EJE, vol. 102 (2005), issue 3

Proceedings of the International Symposium Ecology of Aphidophaga

Edward Evans, Francis Gilbert, Ivo Hodek, J.P. Michaud, John Obrycki

Eur. J. Entomol. 102 (3): 313-315, 2005 | DOI: 10.14411/eje.2005.048

This series of symposia has traditionally been a unique scientific forum for discussions on ecological and behavioural interactions within the guild of insects feeding on aphids. Its focus is to understand how natural control works, with the aim to improve it. After the initial two meetings in Czechoslovakia, symposia were organised in Poland, Hungary, France, Belgium, Canada and Portugal. The ninth meeting was held once again in the Czech Republic.
Details on history of the meetings, with bibliographic data from all Proceedings, can be found at . News will appear there continually.
This issue is the outcome of the 9th meeting...

Seasonal adaptations of green lacewings (Neuroptera: Chrysopidae)


Eur. J. Entomol. 102 (3): 317-324, 2005 | DOI: 10.14411/eje.2005.049

Seasonal adaptations of green lacewings (Neuroptera: Chrysopidae) and their role in the control of aphid populations are discussed. The chrysopids of temperate zones face seasonal changes and must escape cyclic adversity. One way is via the number of broods per year. Most green lacewings are facultatively multivoltine, with the succession of generations most often regulated by photomediated diapause. Others are univoltine and some extend their life-cycle to two years in cold or dry environments. Synchronization is an important feature of seasonality, often starting in spring. In univoltine species, it is sometimes the result of subtle mechanisms, such...

Syrphid aphidophagous predators in a food-web context


Eur. J. Entomol. 102 (3): 325-333, 2005 | DOI: 10.14411/eje.2005.050

The main influences on the specificity of hoverfly larvae (Diptera: Syrphidae) to particular aphids are outlined. There are four main ones: aphid species, host plant, parasitoid impact and the presence of ants. Studies in the literature are used to illustrate the effect of these factors on larval performance. The use of single components of fitness as measures of performance can be misleading: only "individual fitness" includes all the appropriate components of survival, development time and reproduction. Even generalists appear to choose among aphids on the basis of expected fitness. A new level of complexity is therefore required in studies of food...

Quantifying aphid predation rates of generalist predators in the field


Eur. J. Entomol. 102 (3): 335-350, 2005 | DOI: 10.14411/eje.2005.051

The community of predators within agroecosystems has the potential to restrict aphid populations, especially early in the season before exponential increases in density and prior to the arrival of specialist natural enemies. Although direct observations of predation, laboratory feeding trials and manipulative field studies have been used to estimate levels of biological control exerted by different species (or potentially negative interactions between them), it is often difficult to extrapolate results to naturally occurring interactions in the field.
Over 100 investigations have utilized gut-content analysis to estimate aphid predation rates by...

Intraguild predation among aphidophagous predators


Eur. J. Entomol. 102 (3): 351-364, 2005 | DOI: 10.14411/eje.2005.052

Since the publication of papers by Polis et al. (1989, 1992), intraguild predation (IGP) has been considered in numerous systems and a growing number of papers have been published, demonstrating the ubiquity and the importance of this interaction. It appears that aphidophagous guilds constitute especially favourable systems for IGP. Temporal and spatial distributions of aphids promote interactions, such as IGP, among natural enemies. However, despite extensive laboratory and field studies, several questions remain to be answered: Which traits of the different protagonists of the system may promote or hamper the occurrence of IGP? How do ants tending...

Foraging in a complex environment - semiochemicals support searching behaviour of the seven spot ladybird


Eur. J. Entomol. 102 (3): 365-370, 2005 | DOI: 10.14411/eje.2005.053

Knowledge of semiochemically-mediated behavioural mechanisms of the seven-spot ladybird, Coccinella septempunctata L., is limited but sufficient to encourage further studies in the behavioural ecology of this well known insect. Recent findings on semiochemicals are discussed in relation to the main traits in the ecology of C. septempunctata. A putative autumn aggregation pheromone, and effects of allelobiotic plant interactions on habitat preferences of adults are reported. Mechanisms for interaction between an aphid alarm pheromone and plant substances are described, and the kairomonal functions of volatiles from C. septempunctata...

