Recruiting pheromones

W-PyG Antennal response of previously identified recruitment pheromone cz s-Isogeraniol 135 [177]... 

Holldobler B., Morgan E. D., Oldham N. J. and Liebig J. (2001) Recruitment pheromone in the harvester ant genus Pogonomyrmex. J. Insect Physiology. 47, 369-374. 

Fig. 15.8 Contrasting postures adopted by two myrmicine ants when releasing their recruitment pheromones via the sting, (a) Leptothorax acervorum in calling position (after Mdglich et al., 1974) (b) Solenopsis saevissima laying an odour trail (after Wilson, 1971).

Recognition pheromones This type of pheromone allows members of the same species to recognize one another. This type of pheromone serves a similar function to recruiting pheromones. 

Recently the sesquiterpene a-farnesene has been demonstrated to be a constituent of the secretion of Dufour s gland in the ant Aphaenogaster longiceps [736], while citral has been shown to serve as a recruiting pheromone when workers of the stingless bee, Lestrimelitta limao, attack the nests of other stingless bees [736 a]. 

Roisin, Y., C. Everaerts, J.M. Pasteels O. Bonnard. 1990. Caste-dependent reactions to soldier defensive secretion and chiral alarm / recruitment pheromone in Nasutitermes princeps. J. Chem, Ecol, 16 2865-2875. 

Sex pheromones are secreted by one sex to attract the other as an initial part of the mating process. A variety of chemicals have been identified by screening as attractive to one sex, but until these compounds have been isolated and identified from the opposite sex, they should be termed sex attractants or parapheromones. In some species, particularly among beetles (Coleoptera), the pheromones may attract both sexes and therefore serve more than one function. Such compounds are called aggregation or recruitment pheromones. Many social insects use alarm pheromones to alert other members of their species, or trail pheromones for foraging. 

W-SA Previously identified alarm pheromone components that (a) change flight activity, (b) increase recruitment, or (c) help localize target Isopentyl acetate 91 (a,b,c),butan-l-ol 92 (b), hexyl acetate 95 (b),butyl acetate 93 (b,c), hexan-l-ol 94 (b,c),octan-l-ol 96 (b),octyl acetate 97 (c),nonan-2-ol 98 (a,b), benzyl acetate 99 (a) [151]... 

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. 

As an undergraduate at Wellesley College, Martha McClintock noted that her female dormmates tended to synchronize their menstrual cycles over time. When she pointed this out to a group of scientists at a pheromone conference, she was challenged to study the phenomenon scientifically if she wanted to be believed. She took up the challenge, recruited 135 women from her dorm, and collected the data on dates of onset of menstrual cycles. The data strongly supported her informal observations and she wrote up the results of her study as her senior thesis. 

Dictyoptera. Notwithstanding the economic importance of termites and cockroaches, relatively few pheromones have been identified in species in this order. In the case of termites, most of the chemical research has been undertaken on trail pheromones, which are utilized for a variety of critical social functions, such as emigration and recruitment to nest breaks or food finds. 

Although insect pheromone structures represent a myriad of chemical functionalities [6], the composite pheromones can be classified into six behaviourally functional groups sex, aggregation, dispersal (spacing or epideictic), alarm, recruitment (trail), and maturation. 

In the social insects, alarm pheromones are critical in detecting and escaping dangerous predators and protecting the colony. However, in a bioassay it is difficult to dissociate other stimuli and thus alarm is often confused with defence, recruitment or attraction. 

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