Rupert Kellner

Paederus rove beetles contain a defensive compound, pederin, that is biosynthesized only by (+)-females. These females accumulate large amounts of the amide, lay eggs containing the toxin and produce both (+)-females and (_)-females in the next generation. (_)-Females do not transfer pederin into the eggs and produce only (_)-females. Experimental feeding of larvae descended from (_)-females with (+)-eggs, however, produces females that are able to accumulate pederin, that means (+)-females. This hints at microorganisms needed for pederin biosynthesis that are transferred from (+)-females to their offspring or, experimentally, to (_)-larvae fed with (+)-eggs. Using P. sabaeus as a model, the (+)-eggs fed to (_)-larvae have been treated with antibiotics (benzylpenicillin, erythromycin, oxytetracycline, streptomycin) in order to prove the importance of microorganisms for pederin biosynthesis. These experiments show that the frequency of (+)-females depends on the antibiotic used, its concentration and the duration of the treatment. The microorganisms needed for pederin biosynthesis can thus be eliminated by application of antibiotics, which is in most cases very effective. Pederin appears to be the first defensive substance in insects traceable to endosymbionts.

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Lehrstuhl Tieroekologie II, Universitaet Bayreuth, D-95440 Bayreuth, Germany

rupert.kellner@uni-bayreuth.de

Sandrine Gouinguené, Thomas Degen, and Ted Turlings.

Many parasitoids that attack phytophageous insects make use of plant odors to locate the habitat of their host. In maize large amount of these odors are specifically emitted by a plant after it has been damaged by a herbivore, but not after mechanical damage. The odor emissions occur systematically throughout the plant. Factors in the oral secretion of the herbivores are the main elicitors of the plants' reaction. One such elicitor, volicitin, was recently isolated and identified. The induced maize odours are useful cues for the parasitoids and indicate the presence of a potential host. This odour is mainly composed of terpenoid compounds. We have studied different abiotic and biotic factors that determine the specificity and variation of the signal emitted by maize plants in response to caterpillar damage. Light intensity is the most important factor, but odour emissions were also affected by the soil and air humidity, temperature and the degree of fertilization. We found enormous quantitative and qualitative differences among maize genotypes. The absolute amount of volatiles emitted was negatively correlated with the plant age, while larval instar appeared to have little or no effect. We discuss these results in the context of reliability of plant-induced signals as cues that allow parasitic wasps to find a suitable host.

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University of Neuchâtel, Institute of Zoology, Lab. of Animal Ecology and Entomology, Case Postale 2, Ch-2007 Neuchâtel, Switzerland.

Thomas Degen^1,2,3, Christine Dillmann², Frédéric Marion-Poll³, and Ted C.J. Turlings¹

Maize plants attacked by leaf-eating caterpillars respond by releasing specific volatile compounds that attract parasitic wasps. We assessed genetic variability in herbivore-induced odour emission among 31 maize inbred lines that are representative of a large spectrum of presently grown maize varieties. Odour release was induced by injecting caterpillar regurgitant with a syringe into the stem of about 10-day old seedlings or by exposing the plants to caterpillar feeding. We found significant heritable variation among the lines for all compounds (e.g. monoterpenes, sesquiterpenes, homoterpenes, indole) that were included in the analysis. The lines varied enormously in the total amount of volatiles emitted, the difference between the two extreme lines being approximately seventy-fold. In addition to this pronounced quantitative variation, the lines were also characterised by distinct profiles, i.e. the relative proportion of particular odorous compounds in the blend was very variable. There was no correlation between the distances among the lines according to their profile and their respective genetic distances previously established in a study using neutral RFLP-markers. This suggests that induced odours or linked characters are subject to selection. Odour collections from the F2-generation of a cross between two lines that differed largely in quantitative odour emission indicated that the differential production of odorous compounds is usually not controlled by a single gene. This first comprehensive study on intraspecific variation in induced odour emission by maize plants provides a further example for the remarkably high genetic diversity conserved within this important crop plant.