The quality of aphids as food for generalist predators: implications for natural control of aphids

Søren TOFT

Eur. J. Entomol. 102 (3): 371-383, 2005 | DOI: 10.14411/eje.2005.054

The paper reviews existing data on the food quality of cereal aphids for generalist predators. Data are presented for spiders, harvestmen, carabid and staphylinid beetles, cockroaches, ants and one species of bird. All results agree that cereal aphids are low-quality food compared to alternative prey types (in most studies fruit flies). This is associated both with a low consumption capacity for aphids and a low utilization efficiency of the aphid food. A pure aphid diet allows full juvenile development in only a few species. Aphids as part of mixed diets can have negative, neutral or positive effects, which depends on the quality of the remaining...

On the assessment of prey suitability in aphidophagous Coccinellidae


Eur. J. Entomol. 102 (3): 385-390, 2005 | DOI: 10.14411/eje.2005.055

Empirical protocols for assessing the suitability of prey for aphidophagous coccinellids are examined and a modified scheme of categorization is presented. It is argued that prey suitability should be assessed independently for larval development and adult reproduction because of potentially divergent nutritional requirements between these life stages. A scheme is proposed for assessing prey suitability for larval development using conspecific eggs as a reference diet against which diets of various prey types can be compared both within and among coccinellid species. Among suitable prey (those that support ca. 100% survival of larvae to the adult stage),...

Are we studying too few taxa? Insights from aphidophagous ladybird beetles (Coleoptera: Coccinellidae)


Eur. J. Entomol. 102 (3): 391-398, 2005 | DOI: 10.14411/eje.2005.056

Many areas of biology employ standard model organisms on which a majority of research effort is concentrated. However, there is invariably a danger associated with the use of too few or atypical models for studies of particular taxonomic groups, guilds or biological phenomena. Using aphidophagous ladybirds, I show that in this group, in the last ten years, 69% of research has been concentrated on just five species, all generalist ecotypes. Much research is now concentrated on invasive species, originally biocontrol agents, and over half the aphidophagous ladybird work on intraguild interactions is centred on two of the five predominant species, Coccinella...

Development of a sampling plan for Myzus persicae (Hemiptera: Aphidoidea) and its predator Macrolophus costalis (Hemiptera: Miridae) on tobacco


Eur. J. Entomol. 102 (3): 399-405, 2005 | DOI: 10.14411/eje.2005.057

A tobacco field in Greece was sampled during the 2001 and 2002 growing seasons to assess the seasonal trends in densities and spatial distributions of the aphid Myzus persicae (Sulzer) and its predatory mirid Macrolophus costalis (Fieber). On repeated occasions between June (just after the transplantation) and September (just before harvest), 20 tobacco leaves (10 from the upper and 10 from the lower plant part) were taken from randomly chosen plants. These leaves were sampled for aphids and mirids. In both years, the highest aphid densities were recorded during July and August, while aphid numbers were low in September. In contrast,...

Thermal requirements for development and resource partitioning in aphidophagous guilds

Anthony F.G. DIXON, Vojtěch JARO©ÍK, Alois HONĚK

Eur. J. Entomol. 102 (3): 407-411, 2005 | DOI: 10.14411/eje.2005.058

The duration of the increase, peak and decline in abundance of the immature stages of sycamore and cereal aphids each year is ephemeral. These temporary resources are exploited by a sequence of aphidophagous insect predators. The temporal sequence in the appearance of the immature stages of coccinellids and syrphids in the sycamore and cereal aphid systems is defined. In spring in the sycamore aphid system and early summer in the cereal aphid system the immature stages of syrphids consistently appeared before those of coccinellids. In the case of the sycamore aphid the autumnal peak in abundance was on average larger than the spring peak, and although...

Evolution of prey specialization in aphidophagous syrphids of the genera Melanostoma and Platycheirus (Diptera: Syrphidae) 1. Body size, development and prey traits


Eur. J. Entomol. 102 (3): 413-421, 2005 | DOI: 10.14411/eje.2005.059

Interactions between syrphid predators and their prey are poorly known. The adaptations of syrphids to aphid defences and the consequences for the evolution of life history traits in these predators especially are mostly unstudied. This is the first of two papers investigating the evolution of prey specialization in aphidophagous hoverflies. The study focuses on two questions: (1) Are differences in the body size of syrphid predators reflected in differences in the size of their prey? (2) Are differences in body size, body mass and development time of the syrphid predators correlated with the defence strategies of their aphid prey (e.g. mobility, toxicity)?...

