Edleide Leite da Silva, Ruth Rufino do Nascimento, Eda Flávia Lotulfo Patrício and Antônio Euzébio Goulart Sant'Ana

Exocrine glands (i.e. those secreting to the outside) are usually responsible for the production of chemical compounds, with most of them being involved in communication, particularly in the case of social insects, such as ants and bees. In social hymenopteran, these glands are distributed throughout the female's body and according to the genera or species, their secretions may function as source of alarme, trail, recognition or sex pheromones. Although these glands have been well studied in social hymenopteran, their presence and function in hymenopteran parasitoids are not well known. So far, histological studies performed with parasitoids have shown that the Dufour's gland is the source of the sex pheromone in Cardiochiles nigriceps and in two species belonging to genus Apanteles (=Cotesia), A. melanoscelus e A. liparidis (Syvertsen et al., 1995; Weseloh, 1976). Apart from that, to our knowledge, no such study has been performed with any other parasitoid.

Early studies carried out by some of us have shown that females of Bephratelloides pomorum (Hymenoptera: Eurytomidae), the Annona seed borer, are responsible for the production of a sex pheromone which enables males to find females. These studies, also revealed that the most active region of the female's body is the thorax. Therefore, histological studies were performed, in order to find out if there were any exocrine glands in the thoracic region of B. pomorum female's which could be related to the production of a sex attractant for males from this species. A cluster of dermal glands connected to the cuticle and a pair of salivary thoracic glands were found on that region. Searching for other exocrine glands, it was found a pair of mandibular and salivary glands in the head and a pair of accessory glands, a Dufour gland and a venom gland in the abdomen.

Syvertsen, T. C.; Jackson, L. L.; Blomquist, G. J. & Vinson, S. B. (1995). Alkadienes mediating courtship in the parasitoid Cardiochiles nigriceps (Hymenoptera: Braconidae). J. Chem. Ecol. 21 (12): 1971-1989.

Weseloh, R. M. (1976). Dufour's gland: source of sex pheromone in a hymenopterous parasitoid. Science 193: 695-697.

[IFS, CNPq & CAPES]

PO 46
Laboratório de Ecologia Química, Departamento de Química, Universidade Federal de Alagoas 57072-970, Maceió, Alagoas, Brasil

Fone: +214 1362; Fax: +214 1615; e-mail: rrn@ccen.ufal.br

Edleide Leite da Silva, Luciano Clibison Nunes da Silva, Ruth Rufino do Nascimento and Antônio Euzébio Goulart Sant'Ana

Species of Anonaceae, particularly the ones belonging to the genus Annona, Annona muricata and A. squamosa, respectively, occur in the Northeast region of Brazil. Their fruits, called soursop and custard apples, are very well apreciated to be eaten in natura, but it can also be used in preparations of juices, ice-creams, etc. Besides, human beings, these fruits are also appreciated by insects, such as the seed wasp, Bephratelloides pomorum (Hymenoptera: Eurytomidae) and the fruit borer, Cerconota anonella (Lepidoptera: Oecophoridae), which causes serious damages to these fruits. The attraction of males B. pomorum towards riped, almost riped and unriped soursop and custard apples, either damaged by their insect pests or intact was observed in semi-field conditions. Males showed similar behaviour on the surface of both fruits, however, they showed preference for riped and almost riped soursop and unriped and almost riped custard apple. It was also observed that the number of males attracted to soursop was higher than to custard apple. In addition, on the surface of damaged soursop fruits, from where virgin females were emerging, males showed a courtship behaviour: antennation, lateral bouncing and wing vibrations in front of the orifice from where a virgin female was emerging, followed by copulation upon female emergence. The significance of these results are not yet known, but it is possible that volatile compounds from the fruits play a role in the preference of males towards these fruits.