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¹Institut de Zoologie, Université de Neuchâtel, Case postale 2, CH-2007 Neuchâtel, Switzerland

²Station de Génétique Végétale, INRA Ferme du Moulon, F-91190 Gif-sur-Yvette, France

³Unité de Phytopharmacie & Médiateurs Chimiques, INRA Versailles, Route de Saint-Cyr,

F-78026 Versailles Cedex, France

Torsten Meiners¹, Felix Waeckers² and Wallace Joe Lewis³

Parasitoids can use a range of host- or plant-derived volatiles during host location. Associative learning allows parasitoids to focus on the most reliable cues. Most work on odour learning has focussed on single odour conditioning. In this paper we address the question how parasitoids deal with more complex odour bouquets, using the parasitoid Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) as a model. First, we examined the capacity of M. croceipes to learn and subsequently to respond to the presence of non-plant derived 2-Octanone and plant derived Methyljasmonate and Caryophyllene. We used flight response in dual choice tests for elucidation whether the parasitoids did learn and identify the single components after being trained to the mix of the compounds. We demonstrated that trained females are able to respond by directed flight to a single compound that was trained in a mix during contact with host faeces. However, the accuracy of this ability depended on the chemical to which the females had been trained and tested.

A second set of experiments investigated the capacity of M. croceipes to learn and to differentiate between alcohols of different chain length and different position of the alcoholic group. This was also tested using dual choice tests in the windtunnel. Depending on the training compound parasitoids were able to differentiate between closely related alcohols. Discrimination improved with increasing difference in chain length. The combination of the high sensory and memory capacities of parasitoids is one mechanism that can explain their immense success in host location.

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¹ Freie Universitaet Berlin, Angewandte Zoologie/Oekologie der Tiere, Haderslebener Str. 9, D-12169 Berlin, Germany, meito@zedat.fu-berlin.de

²NIOO CTO, PO Box 40, 6666 ZG Heteren, the Netherlands, waeckers@cto.nioo.knaw.nl

³USDA-ARS-IBMRL, P.O. Box 748, Tifton, Georgia, 31793, USA, wjl@tifton.cpes.peachnet.edu

Tristram D. Wyatt

Why has the application of pheromones has not been greater? Each pheromone symposium since the 1960's has emphasised the potential for pest control but even potential has a shelf-life. However, we should remember that it is still less than 40 years since the first chemical identification of an insect pheromone and we have made massive strides since then. Far from being a time for pessimism, I will argue that the basis for optimism is strong and there should be a big push for support. Compared with conventional pesticides, pheromone research has been only modestly funded. The rationale for increasing funding on pheromone research includes the negligible environmental impact of pheromones and increasing evidence of their effectiveness in pest control. Nonetheless pheromones represent but 2% of the dollar sales of insecticides world-wide, despite great efforts on the part of researchers, companies and extension workers. How far can slow deployment be blamed on unanswered questions in the scientific understanding of pheromone communication as opposed to practical difficulties in implementation?

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Department of Zoology, University of Oxford, South Parks Rd, Oxford OX1 3PS, UK

tristram.wyatt@zoo.ox.ac.uk

J. Engelberth, T. Koch, G. Schüler, N. Bachmann, J. Rechtenbach, and W.Boland*

Alamethicin (ALA), a voltage-gated, ion channel-forming peptide mixture from Trichoderma viride, is a potent elicitor of volatile biosynthesis in the Lima bean Phaseolus lunatus. Unlike elicitation with jasmonic acid (JA) or herbivore damage the emitted blend comprises only the two homoterpenes, 4,11-dimethylnona-1,3,7-triene (DMNT) and 4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT), and methyl salicylate (MeSA). Inhibition of octadecanoid signaling by aristolochic acid and phenidone as well as mass spectrometric analysis of endogenous jasmonate demonstrate that ALA induces volatile biosynthesis principally via the octadecanoid-signaling pathway (20-fold increase of JA). ALA also up-regulates salicylate biosynthesis, and the time course of the production of endogenous salicylate correlates well with the appearance of the methyl ester in the gas phase. The massive up-regulation of the SA-pathway (90-fold) interferes with steps downstream of 12-oxophytodienoic acid (OPDA) and thereby reduces the pattern of emitted volatiles to compounds previously shown to be induced by OPDA. 2-Aminoindan-2-phosphonic acid (AIP) suppresses salicylate biosynthesis but, at the same time, affects the octadecanoid pathway analogous to SA. Other channel forming peptaibols also induce the same pattern of emitted volatiles in the Lima bean, suggesting a common mode of action and supporting the pore-forming activity of peptaibols as the essential property for the elicitation process. Channel forming peptides such as ALA and related compounds may therefore be used as valuable tools to unravel the early events of plant defense under well defined conditions.

