Female mating behavior in the field cricket,Gryllus pennsylvanicus (Orthoptera: Gryllidae) at different operational sex ratios

The influence of operational sex ratio on the mating behavior of female field crickets,Gryllus pennsylvanicus, was investigated. Females were predicted to be more discriminating under conditions of high mate availability and show less selectivity when males were rare. Such selectivity was indicated in this study with the proportion of courtships leading to a mating changing with sex ratio. Females accepted almost 70% of all courtships at the female-biased sex ratio, but only about half of all courtships were successful at even or male-biased sex ratios. Females moved least at the female-biased sex ratio. There was also a trend for females to be guarded more under male-biased conditions. Female weight did not influence any of the behaviors examined.     

Interactions of the Males and Females of Three Sympatric Drosophila virilis-Group Species, D. montana, D. littoralis, and D. lummei, (Diptera: Drosophilidae) in Intra- and Interspecific Courtships in the Wild and in the Laboratory

Four species of the Drosophila virilis group, D. montana, D. littoralis, D. lummei, and D. ezoana, occur sympatrically in several locations in northern Europe. Courtship interactions between the flies of the three first-mentioned species were observed at malt baits in Kemi, northern Finland, to find out how the flies of different species recognize conspecific individuals and how interspecific courtships differ from intraspecific ones in the wild. Intraspecific courtships (including females of different reproductive stages) and interspecific courtships were also videotaped and analyzed in laboratory. In the wild the males courted both conspecific and allospecific females, even though the species varied in how much the males were attracted to females of different species. Interspecific courtships usually broke off when the male touched the female or when the male and/or the female vibrated his/her wings, producing acoustic cues. In the laboratory males courted conspecific females irrespective of the reproductive stage of the female, even though the courtships directed toward immature and fertilized females usually included only orienting and touching (no licking and singing). D. littoralis, and very rarely D. montana and D. lummei, males courted also allospecific females. In the few interspecific courtships between these three species, where the male proceeded to singing, females responded to male singing by vibrating their wings. This ended the courtship. It is suggested that both the chemical cues affecting female attractivity and the acoustic signals of males and females, which are produced by wing vibration, function in maintaining sexual isolation between these three species.     

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.     

Analysis of the Courtship Behavior of the Navel Orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), with a Commentary on Methods for the Analysis of Sequences of Behavioral Transitions

The courtship behavior of the navel orangeworm, Amyelois transitella, was examined in a wind tunnel. Sixty nine courtship sequences were analyzed and successful sequences divided into two categories: rapid courtship sequences, which involved few breaks in contact, short or no periods of male/female chasing and lasted <10 s between initial contact and mating; and prolonged courtship sequences, which involved many breaks in contact, extended periods of male/female chasing and lasted >10 s. Fifty six (81%) courtships were successful (50.7% rapid courtship and 30.4% prolonged courtship); the remaining 13 (18.8%) sequences were failed courtships. Of failed courtships, 9 (13.0%) were due to males losing contact with females during courtship chases and 4 (5.8%) due to females flying away immediately after male contact. Of all courtship sequences involving a break in contact during a chase, 38.5% resulted in an unsuccessful mating attempt. These findings contrast with previous studies of the courtship behavior of the navel orangeworm, potentially indicating that the type of bioassay used to study courtship may have a large effect on the behavioral sequences displayed. We evaluate several diagnostic techniques for the analysis of sequences of behavioral transitions.     

Reproductive interference between two serious pests,oriental fruit flies <Emphasis Type="Italic">Bactrocera carambolae</Emphasis> and <Emphasis Type="Italic">B. dorsalis</Emphasis> (Diptera: Tephritidae), with very wide but partially overlapping host ranges

Bactrocera carambolae and B. dorsalis (Diptera: Tephritidae) are extremely destructive pests of fruits and vegetables in the Asia-Pacific region. Earlier reports have described that B. carambolae and B. dorsalis, respectively, use mainly star fruit and mango, suggesting a certain level of host partitioning which can be ascribed neither to differences in larval food qualities nor host-specific parasitoid mortality. This study specifically examined reproductive interference (antagonistic sexual interaction) between B. carambolae and B. dorsalis as a potential factor strongly affecting their host partitioning. We observed mating behaviors, especially interspecific courtships and mating, by cohabiting the conspecific and heterospecific pairs together. Consequently, we quantified their effects on the reproductive success of females. Males of both species frequently courted their own females, but they also courted females of other species. Courtship refusal by females was not selective in males of either species. This incomplete discrimination of both sexes led to frequent occurrences of interspecific sexual interactions in both species, but only B. carambolae females showed reduced reproductive success. These results suggest that B. dorsalis, superior in reproductive interference, can occupy high-quality mango, whereas B. carambolae, inferior in reproductive interference, must use low-quality star fruit.     

