Pyrrolizidine alkaloids: morphogens regulating F I [email protected] specifically the growth of androconial organs

in several arctiine () ¢ ¢ ¢ ¢ ¢ ¢ ¢ ¢ ¢ ¢ Michael Boppré Forstzoologisches Institut, Albert-Ludwigs-Universität, D-79085 Freiburg i.Br., Germany ¢ ¢ ¢ ¢ ¢ ¢ ¢ ¢ ¢ ¢ ... we are in search for co-operation partners ... ™ ™ ™ ™ ™ ™ ™ ™ ™ ™ ¢ ¢ ¢ ™ ™ ™ ™ ¢ ¢ ¢ ¢ ™ ™ ™ Morphogenesis in Creatonotos Further cases ™ ™ ™ ¢ ¢ ¢ ™ ™ ™ ™ ™ ™ While investigating chemical communi- Teracotona, Aloa and Pericallia are arc- ™ ™ ™ ™ ™ ™ ™ ™ ¢ ¢ ¢ ¢ ¢ ¢ ¢ cation with male pheromones in butter- tiines from Africa and SE-Asia, re-spec- ™ ™ ™ ™ ™ ™ ¢ ¢ ¢ flies and moths, Dietrich Schneider and tively. Species of these genera have M.B., ('a while ago', i.e. back in 1981) differently structured core-mata, and found that the size of the coremata of the arctiines and C. transiens varies with diet. Males ™ ¢ ¢ ¢ from larvae reared on plants devoid ™ ¢ ¢ ¢ of pyrro-lizidine alkaloids (PAs) or on ™ ¢ ¢ ¢ ¢ artificial diet had minute scent organs Fig. 4 Coremata of Teracotona sp. ™ ¢ ¢ ¢ ™ ¢ ™ (core-mata), in males the larvae of we observe great ¢ ™ ¢ ™ H O which had access to PAs coremata variation in their O H H were enor-mous (Figs 1, 2). There is a size; in contrast O OH OH dose-de-pendent morphogenetic effect to Creatonotos, N of these secondary plant metabolites, the morphogene- HO H CHO which is limited to the coremata; all tic effect is less other mor-phological features remain pronounced alt- N unaffected. However, pheromone bio- hough obvious Fig. 5 Coremata of Aloa sp. synthesis also depends on PAs, i.e. tiny (Boppré et al. unpubl.). Recently, Fig. 6 Scheme of relations of (Arctiidae) to pyrrolizidine alkaloids. The caterpillars are polyphagous and feed on a wide spectrum of hostplants. If they contain PAs, these secondary metabolites are being stored for protection against predators. In males, PAs specifically determine the growth of the coremata, and they serve as precursors for biosynthesis coremata do not emit pheromone while Fig. 1 Male Creatonotos gangis displaying its coremata Davenport & Conner published on a of hydroxydanaidal in addition. Courtship behaviour is not yet understood; perhaps, several mate-finding mechanisms exist, depending on the outfit of the individual with PAs, i.e. depending large ones synthesize amounts of up to morphogenetic effect in Estigmene and on the larval hostplant(s). 500µg/male. more cases are likely to be found. Pyrrolizidine alkaloids (PAs) Androconial organs Selected references Bergomaz R, Boppré M (1986) A simple instant diet for rearing Arctiidae Creatonotos larvae are pharmaco- Research perspectives are a large group of ester alkaloids of occur in many species of Lepidoptera. and other moths. J Lep Soc 40: 131-137 Boppré M (1990) Lepidoptera and pyrrolizidine alkaloids: exemplification phagous Fig. 2 Artificially expanded coremata of a male reared on We have four systems of specific and diverse structure. They are composed There are no commonalities, except of complexity in chemical ecology. J Chem Ecol 16: 165-185 " are pharmacophagous if they food free of PAs (A) and organs of males, the larvae had dose-dependent regulation of organ of a necic acid and a necine alcohol that they all are composed of glandu- Boppré M (1986) Insects pharmacophagously utilizing defensive plant consumed PAs (B, C) chemicals (pyrrolizidine alkaloids). Naturwissenschaften 73: 17-26 search for certain secondary (plant) growth by non-nutritional secondary forming open-chain mono- or diesters or lar cells associated with scales / hairs. Boppré M (1995) Sex und Drogen bei Schmetterlingen. Biologie in unserer Zeit 25: 8-17 substances directly, take them up and plant metabolites. We can rear them macrocyclic diesters; in nature (in plants Andro-conial organs can occur as glan- Boppré M, Schneider D (1985) Pyrrolizidine alkaloids quantitatively regu- Fig. 3 Caterpillar of Creato- late both scent organ morphogenesis and pheromone bio-synthesis in utilize them for a specific purpose other notos consuming a glass- routinely, PAs can be fed quantitatively, as well as in insects which store them) dular scales scattered on the wings but Creatonotos moths (Lep.: Arctiidae). J comp Physiol 157: 569-577 Boppré M, Schneider D (1989) The biology of Creatonotos (Lepidoptera: than primary metabolism or merely host fibre disk impregnated with pure PAs and metabolites are available they are usually present as N-oxides. also as brushes of hairs at almost any Arctiidae) with special reference to the