[IFS, CAPES]

PO 47
Laboratório de Ecologia Química, Departamento de Química, Universidade Federal de Alagoas 57072-970, Maceió, Alagoas, Brasil

Fone: +214 1362; Fax: +214 1615; e-mail: rrn@ccen.ufal.br

Edleide Leite da Silva, Luciano Clibison Nunes da Silva, Ruth Rufino do Nascimento and Antônio Euzébio Goulart Sant'Ana

Bephratelloides pomorum (Hymenoptera: Eurytomidae) is the main pest of Annona muricata in the Brazilian Northeast region. Mated and unmated females of this species lay eggs inside of seeds of developing A. muricata fruits, which serve as food for the larvae. This wasp also causes indrect damage, as fungi and bacteria may invade the fruit through the exiting holes made by adult wasps, making the fruits not suitable for commercialization. The attraction and oviposition behaviours of B. pomorum males and females towards A. muricata fruits, in different maturation stages, were studied in semi-field conditions. The results have shown that mated females were attracted to unriped fruits soursop fruits whereas males were attracted to riped and almost riped soursop. These results suggest that volatile released by unriped and riped soursop may act as clue to help females and males to find a suitable place for oviposition and mating, respectively. Behavioural and chemical analyses are being performed in order to find out which of the volatile compounds released by soursop attract B. pomorum females and males towards the fruits.

[IFS, CAPES]

PO 48
Laboratório de Ecologia Química, Departamento de Química, Universidade Federal de Alagoas 57072-970, Maceió, Alagoas, Brasil

Fone: +214 1362; Fax: +214 1615; e-mail: rrn@ccen.ufal.br

Maria do Rosário Tenório de Freitas, Adriana de Lima Mendonça, Ruth Rufino do Nascimento and Antônio Euzébio Goulart Sant'Ana

The mating behaviour of Cotesia flavipes Cameron (Hymenoptera: Braconidae) was observed under laboratory conditions. The results have shown that visual or chemical stimulus or a combination of both play an important role in bringing male and female together for mating. Females release chemical compounds to attract males. Ethological tests using hexane extracts from two different parts of the female's body (head plus tórax and abdomen) demonstrated that males are more attracted and also display a courtship behaviour when a filter paper containing hexane extracts from the abdomen was presented to them. In addition, these tests have shown C. flavipes females mate only once, whereas virgin males did not show any preference for virgin or mated females, suggesting that mated females of this species continue to produce sex attractants after mating.

[CNPq]

PO 56
Universidade Federal de Alagoas, Departamento de Química, Laboratório de Ecologia Química, BR 104 N, Km 14, Tabuleiro, CEP: 57072-970, Maceió, Alagoas, Brazil

Maria do Rosário Tenório de Freitas, Adriana de Lima Mendonça, Ruth Rufino do Nascimento and Antônio Euzébio Goulart Sant'Ana

The feeding behaviour of Diatraea saccharalis (Lepidoptera: Pyralidae) larvae was observed under laboratory conditions. Larvae from third, fourth and fifth instars, which were feeding on an artificial diet were parasitized by mated Cotesia flavipes (Hymenoptera: Braconidae) females and behaviours were observed each two days, during twenty days. It was observed that the moults from one instar to the next one occurred in a manner similar to the unparasitized larvae, whereas parasitized larvae did not pupate, except for in those cases where parasitation was not sucessfull. It was also observed that after parasitoid emergence, the Diatraea larvae stopped their locomotory and feeding activities, dying immediately or living only for a few hours.

These results have shown that the development of parasitized and unparasitized larvae is similar. However, their feeding activity dimishes gradually as the parasitoid larvae start to develop inside of their bodies.