OR 2
Max Planck Institute for Chemical Ecology, Carl-Zeiss-Promenade 10,

D-07745 Jena, Germany

Miryan D. A. Coracini, Marie Bengtsson, Jan Löfqvist, Evaldo F. Vilela¹, Alvaro E. Eiras², Adalécio Kovaleski³, and Peter Witzgall

Analysis of sex pheromone glands of Bonagota cranaodes (Meyrick) by GC-MS showed the presence of the main pheromone component, E3,Z512Ac, together with Z512Ac, Z3,Z512Ac, Z714Ac, E3Z512OH, E3,Z514Ac, Z916Ac, Z1118Ac, and a number of saturated acetates and alcohols of the chain length 12 to 18. Three of these compounds elicited an antennal response in GC-EAD analysis of female pheromone glands. Traps baited with a four-component blend were significantly more attractive than the main compound alone. The addition of minor compounds increases the attractivity and reliability of monitoring traps in apple orchards.
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Department of Plant Protection Sciences, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden

¹Department of Animal Biology, Federal University of Viçosa, 36571-000, Viçosa-MG, Brazil

²Department of Parasitology - ICB/UFMG, Federal University of Minas Gerais, Box 486, 31270-901, Belo Horizonte-MG, Brazil

³Department of Entomology, CNPUV/EMBRAPA, 25200-000, Vacaria-RS, Brazil

John G. Hildebrand

Pheromone components are detected by olfactory receptor cells (ORCs) in antennal sensilla. The odorants are carried to ORC dendrites by odorant-binding proteins (OBPs) in the lymph bathing the dendrites. For each type of ORC, odorant molecules to which it responds bind to membrane receptors, triggering intracellular signal-transduction events that lead to membrane depolarization and ORC excitation. The specificities of OBPs and receptors determine the "tuning" of an ORC, which may be narrowly (e.g. ORCs specialized for pheromone components) or more broadly tuned (e.g. some ORCs for plant volatiles). Impulses propagated along the ORC's axon report the presence, intensity, and temporal properties of the effective odor stimulus to the ipsilateral antennal lobe (AL), the primary olfactory center in the brain.

ALs are characterized by glomeruli — neuropil modules in which primary-afferent and central neural elements interact synaptically ^ whose functional significance has been unclear until recently. In male Manduca sexta, the glomeruli of the male-specific macroglomerular complex (MGC) process information about the female's sex pheromone. Using physiological and morphological techniques, we have characterized many projection neurons (PNs) associated with MGC glomeruli, as well as PNs of other identified glomeruli in male and female ALs. This work shows that glomeruli are organized chemotopically and are responsible for qualitative, quantitative, and temporal coding of odor information.

Little is known about further processing of AL outputs in higher-order way-stations in the CNS to shape behavior. This presentation will conclude with a glimpse of efforts along those lines.

Supported by NIH and NSF grants.)

