Male Wing Vibration Research Articles

Acoustic characteristics of sound produced by males of Bactrocera oleae change in the presence of conspecifics

Males of the olive fruit fly Bactrocera oleae vibrate and stridulate their wings at dusk producing sounds different from flight sounds with no confirmed behavior role. We recorded and performed a temporal-spectral analysis of this sound. Sound produced by male wing vibration/stridulation consists of intermittent pulses of highly variable duration and of fundamental frequency of around 350 Hz. Flight sound has a much lower fundamental frequency of approximately 180 Hz. Males begin to display wing vibration and sound production at the beginning of their sexual maturity at the 5th day of their age. This behavior is more pronounced in the presence of another conspecific male and observed less in male–female pairs or in solitary males. Broadcasts of the recorded sound did not attract flies of either sex. The highest fundamental frequency was found in association with wing vibrations emitted by male–male pairs, followed by those emitted by male–female pairs and then solitary males, which showed the lowest frequency values. The mean pulse duration and interpulse interval were shorter in male–male pairs than in male–female pairs. We assume that the male wing vibration and the produced signal, apart from its possible role in the courtship of the females, could also be associated with male–male interactions for territorial and rival activities, for which further experiments are required.

Does indirect mating trophallaxis boost male mating success and female egg load in Mediterranean fruit flies?

Mating trophallaxis represents a fascinating strategy adopted by males of several animal species to affect the decision-making of females during mating. Among tephritids, few species perform mating trophallaxis. However, this phenomenon has been little studied in major tephritid pests. We reported the presence of indirect mating trophallaxis in Mediterranean fruit flies, Ceratitis capitata, showing its influence on the main mating traits, male mating success and female egg load. Of 219 mating pairs, only 27 of them showed mating trophallaxis, indicating that mating trophallaxis may represent a significant male energy investment. The duration of male wing vibration and the whole precopula phase was longer in pairs that mated without trophallaxis compared to the pairs displaying mating trophallaxis. Males that displayed trophallaxis performed a longer whole duration of the courtship and mating sequence, with no differences in copula duration. Male mating success was slightly increased by trophallaxis. The majority of males performing trophallaxis skipped wing vibration during courtship, while all males courting females without trophallaxis relied on wing vibration to attract females within short distances. No egg load differences were reported for females that consumed nuptial gifts over control females. Overall, our research sheds light on the relation between indirect mating trophallaxis and egg load production in medflies, providing a better understanding of sexual selective mechanisms as the basis of courtship and mating behaviour in tephritid flies. Furthermore, this behaviour could be used as a quality control parameter to assess medfly mass-reared strains, in order to improve sterile insect technique programmes.

Male Wing Vibration in the Mating Behavior of the Olive Fruit Fly Bactrocera oleae (Rossi) (Diptera: Tephritidae)

The olive fruit fly, Bactrocera oleae (Diptera: Tephritidae), is a worldwide pest of olive fruits. To date, the mating behavior of this tephritid has not been fully clarified. Little has been reported regarding the characteristics and behavioral role of B. oleae male wing vibration. This study provides a detailed description of male wing vibration, recorded by a high-speed video camera and compared with a frame-by-frame analysis, prior to successful and unsuccessful matings. Experimental evidence is given of the importance of male wing vibration during courtship for successful mating. Firstly, when the males did not perform wing vibration, but simply jumped onto the female and immediately attempted to copulate, no successful matings were registered. Secondly, when the male’s wings were removed, the probability of successful mating was significantly reduced. Thirdly, the frequency and pulse duration of the male wing vibration during courtship were higher in successful matings than in unsuccessful ones. Lastly, a wing sexual dimorphism was found: length and total wing area were significantly higher among males. Overall, our research increases the knowledge of the reproductive behavior of B. oleae, by suggesting the importance of wing vibration among the range of sensory modalities used by this tephritid in sexual communication.

The genomic response to courtship song stimulation in female Drosophila melanogaster.

Courtship behaviour involves a complex exchange of signals and responses. These are usually studied at the phenotypic level, and genetic or transcriptional responses to courtship are still poorly understood. Here, we examine the gene-expression changes in Drosophila melanogaster females in response to one of the key male courtship signals in mate recognition, song produced by male wing vibration. Using long oligonucleotide microarrays, we identified several genes that responded differentially to the presence or absence of acoustic courtship stimulus. These changes were modest in both the number of genes involved and fold-changes, but notably dominated by antennal signalling genes involved in olfaction as well as neuropeptides and immune response genes. Second, we compared the expression patterns of females stimulated with synthetic song typical of either conspecific or heterospecific (Drosophila simulans) males. In this case, antennal olfactory signalling and innate immunity genes were also enriched among the differentially expressed genes. We confirmed and investigated the time course of expression differences of two identified immunity genes using real-time quantitative PCR. Our results provide novel insight into specific molecular changes in females in response to courtship song stimulation. These may be involved in both signal perception and interpretation and some may anticipate molecular interactions that occur between the sexes after mating.