Sperm Competition and Optimal Timing of Matings in Microcebus murinus

Female promiscuity is common in mammals and leads to sperm competition: the sperm of ≥2 males compete for ova. Scientists understand the possible role of optimal insemination periods for male reproductive success in many species as well as the impact of monopolization of receptive females. Information from experiments combined with detailed observations from the field that allow determining the relative impacts of the elements in the same species are rare. We studied sperm competition and the role of optimal insemination periods in gray mouse lemurs (Microcebus murinus), a small solitary nocturnal primate from Madagascar. We used controlled matings to identify the relative impact of both contest and scramble competition, which characterize their mating system, on paternity. Fifteen females mated with 3–6 males in quick succession. Our experiments revealed that the optimal insemination period is during early receptivity. Early but not first mating males are more likely to sire offspring. Comparison with our field data indicate that the timing of male monopolization efforts correspond with the optimal insemination period.     

中、西蜂间自然交尾干扰问题的观察

中西蜂蜂王性引诱信息素对中、西蜂雄蜂具有交互引诱交尾作用 ,且处女王婚飞和雄蜂出游时间一致。在中、西蜂 (主要指意蜂 )混养区 ,空中交尾竞争处于劣势的中蜂 ,受到西蜂严重干扰而繁殖受阻 ,是中蜂在平原等地区日益缩减多因素中的一个重要原因。蜂种间“自然交尾干扰”论点的提出 ,为保护中蜂资源、发展中蜂生产提供了科学依据。     

The role of mating preferences in shaping interspecific divergence in mating signals in vertebrates

Vertebrates represent one of the best-studied groups in terms of the role that mating preferences have played in the evolution of exaggerated secondary sexual characters and mating behaviours within species. Vertebrate species however, also exhibit enormous interspecific diversity in features of mating signals that has potentially led to reproductive isolation and speciation in many groups. The role that sexual selection has played in interspecific divergence in mating signals has been less fully explored. This review summarizes our current knowledge of how mating preferences within species have shaped interspecific divergence in mate recognition signals among the major vertebrate groups. Certain signal modalities appear to characterize mating signal diversification among different vertebrate taxa. Acoustic signals play an important role in mating decisions in anuran amphibians and birds. Here, different properties of the signal may convey information regarding individual, neighbor and species recognition. Mating preferences for particular features of the acoustic signal have led to interspecific divergence in calls and songs. Divergence in morphological traits such as colouration or ornamentation appears to be important in interspecific diversity in certain groups of fishes and birds. Pheromonal signals serve as the primary basis for species-specific mating cues in many salamander species, most mammals and even some fishes. The evolution of interspecific divergence in elaborate courtship displays may have played an important role in speciation of lizards, and particular groups of fishes, salamanders, birds and mammals. While much research has focused on the importance of mating preferences in shaping the evolution of these types of mating signals within species, the link between intraspecific preferences and interspecific divergence and speciation remains to be more fully tested. Future studies should focus on identifying how variation in mating preferences within a species shapes interspecific diversity in features of mating signals in order to better understand how sexual selection may have led to speciation in vertebrates.     

Frequency of interspecific mating in salamanders of the plethodontid genus Desmognathus: different experimental designs may yield different results

Heterosexual courtship trials were staged between dusky salamanders of two species ( Desmognathus fuscus and D. santeetlah ) from two allopatric populations in the southern Appalachian Mountains of eastern North America. Two experiments were conducted in order to test for effects of experimental design on estimates of the strength of sexual isolation between these species. In Experiment 1, frequencies of interspecific mating were determined when: (1) a male was presented with a conspecific and a heterotypic female successively; and (2) both types of females were presented simultaneously to a male. The frequency of interspecific mating by male D. fuscus was greatest when females were presented successively. The frequency of interspecific mating by male D. santeetlah was not influenced by method of female presentation. An index of sexual isolation of +0.29 was obtained between D. fuscus and D. santeetlah when females were presented successively, and of +0.63 when females were presented simultaneously. In Experiment 2, interspecific mating frequencies were determined in courtship arenas of two different sizes. No significant effect of arena size on frequency of interspecific mating was found for D. fuscus. In D. santeetlah , a trend towards greater mating frequency in small arenas was almost significant. These results suggest that interspecific mating frequencies (and thus estimates of the strength of sexual isolation between populations or species) may be sensitive to the experimental design employed. The validity and generality of this conclusion for other animals is an urgent, empirical issue.     