The link between food and reproduction in aphidophagous predators: a case study with Harmonia axyridis (Coleoptera: Coccinellidae)

Edward W. EVANS, Derrick I. GUNTHER

Eur. J. Entomol. 102 (3): 423-430, 2005 | DOI: 10.14411/eje.2005.060

For polyphagous predators, the link between food consumption and reproduction is not always straightforward, and instead may reflect that even predators with very broad diets may have reproductive tactics that are tied to consumption of a restricted range of prey. We studied the consumption and use of two prey species for reproduction by the ladybird, Harmonia axyridis Pallas. This polyphagous predator feeds on both pea aphids [Acyrthosiphon pisum (Harris)] and larvae of the alfalfa weevil [Hypera postica (Gyllenhal)] that it encounters when foraging in alfalfa fields. When provided a diet of pea aphids or of alfalfa weevils and/or...

Role of (E)-β-farnesene in systematic aphid prey location by Episyrphus balteatus larvae (Diptera: Syrphidae)

Frédéric FRANCIS, Thibaut MARTIN, Georges LOGNAY, Eric HAUBRUGE

Eur. J. Entomol. 102 (3): 431-436, 2005 | DOI: 10.14411/eje.2005.061

The foraging behaviour of beneficials such as aphidophagous predators depend largely on volatile compounds emitted by potential preys. Even if polyphagous predatory species are considered, all the potential preys are not systematically localised and accepted. In this work, chemical cues from different aphids and plants, each alone or in association, were studied to elucidate their role in prey location. Using a four-arm olfactometer, attraction of combinations of three aphid (Megoura viciae, Acyrthosiphon pisum and Aphis fabae) and one plant (Vicia faba) species for Episyrphus balteatus larvae was observed. Predatory...

Temporal stability of morph frequency in central European populations of Adalia bipunctata and A. decempunctata (Coleoptera: Coccinellidae)


Eur. J. Entomol. 102 (3): 437-442, 2005 | DOI: 10.14411/eje.2005.062

In central Europe Adalia bipunctata (L.) occurs in two main colour morphs (typical, melanic), and A. decempunctata (L.) occurs in 3 morphs (spotted, chequered, dark). Temporal variation in the relative frequency of morphs was recorded in populations of the Czech Republic where geographic variation in morph frequency is low. Seasonal trends were investigated in samples collected by a light-trap run daily from March to November for 14 years. In A. bipunctata the melanic form was more abundant in autumn than in spring but the difference was not significant. In A. decempunctata morph proportions did not change seasonally. Samples...

Long term changes in abundance of Coccinella septempunctata (Coleoptera: Coccinellidae) in the Czech Republic


Eur. J. Entomol. 102 (3): 443-448, 2005 | DOI: 10.14411/eje.2005.063

Since 1978, the abundance of Coccinella septempunctata L. has been recorded at a hibernation site in the western Czech Republic. Over the years, abundance varied by two orders of magnitude and a long-term trend for decrease in C. septempunctata abundance was observed beginning in the early 1990s. This recession was correlated with the decreasing abundance of its dominant prey, cereal aphids. The acreage of small grain cereals and other crops suitable for breeding C. septempunctata populations also decreased. The change in abundance of cereal aphids may be associated with a dramatic decrease in fertilizer input after 1990. Decreasing...

The effects of six species of aphids on some life history parameters of the ladybird Propylea quatuordecimpunctata (Coleoptera: Coccinellidae)


Eur. J. Entomol. 102 (3): 449-452, 2005 | DOI: 10.14411/eje.2005.064

One of the factors affecting the effectiveness of predatory coccinellids in an aphid infested crop is the food specificity of the predator. The response towards six species of aphids (Sternorrhyncha: Aphididae) was therefore tested in one of the most abundant aphidophagous coccinellids in Bulgaria - Propylea quatuordecimpunctata (L.) (Coleoptera: Coccinellidae). All aphid species studied (Acyrthosiphon pisum Harris, Aphis craccivora Koch, Eucallipterus tiliae (L.), Euceraphis betulae (L.), Phorodon humuli (Schrank) and Myzus persicae (Sulzer) cultured on transgenic Bt and conventional (non-Bt) potatoes...

