Courtship Frequency Research Articles

A red flag: an experimental analysis of the function of pink colouration in males of Calopteryx haemorrhoidalis asturica (Odonata: Calopterygidae).

Males display phenotypic characteristics that may be associated with their quality, allowing non-random mating and post-copulatory female choice. In the damselfly Calopteryx haemorrhoidalis asturica, males have a conspicuous pink colouration in the underside of abdominal segments 8-10, which they exhibit during pre- and post-copulatory courtship. We hypothesized that this colouration functions to increase male mating success and/or to elicit females to oviposit. We estimated mating and oviposition success of 27 males, and on the following day, treated males had their segments 8-10 painted black and control males the seventh segment. We recorded the number of male-male fights and courtships, whether the courtship ended in copulation, and whether the female remained in the territory and laid eggs. Our results indicate that the mating success of male C. h. asturica was not significantly affected by the removal of the pink colouration of the abdominal tip, but this colouration clearly affected their success in enticing females to oviposit. Courtship frequency, fat content and muscle mass were positively correlated to male mating rate, and the number of aggressive encounters was negatively correlated. Our study yields experimental evidence for the function of pink colouration of male C. h. asturica, in the context of post-copulatory sexual selection.

Investment Trade-Off between Mating Behavior and Tonic Immobility in the Sweetpotato Weevil Cylas formicarius (Coleoptera: Brentidae).

Numerous studies have confirmed that the trade-off between anti-predator behavior and mating behavior occurs in certain insect species. This suggests that insects invest more in anti-predator behavior, and fewer resources or time can be used in mating behavior. However, few studies focus on tonic immobility, an important anti-predator behavior in nature, and different stages in mating behavior. Tonic immobility (TI) is considered to be an important anti-predator behavior. Herein, we investigated the relationship between TI and mating behavior in the sweetpotato weevil (SPW), Cylas formicarius. As the first step, we artificially selected SPWs for the longer duration of TI (L-strain) and the shorter duration of TI (S-strain). The effect of courtship and copulation on the duration of TI in two artificial selection strains was tested. Furthermore, we compared the frequency and duration of two mating behaviors in four kinds of pairs (LF×LM, LF×SM, SF×LM, and SF×SM: LM-L-strain male; SM-S-strain male; LF-L-strain female; SF-S-strain female). Finally, we tested insemination success in four kinds of pairs (male and female SPWs from the L-strain or the S-strain). The courtship and copulation significantly reduced the duration of TI. Pairs with males from the L-strain showed lower frequency and longer duration of courtship than pairs with males from the S-strain. Similarly, males from L-strain pairs showed a longer period of copulation than pairs with males from the S-strain. However, there is no significant difference in the frequency of copulation and the success of insemination. These results support that there was a significant trade-off between TI and courtship as well as copulation in the SPW.

Male mating success evolves in response to increased levels of male-male competition.

Male-biased operational sex ratios can increase male-male competition and can potentially select for both increased pre- and postcopulatory male success. In the present study, using populations of Drosophila melanogaster evolved under male-biased (M) or female-biased (F) sex ratios, we asked whether (a) male mating success can evolve, (b) males are better at mating females that they have coevolved with, (c) males mating success is affected by female mating status, and (d) male mating success is correlated with their courtship effort. We directly competed M and F males for mating with (a) virgin ancestral (common) females, (b) virgin females from the M and F populations, and (c) singly mated females from the M and F populations. We also assessed the courtship frequency of the males when paired with mated M or F females. Our results show that M males, evolving under an increased level of male-male competition, have higher mating success than F males irrespective of the female evolutionary history. However, the difference in mating success is more pronounced if the females had mated before. M males also have a higher courtship frequency than F males, but we did not find any correlation between mating success and courtship frequency.