Aspects of mating, reproduction, and co-occurrence in three freshwater calanoid copepods

SUMMARY. 1. We examined the seasonal distributions and mating behaviour of Epischura lacustris, Diaptomus minutus and Diaptomus oregonensis to evaluate several proposed mechanisms for reproductive isolation. There was no divergence in onset of maturity or timing of breeding periods between sympatric diaptomid populations; size displacement between co-occurring diaptomid species did not result in concomitant reduction in mating frequency between heterospecific pairs in the laboratory.
2. Divergence in mating behaviour was supported by observations that, in conspecific mating experiments, males of both diaptomid species discriminated between females bearing ripened ovaries (gravid) and those that did not (non-gravid), and that, in heterospecific trials, males either mated indiscriminantly with all females, or engaged in mating very infrequently.
3. In mating experiments with Epischura. males did not discriminate between gravid and non-gravid females, but mated exclusively with virgins of a specific relative size. Divergence in timing of breeding seasons between Epischura and the two diaptomid species suggests that even if mating between genera is possible, it does not occur often in nature.
4. We discuss the adaptive significance of different reproductive strategies of these three copepods and speculate on mechanisms that allow for coexistence of the closely related taxa in nature.     

Mate Discrimination in Invasive Whitefly Species

Mate discrimination could be critical for invasive species that need to locate rare suitable mates and avoid costs associated with misdirected courtships to establish in new environments. Here, we tested whether individuals of two invasive whitefly species in the Bemisia tabaci species complex, commonly known as the B and Q biotypes, could discriminate between potential mates based on their species and sex. Behavioral observations showed that B females were more discriminating than Q females. Males of both species were able to discriminate between mates based on their species and sex, but in general B males discriminated more effectively than Q males. By incorporating these behavioral data into a conceptual model, we show that variation in mating behavior between females of different species was a more significant factor affecting mating than variation between males. These results indicate that mate discrimination could affect interactions between whitefly species and influence a species’ ability to colonize novel environments.     

Male courtship success and female discrimination in the mediterranean fruit fly (Diptera: Tephritidae)

The mating success of individually marked male Mediterranean fruit flies was monitored over 6 consecutive days in the laboratory. Mating frequency was nonrandom, as the numbers of both males that failed to mate and males that mated many (more than four) times were much higher than expected by chance alone. Differential mating success resulted in part from intermale variation in activity level. Male copulatory success was positively correlated with the numbers of courtships performed, attempted copulations (mountings), and females courted. Male-male aggression, on the other hand, and a negligible effect on male mating success. Female choice also appeared to influence male mating frequency. Fewer than 10% of courtships resulted in mating, and in most cases females terminated courtship by simply moving away from the male. Females that did mate generally selected males having higher copulatory scores than previously rejected males.     

Field observations of the sexual behaviour of the smooth newt, Triturus vulgaris vulgaris (Amphibia: Salamandridae)

This study reports observations of smooth newts, Triturus vulgaris vulgaris , breeding in a pond in southern England. Efforts were made to collect data on the timing of oviposition and on sexual behaviour during the breeding seasons of 1985 and 1986. Despite some between-year differences in the timing of certain events, the qualitative pattern of reproduction was similar in both years. Courtship interactions were seen most frequently during a relatively short period of time before females began laying their eggs, which occurred in a highly synchronized manner. It seems likely that the probability of any one courtship encounter resulting in spermatophore transfer was low. Males competed for mates by chasing females and by interfering with one another's courtships, but no overt aggression was seen. Females appeared to find such male-male interactions 'aversive'. Scramble competition between males was most intense when the majority of females in the population were laying their eggs and were unresponsive to courtship. The mating system of the smooth newt most closely resembles a lek in which the intensity of sexual selection among males varies as a function of female availability.     