[CNPq]

PO 58
Universidade Federal de Alagoas, Departamento de Química, Laboratório de Ecologia Química, BR 104 N, Km 14, Tabuleiro, CEP: 57072-970, Maceió, Alagoas, Brazil

Eva Pettersson

Female Coeloides bostrichorum Gir. (Braconidae) are attracted by synthetic kairomone baits, prepared by compounds associated with their natural host. The parasitic wasp C. bostrichorum preys on Ips typographus L. (Scolytidae), and some other economically important bark beetle species, breeding in conifers. Late instar larvae of the bark beetle, concealed under the bark of the brood tree, are the preferred host stage. Odours from spruce bolts (Picea abies) were collected during I. typographus infestations, from day one to day 40 when callow bark beetles emerged. Chemical analysis (GC-MS) showed that certain oxygenated monoterpenes increased in quantities as the larval host developed into the preferred stage. By electrophysiology (GC-EAD) these compounds were found to elicit nerval responses in the parasitoid antennae. Synthetic kairomone baits were subsequently prepared, by one to four compounds, based on the relative proportions found in the odour samples from bark beetle infested spruce bolts. In a wind tunnel the baits were supplied by a sprayer, enabling a very controlled dosage. Odour samples from bark beetle infested spruce bolts were attractive, while uninfested bolts failed to elicitany flight activity. However, when adding certain synthetic kairomone baits to odours from uninfested spruce bolts, this mixture was as attractive as odours from infested spruce bolts.

PO 60

Chemical Ecology, Göteborg University, Box 461, SE-405 50 Göteborg

Francisco de Assis Marques^1,2, Jocelyn G. Millar¹, and J. Steven Mcelfresh¹

The complete identification of conjugated trienes from insect pheromone gland extracts, such as E10,E12,Z14-hexadecatrienal, a pheromone component of the sphingid moth Manduca sexta, can be difficult because of the small quantities available and the limited stability of the compounds. The situation is further complicated by the lack of a straightforward method to locate the positions of the double bonds. By modification of a method for location of coujugated dienes, we have successfully located the double bonds of several conjugated triene pheromones. The method involves 2 steps. First, a triene is reacted with the powerful dienophile 4-methyl-1,2,4-triazoline-3,5-dione (MTAD), yielding a cyclic adduct which gives large diagnostic mass spectral fragments that usually allow the positions of the double bonds to be determined. The reaction is essentially instantaneous at room temp, and no workup is required. The locations of the double bonds can be further confirmed by GCMS ofthe product from catalytic hydrogenation of the crude solution of the cycloadduct. The scheme shows the key cleavages giving rise to the diagnostic mass spectral fragments from the derivatives, that allow unambiguous determination of the double bond positions in the parent molecule.

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¹ Department of Entomology, University of California, Riverside, CA, 92521, USA.

² Current address: Laboratory of Chemical Ecology and Organic Synthesis, Department of Chemistry, Federal University of Paraná, P. O. Box 19081, 81531-990, Brazil. Email tic@quimica.ufpr.br

Davyson de L. Moreira, ^aRenata L. Engelhardt, aGilda G. Leitão, ^bSuzana G. Leitão, ^cZelinda B. Hirano, ^bRose Mari M. Silveira, ^dEunice R. Batista, ^dJose Roberto Trigo.

Howler monkeys (Alouatta spp) are the most widely distributed monkeys of the New World. They are predominantly folivorous, which may have accounted for their adaptation to many different habitats. Among the endemic species of primates of the Atlantic Forest, Alouatta fusca is the most widespread, occurring from the States of Bahia (Brazil) to the Northeast of Argentine. Food selection by mammalian herbivores has been associated with the chemical composition. High levels of condensed tannins first considered a repellence factor, is now being questioned towards mammalians.