Effects of cadmium stress at different concentrations on the reproductive behaviors of beet armyworm Spodoptera exigua (Hübner)

Insects are exposed to cadmium stress since cadmium pollution has increasingly become a serious global environmental issue. However, until now few studies have paid attention to the effect of heavy metals on insect reproductive behaviors. In our study, the courtship behaviors, mating behaviors and fecundity of beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae) exposed to different concentrations of cadmium in artificial diets at larval stage were studied. The results showed that cadmium stress changed the courtship rhythm by significantly advancing or delaying the courtship starting time. Low dose of cadmium (0.2 mg/kg) increased the courtship frequency in the first two scotophases, but in the fourth phase, the two cadmium treatments reduced the frequency. The total courtship duration was significantly shortened in the first six scotophases except high dose of cadmium treatment (51.2 mg/kg) in the sixth dark phase. Paired adults did not mate after the seventh scotophase under low cadmium exposure, while high cadmium stress made the paired adults just copulate in the first four scotophases. The daily mating rate and total mating rate decreased with the increase in cadmium concentration. The number of eggs of low cadmium treatment was higher than that of control, but the difference was not significant; the number of eggs in high cadmium treatment was lower than that of control and low cadmium treatment. Our results indicate that cadmium exposure can disrupt the courtship rhythm for females and has negative influences on copulation behavior and high cadmium stress can reduce fecundity. Hence, the insect population increase will be affected by heavy metal pollution. Our study will provide scientific reference for environmental risk assessment of heavy metal pollution.

Dynamic Courtship Signals and Mate Preferences in Sepia plangon.

Communication in cuttlefish includes rapid changes in skin coloration and texture, body posture and movements, and potentially polarized signals. The dynamic displays are fundamental for mate choice and agonistic behavior. We analyzed the reproductive behavior of the mourning cuttlefish Sepia plangon in the laboratory. Mate preference was analyzed via choice assays (n = 33) under three sex ratios, 1 male (M): 1 female (F), 2M:1F, and 1M:2F. We evaluated the effect of modifying polarized light from the arms stripes and ambient light with polarized and unpolarized barriers between the cuttlefish. Additionally, to assess whether a particular trait was a determinant for mating, we used 3D printed cuttlefish dummies. The dummies had different sets of visual signals: two sizes (60 or 90 mm mantle length), raised or dropped arms, high or low contrast body coloration, and polarized or unpolarized filters to simulate the arms stripes. Frequency and duration (s) of courtship displays, mating, and agonistic behaviors were analyzed with GLM and ANOVAs. The behaviors, body patterns, and their components were integrated into an ethogram to describe the reproductive behavior of S. plangon. We identified 18 body patterns, 57 body patterns components, and three reproductive behaviors (mating, courtship, and mate guarding). Only sex ratio had a significant effect on courtship frequency, and the male courtship success rate was 80%. Five small (ML < 80 mm) males showed the dual-lateral display to access mates while avoiding fights with large males; this behavior is characteristic of male “sneaker” cuttlefish. Winner males showed up to 17 body patterns and 33 components, whereas loser males only showed 12 patterns and 24 components. We identified 32 combinations of body patterns and components that tended to occur in a specific order and were relevant for mating success in males. Cuttlefish were visually aware of the 3D-printed dummies; however, they did not start mating or agonistic behavior toward the dummies. Our findings suggest that in S. plangon, the dynamic courtship displays with specific sequences of visual signals, and the sex ratio are critical for mate choice and mating success.

Me against who? Male guppies adjust mating behaviour according to their rival’s presence and attractiveness

AbstractSexual selection theory suggests that males need to constantly reappraise their mating decisions to take account of the presence and the phenotypes of their rivals. Here we examine this expectation by asking: (i) If the presence of a rival influences male mating behaviour; (ii) How important is the attractiveness of the rival (absolute attractiveness) in shaping male behaviour; and (iii) How does a male's attractiveness in comparison to his rival (relative attractiveness) influence a male's mating decisions. Using the Trinidadian guppy, a species in which female mate choice (based on males’ attractive traits) plays an important role in male mating outcomes, we recorded the frequency of courtship displays and unsolicited attempts by focal males. First, we quantified focal male mating behaviour with and without a rival. Since the probability of a successful mating is, on average, halved by the presence of a rival, we predicted that under competition the focal male would invest more in less costly mating tactic—unsolicited attempts. Second, we examined how the rival's standard length and area of orange coloration mediated focal male mating behaviour. We found that rival presence influenced how focal males responded to females in terms of both mating tactics. However, the rival attractiveness elicited changes only in male courtship display. Focal males increased courtship display rate if his rival was small or if possessed large amounts of orange, regardless of considering rival absolute or relative attractiveness. Our results show that males invest in the costlier mating tactic when there is no rival or in the presence of a smaller rival. Interestingly, they make a similar investment in the presence of an attractive orange rival. Overall, this study highlights the importance of fine‐grained male decisions in mating encounters and shows that mating tactics are differentially shaped by multiple competition risk cues.