IS 5
Arizona Research Laboratories Division of Neurobiology, University of

Arizona, Tucson AZ 85721-0077 (USA) jgh@neurobio.arizona.edu

Thomas Hartmann, Dietrich Ober and Claudia Naumann

Pyrrolizidine alkaloids (PAs) are typical plant secondary constituents with scattered occurrence in the plant kingdom. They are part of the plant's defense against insect herbivores. Specialized insects recruit PAs from their host plants and utilize them for their own benefit. To understand the evolutionary origin of the pathway in plants and the evolution of insect adaptations to plant PAs we have to access the gene level. Two examples are presented: (1) the first pathway-specific enzyme of PA biosynthesis was shown to be derived from a ubiquitous enzyme (gene) and to be integrated into PA biosynthesis by change of function [1-3]; (2) the enzyme which in larvae of PA-adapted lepidopterans specifically transforms the ingested toxic tertiary PAs into the non-toxic N-oxides [4] was shown to be structurally related to multisubstrate flavin monooxygenases (FMOs) as yet not known to occur in insects.

1. D. Ober & T. Hartmann (1999) J. Biol. Chem. 274:32040-32047

2. D. Ober & T. Hartmann (1999) Proc. Natl. Acad. Sci. USA 96:14777-14782

3.T. Hartmann & D. Ober (2000) Top. Curr. Chem. 209:207-243

4.R. Lindigkeit, A. Biller, M. Buch, HM. Schiebel, M. Boppré & T. Hartmann
(1997) Eur. J. Biochem. 245:626-636

OR 14

Institut für Pharmazeutische Biologie der Technischen Universität, D-38106 Braunschweig, Germany

Cyanogenic glucosides are found in more than 2.500 different higher plants including important crop plants like cassava, sorghum, flax and almonds. The same plants also contain degradative enzymes, which upon cellular disruption of the plant tissue get in contact with the cyanogenic glucosides thereby causing the rapid release of hydrogen cyanide. This binary system- two sets of components which are inert individually- comprises the "cyanide bomb" and is thought to play a role in the chemical warfare of plants towards herbivors and pathogens.

Sorghum contains the cyanogenic glucoside dhurrin which is synthesized from the amino acid tyrosine. The biosynthetic pathway is highly channelled and is catalyzed by two multifunctional microsomal cytochrome P450s (CYP79A1 and CYP71E1) and a soluble UDPG-glucosyl transferase. The three enzymes have been isolated, reconstituted, cloned and heterologously expressed in E. coli. The complete pathway for cyanogenic glucoside biosynthesis has been reconstituted in vitro using the heterologously expressed proteins. When the two P450s and the glucosyltransferase were transformed into Arabidopsis and tobacco, cyanogenic plants were obtained indicating the ability of these previous acyanogenic plants to properly transport and store "foreign natural products". The production of "unnatural natural products" in plants as a result of the introduction of new points of cross-talk between the pathways for synthesis of cyanogenic glucosides and glucosinolates and based on the broad substrate specificity of CYP71E1 and the glucosyltransferase will be documented. Foods derived from crop plants like cassava that contains large amounts of cyanogenic glucosides require careful processing. Acyanogenic cassava plants are being generated using anti-sense constructs towards the two different CYP79 genes present in this allotetraploid species.

KS 3
Plant Biochemistry Laboratory, Dept. Plant Biology, Royal Veterinary & Agricultural University, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark. E-mail: blm@kvl.dk

James E. Oliver¹ and Robert P. Doss²

We have recently reported the identification of 3-(hydroxypropanoyl) esters of unsaturated C₂₂ and C₂₄-a,w-diols (bruchins, 1-4) from two species of weevils in the Bruchidae family. These unusual compounds stimulate rapid cell division when applied to pods of pea carrying the Neoplastic pod (Np) gene. From studies with the natural products and synthetic analogs, we have defined several structural requirements for mitogenic activity: at least one 3-(hydroxypropanoate) is essential (related esters such as propanoates, 3-(hydroxybutanoates), lactates, etc., are inactive). Difunctionalization is important (3-(hydroxypropanoates) of long-chain monoalcohols are much less active). The optimum chain length is C₂₂-C₂₄ (analogs shorter than about C₂₀ or longer than C₂₆ are much less active or inactive). On the other hand, structural requirements for the center of the molecule appear to be less stringent; the unsaturation in the diol chain, for example, is unnecessary.

