Abstract
The vertebrate hormone deoxycorticosterone is the most commonly occurring component of defensive secretions from aquatic beetles in the family Dytiscidae. Deoxycorticosterone and the structurally related steroids pregn-4-en-20α:-ol-3-one and pregn-4-en-20β-ol-3-one were tested for their ability to inhibit feeding by bluegill sunfish,Lepomis macrochirus, in laboratory assays. Deoxycorticosterone at oral doses of 660μg (2 x 10−6 mol) per pellet caused 94% inhibition in the acceptance of artificial food pellets. At the same molar dosage, pregn-4-en-20α-ol-3-one inhibited food consumption by 58%, while its epimer, pregn-4-en-20β-ol-3-one, did not significantly inhibit feeding. These results indicate that specific stereochemical conditions must be satisfied for the pregnenes to be noxious toL. macrochirus and suggest the existence of a receptor-ligand interaction. The potency of the three steroids in assays of feeding inhibition contradicts earlier results based on toxicity and anesthetic assays in which fish were immersed in solutions of steroids.
Similar content being viewed by others
References
Blum, M.S. 1981. Chemical Defenses of Arthropods. Academic Press, New York.
Clayton, R.B. 1964. The utilization of sterols by insects.J. Lipid Res. 5:3–18.
Eisner, T. 1970. Chemical defense against predation in arthropods, pp. 235–280, in E. Sondheimer and J.B. Simeone (eds.). Chemical Ecology. Academic Press, New York.
Fescmeyer, H.W., andMumma, R.O. 1983. Regeneration and biosynthesis of dytiscid defensive agents (Coleoptera: Dytiscidae).J. Chem. Ecol. 9:1449–1463.
Gerhart, D.J. 1984. Prostaglandin A2: An agent of chemical defense in the Caribbean gorgonian Plexaura homomalla.Mar. Ecol. Progr. Ser. 19:181–187.
Gerhart, D.J., Rittschof, D., andMayo, S.J. 1988. Chemical ecology and the search for natural antifoulants: Studies of a predator-prey symbiosis.J. Chem. Ecol. 14:1905–1917.
Kerfoot, W.C. 1982. A question of taste: Crypsis and warning coloration in freshwater zooplankton communities.Ecology 63:538–554.
Legendre, L., andLegendre, P. 1983. Numerical Ecology. Elsevier Scientific, Amsterdam.
Miller, J.R., andMumma, R.O. 1976a. Physiological activity of water beetle defensive agents. I. Toxicity and anesthetic activity of steroids and norsesquiterpenes administered in solution to the minnow Pimephales promelas Raf.J. Chem. Ecol. 2:115–130.
Miller, J.R., andMumma, R.O. 1976b. Physiological activity of water beetle defensive agents. II. Absorption of selected anesthetic steroids and norsesquiterpenes across the gill membranes of the minnow Pimephales promelas Raf.J. Chem. Ecol. 2:131–146.
Schildknecht, H. 1971. Evolutionary peaks in the defensive chemistry of insects.Endeavour 30:136–141.
Schildknecht, H., Siewerdt, R., andMaschwitz, U. 1966. A vertebrate hormone as defensive substance of the water beetle (Dytiscus marqinalis).Angew. Chem. Int. Ed. Eng. 5:421–422.
Scrimshaw, S., andKerfoot, W.C. 1987. Chemical defenses of aquatic organisms: Beetles and bugs, pp. 240–262, in W.C. Kerfoot and A. Sih (eds.). Predation: Direct and Indirect Impacts on Aquatic Communities. University of New Hampshire Press, New Hampshire.
Selye, H., andHeard, R.D.H. 1943. The fish assay for the anesthetic effect of the steroids.Anesthesiology 4:36–47.
Sokal, R., andRohlf, F.J. 1981. Biometry: Principles and Practice of Statistics in Biological Research. Freeman Press, New York.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gerhart, D.J., Bondura, M.E. & Commito, J.A. Inhibition of sunfish feeding by defensive steroids from aquatic beetles: Structure activity relationships. J Chem Ecol 17, 1363–1370 (1991). https://doi.org/10.1007/BF00983769
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00983769