Chemo-attractant for the garter snake: Characterization of vomeronasally-mediated response-eliciting components of earthworm wash—III

Earthworm excreta attract soil springtails: laboratory experiments on Heteromurus Nitidus (Collembola: Entomobryidae)

“…Earthworm mucus is known to affect insect behaviour, either as an attractant (Morris and Pivnick, 1991), or as a repellent (Laakso and Setailai, 1997). The earthworm Lumbricus terrestris has been shown to excrete a cutaneous snake-attracting compound that acts after contact through the vomeronasal system of the snake (Halpern et al, 1984;Kirschenbaum et al, 1985;Wang et al, 1988). Attraction could be mediated by various nitrogenous molecules which are contained in the epidermal earthworm mucus (glycoproteins, peptides, amino acids) and in urine (ammonia, urea) which mingles with mucus (El Duweini and Ghabbour, 1971;Cortez and Bouché, 1987).…”

Earthworms produce a collagen-like substance detected by the garter snake vomeronasal system.

“…When a 0.1 M HCl solution of EWW was heated in a boiling water bath, chemoattractant activity was lost within 15 min. However, even after a 0.1 M HCl solution of EWW had been heated for 3 hr in a boiling water bath, an F2 peak could still be detected by absorption at 280 nm, carbohydrate assay, and reaction with ninhydrin, although the amount of material detected in the F2 fraction was much less than originally present at zero time (17). When a 0.1 M NaOH solution of EWW was heated in a boiling water bath, chemoattractant power was lost in <15 min (17).…”

“…However, even after a 0.1 M HCl solution of EWW had been heated for 3 hr in a boiling water bath, an F2 peak could still be detected by absorption at 280 nm, carbohydrate assay, and reaction with ninhydrin, although the amount of material detected in the F2 fraction was much less than originally present at zero time (17). When a 0.1 M NaOH solution of EWW was heated in a boiling water bath, chemoattractant power was lost in <15 min (17). Concomitant with the loss of the chemoattractant was the disappearance of the F2 peak, as shown by the absence of 280 nm absorption, carbohydrate, and ninhydrin-positive material (17).…”

“…Earthworm washings (EWW), prepared as described by Wilde (3) and Burghardt (1), have been found to contain a chemoattractant for garter snakes that is water-soluble, absorbs at 280 nm, contains carbohydrate, and gives a positive reaction with ninhydrin and positive Lowry and Bradford tests for protein (15)(16)(17).…”

“…Garter snakes use their vomeronasal systems, but apparently do not require a functional olfactory system, to detect and appropriately respond to this chemoattractant contained in earthworm washings (3,(6)(7)(8). Substances that stimulate the vomeronasal organs are typically naturally occurring complex large molecules that have been difficult to characterize chemically (9)(10)(11)(12)(13)(14).Earthworm washings (EWW), prepared as described by Wilde (3) and Burghardt (1), have been found to contain a chemoattractant for garter snakes that is water-soluble, absorbs at 280 nm, contains carbohydrate, and gives a positive reaction with ninhydrin and positive Lowry and Bradford tests for protein (15)(16)(17).A solution of EWW that had been dialyzed, lyophilized, and reconstituted in 0.15 M NaCl to 5 times its original concentration was separated on various calibrated gel-exclusion columns (16). When 0.15 M NaCl was used as eluent, two peaks were detected by 280 nm absorption (16).…”