OR 32
¹Insect Chemical Ecology Laboratory, USDA-ARS, Beltsville, MD 20705, USA oliverj@ba.asr.usda.gov

²Horticultural Crops Research Unit, USDA-ARS, Corvallis, OR 97330, USA dossr@bcc.orst.edu

Augusto Henrique Arantes Portugal & José Roberto Trigo

Phytophagous insects use a variety of defense strategies against their natural enemies. One of the most studied strategies is the chemical defense due to toxic, impalatable or deterrent substances. These substances may be acquired, sequestered, and accumulated by the insect through ingestion of the insect's hostplants, or they can be biosyntesized de novo. The major function of insects and terrestrial plants cuticular lipids is the protection against water loss. Because they are located on the external surface of the body they can have a role in chemical communication both intra and interspecific. This work reports the role of cuticular lipids in the interaction between Mechanitis polymnia larvae, one of its hostplants (Solanum tabacifolium, Solanaceae), and a natural enemy, the generalist predatory ant Camponotus crassus (Formicidae: Formicinae). It was observed that the cuticular lipids chemical profile of M. polymnia larvae is very similar to the leaves of S. tabacifolium. In laboratory bioassays C. crassus did not predate both live and dead larvae of M. polymnia. This may be because the ants did not recognise the larvae as prey due to the similarity between the cuticular lipids chemical profiles. Upon placing M. polymnia on leaves with which they had low similarity (14%) the larvae were then predated by C. crassus. In another bioassay two palatable larvae of Spodoptera frugiperda (Lepidoptera: Noctuidae) were simultaniously ofered to the ants. One of the larvae had its chemical profile altered to resemble the pattern of the leaf where they were ad had a smaller predation rate than the other larvae that had a different profile than the leaf of S. tabacifoium.

FAPESP, CNPq.

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Laboratório de Ecologia Química, Departamento de Zoologia, IB, UNICAMP, Campinas, SP, Brazil, Caixa Postal 6109, trigo@unicamp.br

B. DiGiusto, G. Gigot, M. Rahier, F. Venel, M. Morton, and d. McKey

Larvae of the leaf beetle Lilioceris Latipennis( Chrysomelidae, sybfamily Criocerinae) feed on growing shoot apices of Dioscorea praehensitis (Dioscoreaceae), a wild yam of semi-deciduous tropical forest in Cameroon that produces abundant extrafloral nectar at the growing shoot apex, which is frequently visited by various species of nectar-gathering ants. Eggs of the beetle were not removed by ants, but ant visitation on plants affects oviposition bahaviour of the beetle. Femalcs avoided laying egges on plant parts patrolled by ants. Number of chutches and number of eggs on patrolled stems than on stemas from which ants has been experimentally excluded. Larval survival was also strongly affected by the level of ant visitation, and varied depending on the ant specioes present on a plant. Larvae of L. latipennis, like othre Criocerinae, construct fecal shields containing secondary metabolites sequestered from the host plant. Presence of a fecal shield is deterrent to ants. In field esperiments in which larvae werw placed on shoot apices patrolled by different species of ants, survival of larvac with an intact fecal shield was higher than for larvae of comparable size from which the fecal shiel had been experimentally removed. Effectiveness of the fecal shield in deterring ant predation increases with larval size, and also varied as a function of ant species and number of workers present on the shoot apex.

Preliminary finding indicate the presence of host-derived saponins in feces, along with a suite of primary metabolites of the plant. There is evidence of significant transformation of sapogenis of D. praehensilis by larvae of L. latipennis. Fecal shields of L. latipennis displayed a qualitatively and quantitatively different pattern of saponins from that of the shoot apices on which they feed. Secondary metabolites derived from the host plant thus appear to be important for the anti-predator adaptations of this beetle, necessary for its survival and reproduction on a host plant that actively recruits ants as a biotic defense against herbivores.

