A Female-Emitted Pheromone Component Is Associated with Reduced Male Courtship in the Parasitoid Wasp Spalangia endius

During courtship interactions, the courted individual may not always be prepared to mate. For example, mating or courtship may be detrimental to its fitness and resistance is expected under these circumstances. As such, various resistance strategies have evolved, from physically fending off courting individuals to producing behavioural signals of unreceptivity. In the parasitoid wasp Spalangia endius, females rarely re-mate and mated females are avoided by males in favour of virgin females. Further, mated females appear to advertise their mating status by the release of a pheromone component (methyl 6-methylsalicylate), but direct evidence of the nature of this release is lacking. Here we used real-time chemical analysis to track the emission of the pheromone component during courtship interactions between virgin males and either virgin or mated females. We found that females actively release methyl 6-methylsalicylate when courted and that significantly greater concentrations are released by previously mated females. Further, high concentrations of this component are associated with both the prevention and termination of courtship.     

Courtship behavior of Heliconius erato phyllis (Lepidoptera, Nymphalidae) towards virgin and mated females: conflict between attraction and repulsion signals?

Previous observations of Heliconius erato phyllis females being intensively courted a few days after mating contradict the proposal of sexual repulsion caused by a male-transferred antiaphrodisiac. Furthermore, data on courtship in Heliconius butterflies are almost absent from the literature. In this work we aim to describe the courtship behavior of H. erato phyllis and to compare it towards virgin and mated females. Sexual interactions using both kinds of females were observed and filmed in seminatural conditions for subsequent analysis and quantification. Courtship of virgin and mated females differed qualitatively and quantitatively, but the results do not agree with the proposal of sexual repulsion. The differences found indicate that the courtship sequence towards mated females is interrupted in the transition that would lead to the behavior immediately prior to copulation, in such a way that the male continues courting the female in an intermediate phase. Preliminary tests even showed that older females, virgin or not, are much less courted by males. We suggest that there is a trade-off between an attraction pheromone, important for males to locate female pupae, and the male-transferred antiaphrodisiac, so that young, mated females may have both signals active. .     

Pheromones exchanged during mating: a mechanism for mate assessment in Drosophila

Many insect species are sexually dimorphic for volatile compounds associated with the cuticle. In these species, females may acquire volatile compounds from males through direct contact with males during mating. In some cases, these compounds function as antiaphrodisiacs, which inhibit subsequent male precopulatory behaviour. During mating, males may also acquire female compounds, which normally stimulate males to court. Contact during mating thus results in a mutual exchange of compounds usually found primarily, or exclusively, on one or the other sex. Drosophila melanogaster is a sexually dimorphic dipteran species in which predominant male and female cuticular hydrocarbons are mutually exchanged during mating. Using synthetic compounds, the effect of this exchange on the post-mating sexual attractiveness of both males and females was tested. The sex-predominant hydrocarbons acquired during mating decreased the attractiveness of both males and females to members of the other sex. Mated females are courted less actively than virgins, and are usually unwilling to re-mate. Similarly, recently mated males are less attractive to females than virgin males are, and may be less fertile. Thus, cuticular hydrocarbons acquired by the other sex during mating could allow both males and females to assess the immediate reproductive potential of prospective mates.     

Courtship-stimulating volatile compounds from normal and mutant Drosophila

Volatile compounds from Drosophila melanogaster males and females dramatically affect male courtship behaviour. These substances, which have been extracted from flies of different ages and genotypes, have been analysed by gas chromatography (GC) and in behavioural assays. Extracts from virgin females and males have different gas chromatographic profiles, which may reflect the fact that extract from virgin females stimulates high levels of courtship between males over short distances, while extract from mature wild-type males does not affect sexual behaviour. However, volatile compounds from very young males or males expressing the fruitless (fru) mutation do stimulate courtship between males, and chromatographic profiles of young male and fru male extracts differ from the GC profile of extracts from mature wild-type males.     

