Signature mixture

In this chapter I would like to introduce concepts of chemical ecology, to discuss pheromones and signature mixtures, and contrast the research on terrestrial pheromones with research on aquatic pheromones. 

Signature Mixture A variable chemical mixture (a subset of the molecules in an animal s chemical profile) learned by other conspecifics and used to recognize an animal as an individual (e.g., lobsters, mammals) or as a member of a particular social group such... 

Table 2.2 Contrasting pheromones with signature mixtures...

Signature Mixtures Variable Individual, family, colony odors Learning required... 

Fig. 2.3 Most animals have both anonymous pheromone signals and signature mixtures (Wyatt 2010). This is demonstrated in the cuticular hydrocarbons of the queenless ant Dinoponera quadriceps (Monnin et al. 1998). A gas chromatographic analysis of the cuticular hydrocarbons on the alpha female, the only fertilized and egg-laying individual in the colony, shows the anonymous hydrocarbon pheromone 9-hentriacontene (indicated by the asterisk) characteristic of alpha females in all colonies, together with the diverse range of other hydrocarbons which make up the colony odor. Her fellow colony members have the colony odor but lack the 9-hentriacontene. Ants photograph, courtesy Thibaud Monnin. Gas chromatogram, Monnin et al. (1998), with permission...

A given animal will produce both pheromones and signature mixtures (Fig. 2.3). In addition to its sex pheromone(s), each lobster has its own highly individual odor mixture and this complex bouquet can be used by other lobsters for recognition (see Atema and Steinbach 2007). 

One area of debate, for chemical communication in all animals, is the definition of pheromone and whether the signature mixtures used for recognition should count as pheromone signals or cues (Wyatt 2010). While this is partly of semantic... 

Wyatt TD (2010) Pheromones and signature mixtures defining species-wide signals and variable cues for individuality in both invertebrates and vertebrates. J Comp Physiol A 196 685-700... 

As a first step, the authors built a database of the volatile terpenes for six olibanum samples with certified botanical origin and derived characteristic signatures associated with the botanical origin. In the second step they used these signatures to define the species of samples of different origin (commercial societies or markets from various countries of the Middle East) and to recognise the markers of olibanum in a mixture with other plants substances. 

In terms of Li content and isotopic signature, the Yellowknife mine waters are similar to waters from Sudbury (Ontario) area mines (0.05 to 2.9 ppm Li and 5T i = +27.9 to +42.6 Bottomley et al. 2003). Composihons of the Sudbury brines are consistent with predominance of preserved marine Li. These waters contrast with samples from mines in central Manitoba, which are dilute (Li concentration < seawater) and show a wide range of 5 Li (+15.0 to +46.9 Bottomley et al. 2003). These waters are plausibly mixtures of isotopically heavy brine (developed through fluid-rock interachon in fracture zones) and waters that had interacted with isotopically hght cormtry rocks. 

A water parcel sampled from anywhere in the mixing zone should have a T-S signature that plots on the conservative mixing line established by the mixing end members. Thus, a 50-50 mixture of two adjacent water masses (or types) generates a temperature and salinity signature that is midway between that of the end members. Because of this linear relationship, the relative proportions of these end members in any admixture can be calculated from a system of two simultaneous equations ... 

The ancient Chinese wrote extensively on medical subjects. The Pen Tsao, for instance, was written about 2700 B.c. and contained classifications of individual medicinal plants as well as compilations of plant mixtures to be used for medical purposes. The Chinese doctrine of signatures (like used to treat like) enables us to understand why medicines of animal origin were of such great importance in the Chinese pharmacopoeia. 

Figure 12.10—Emission matrix—excitation of a mixture containing two fluorescent ions. This topography of total fluorescence as a function of excitation and emission wavelengths constitutes a signature for each compound studied. This type of recording allows the optimum conditions to be determined.

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