OR 7

Nélida E. Gómez, Smithsonian Tropical Research Institute,

For about a century there has been much speculation concerning the construction of cassidine larval fecal appendages (1, 2, 3, 4)., structures remarkable for their diverse morphological characteristics (5). Some species that eat Cordia construct very hard, dark and stable fecal appendages, which vary in shape and weight; others carry only exuvial appendages or none. Examination of phenoloxidase activity in freshly produced feculae of seven Cordia feeders, using L-DOPA as substrate, disclosed melanin in feculae of larvae that build stable fecal appendages. Melanization and certain anatomical features of the larvae account for the diversity found in theses bizarre structures.

1. Fiebrig, K., Zool. Jahrbuch, Suppl. 12:161-264, 1910.

2. Engel, H. , Zool. Morph. Ökol. der Tiere 30:42-96., 1935

3. Eisner, T. et al., Science 158:1471-1473, 1967.

4. Eisner, T. and Eisner, M. Proc. Nat. Acad. Sci. 97:2632-2636, 2000.

5. Windsor, D.M. et al., in: Insects of Panama and Mesoamerica: selected studies (ed. D. Quintero Arias and A. Aiello), pp. 372-391. Oxford University Press, Oxford, 1992.

OR 25

PO Box 2072, Balboa, Ancón, Republic of Panama

John T. Trumble

In the late 1980s and early 1990s, the one billion dollar tomato industry in Mexico was struggling with exceptionally large outbreaks of the tomato pinworm, Keiferia lycopersicella. In spite of up to 40 applications of 2-6 pesticides per application, over 80% of the fruit infested were in some plantings, and thousands of hectares of tomatoes were abandoned prior to harvest. A low input, integrated pest management (IPM) program based on pheromone disruption, an insect pathogen (Bacillus thuringiensis), and parasite releases was developed and proved economically superior to the commercial program used on fresh market tomatoes in Mexico. Remarkably, even very high populations of pinworms could be controlled with pheromones. Fruit production was similar between commercial and IPM treatments in the Fall plantings, but much higher in the IPM program during the Winter and Spring plantings. Fruit in the IPM program were larger than those produced by commercial practices. Net profits were substantially higher in the UC IPM plots than in commercial treatments.

In addition, the pheromone-based approach offered significant advantages for all of the following factors which were not included in the economic analysis:

a) leafminer populations were largely eliminated through action of naturally occuring parasites,

b) the potential for pesticide resistance development was greatly reduced,

c) soil compaction was minimized because fewer trips were made through the field,

d) obvious advantages in marketing were not incorporated,

e) the contact of farm workers with highly toxic pesticides was eliminated as the control strategies utilized in the IPM program have little or no contact toxicity to mammals.

IS 7

Department of Entomology, University of California, Riverside U.S.A. 92521

Adriana Guimarães Duarte¹, Ivanildo Soares de Lima^1,2, Marcelo de Menezes Cruz² and Sandra Márcia Sarmento²

The palm weevil, R. palmarum (Coleoptera: Curculionidae), is the most important insect pest of coconut plantation, causing direct and indirect damages. The larva feeds on the plant tissues and the adult act as a vector of the red ring disease nematode Bursaphelenchus cocophilus (Cobb) Baujard. The red ring disease kills the palm and spreads on the plantation. For estimating the number of nematodes in adult R. palmarum, traps baited with the aggregation pheromone (Rhynchophorol) and sugar cane are being set up along the coastal coconut plantation of Alagoas. To minimise the possibility of cross contamination, the weevils are taken out of the traps as soon as they are captured and placed inside small plastic tubes. All trapped adults of R. palmarum form the North, Central and South regions of Alagoas will be examined for B. cocophilus. Estimating the number of nematodes in adult R. palmarum will help to define areas with high incidence of contaminated weevils. Therefore, the growers can develop more efficient control system using pheromone-based traps. The number of worms present is made under a microscope with a Peters counting slide. Up to date, only weevils captured in the Central region were examined, and a high degree of contamination has been found.