The present study deals with the feeding behaviour of a group of A. fusca in a fragment of Atlantic Forest near the city of Indaial, State of Santa Catarina, Brazil. During winter season (June, July and August/1999) observations on the items of their diet as well as the time spent on feeding on each item were recorded. At the same time, samples of these items were collected in order to perform phenolic analysis and nutritional factors dosage. Plants which were not consumed were also collected. Dried and ground samples were evaluated for nitrogen, soluble/insoluble fibers, lipids, condensed tannins (CT), gallic tannins (GT) and total phenolics (TP) content. Results from the analysis of primary metabolites showed that plants of the diet have higher amounts of lipids and soluble fibers than those which are not eaten. No significant difference could be observed for nitrogen or insoluble fiber content. Regarding the TP content of consumed/non-consumed plants it was possible to observe a variation pattern which was very similar among the non-consumed plants. Almost all of the analysed samples reached the highest percentage values in July, followed by the lowest values in August. This was not true for the consumed plant samples suggesting that predation could alter the observed pattern. Analysis of CT variation of non-consumed plant samples showed a tendency to reach maximum values in August. Again, this pattern could not be observed for the consumed plant samples. We could not find any variation pattern for GTcontent. In a preliminary analysis it was not possible to correlate foliage comsumption by A. fusca with CT or TP variation. However, this study pointed out two plants with similar high content of CT (aprox. 12 %) _ Buchenavia kleinii and Diatenopteryx sorbifolia; and extremely different times spent on feeding (June + July + August): 36.9 % and 0.5 %, respectively. This observation reinforce the theory that differences in the CT structure may influence food preference rather than CT content. Comparison of GT content and food prefence apparently shows a correlation between them. Plant samples with detectable GT content were those which were less or not consumed.

PRONABIO/ MMA/ CNPq/ BIRD

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^aNúcleo de Pesquisas de Produtos Naturais, UFRJ, CCS, Bloco H, Ilha do Fundão, 21941-590, Rio de Janeiro, Brazil, ^bFaculdade de Farmácia, UFRJ, Rio de Janeiro, Brazil, ^cCEPESBI, Indaial, Santa Catarina, Brazil, ^dDepartamento de Zoologia, UNICAMP, Campinas, Brazil.

Göde Schüler and Wilhelm Boland

Coronatine (1) is known as a highly active phytotoxin, which is produced by several pathovars of Pseudomonas syringae (eg. tomato, glycinea). Coronatine can activate the stress signaling of plants, which results for example in volatile emission or tendril coiling. Its biological properties are very similar to 12-oxo-phytodienoic acid (PDA, 3), an early intermediate of the octadecanoid pathway, that leads to the phytohormone jasmonic acid (JA). According to this fact and to the structural similarities it seems possible that PDA and coronatine bind to the same receptors or binding proteins.

The synthetic 6-azido-1-oxo-indanoyl isoleucine (2) resembles the biological activity of the phytotoxin. It was accordingly designed to serve as a photoaffinity label, to offer a way to determine the place of action of coronatine. The azide (2) can induce both, volatile emission and tendril coiling. Different bioassays show the versatility of the new photoaffinity label. Decomposition of the molecule in presence of Myoglobin as a model protein, for example, results in significant binding. 6-Azido-1-oxo-indanoyl isoleucine (2) may thus become an interesting tool to study the mode of action of the phytotoxin coronatine and of PDA, which an important intermediate of the octadecanoid pathway.

¹Schüler G, Wasternack C, Boland W, Tetrahedron, 55 3897-3904 1999.

PO 31

Max-Planck-Institut für Chemische Ökologie, Tatzendpromenade 1a, 07745 Jena, Germany

Hélio Teixeira Prates¹, Nádja de Moura Pires², Israel Alexandre Pereira Filho².