Summer diapause and winter quiescence of Hippodamia (Semiadalia) undecimnotata (Coleoptera: Coccinellidae) in central Greece


Eur. J. Entomol. 102 (3): 453-457, 2005 | DOI: 10.14411/eje.2005.065

The aestivo-hibernation in central Greece of the aphidophagous ladybeetle Hippodamia (Semiadalia) undecimnotata (Schneider) (Coleoptera: Coccinellidae) was studied. H. undecimnotata is a multivoltine species in Greece. In the lowlands, all instars are abundant in spring, becoming scarce from July until the end of October and they are absent in winter. In June, most H. undecimnotata adults migrate to mountainous aestivo-hibernation sites. The duration of pre-oviposition period in females sampled monthly from the summits of the mountains Chlomo and Kitheron in central Greece and transferred to laboratory conditions...

Seasonal occurrence, distribution and sampling indices for Myzus persicae (Hemiptera: Aphidoidea) and its parasitoids (Hymenoptera: Braconidae: Aphidiinae) on tobacco


Eur. J. Entomol. 102 (3): 459-468, 2005 | DOI: 10.14411/eje.2005.066

Field studies were conducted, in order to assess the seasonal occurrence and the spatial distribution of Aphidius colemani Viereck, Aphidius matricariae Haliday, Diaeretiella rapae (M'Intosh), Praon staryi Kavallieratos & Lykouressis and Praon volucre (Haliday), all parasitoids of Myzus persicae (Sulzer) on tobacco. The experiments took place in western Greece (Agrinion, Aitoloakarnania), during the 1996 and 1997 growing seasons, in an area of approximately 2.5 ha, where tobacco was the main crop. The experimental field was insecticide-free and tobacco leaf samples (from the upper and lower half...

Comparative genetic studies of native and introduced Coccinellidae in North America


Eur. J. Entomol. 102 (3): 469-474, 2005 | DOI: 10.14411/eje.2005.067

During the past four decades, several species of aphidophagous Coccinellidae became established in North America, including Coccinella septempunctata, Harmonia axyridis, Hippodamia variegata, and Propylea quatuordecimpunctata. After their establishment, unknown circumstances favoured a rapid increase in population densities and distribution of H. axyridis and C. septempunctata at localities hundreds and thousands of kilometers from their release sites. Propylea quatuordecimpunctata and Hippodamia variegata have spread more slowly after becoming...

Sex ratio shift caused by hyperparasitism in the solitary parasitoid Lysiphlebus hirticornis (Hymenoptera: Braconidae: Aphidiinae)

Manfred MACKAUER, Wolfgang VÖLKL

Eur. J. Entomol. 102 (3): 475-481, 2005 | DOI: 10.14411/eje.2005.068

We examined the influence of offspring mortality caused by hyperparasitism on the secondary sex ratio of Lysiphlebus hirticornis Mackauer, a solitary endoparasitoid of the aphid Metopeurum fuscoviride Stroyan, in the field. Females of L. hirticornis produce pseudo-gregarious broods, which may comprise more than 200 offspring. Hyperparasitoids [mainly Syrphophagus aphidivorus (Mayr)] attacked and killed up to 60% of the primary parasitoids inside mummified aphids, especially late in the season. Hyperparasitized broods were larger than hyperparasitoid-free broods, which suggests that the risk of hyperparasitism increased with...

Induction of reproductive diapause in Hippodamia convergens (Coleoptera: Coccinellidae) hinges on prey quality and availability


Eur. J. Entomol. 102 (3): 483-487, 2005 | DOI: 10.14411/eje.2005.069

In the High Plains of western Kansas, USA, the convergent lady beetle Hippodamia convergens Guérin completes a spring generation feeding on cereal aphids in winter wheat before leaving fields in large numbers around the time of harvest. In late May, large aggregations of coccinellids form on wild sunflowers, Helianthus annuus, and certain other weeds, that appear to serve as important sources of water absorption for the beetles, and other beneficial insects, during the dry prairie summer. Adult beetles were collected from sunflower plants and held in four treatments: (1) access to water only, (2) access to sunflower stalks only, (3) eggs...

