Alarm signals chemical identification

Within Hymenoptera, pheromones produced by workers in social colonies are the best studied across many genera, principally in ants [6], with those eliciting trail following most extensively studied. The distinct behavior and the relative ease of the bioassay have resulted in chemical identifications in many species [ 113,114]. Those that have been recently identified are listed in Table 5. In addition, several alarm and recruitment signals have recently been identified. Many of the compounds recently identified in ants have previously been reported as trail or alarm pheromones in other ant species. For example, methyl 4-methylpyrrole-2-carboxylate 64, 3-ethyl-2,5-dimethylpyrazine 65, (9Z)-hexadec-9-enal 66,4-methylheptan-3-ol 67, and methyl 6-methylsalicy-late 68 have been identified as trail pheromone components, and heptan-2-one 69,4-methylheptan-3-one 70, formic acid 71, undecane 61,4-methylheptan-3-ol 67, methyl 6-methylsalicylate 68, and citronellal 72 have been identified as alarm pheromone components [6]. The use of the same chemicals across genera, with some used for very different functions, is an interesting phenomenon. 

The basic results from the individual units are processed and then combined to form the final result which is produced on the report printer. Results that deviate from an expected value by more than a preset tolerance may be marked or commented on. Additional information, such as sample identification and origin, is also made available. To ensure complete control by the analyst, the basic raw results may also be recorded in analogue form. Sample identification is provided so that the data can be re-analysed. Fully automatic systems require careful monitoring of the supply of reagents and the disposal of waste chemicals. To achieve this, fluid levels are monitored, and if they are low, an alarm signal is issued to the operator. 

Insects commonly use pheromones as chemical signals for species identification orto signal alarm or to advertise for prospective mates. Esters, particularly acetate esters, are some of the most common insect sex pheromones. 

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