resistancewas accompanied by severe deterioration of regeneration potential.Regenerated shoots still manifested resistance to 50 mmol m^–3.MTX-resistant colonies and tiny shoots were recovered followingasymmetric fusion between -irradiated NP-19 protoplasts andN. plumbaginifolia leaf mesophyll-derived protoplasts on a mediumcontaining 10 mmol m^–3 MTX. The development of the shootsderived both from NP-19 calli and following somatic fusion wasarrested at the stage of 6–8 leaves. No difference wasfound in uptake of ³H-MTX between cell suspension of NP-19 andthe parental cell line. A 30-fold increase in binding of ³H-MTXto protein extract was found in cell line NP-19, suggestingdifferential capacity of MTX binding as a mechanism involvedin the MTX resistance of this cell line. Since differentiatedorgans seem more sensitive to MTX than undifferentiated tissues,this cell line is a promising source for a gene(s) conferringenhanced MTX-tolerance both in non-differentiated and differentiatedtissues. Key words: Methotrexate resistance, MTX-binding capacity, MTX uptake, tobacco cell culture     

The maintenance of evolutionary equilibrium in Late Ordovician benthic marine invertebrate faunas

An upper evolutionary limit on species equilibrium number (S of MacArthur & Wilson) has been postulated but never demonstrated. Results of the present study indicate that an S of about 10 was attained very rapidly in a Late Ordovician benthic marine invertebrate faunal succession. This S value was then maintained for perhaps five million years within a marine environment that did not remain uniform but changed progressively from relatively deep to shallow water. Most importantly, significant taxonomic and presumed trophic changes that accompanied the gradual habitat alteration seem to have had a negligible effect on the plateau-like limit to species equilibrium number. We conclude from these preliminary results that the maintenance of evolutionary equilibrium in an open ecosystem strongly suggests a long-term component of biotic resiliency, at least within this one marine ecosystem, and perhaps in many others. The reasons for this resiliency remain to be explored.     

Optimal foraging by an aphid parasitoid affects the outcome of apparent competition

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