Leucaena is a legume found in tropical region and has been used as protein source for animal food and recovery of degraded areas. Leucaena shoot as mulch or incorporated to the soil can liberate substances produced in its secondary metabolism, such as mimosine (b-[N-(3-hydroxi-4-oxopyridil)]-a-aminopropionic acid), which has the ability to influence the growth of other plants. The use of those compounds as alternative to synthetic herbicides has been the focus of research to prevent environmental contamination. Bioassays were conducted to determine the potential effect of leucaena (Leucaena leucocephala) on the germination and growth of three weeds occurring in the savanas maize crop, namely Amaranthus deflexus, Bidens pilosa, Siegesbeckia orientalis. Two aqueous extracts from fresh and dry shoots were prepared in a concentration of 20% (w/v), using either hot (80 ^oC) and cold water. Different concentration (2.5; 5.0; 10.0 and 20.0%) of the aqueous extracts have not shown significant reduction on the germination of the species tested. However, the growth of seedling of those species decreased with the increasing amounts of the aqueous extracts, specially with the extract obtained with hot water. Radicle elongation was the most sensitive indicator of the effect of extracts. HPLC analysis showed mimosine in high concentration (~1400 mg mL^-1) in the hot crude extract, but lower concentration (~530 mg mL^-1) was found in the cold extract. It is supposed that mimosine is the substance responsible for the effect on the growth of the species tested.

PO 10
¹Pesquisador Embrapa Milho e Sorgo. C.Postal 151, 35701-970, Sete Lagoas, MG.

E-mail: htprates@cnpms.embrapa.br.

²Bolsista Recém-doutor CNPq/Embrapa Milho e Sorgo.

Nádja de Moura Pires¹, Isabel Regina Prazeres de Souza², Hélio Teixeira Prates², Trícia Cristina Lessa de Faria³, Israel Alexandre Pereira Filho²

Leucaena (Leucaena leucocephala) has been observed to control weeds when used as soil mulch. It contains mimosine which, among other allelochemicals, is responsible for the majority of the allelophatic effect. The objective of the present study was to evaluate the effect of leucaena aqueous extract on the development, root mitotic index, peroxidase activity and isoenzymes in the shoots and roots of maize seedlings. Inhibition of root growth and mitotic index was drastically affected by the increase in aqueous extract concentration. It was observed no cellular division in extract concentration from 8% to 32%. Increase of extract concentration was followed by high peroxidase activity values in roots and shoots, but, without changes in peroxidase isoenzymes pattern. The peroxidase activity in roots was positively correlated with the increase in anionic isoenzymes, pI 4,99 and 4,86, what could explain the thickening of the root diameter and dry weight (mg/root cm). High doses of the allelochemical mimosine was detected in concentrated aqueous extract influencing seedlings development.

PO 11
¹Bolsista Recem-doutor CNPq/Embrapa Milho e Sorgo. C.Postal 151, 35701-970, Sete Lagoas, MG. E-mail: nadja@cnpms.embrapa.br.

²Pesquisador Embrapa Milho e Sorgo.

³Bolsista CNPq

HYEON-GYEONG YOO ·BONG-SEOP KIL AND YOUNG-SIK KIM^*

To investigate allelopathic effects of Artemisia scoparia, one of the main weed in Korea, as donor plant, and their biological activities, seed germination and seedling growth of receptor plants were examined at different concentrations of essential oil of the donor plant.

The treatment of the volatile essential oils of the A. scoparia caused significant inhibition in the germination, shoot and radicle growth of the receptor plants. The radicle growth of receptor plants was inhibited more severely than that of shoot growth. The essential oils of A. scoparia extracted by Karlsruker's apparatus was significantly inhibited on several bacteria and fungi. The essential oils of A. scoparia inhibited the induction and growth of callus of the receptor plant; Acyranthes japonica, Brassica campestris subsp. napus var. pekinensis, Oryza sativa and Sesamun indicum. The GC/MS was employed for analysis and identification of allelochemicals from A. scoparia leaves, i.e. camphene, n-methyl-2,1-borazarene, _-phellendrene, _-terpinene, p-cymene, 1,8-cineole, _-terpinene, 1-camphor, endo-borneol, terpinen-4-ol, trans-ocimene, (-)-_-elemene, trans-caryophyllene and ledene. The bioassay with the four commercial commpounds was shown from identified chemical compound was done. 1,8-cineole showed as the strongest growth inhibitor of the chemicals. The results of this experiment on seed germination seedling growth, anti- microbial test and tissue and culture indicated that naturally occurring chemical substances of essential oil from A. scoparia would for the allelopathic effects.