The mushroom body D1 dopamine receptor controls innate courtship drive

Mating is critical for species survival and is profoundly regulated by neuromodulators and neurohormones to accommodate internal states and external factors. To identify the underlying neuromodulatory mechanisms, we investigated the roles of dopamine receptors in various aspects of courtship behavior in Drosophila. Here, we report that the D1 dopamine receptor dDA1 regulates courtship drive in naïve males. The wild‐type naïve males actively courted females regardless their appearance or mating status. On the contrary, the dDA1 mutant (dumb) males exhibited substantially reduced courtship toward less appealing females including decapitated, leg‐less and mated females. The dumb male's reduced courtship activity was due to delay in courtship initiation and prolonged intervals between courtship bouts. The dampened courtship drive of dumb males was rescued by reinstated dDA1 expression in the mushroom body α/β and γ neurons but not α/β or γ neurons alone, which is distinct from the previously characterized dDA1 functions in experience‐dependent courtship or other learning and memory processes. We also found that the dopamine receptors dDA1, DAMB and dD2R are dispensable for associative memory formation and short‐term memory of conditioned courtship, thus courtship motivation and associative courtship learning and memory are regulated by distinct neuromodulatory mechanisms. Taken together, our study narrows the gap in the knowledge of the mechanism that dopamine regulates male courtship behavior.     

Chemosensory cues allow male Tenebrio molitor beetles to assess the reproductive status of potential mates

Males of many insect species, including beetles, choose their mates according to their reproductive status. However, the ways in which male beetles evaluate female reproductive status have received little attention. We tested the existence of male mate choice in the mealworm beetle, Tenebrio molitor, by observing mating and courtship behaviour of males given simultaneous access to pairs of females differing in their reproductive status: (1) mature versus immature; (2) virgin versus previously mated; (3) familiar (mated with the experimental male) versus unfamiliar (mated with a different male). Males courted and mated preferentially with mature and virgin females. To determine whether chemical cues played a role in these discriminations, we exposed males to filter paper squares bearing chemical cues from different types of females: (1) virgin versus mated; (2) mature versus immature. Males were significantly more attracted to those squares bearing chemical cues from virgin and mature females, suggesting that males can assess female reproductive status on the basis of chemical cues alone.     

Effects of male age on the mating behavior of both sexes in the sorghum plant bug, Stenotus rubrovittatus (Hemiptera: Miridae)

In the sorghum plant bug Stenotus rubrovittatus (Matsumura) (Hemiptera: Miridae), mating behavior consists of male courtship and female mating receptivity. Previous studies have found that female age is correlated with ovary development and that mature females with developed ovaries are more receptive to male courtship. Thus, we examined whether male age affects the mating behavior of both sexes and male accessory gland development. Unmated males 0–9 days after emergence and 3-day-old virgin females receptive to male courtship were studied. Immediately after emergence, only 20 % of the males courted females (n = 25). At 3 days old, 68 % of the males courted females (n = 25), the most active age. In contrast, more than 75 % of the courted females were receptive to the male courtship regardless of male age. These results indicate that only male courtship behavior is affected by male age, although it is not enhanced in proportion to male age. Male accessory glands developed with male age. However, no clear relationship was detected between male courtship behavior and accessory gland development. In S. rubrovittatus, it is difficult to explain male courtship behavior solely from male age and accessory gland development.     

Competitive Mating Success and Attractiveness of Sterile and Fertile Males of Drosophila montana

The attractiveness and the mating success of fertile (normal and brownie, br) and sterile (rudimentary testis, rt) Drosophila montana males were studied in female-choice experiments (one female + two males). The normal males courted the sterile rt males nearly as much as they courted the females, while they courted other males less frequently. The females required a long courtship with the rt males and accepted them as their mating partner less often than normal males. The courtship behaviour of normal, br and rt males was recorded in single pair situations with a normal female. The courtships of the males of all types proceeded in a similar manner, but the successful courtships of the rt males included more licking and touching than those of the normal and br males. The licking and touching periods are probably the critical phases at which the females are able to detect differences in male fertility.     