Courtship song recognition in the Drosophila melanogaster complex: heterospecific songs make females receptive in D. melanogaster, but not in D. sechellia.

The courtship song emitted by male wing vibration has been regarded as one of the most important signals in sexual isolation in the species of the Drosophila melanogaster complex. Inter- and intraspecific crosses were observed using males whose wings were removed (mute) or females whose aristae were removed (deaf). Females of D. melanogaster, D. simulans, and D. mauritiana mated with heterospecific males in the song-present condition (cross between normal females and winged males) more often than in the no-song condition (cross between normal females and wingless males or between aristaless females and winged males) or they showed no preference between the two conditions. It is possible that in these females heterospecific courtship songs play a role as if they were conspecific. In contrast, the females of D. sechellia mated with D. melanogaster or D. simulans males in the no-song condition more often than in the song-present condition, suggesting that they reject males with heterospecific song. Female mate recognition depending on the courtship song in D. melanogaster, D. simulans, and D. mauritiana is considered to be relatively broader and that in D. sechellia narrower.

COURTSHIP SONG RECOGNITION IN THE DROSOPHILA MELANOGASTER COMPLEX: HETEROSPECIFIC SONGS MAKE FEMALES RECEPTIVE IN D. MELANOGASTER, BUT NOT IN D. SECHELLIA

The courtship song emitted by male wing vibration has been regarded as one of the most important signals in sexual isolation in the species of the Drosophila melanogaster complex. Inter- and intraspecific crosses were observed using males whose wings were removed (mute) or females whose aristae were removed (deaf). Females of D. melanogaster, D. simulans, and D. mauritiana mated with heterospecific males in the song-present condition (cross between normal females and winged males) more often than in the no-song condition (cross between normal females and wingless males or between aristaless females and winged males) or they showed no preference between the two conditions. It is possible that in these females heterospecific courtship songs play a role as if they were conspecific. In contrast, the females of D. sechellia mated with D. melanogaster or D. simulans males in the no-song condition more often than in the song-present condition, suggesting that they reject males with heterospecific song. Female mate recognition depending on the courtship song in D. melanogaster, D. simulans, and D. mauritiana is considered to be relatively broader and that in D. sechellia narrower.Corresponding Editor: J. Mallet

FEMALE MATE DISCRIMINATION OR MALE RESPONSES TO FEMALE STIMULATION?

Determining which partner is responsible for any given effect in a dyadic interaction is extremely difficult. In Drosophila, even complex multifactorial studies may be unable to discover the basis for patterns of courtship and mating (Cobb et al. 1990; for a review see Cobb and Ferveur 1996). Scott (1994) claims to have found evidence for female mate discrimination in Drosophila melanogaster. We consider that his data do not necessarily justify his conclusions and that other interpretations could usefully be taken into account. In D. melanogaster, mating is preceded by courtship: the male will orient to the female, follow her if she moves, vibrate his wing, lick her genitalia, and eventually copulate with her. Since the beginning of the 1980s, it has been known that female cuticular hydrocarbons induce male courtship (Antony and Jallon 1982; Jallon 1984). The principal sex-specific hydrocarbon on females of most laboratory strains, the 27 carbon diene 7,11 heptacosadiene (7,11 HD), is a pheromone and induces male wing vibration in a dose-response fashion (Antony et al. 1985). We have carried out a world-wide survey of D. melanogaster and found that in sub-saharan Africa and the Caribbean, 7,11 HD is largely replaced by its position isomer, 5,9 heptacosadiene (5,9 HD), which is behaviorally inactive. This polymorphism is controlled by gene(s) on chromosome III (Ferveur et al. 1996). Scott (1994) studied courtship and mating between two strains of D. melanogaster, Canton-S (CS), a US laboratory strain, and Tai-Y, a strain from West Africa. Although he found that Tai females mated with an equal frequency with males from either strain, CS females mated at relatively low levels with Tai-Y males while mating at normal frequencies with CS males. Scott's interpretation of this result is that CS females were discriminating between the two types of males on the basis of variations in the males' cuticular hydrocarbons. Males from Scott's CS strain show high levels of the 23 carbon monoene 7-tricosene (7-T) and low levels of the 25 carbon monoene 7-pentacosene (7-P), whereas the proportions are inversed in Tai-Y males. As yet, there is no decisive evidence for any male cuticular hydrocarbons acting as a pheromone from males to females in this species. The conclusion presented by Scott (1994) would appear to represent an important proof of this hypothesis. However, we consider that there are four weaknesses in both the data and the interpretation. (1) What is the role of the female? The biggest interpretative weakness is the lack of any information as to the role of the