androconial system. Zool J PAs Linn Soc 96: 339-356 recognition." E.g., various adult Lepido- for experiments, and methods to ana- Vertebrates metabolize 1,2-dehydro- part of the body which can be everted Davenport JW, Conner WE (2003) Dietary alkaloids and the development of androconial organs in Estigmene acrea. J Sci 3:3 ptera forage for PAs independent of Thus, dietary PAs have three lyse PA-metabolites are established. pyrrolizidines into "pyrroles" that are, direc-tly by muscles, hydraulically, or Egelhaaf A, Rick-Wagner S, Schneider D (1992) Development of the nutritional requirements, store them for functions: to regulate growth of core- In our view, these systems are e.g., hepatotoxic. About 370 structures pneu-matically. male scent organ of Creatonotos transiens (Lepidoptera, Arctiidae) during metamorphosis. Zoomorphology 111: 125-139 protection and use them as pheromone mata, to enable pheromone synthesis, ideal for studying "Shaping Cells into of PAs have been identified in 560 Usually, androconial organs Hartmann T, Witte L (1995) Chemistry, biology and chemoecology of the pyrrolizdine alkaloids. Pp 155-233 in Pelletier SW (ed.) Alka- precursors. and to serve chemical protection. Organs". However, basically, we are species of plants, mainly belonging to come into play in close-range courtship loids: Chemical and Biological Perspectives. Vol 9. GB-Oxford: Perga-mon Press For larvae of Creatonotos, pure chemoecologists and have neither ex- the families Asteraceae (Eupatorieae, be-haviour; in Creatonotos, Teracotona Hartmann T (1999) The chemical ecology of pyrrolizidine alkaloids. Planta 207: 483-495 PAs are feeding stimulants (Fig. 3). It is Much knowledge exists on perience nor equipment for doing cell Senecioneae), Bora-ginaceae and and Aloa, however, the males display Hartmann T, Biller A, Witte L, Ernst L, Boppré M (1990) Transformation of plant pyrrolizidine alkaloids into novel insect alkaloids by arctiid thus not only possible to bioassay the struc-ture-activity and on quantitative cultures, for working with antibodies, Fabaceae; in general plants produce these organs independent of the pre- moths (Lepidoptera). Biochem System Ecol 18: 549-554 specificity of the receptor system for relation-ships (Boppré et al. unpubl.). for genetic or enzyme studies etc. We mixtures of several PAs. sence of a female – probably the func- Lindigkeit R, Biller A, Buch M, Schiebel H-M, Boppré M, Hartmann T (1997) The two faces of pyrrolizidine alkaloids: a tertiary amine and de-tecting PAs but also to make larvae The PA competence (sensitivity) of the therefore consider it wise to co-operate HO OH tion is the formation of leks to which its N-oxide and their role in chemical defense of insects with acquired plant alkaloids. Europ J Biochemistry 245: 626-636 con-sume pure PAs in known amounts. epidermal corema anlage terminates with a team competent in organoge- O both sexes are attracted. Schmitz B, Buck M, Egelhaaf A, Schneider D (1989) Ecdysone and a dietary alkaloid interact in the development of the pheromone gland It is also possible to use PAs as an in- with the first prepupal day. While the di- nesis .... OH The coremata of Creatonotos of a male (Creatonotos, Lepidoptera: Arctiidae). Roux's Arch OH O O Develop Biol 198: 1-7 etary PA specifies the size of the organ H O O are inflated pneumatically, i.e. the or- gre-dient of an artificial diet. H Schneider D, Egelhaaf A (1988) Pupal growth of male moth pheromone H organ under control of dietary pyrrolizidine alkaloid (which is also O Creatonotos store plant PAs (quanti-tatively through the number of If you are interested in co-operating, OMe gan is expanded by air pumped into the precursor of the pheromone). Pp 37-40 in Sehnal F et al. (eds) Endocrinological Frontiers in Physiological Insect Ecology. Wroclaw: (part-ly modified) for defence, and mitoses of its cells and of endomitotic please, contact us! N it through the tracheal system. Each N Wroclaw Techn Univ Press males – via spermatophores – transfer steps of the hair cells), ecdysone is [email protected] of the up to 300 hairs on the tubes is Schneider D, Boppré M, Zweig J, Horsley SB, Bell TW, Meinwald J, Fig. 7 Molecular structures of the pyrrolizidine alkaloids heli- Hansen K, Diehl EW (1982) Scent organ development in Creatonotos these chemicals to the females. required to induce proliferation of the www.fzi.uni-freiburg.de otrine and monocrotaline, both acting as morphogens associated with a glandular cell. moths: regulation by pyrrolizidine alkaloids. Science 215: 1254-5

ix/03