The role of silk in courtship and chemical communication of the false widow spider, <Emphasis Type="Italic">Steatoda grossa</Emphasis> (Araneae: Theridiidae)

In spiders, sex pheromones are often associated with silk produced by females, and function in mate attraction, recognition, and evaluation. Silk-bound pheromones typically elicit courtship behaviour in web-building spiders. Here we (1) describe courtship interactions of Steatoda grossa males with virgin or mated females, and (2) show that silk and methanol extracts of silk produced by virgin females trigger courtship behaviour (silk production) by males, whereas silk of mated females does not. Our results indicate that (1) virgin females produce a silk-bound sex pheromone, (2) males discriminate between virgin and mated females based on silk cues, and (3) male silk likely functions in sexual communication.     

Sexual imprinting misguides species recognition in a facultative interspecific brood parasite

Sexual reproduction relies on the recognition of conspecifics for breeding. Most experiments in birds have implicated a critical role for early social learning in directing subsequent courtship behaviours and mating decisions. This classical view of avian sexual imprinting is challenged, however, by studies of megapodes and obligate brood parasites, species in which reliable recognition is achieved despite the lack of early experience with conspecifics. By rearing males with either conspecific or heterospecific brood mates, we experimentally tested the effect of early social experience on the association preferences and courtship behaviours of two sympatrically breeding ducks. We predicted that redheads (Aythya americana), which are facultative interspecific brood parasites, would show a diminished effect of early social environment on subsequent courtship preferences when compared with their host and congener, the canvasback (Aythya valisineria). Contrary to expectations, cross-fostered males of both species courted heterospecific females and preferred them in spatial association tests, whereas control males courted and associated with conspecific females. These results imply that ontogenetic constraints on species recognition may be a general impediment to the initial evolution of interspecific brood parasitism in birds. Under more natural conditions, a variety of mechanisms may mitigate or counteract the effects of early imprinting for redheads reared in canvasback broods.     

Bourgeois Males of the Peacock Blenny,Salaria pavo,Discriminate Female Mimics from Females?

In a Portuguese population of Salaria pavo, two types of reproductively active males occur: large bourgeois males that defend nests and have fully developed secondary sex characters (SSC) and small sneaker males that mimic the females’ morphology and behaviour to approach nests and parasitize fertilizations. These two alternative reproductive tactics are sequential, as sneakers develop into bourgeois males. We investigated whether bourgeois males were able to discriminate between sneakers and females of different sizes. In a laboratory experiment bourgeois males were sequentially presented with a female and a sneaker matched for size. Complementary field observations were conducted on the interactions between females and sneakers with bourgeois males. If bourgeois males discriminated females from sneakers, we predicted that they should direct more aggressive behaviours towards sneakers and more courtship acts towards females. In general, bourgeois males courted and attacked small females and sneakers equally. However, large sneakers were courted less and attacked more than large females. Larger sneakers, beginning to develop SSC, were attacked more and courted less by the bourgeois male than smaller sneakers, and larger females were attacked less and courted more than smaller females. These results strongly suggest that only small female‐mimicking males were able to deceive bourgeois males. In S. pavo, if the sneakers’ fertilization success correlates with their female‐mimicking ability, a fitness decrease with an increasing body size can be predicted.     

SEX DIFFERENCES IN MATE RECOGNITION AND CONSPECIFIC PREFERENCE IN SPECIES WITH MUTUAL MATE CHOICE

Sexual isolation is often assumed to arise because choosy females recognize and reject heterospecific males as mates. Yet in taxa in which both males and females are choosy, males might also recognize and reject heterospecific females. Here, we asked about the relative contribution of the sexes to the strong sexual isolation found in limnetic–benthic species pairs of threespine sticklebacks, which show mutual mate choice. We asked whether males and females of the two species recognize conspecifics and also prefer to mate with them. We found evidence for mate recognition by both sexes but only females prefer conspecifics. The nature of male courtship depended on which species of female they were courting, indicating that males recognized conspecific females and differentiated them from heterospecifics. However, males courted both species of females with equal vigor and changed courtship in a manner that would increase the chance of mating with heterospecifics. Females both recognized conspecifics and strongly preferred them. They responded very little to heterospecific male courtship and almost never mated with them. Therefore, males are likely to undermine sexual isolation, but females uphold it. Despite mutual mate choice and mate recognition in both sexes, females are primarily responsible for sexual isolation in these taxa.     