Rubidium marking of Aphidius rhopalosiphi (Hymenoptera: Braconidae) on Sitobion avenae (Hemiptera: Aphididae) reared on a diet supplemented with RbCl

Frédéric MURATORI, Delphine PERREMANS, Thierry HANCE

Eur. J. Entomol. 102 (3): 489-494, 2005 | DOI: 10.14411/eje.2005.070

Markers are essential to study movements of insects in their natural habitat. Among the available techniques, trace elements may be applied to insects as small as parasitoids. Rubidium is the most common element used for marking insects. In this study, we propose a simple marking technique for Aphidius rhopalosiphi De Stefani Perez with Rb, when reared on the grain aphid Sitobion avenae Fabricius (Hemiptera: Aphididae) marked on a RbCl incorporated diet. Our results show that the rubidium in an artificial diet is transferred to the aphid and eventually to the parasitoid. The content in rubidium marking did not differ between genders....

Ant-aphid interactions in multispecies ant communities: Some ecological and ethological aspects


Eur. J. Entomol. 102 (3): 495-501, 2005 | DOI: 10.14411/eje.2005.071

Investigations of the interactions between aphids and ants in multispecies ant communities and an experimental investigation of some ethological aspects of ant-aphid interactions were carried out in mixed forests at Novosibirsk Academic Centre, from 1998-2002. The eight species of ants investigated were characterized by different levels of territorial organization and interaction with aphids, which were associated with different degrees of specialization of the worker ants. The most myrmecophilous species of aphids (24 out of 33 species identified) were associated with the red wood ants. By placing Coccinella septempunctata Linnaeus (Coleoptera:...

The effect of prey availability on ovarian development and oosorption in the ladybird beetle Harmonia axyridis (Coleoptera: Coccinellidae)


Eur. J. Entomol. 102 (3): 503-511, 2005 | DOI: 10.14411/eje.2005.072

The ladybird beetle Harmonia axyridis Pallas was investigated under laboratory conditions to clarify the relationship between food abundance or scarcity and ovarian development or oosorption. Four conditions were used: (1) fully fed for 24 h, (2) 24-h starvation, (3) 48-h starvation, and (4) 24-h starvation followed by 24-h re-feeding. Body length and initial body weight were not significantly related to the number of ovarioles per female. Both starvation conditions significantly increased the percentage of oosorptive individuals and ovarioles per female, and significantly decreased the percentage of mature ovarioles per female. Re-feeding for...

Kin recognition and avoidance of kin cannibalism by the larvae of co-occurring ladybirds: a laboratory study


Eur. J. Entomol. 102 (3): 513-518, 2005 | DOI: 10.14411/eje.2005.073

The role of relatedness and diet in kin recognition was investigated in the aphidophagous ladybirds Propylea dissecta and Coccinella transversalis. Third instar larvae of both species exhibited kin recognition, as they were reluctant to consume related first instar larvae. They spent significantly more time prior to cannibalism when interacting with genetically related victims; this indicates the presence of a kin recognition system. Kin recognition, however, was not evident in fourth instar larvae as they ate both related and unrelated victims. This result reveals that the need of fourth instar larvae to attain a critical weight...

Epigeal aphidophagous predators and the role of alfalfa as a reservoir of aphid predators for arable crops


Eur. J. Entomol. 102 (3): 519-525, 2005 | DOI: 10.14411/eje.2005.074

The relative occurrence and seasonal abundance of aphidophagous predators (Insecta and Arachnida) were determined in alfalfa fields at two locations in the northeast Iberian Peninsula, using D-Vac and sweep-net sampling techniques. Among the insects, Heteroptera, Dermaptera, Neuroptera, Coleoptera and Diptera were found. The relative abundance of predators was similar at the two locations. Polyphagous predators were much more abundant than aphid specific species. Heteroptera were the most abundant order of insect predators: members of the Nabidae, Anthocoridae and Miridae were very common. Coleoptera were also abundant, represented mainly by the family...

Seasonal food of Ceratomegilla notata (Coleoptera: Coccinellidae) in mountain environments of Northern Italian Alps

Carlo RICCI, Luigi PONTI

Eur. J. Entomol. 102 (3): 527-530, 2005 | DOI: 10.14411/eje.2005.075

The aim of this study was to clarify the diet of Ceratomegilla notata (Laicharting), a common species in different mountain habitats of the Palearctic region. In Italy it is found only in alpine ecosystems between 800-1700 m. In these areas, up to 1200 m, various crops (e.g., maize, potatoes) are present. The high meadows are cut for hay. From 2002 to 2003 investigations on the foraging behaviour of this ladybird were carried out in mountain habitats (six near Villabassa, in Bolzano province, and six near Soraga, in Trento province) and in the "Paradisia" Botanic Garden (Gran Paradiso National Park). C. notata adults and larvae...