Financial Support: CNPq and FAPEAL

OR 48
¹CPGQB/QUI/UFAL, ²FIT/CECA/UFAL

Laboratório de Ecologia Química - BR 104 Norte Km 14, Tabuleiro do Martins

57072-970, Maceió-AL, Brasil. Phone: 0xx82 214-1388. E-mail: isl@fapeal.br

A.J. Mordue (Luntz)¹, A. Ingvarsdottir¹, M. Birkett², R. Genna¹, W. Mordue¹, A.W. Pike¹, J. Pickett², L. Wadhams², I. Duce³, J. Reader³, O. Jones⁴

The multi-million pound salmon farming industry in Scotland suffers losses of up to £30 million pounds annually due to sea lice infestations. Salmon farmers are largely dependent on using veterinary medicines but the industry is continually threatened with the development of resistance to treatments. The chemical ecology of sea lice is being studied in this project to define the potential use of semiochemicals in pest management strategies such as trapping and disruption. This study focuses on both host- and mate-finding behaviour in adult sea lice and host-finding in the copepodid, infective stage. Adult male lice are activated by fish derived stimuli and are attracted to salmon odours. Copepodids show both kinetic and taxic responses to host cues which serve to change their swimming behaviour in a column of water. Adult males and pre-adult II virgin females are attracted to each other by the release of pheromones. Extracts of salmon conditioned water, non-host fish conditioned water, and male and female conditioned water are being analysed for the identification of key components by behavioural, electrophysiological and GC-MS techniques.

The project is supported by a NERC Link Aquaculture grant with the SSGA, SSFA, Marine Harvest McConnell and Landcatch UK and by a NERC studentship to R Genna.

OR 51
¹Department of Zoology, University of Aberdeen, Aberdeen AB24 2Z

²Biological and Ecological Chemistry Department, IACR-Rothamsted, Herpenden Herts AL5 2JQ

³Department of Life Sciences, University of Nottingham, University Park, Nottingham

⁴AgriSense-BCS Ltd, Unit 1, Taff's Mead Road, Pontypridd, Mid Glamorgan, CF37 5SU

Jennifer J. Knapp*, Ricardo Gonzalez^§, Diane Sayers*, Melanie Andrews*, Sue Gerty*, Pablo Liedo^§

There is an urgent need for synthetic attractants for the major species of Anastrepha fruit fly pests. Such compounds are required by national detection programmes, pest monitoring in IPM and for organic fruit growers. Until recently traditional protein hydrolysate or fruit extract liquid baits have been used. However these are considered relatively unselective, too short lived and very labour intensive to use. The desire for an effective attractants, particularly for females, which can be used in dry traps is being demanded by all sections of the community. The use of pheromones has been unsuccessful to date, this in spite of Anastrepha spp. having a male produced sex pheromone. The complex courtship behaviour of these insects, together with the interaction of pheromones, host volatiles and visual cues are thought to account for this lack of success. Compounds based on food attractants (ammonium salts and putriscine) have been investigated by various workers and found to be partially effective but the need for additional or alternative compounds to enhance or synergise these base components has been recognised. The possibility of using additional compounds from food sources and components of the sex pheromone were investigated. Experiments to test compounds were carried out in mango orchards in Southern Mexico using both natural wild populations and released sterile A. ludens and A. obliqua. The results indicate that certain compounds were highly effective at improving trap catches. These new attractant mixtures may have potential for use in monitoring/detection systems as well as in control strategies.

OR 34
* Division of Biodiversity and Ecology, School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton, SO16 7PX, UK

^§ El Colegio de la Frontera Sur, Tapachula, Carretera Antiguo Aeropuerto, 30700 Chiapas, Mexico

¹Paulo S. Oliveira, ²Marco A. Pizo & ³Luciana C. Passos.