Courtship Behavior of Zaprionus indianus (Gupta) (Diptera: Drosophilidae) from Populations Colonizing South America

We describe for the first time the sexual behavior and the courtship song of males of the African fly Zaprionus indianus (Gupta), a recent invader of South America. The male courtship song is formed by monocyclic pulses and the courtship behavior is simple when compared to that of species of Drosophila. Two interpulse interval (IPI) distributions were observed: pre-mounting and mounting. No significant difference was observed between the pre-mounting IPIs of males that descended from three geographical populations from South America. We also observed the songs produced by females and the homosexual behavior exhibited by males. A sequence of bursts is produced by females as a refusal signal against males, while males emit a characteristic song that identifies sex genus, which differs from the courtship song. The short courtship and mating latencies recorded reveal vigorous males and receptive females, respectively.     

Courtship in two species of periodical cicadas, Magicicada septendecim and Magicicada cassini

Courtship behaviour of two species of periodical cicadas, Magicicada septendecim and M. cassini, was studied in the field during the 1970, 1973, and 1974 emergences of these insects. In areas where both species were courting there were differences in both male and female courtship patterns, both in acoustic and behavioural components. Experiments with models showed that male M. septendecim were more likely to court crude models of females than were M. cassini males. When females were ‘courted’ with models that could imitate some of male courtship, they were more receptive when the models' ‘songs’ were those of conspecific males. Acoustic differences between species are probably used by females in mate selection, maintaining species separation even in areas where the two species overlap in both space and time.     

Female secondary sexual coloration and sex recognition in the keeled earless lizard, Holbrookia propinqua

Relationships between male social behaviour and female reproductive coloration in the iguanid lizard Holbrookia propinqua were examined by introduction of tethered non-resident lizards into the territories of adult males. Introduced lizards were plainly coloured females, females having bright reproductive coloration, adult males, plain females painted to resemble brightly coloured females, bright females painted to mimic plain females, and males painted with the bright yellow and orange secondary sexual coloration of females. Resident males courted all unpainted females, despite being aggressively rejected by the brightly coloured ones. They also courted all but two females in each of the painted groups. All unaltered non-resident males were challenged, attacked or subjected to other aggressive behaviour by residents, but all non-resident males painted to resemble bright females were courted. This differential treatment is highly significant. It clearly demonstrates that the bright female pigmentation functions in sex recognition, identifying a female to males. Other stimuli, especially pheromonal and behavioural cues, may contribute to sex recognition. Because sex recognition alone seems insufficient to account for the evolution of bright female coloration in H. propinqua and several other iguanids, several proposed additional functions are discussed.     

Courtship and male discrimination between virgin and mated females in the orange tip butterfly Anthocharis cardamines

Recent evidence implies that male butterflies incur non-trivial costs in producing ejaculate, and that the number of ejaculates they can produce is limited. Therefore males should be expected to show some mate discrimination. In butterflies, the reproductive value of females, by necessity, decreases with age and, therefore, males should be expected to court young virgin females more intensively than old mated females. In the orange tip butterfly, Anthocharis cardamines, we show that males exhibit behaviour consonant with this hypothesis. They court unreceptive virgin females for approximately 60 s before giving up, whereas unreceptive mated females are courted for only about 3 s before the male departs. We also show that receptive virgin females usually detain courting males by performing an ‘elevated abdomen’ display for about 4 s before accepting the male, and that this display is identical in form to that used by mated females to reject courting males.     

