Pheromones trail

Swarm intelligence is a term that is applied to two rather different techniques — ant colony or pheromone trail optimization and particle swarm optimization. We deal here briefly with the latter. 

Ford, N.B. (1981) Seasonality of pheromone trailing behavior in two species of garter snake, Thamnophis (Colubridae). Southwest. Nat. 26, 385-388. 

Gehlback, F.R., Watkins, J.F. and Kroll, J.C. (1971) Pheromone trail-following studies of typhlopid, leptotyphlopid, and colubrid snakes. Behaviour 40, 282-294. 

The blind snake Leptotyphlops dulcis is a specialized burrower that feeds on termites and ant brood. It follows the ant pheromone trails to find its prey (Section 12.1). when attacked by ants, this snake tilts its scales individually so that the skin appears silvery. While it writhes, it covers itself with feces and a clear viscous fluid, discharged from the anus. It may also assume a stationary coiled position. when it resumes searching and feeding, it is no longer attacked by ants. The effect lasts from 3 to 30 minutes (Gehlbach etal., 1968). Here a predatory species protects itself from the defensive actions of its prey. 

Blind snakes find their prey by using the prey s pheromones. The wormlike Texas blind snake, Leptotyphlops dulcis, of the southwestern United States leads a subterranean life and feeds on termites and ant brood. It finds ants by following their pheromone trails (Gehlbach etal, 1968). Other blind snakes such as the American blindsnake, Typhlops pusillus (Gehlbach et al, 1971), and the Australian blindsnake, Ramphotyphlops nigrescens (Webb and Shine, 1992), also follow odor trails of ants, their prey. Texas blind snakes are attracted to the simple alkaloid skatole (methyl indole Fig. 12.4), an amine with an unpleasant odor from the ant Neivamyrmex sp. (Watkins etal, 1969). 

Ford, N. B. (1978). Evidence for the species specificity of pheromone trails in two sym-patric garter smakes, [Thamnophis). Herpetological Review 9,10. 

Species specificity of sex pheromone trails of sympatric and allopatric garter snakes Thamnophis). Copeia 1,10-13. 

Gessner S. and Leuthold R. H. (2001) Caste-specificity of pheromone trails in the termite Macrotermes bellicosus. Insectes Soc. 48, 238-244. 

In this approach, pheromone-emitting particulates are broadcast onto crops requiring protection from insects the pheromone enters the atmosphere above the crop, and insects find themselves unable to follow the pheromone trails that normally lead them to a mate. The result a sharp drop in mating, greatly reduced reproduction, and fewer of the insect pests to contend with in the future. 

There has been considerable progress in isolating and identifying compounds that affect Insect behaviour. A recent review contains more than 800 references to the literature and lists over 300 compounds as insect attractants, attractant pheromones and related compounds together with the corresponding insect species (26). Other pheromones (trail pheromones, hair pencil secretions, etc.), feeding deterrents, ovipositlon deterrents, an other types of behavioural compounds are not included in this comprehensive review, but the volume of Information on behavioural compounds is constantly being expanded as new compounds are identified. 

A compound containing a carboxyl group is known as a carboxylic acid, or organic acid. Many pheromones contain carboxyl functional groups. Pheromones are organic compounds used by animals to communicate with each other. When an ant finds food, it leaves behind a pheromone trail that other ants in its colony can follow to get to the food source. 

Pheromones are classified into two categories, releaser pheromones and primer pheromones. Releaser (or signaller) pheromones cause changes of behaviors in the receivers, while primer pheromones cause physiological impacts on the receivers. Releaser pheromones can be further classified as sex pheromones, aggregation pheromones, trail pheromones, etc., according to the type of behavioral change. 

Bagoien E, Kiorboe T (2005) Blind dating - mate finding in planktonic copepods. I. Tracking the pheromone trail of Centropages typicus. Mar Ecol Progr Ser 300 105-115... 

Greene, M. J., Stark, S. L., and Mason, R. T., 2001, Pheromone trailing behavior of the brown tree snake, Boiga irregularis, J. Chem. Ecol. 27 2193-2201. 

Ford, N. B. 1986. The role of pheromone trails in the sociobiology of snakes. In Chemical Signals in Vertebrates (Ed. by D. Duvall, D. Muller-Schwarze R. M. Silverstein), pp. 261- 278. New York Plenum. 

Males may also follow species-specific pheromonal trails in locating mates (Devine, 1977b Ford, 1978, 1981, 1982). Females are recognized by a non-volatile, contact pheromone present on at least their dorsal skin (Burghardt, 1970 Crews, 1976 Garstka and Crews, 1981 Garstka et al., 1982 Gillingham and Dickinson, 1980 Kubie, 1977 Kubie et al.,... 

I review the role of trailing in these social activities, discuss how snakes orient to pheromone trails and describe some aspects of the evolution of trail pheromones. 

Snakes, as a group, are visually cryptic and auditorially impoverished. Therefore, it is probable that chemical cues are quite important in mate location. The utilization of pheromone trails in the reproductive activity of snakes has been examined to some extent in temperate zone colubrids. In these snakes, sexual behavior occurs primarily in the spring. Males leave the hibernacula first and remain in the vicinity to court the females when they emerge. At this time, female snakes leave trails for the males to follow. The pheromone involved is likely the same lipoprotein (vitellogenin) which the females produce in the liver and secrete through the skin to stimulate male courtship activity (Garstka and Crews, 1981, this volume), although the only evidence for this is that the sexual pheromone trails are also produced by skin secretions and, like a lipoprotein, are non-volatile and persistent (Ford and Low, 1984). 

Male snakes are able to extract several pieces of information from the pheromone trail. There is evidence that they can tell both the species and the sexual receptivity of the female laying the trail. 

Species-specific pheromone trails would be a useful prezygotic reproductive isolating mechanism as they would decrease the chance of hybrid matings. Such specificity would also save the male the energy of trailing a nonreceptive heterospecific female and reduce the male s exposure to predators. It seems likely that all species of snakes using trails in a... 

Table 2, Species specificity in sexual pheromone trails of sympatric... 

It was originally reported that pheromone trails might guide rattlesnakes to their dens in the fall (Klauber, 1972). However, it now appears that only juveniles and yearlings use trails and that adults may rely on other orientation mechanisms. Brown and MacLean (1983) documented juvenile timber rattlesnakes (Crotalus horridus) following adult pheromone trails in the fall (Table 3), but King et al. (1983) found that adult prairie rattlesnakes ( viridis, would not trail conspecifics. Adult Crotalus apparently find dens by celestial cues (Landreth, 1973, Duvall et al., 1985) and... 

Aggregations of female snakes that are nearing parturition have been recorded for several species (Duvall et al., 1985 Gregory, 1975 Henderson et al., 1980 Shine, 1979), Females may be aggregating at this time because of a scarcity of suitable refugia or to swamp predators with a mass crop of young. Whether pheromone trails are involved in the formation of these aggregations has not been examined. 

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