PO 6
DIVISION OF LIFE SCIENCE, WONKWANG UNIVERSITY

^*WONKWANG HEALTH COLLEGE, REPUBLIC OF KOREA

Inoue A. Takashi 1), Asaoka Kiyoshi 1), Ozaki Mamilo 2)

We recorded neural spike responses from the foreleg 5th tarsi taste sensilla of Papilio swallowtail butterflies in stimulations with methanol extracts of Rutaceae plants' leaves, and carried out fine analysis of the shape of spikes using our original computer program. These spikes could be classified into four types based on those shapes. Type 1 and type 2 spikes appeared in the responses to almost all Rutaceae plants' extracts. Type 3 and type 4 spikes, in contrast, appeared in the responses to non-host Rutaceae plants' extracts for the tested butterflies. We suggest that type 3 and type 4 spikes represent deterrent signals for oviposition by those butterflies.

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1): Japanese National institute of Sericultural and Entomological Science,

1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan

2): Kyoto Institute of Technology

Goshokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan

Adriana Guimarães Duarte¹ and Ivanildo Soares de Lima^1,2

The American palm weevil Rhynchophorus palmarum L. (Coleoptera: Curculionidae) is the most important pest of the coconut palm tree, because its larvae feed on the plant tissues and the adult weevil is the main vector of the red ring disease caused by the nematode (Bursaphelenchus cocophilus). The aggregation pheromone 6-methyl-(2E)-hepten-4-ol (rhynchophorol) has been used as part of the integrated pest management of coconut pest in several countries, including Brazil, where the pheromone is synthesised e distributed to coconut producers of several States of the country. The use of imported reagents makes the synthesis of the pheromone very expensive. Therefore, this work aimed to obtain information about different release rates of the pheromone in capturing adults of the American palm weevil in the field. When kept inside eppendorf vials, containing a small hole on the lid (1 mm), the mean release rate of the pheromone was 4,3 mg/day. Weevil catches by pheromone traps baited with sugar cane and rhynchophorol at release rates of 4,3 mg/day; 8,6 mg/day; 17,2 mg/day; 34,4 mg/day and 68,8 mg/day during 60 days, showed that the release rate of 4,3 mg/day was the most economic because all release rates captured equal number of weevils. Weevil catches by pheromone traps baited with eppendorf vials without a hole on the lid were significantly lower than those traps baited with vials containing a hole. Vials without holes on the lid release 2,2 mg/day of rhynchophorol in the environment.

PO 64
¹QUI/CCEN/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

Sheila Soraya Albuquerque de Carvalho¹, Simone Cristian Rocha de Amorim² and Ivanildo Soares de Lima^1,2

The calling behaviour of the sugar cane borer Diatraea saccharalis starts with the female raising the abdomen and protracting its extremity, in a typical pheromone release behaviour. In the laboratory, under a 12:12 light/dark photoperiod, female D. saccharalis showed calling activity after five hours of darkness. From a total of 159 one-day-old virgin females observed, 35 started calling on the fifth hour of darkness. 36 females started calling after six hours, 29 after seven hours, 31 after eight hours, 18 after nine hours, and only 4 females started calling activity after ten hours into darkness. The age of calling activity was observed in 167 virgin females. From those, 110 started calling on the day they emerged, 42 started on the second day, and only 15 females called for the first time when they were three days old. Females older than three days were not seen calling. Mating activity is frequently observed between moths that are one day old. The arriving male touches the terminal portion of the female's abdomen with his proboscis. Then, he walks in a manner that his body faces the same direction of the female's body. Usually, the male mounts the female walking backwards. After mounting a female, the male turns 180 degrees over his body and the couple remains still until the end of the copula.