The Payoff of Fighting in House Crickets: Motivational Asymmetry Increases Male Aggression and Mating Success

Motivational asymmetry caused by differences in subjective resource value is a key component of strategic models of aggression. We study the role of motivational asymmetry in determining differential aggression and mating success of male house crickets, Acheta domesticus. We also assess the extent to which mating differences associated with motivational asymmetry are due to direct male–male fighting vs. male–female interactions. We manipulated male motivation to compete for a mating opportunity by providing males with either no access or nightly access to females for 4 d prior to the experiment. As predicted, when males from each treatment had to compete for the female, those with lower prior access were more aggressive and mated more often. In contrast, when males from each treatment were paired individually with females, there was no significant difference in the frequencies with which they pursued, courted or mated with females. We also found no evidence for female choice based on motivational asymmetry; the rate of successful courtship did not differ between treatments. We conclude that prior mate encounter rate can generate motivational asymmetry, leading to differential mating success mediated by direct male–male aggression.     

Sexual cooperation and conflict in butterflies: a male-transferred anti-aphrodisiac reduces harassment of recently mated females

Sexual selection theory predicts that the different selection pressures on males and females result in sexual conflict. However, in some instances males and females share a common interest which could lead to sexual cooperation. In the pierid butterfly Pieris napi the male and the recently mated female share a common interest in reducing female harassment by other males soon after mating. Here we show that P. napi males transfer an anti-aphrodisiac to the female at mating, methyl-salicylate (MeS), which is a volatile substance which mated females emit when courted and which makes males quickly abandon them. A 13C-labelling experiment demonstrated that only males synthesize MeS. The effect of this antiaphrodisiac is so strong that most males will refrain from mating with virgin females to whom MeS has been artificially applied. In P. napi, males also transfer nutrients to females at mating. This increases female fecundity and longevity and so females benefit from remating. Hence, sexual cooperation gradually turns to conflict. Future research is required to reveal which sex controls the gradual decrease in the MeS titre which is necessary for allowing mated females to regain attractiveness and remate.     

Do Psyttalia concolor (Hymenoptera: Braconidae) males gain in mating competitiveness from being courted by other males while still young?

The role of male–male courtship in parasitic wasps is not well understood and nothing has been reported on the implication of learning in regard to homosexual behavior in hymenopteran parasitoids. In Psyttalia concolor (Hymenoptera: Braconidae), a synovigenic koinobiont larval–pupal endoparasitoid of many Diptera Tephritidae of economic importance, courtship and mating attempts are frequently displayed among males. Here we determine whether P. concolor males that are courted while still young by sexually mature males can compete better with other males when they court females. The results showed that P. concolor immature males do not appear to gain from receiving male courtship, but they develop a higher intensity (more wing fanning and shorter latency time) in the successive courtship of the females. The hypothesis that, under some conditions, such higher courtship intensities may increase the probability of gaining a mating advantage is discussed.     

Does sexual experience affect the strength of male mate choice for high‐quality females in Drosophila melanogaster?

Although females are traditionally thought of as the choosy sex, there is increasing evidence in many species that males will preferentially court or mate with certain females over others when given a choice. In the fruit fly, Drosophila melanogaster, males discriminate between potential mating partners based on a number of female traits, including species, mating history, age, and condition. Interestingly, many of these male preferences are affected by the male''s previous sexual experiences, such that males increase courtship toward types of females that they have previously mated with and decrease courtship toward types of females that have previously rejected them. D. melanogaster males also show courtship and mating preferences for larger females over smaller females, likely because larger females have higher fecundity. It is unknown, however, whether this preference shows behavioral plasticity based on the male''s sexual history as we see for other male preferences. Here, we manipulate the sexual experience of D. melanogaster males and test whether this manipulation has any effect on the strength of male mate choice for large females. We find that sexually inexperienced males have a robust courtship preference for large females that is unaffected by previous experience mating with, or being rejected by, females of differing sizes. Given that female body size is one of the most common targets of male mate choice across insect species, our experiments with D. melanogaster may provide insight into how these preferences develop and evolve.