A comparison of the developmental and reproductive biology of two soybean pod borers, Etiella spp. in Indonesia

Experiments conducted in West Java, Indonesia investigated the developmental biology and reproductive behavior of two sympatric soybean pod borers, Etiella zinckenella Treitschke and E. hobsoni Butler (Lepidoptera: Pyralidae). It was determined that: (1) significant interspecific differences occurred between the egg, larval, pupal and total egg-to-adult developmental periods of laboratory raised E. zinckenella and E. hobsoni; (2) the pre-pupal and total egg-to-adult development periods of female E. zinckenella were significantly shorter than for males; (3) the longevity of virgin female E. zinckenella was significantly longer than that of virgin males, or virgin male and female E. hobsoni; (4) interspecific differences occurred in the female: male sex-ratios of laboratory raised adults; (5) peak mating for both species occurred on the second night after eclosion; (6) interspecific differences occurred in the temporal distribution of calling and mating behaviors; (7) repeated mating was observed for both species at a very low frequency; (8) interspecific mating did not occur; (9) female E. zinckenella were significantly more fecund than E. hobsoni; (10) the duration in copulo of E. zinckenella was significantly longer than that of E. hobsoni; and (11) wingtraps baited with virgin females caught only conspecific males, and reduced numbers of males were captured in traps simultaneously baited with virgin females of both species. This study demonstrates distinct biological differences and reproductive isolation between the two Etiella spp.     

Sexually antagonistic coevolution in a mating system: combining experimental and comparative approaches to address evolutionary processes

We combined experimental and comparative techniques to study the evolution of mating behaviors within in a clade of 15 water striders (Gerris spp.). Superfluous multiple mating is costly to females in this group, and consequently there is overt conflict between the sexes over mating. Two alternative hypotheses that could generate interspecific variation in mating behaviors are tested: interspecific variation in optimal female mating rate versus sexually antagonistic coevolution of persistence and resistance traits. These potentially coevolving traits include male grasping and female antigrasping structures that further the interests of one sex over the other during premating struggles. Both processes are known to play a role in observed behavioral variation within species. We used two large sets of experiments to quantify behavioral differences among species, as well as their response to an environmentally (sex-ratio) induced change in optimal female mating rate. Our analysis revealed a large degree of continuous interspecific variation in all 20 quantified behavioral variables. Nevertheless, species shared the same set of behaviors, and each responded in a qualitatively similar fashion to sex-ratio alterations. A remarkably large proportion (> 50%) of all interspecific variation in the magnitude of behaviors, including their response to sex ratio, could be captured by a single multivariate axis. These data suggest tight coevolution of behaviors within a shared mating system. The pattern of correlated evolution was best accounted for by antagonistic coevolution in the relative abilities of each sex to control the outcome of premating struggles. In species where males have a relative advantage, mating activity is high, and the opposite is found in species where females have gained a relative advantage. Our analyses also suggested that evolution has been unconstrained by history, with no consistent evolutionary tendency toward or away from male or female relative advantage.     

The Foraging Costs of Mating Effort in Male Chimpanzees (Pan troglodytes schweinfurthii)

Costs of mating effort can affect the reproductive strategies and lifetime fitness of male primates, but interspecific and interindividual variation in the magnitude and distribution of costs is poorly understood. Male costs have primarily been recognized in seasonally breeding species that experience concentrated periods of mating competition. Here, we examine foraging costs associated with male mating effort in chimpanzees (Pan troglodytes schweinfurthii), a polygynandrous species, in which mating opportunities occur intermittently throughout the year. To quantify male feeding, aggression, and mating, we conducted focal follows on 12 males in a wild community (Kanyawara, Kibale National Park, Uganda) for 11 mo. Males fed less on days when high-value mating opportunities (estrous parous females) were available than on days without any mating opportunities. Reductions in feeding time were related to increased rates of aggression and copulation, indicating that the proximate cause of changes in male foraging was mating effort. Surprisingly, however, there was no relationship between dominance rank and the extent to which feeding time was reduced. High costs of mating effort may reduce the degree of reproductive skew and limit the use of possessive tactics in chimpanzees. We suggest that male bonding in chimpanzees may be favored not only for its benefits but because intragroup competition is so costly. Our results complement the available data on mammals, and primates in particular, by showing that mating effort can have measurable foraging costs even in species, in which breeding is aseasonal and only moderately skewed.     