Migratory flight and pre-diapause feeding of Coccinella septempunctata (Coleoptera) adults in agricultural and mountain ecosystems of Central Italy

Carlo RICCI, Luigi PONTI, Alvaro PIRES

Eur. J. Entomol. 102 (3): 531-538, 2005 | DOI: 10.14411/eje.2005.076

The research on pre-diapause feeding of C. septempunctata L. adults was carried out from 1998 to 2002 in the Tiber Valley, in the Botanical Garden of Perugia University, and in the Sibillini Mountains National Park (Central Italy). The species reproduces in spring feeding mostly on aphids infesting Graminaceae. In the second half of June, newly emerged adults have various migratory behaviours. Some of them remain in the valley while some leave the cereals and fly to other crops, where they feed both on 15 aphid species (e.g., Aphis gossypii Glov. on melon, Aphis fabae Scop. on sugarbeet), and also on pollens of wild plants...

Landscape parameters explain the distribution and abundance of Episyrphus balteatus (Diptera: Syrphidae)

Jean-Pierre SARTHOU, Annie OUIN, Florent ARRIGNON, Gaël BARREAU, Bernard BOUYJOU

Eur. J. Entomol. 102 (3): 539-545, 2005 | DOI: 10.14411/eje.2005.077

We studied the importance of forest structure (shape, edge length and orientation) and the crop mosaic (percentage of crops in the total land cover, within 100 and 2000 m from the forests) to the dynamics of an aphidophagous hoverfly Episyrphus balteatus. Adults were collected by Malaise traps located within and on the south- and north-facing edges of 54 forests. In winter, E. balteatus was only found on south-facing edges because of the greater insolation and temperature. In summer, it was more abundant on north-facing edges because of the abundant presence of flowers. In spring, more adults were found on long and south-facing edges...

The pollens consumed by common green lacewings Chrysoperla spp. (Neuroptera: Chrysopidae) in cabbage crop environment in western France

Johanna VILLENAVE, Dominique THIERRY, Abdullah AL MAMUN, Thierry LODÉ, Elizabeth RAT-MORRIS

Eur. J. Entomol. 102 (3): 547-552, 2005 | DOI: 10.14411/eje.2005.078

The pollens consumed by common green lacewings Chrysoperla spp. in crop environment in western France, were analysed. The diverticulum contents including quantity of pollen of Chrysoperla adults were analysed to compare a feeding behaviour between the sexes. Females consume more pollen than males. The feeding behaviour of the two main species present was compared, yielding new insights into differences between species within the complex Chrysoperla carnea (Stephens).

Phenotypic plasticity of elytron length in wingless two-spot ladybird beetles, Adalia bipunctata (Coleoptera: Coccinellidae)


Eur. J. Entomol. 102 (3): 553-556, 2005 | DOI: 10.14411/eje.2005.079

Winglessness in the two-spot ladybird beetle Adalia bipunctata (L.) is determined by a single locus with the wingless allele recessive to the winged wildtype allele. The expression of the wingless trait is highly variable, with individuals missing a variable part of elytra and flight wings; the elytra and wings appear to be truncated rather than miniature in form. The degree of winglessness is partly determined genetically. Here we report on the phenotypic plasticity of the degree of winglessness. The environmental effect on elytron length relative to maximal elytron length in wingless phenotypes was studied by rearing offspring of single pair...

Associative odour learning affects mating behaviour in Aphidius ervi males (Hymenoptera: Braconidae)

Cristian A. VILLAGRA, Rodrigo A. VÁSQUEZ, Hermann M. NIEMEYER

Eur. J. Entomol. 102 (3): 557-559, 2005 | DOI: 10.14411/eje.2005.080

We used the aphid parasitoid Aphidius ervi reared in its host Acyrthosiphon pisum to examine if male sexual attractive responses can be conditioned to an odour (vanilla) that is not present in the natural environment. We used prior mating experience (exposure to females) as a non-conditioning stimulus and vanilla odour as a conditioning stimulus. The behavioural responses were tested in a glass Y-olfactometer just after eclosion (i.e., initial response) and after a training experience (i.e., trained response). During the 10-min training period individual males were allowed to copulate with a virgin female with or without vanilla odour...