World-wide variation inDrosophila melanogaster sex pheromone: behavioural effects, genetic bases and potential evolutionary consequences

In Drosophila melanogaster, male wing vibration, a key element of courtship behaviour, is most efficiently induced by a female-specific contact pheromone cis, cis 7,11 heptacosadiene (7,11 HD), which is the main mature female cuticular hydrocarbon in the CS laboratory strain. A study of 63 strains from around the world revealed that flies from Sub-Saharan Africa and the Caribbean are unique in showing low levels 7,11 HD and high levels of the position isomer 5,9 HD. This difference maps to chromosome III, perhaps indicating a simple genetic control of the 7,11 HD:5,9 HD ratio. Females from strains with high levels of 7,11 HD showed higher levels of mating and mated more rapidly than females with low levels of 7,11 HD. The results are discussed in light of recent discoveries of genetic differences between D. melanogaster strains from Africa and those from elsewhere around the world.

Courtship inDrosophila sechellia: Its structure, functional aspects, and relationship to those of other members of theDrosophila melanogaster species subgroup

The courtship behavior of Drosophila sechelliais described. Male wing displays are mainly vibration and scissoring, with low levels of rowing. As courtship proceeds the proportion of courtship spent in male wing vibration and licking increases, whereas female movement decreases. The male courtship song of sechelliacontains pulse song but no sine song. This species also shows a distinctive “copulation song” associated with mounting and copulation. The main cuticular hydrocarbon in females is 7,11-heptacosadiene. The number of copulations increased when flies were placed in the presence of food. Visual and acoustic stimuli appear to be important for mating. A multidimensional comparison was used to compare members of the melanogaster species subgroup, based upon courtship behavior, song characteristics, and cuticular hydrocarbons. A multidimensional comparison of courtship sequences in sechellia, melanogaster, simulans,and mauritianashowed differences in variability between the two island species as compared to the two cosmopolitan species. The courtship song of D. orenais described: it shows both sine and pulse song; there is also a “copulation song” in this species.

Observations on the mating behavior of the alfalfa blotch leafminer,Agromyza frontella (Rondani) (Diptera: Agromyzidae), and evidence of a female sex pheromone

The mating behavior of Agromyza frontella was studied under laboratory conditions. Adults were able to mate on the day of emergence, with no evident periodicity throughout the photophase. The host plant was essential for mating to occur, its presence affecting female receptivity rather than male copulatory behavior. Males generally entered a stationary phase once in the proximity of a female, before undertaking a final approach. This stationary behavior frequently resulted in male aggregations around a female, and under such conditions males exhibited a characteristic wing vibrating behavior. As male wing vibration was not an essential behavior for successful mating, and rarely occurred during male encounters in the absence of females or when only one male was near a female, it was considered as being primarily a male-male signal. The majority of females that mated exhibited an ovipositor pumping behavior that stimulated the male approach. However, such behavior was not essential to attract mates, as dead females elicited the entire sequence of male mating behavior. This suggested the presence of a cuticular sex pheromone, as reported for other species of higher Diptera. Whole virgin female (<24- h or 3- day-old) hexane extracts applied to male cadavers increased the time males spent on the plant, the number of contacts with the treated cadavers, the incidence of attempted copulations, and the wing vibrating behavior between males compared with controls using untreated cadavers. The results obtained indicate that females control copulation in A. frontella and that both semiochemical and visual cues are important in eliciting male mating behavior.

Evidence for an aphrodisiac pheromone of femaleDrosophila

We report here direct evidence for the involvement of a pheromone in the induction of male wing vibration, an important fixed action of theDrosophila melanogaster courtship pattern. This chemical stimulus is produced by mature females but not by mature males. The behavioral response is proportional to the pheromone concentration.

The function and processing of auditory information in the courtship behaviour of Drosophila melanogaster

The function and processing of auditory information in the courtship behaviour of Drosophila melanogaster was investigated using combination of mutant genes which cause stepwise reduction in the size of the arista. Reduction of the effective surface area of the arista lowers female sexual receptivity and the courtship success of males. Since female receptivity is known to be dependent upon accurate perception of the characteristics of male wing vibration, the results confirm that the aristae are essential for adequate auditory perception. The female, as elsewhere suggested, may compare the sound perceived to a neural representation of the parameters of the species code, which is genetically determined, and reject or accept the male depending on the outcome of the comparison. Quantitative analysis of male courtship behaviour suggests that the sound which mutant males produce is distorted as a result of imperfect auditory feedback. It is suggested that veridical feedback of the efferent signal, which may be compared to a neural representation in the same way as in the female, could be a necessary condition for production of an accurate species specific wing vibration code.