A comparative study of interspecies mating of Phratora vulgatissima and P. vitellinae using behavioural tests and molecular markers

The leaf beetle genus Phratora L. (Coleoptera: Chrysomelidae) has been used to study the ecology of host plant chemicals in herbivore preference, and the evolution of host use in chemical defence. Phratora vulgatissima and P. vitellinae are sympatric species distributed widely across Europe. Their trophic niches are largely separate due to strong differences in their host feeding preference, but they have occasionally been recorded together, feeding on Salix burjatica‘Germany’ and, only in early spring, on Populus trichocarpa (Torr & A. Gray) ‘Trichobel’. Using behavioural tests and recently developed species‐specific microsatellite markers, the intra‐ and interspecific mating of both beetle species were investigated. The microsatellite markers provided evidence that interspecific mating occurred under field conditions. Interspecific mating also took place under laboratory conditions, but less frequently than mating within species. Females of both species laid fewer eggs, and fewer eggs per clutch, when isolated with an interspecific male than with a conspecific male. Female P. vulgatissima were polyandrous, as microsatellite markers showed that their larvae were the progeny of both P. vulgatissima males that had been isolated with a single female. While only 0.55% of eggs laid in interspecific pair combinations hatched, microsatellite markers provided evidence of hybridisation between beetle species; however, these larvae died within a week when reared in a Petri dish containing ‘Germany’ and P. trichocarpa leaves. It can therefore be inferred that reproductive isolation is complete. The results are discussed in relation to species integrity and the implications for diverse mixtures of short‐rotation coppice willow plantations.     

Significance of kin relations and individual preferences in the social behaviour of Cebus apella

Captive tufted capuchins (Cebus apella) formed a group characterized by greater affiliative behaviour within matrilines. Affiliation within the matriline is dependent upon social intimacy during infancy with matriline members. Courtship and mating are not identically distributed: subordinate and subadult males participate in a larger proportion of matings than of courtships. In all these aspects of social behaviour, variability across individuals contributes to the complex dynamics of the social group.     

Prezygotic barriers to hybridization in marine broadcast spawners: reproductive timing and mating system variation

Sympatric assemblages of congeners with incomplete reproductive barriers offer the opportunity to study the roles that ecological and non-ecological factors play in reproductive isolation. While interspecific asynchrony in gamete release and gametic incompatibility are known prezygotic barriers to hybridization, the role of mating system variation has been emphasized in plants. Reproductive isolation between the sibling brown algal species Fucus spiralis, Fucus guiryi (selfing hermaphrodite) and Fucus vesiculosus (dioecious) was studied because they form hybrids in parapatry in the rocky intertidal zone, maintain species integrity over a broad geographic range, and have contrasting mating systems. We compared reproductive synchrony (spawning overlap) between the three species at several temporal scales (yearly/seasonal, semilunar/tidal, and hourly during single tides). Interspecific patterns of egg release were coincident at seasonal (single peak in spring to early summer) to semilunar timescales. Synthesis of available data indicated that spawning is controlled by semidiurnal tidal and daily light-dark cues, and not directly by semilunar cycles. Importantly, interspecific shifts in timing detected at the hourly scale during single tides were consistent with a partial ecological prezygotic hybridization barrier. The species displayed patterns of gamete release consistent with a power law distribution, indicating a high degree of reproductive synchrony, while the hypothesis of weaker selective constraints for synchrony in selfing versus outcrossing species was supported by observed spawning in hermaphrodites over a broader range of tidal phase than in outcrossers. Synchronous gamete release is critical to the success of external fertilization, while high-energy intertidal environments may offer only limited windows of reproductive opportunity. Within these windows, however, subtle variations in reproductive timing have evolved with the potential to form ecological barriers to hybridization.     

Sexual selection for symmetrical male medflies (Diptera: Tephritidae) confirmed in the field

The role of fluctuating asymmetry as an indicator of fitness to females in mate choice remains controversial. Previous studies indicated that male medflies with symmetrical supra-fronto-orbital (SFO) bristles achieve relatively high mating success under laboratory conditions. Here we present data from field cage studies of wild collected medflies in Guatemala and Crete, which reveal the same association between fluctuating asymmetry in SFO bristle length and mating success as that seen in the laboratory. The experiments in Crete included males that were missing one or both of their bristles. A comparison of mating success between the three groups indicated that the mere presence of bristles did not exert a major influence. Analysis of attempted courtships suggests that the association between male mating success and FA in bristle length appears to be generated as a result of females being more likely to enter into courtships with symmetrical males, rather than through a rejection of asymmetrical males during or after it. This raises the possibility that the primary stimulus that makes a symmetrical male attractive is acting at too great a distance to depend on symmetry itself. Alternatives might include superior pheromone emissions or the occupation of a prime location within the lek.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 81 , 347–355.