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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

Kim, J. H., W. H. Kim and K. W. Yun

The volatile constituents of 2 medicinal plants(Ledebouriella seseloides, Bupleurum falcatum) were investigated for phytotoxic and antimicrobial activities. Essential oil extracted from roots and shoots of 2 medicinal plants inhibited the seed germination and radicle elongation of 3 receptor plants(Lactuca sativa, Bupleurum falcatum, Scutellaria baicalinsis). Specially, the concentration of essential oil extracted from root of Ledebouriella seseloides and radicle elongation of Scutellaria baicalinsis was inversely correlated.

The growth of calluses in media added with essential oil extracted from root of Ledebouriella seseloides was suppressed, and the degree of inhibition was proportional to the concentration of the essential oil. Escherichia coli was not effected by volatile substances from root of Ledebouriella seseloides. In contrast, the growth of Bacillus subtilis and Micrococcus luteus was severely inhibited by the essential oil. The essential oil of 2 medicinal plants exhibited strong toxicity to fungi. The essential oil extracted from root of Ledebouriella seseloides was the most inhibitory to growth of Actinobacillus actinomycetemcomitans in the 4 essential oils (Essential oil extracted from roots and shoots of 2 medicinal plants).

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Dept. of Biology and 1Dept. of Oriental Medicine Resources, Sunchon National University, Sunchon, 540-742, Republic of Korea

Johanne Delisle¹ and Charles Vincent²

The present study examines the impact of insecticide resistance on the periodicity of the calling behaviour and pheromone production in different-aged virgin females of the obliquebanded leafroller, Choristoneura rosaceana Harris (Lepidoptera: Tortricidae). While both resistant and susceptible females initiated calling on the first night following emergence, the periodicity of the calling behaviour significantly differed between the two strains. Resistant females started calling significantly later in the night and called for a shorter period than susceptible individuals. However, since resistant females advanced their onset time of calling as they aged while susceptible females did not, the difference observed between strains was more pronounced in younger than older females. Furthermore, as the time spent calling increased with age in both resistant and susceptible females, the difference between individuals of the two strains remained fairly constant for each night of calling. Overall, pheromone production significantly decreased with female age; however, the decline was more pronounced in resistant than susceptible individuals. Thus resistant females may have a lower mating success. Male mating success and spermatophore size generally declined with successive matings for both strains, but there was no significant difference between susceptible and resistant individuals. Further research is required as resistant males are smaller and may be disadvantaged through female choice and/or may respond differentially to pheromone source compared to susceptible individuals. If the reproductive success of both sexes is affected, this may have a major influence on the dynamics of insecticide resistance in the presence and absence of selection in C. rosaceana populations.

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¹Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 3800, Sainte-Foy, Quebec, Canada, G1V 4C7. E-mail: jdelisle@cfl.forestry.ca ²Horticultural Research and Development Centre, Agriculture and Agri-Food Canada, 430 Gouin Blvd., Saint-Jean-sur-Richelieu, Quebec, Canada, J3B3E6. E-mail: vincentch@em.agr.ca

J. V. Hernández, W. Goitía and K. Jaffe

Behavioral tests with field colonies of Atta laevigata and Atta cephalotes were performed in order to study the odors used in nestmate recognition for these species. We tested the postpharyngeal (PPG), intramandibular and mandibular glands (MG) as putative organs producing chemical signals for nestmate recognition. We confirmed that nestmate recognition is based on cephalic odors and that these odors can be lost over time in headless ants, and these odors come mainly from the mandibular gland secretion at least in A. laevigata.. Although odors from PPG elicit colony-specific behavioral responses, the types of behaviors they elicit differ from those of nestmate recognition of whole ants or mandibular gland extracts. The results are discussed in relation to the chemical composition of the postpharyngeal glands and mandibular glands of these an

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Universidad Simón Bolívar, Departamento de Biología Organismos, Caracas, 1080A, Venezuela. e-mail: jnandez@usb.ve; kjaffe@usb.ve