Nearly 90% of the shrubs and trees in tropical forests may depend on vertebrates (mainly birds and mammals) for seed dispersal. A huge amount of fleshy seeds and fruits, however, can reach the ground by falling directly from the tree, by being dropped by frugivores, or within defecation of the latter. Here we show that ant activity at fallen fleshy diaspores can markedly affect seed biology in the Atlantic rainforest. Over 30 ant species exploit fallen fleshy diaspores from 56 plant species (28 families) at Parque Estadual Intervales in SE Brazil. Field and greenhouse experiments showed that ants can secondarily disperse the seeds, protect the latter against fungal attack by removing the fleshy material, as well as increase germination success. Ants are generally rapid at discovering and cleaning the diaspore's pulp or aril. Recruitment rates and ant attendance are higher for lipid-rich diaspores than for lipid-poor ones. Removal rate and displacement distance are higher for small diaspores. Predatory ants (Ponerinae) are the most frequent attendants to lipid-rich arillate diaspores, probably because the food reward is chemically very similar to insect prey. Ponerine-induced seed movements was shown to affect seedling establishment. Although ant-derived benefits to diaspores can vary across different plant species, the data enhances the role of ant-diaspore interactions in the post-dispersal fates of primarily vertebrate-dispersed seeds. Given the dominance of ants in tropical forests, and the huge amount of fleshy diaspores on the ground of such habitats, these insects may likely affect seed biology of a number of plants in the tropics.

IS 8
¹Depts. de Zoologia e ³Botânica, Univ. Estadual de Campinas, Campinas, & ²Dept. de Botânica, Univ. Estadual Paulista, Rio Claro.

Rosângela de A. Epifanio

Secondary metabolites produced by living organisms have adaptive value that favors their evolution. Recent research has provided better understanding of a variety of functions of these compounds, as chemical mediators in different intra- and interspecific interactions of marine communities.

Marine sponges, octocorals and ascidians are a prolific source of biologically active and structurally unique compounds isolated and described by natural-products chemists. Chemists and biologists assumed marine natural products production as a biochemical explanation for the success of these invertebrates in the marine environment. Nevertheless, only during the last two decades marine chemical ecology has matured from a science where chemists discovered chemicals and proposed their ecological functions or where biologists observed ecological interactions and proposed chemical mechanisms to explain their observations. Simultaneous experimental investigations of chemical and ecological aspects of marine chemical interactions are providing advances in this field, confirming old hypothesis.

Among the properties attributed to these compounds, a defensive role against predation has been the most analyzed, in part due to the low predation rates found in these sessile and soft-bodied animals. Living in habitats characterized by high levels of predation and nutrient scarcity, all seem to be free from predation with the exception of some specialized consumers.

The extensive Brazilian coast is rich in marine organisms, but assessments of their natural products have been rare and restricted to very few publications.

The purpose of the present communication is to overview recent results in the investigation of natural products of marine invertebrates sampled at different Brazilian coastal sites, trying to elucidate their ecological significance and their biological activities.

CNPq, IFS, PADCT, CNPq-NSF

IS 9
Departamento de Química Orgânica, Instituto de Química,

Universidade Federal Fluminense, 24020-150, Niterói, Rio de Janeiro, Brazil.

José Oswaldo Siqueira & Marco Aurélio Carbone Carneiro

Higher plants have a remarkable capacity to produce a variety of secondary metabolites with recognized role in plant and ecosystems ecology. Phenolics are among the most widespread class of these plant chemicals and are known to be of great interest in medical and biological research, important natural toxicants and pesticides, allelochemicals, signal molecules and components of the plant litter and soil organic matter. More recently their involvement as natural regulator in ecosystem function and as signal molecules in plant interactions with parasitic angiosperms and with pathogenic and mutualistic microorganisms are widely demonstrated as the case for flavonoids. Certain flavonoids that are released in rhizosphere of leguminous plants are potent inducers for nodulating genes in rizobia while the isoflavonoid formononetin is active on mycorrhizal fungi. The importance and technological development of flavonoids in plant-soil systems are discussed mainly in regard to commercial application of arbuscular mycorrhiza stimulants.

IS 10
Universidade Federal de Lavras, Departamento de Ciência do Solo, Lavras (MG), CP 37, CEP 37200-000, e-mail: siqueira@ufla.br.