Differential effects of androgens, estrogens and socio-sexual context on sexual behaviors in the castrated male goat

The behavioral and endocrine activation of sexual behaviors exhibited by male goats, especially self-enurination (SE), is poorly understood. In the first experiment, to assess the influence of socio-sexual context on SE in bucks, the effects of distance from does, the presence of estrous versus non-estrous does and the presence of another buck on SE and courtship frequencies of intact male goats (bucks; n = 12) were tested using a unique behavior test apparatus. For experiments 2 and 3, to test the relative contributions of sex steroid hormones and socio-sexual context on SE, castrated male goats (wethers; n = 20) were randomly divided into five groups and injected for seven weeks with one of the following: 25 mg testosterone propionate (T), 25 mg dihydrotestosterone propionate (DHT), 100 μg estradiol benzoate (E), 100 μg E and 25 mg DHT (E + DHT), or oil (CON). The effects of these treatments on frequency of SE and courtship were assessed using the behavior test apparatus (social scenarios) adapted from the findings in experiment 1. In one scenario, a wether could observe (from 4.6 m) a buck and estrous female (doe) together in a wire mesh holding pen. In a different scenario, the wether could observe (from the same distance) a buck that could only court the estrous doe through a wire mesh barrier. Finally, to observe the effects of steroid treatment on mounting and ejaculation frequencies, in addition to SE and courtship, each wether was placed in a pen with an estrous doe for 10 min. After a five-week, treatment-washout period, wethers were randomly assigned to different treatment groups and retested. In experiment 1, bucks that were distanced from females displayed more SEs than those with fence-line contact, while those with fence-line contact displayed more bouts of courtship (P < 0.05). In experiments 2 and 3, courtship frequencies displayed in all three scenarios were greater than CON only for groups exposed to estrogen directly or via aromatization (T, E + DHT, E; P < 0.05). Frequencies of SE exhibited during behavior tests in which the wether was watching were greater than CON only for androgen-treated groups (T, E + DHT, DHT; P < 0.05). In contrast, when the wether was free to interact with the female, only the DHT group displayed SE at a higher frequency than CON (P < 0.05). Treatment had no effect on mount frequencies in this test scenario, however ejaculation frequencies were highest for T and E + DHT (P < 0.05). These studies suggest that the courtship behaviors of the male goat are estrogen-dependent. However, SE appears to be activated by androgens. It was also demonstrated that social context contributes as much to behavior expression as steroid treatment, as in social scenario 2 some sexual behaviors were displayed in similar frequencies across groups, despite differing sex steroid treatments.

Adverse Effects of Triclosan and Binary Mixtures with 17β-Estradiol on Testicular Development and Reproduction in Japanese Medaka (Oryzias latipes) at Environmentally Relevant Concentrations

Considering triclosan (TCS) is ubiquitous in surface water and wild fish at relatively high concentrations, its adverse effects on gonadal development and reproduction were evaluated. After exposure for 100 days after hatching, the lowest observable effective concentration (LOEC) of TCS to significantly induce gonadal intersex in male Japanese medaka (Oryzias latipes) was 117.9 ng/L. Courtship frequency and hatching rates in male medaka were significantly inhibited, and the LOECs of TCS to impact courtship frequency and hatching rates were 117.9 and 17.2 ng/L, respectively. Male medaka were also exposed to binary mixtures of 2.2 ng/L 17β-estradiol (βE2) with 2.3 ng/L TCS and 2.4 ng/L βE2 with 117.9 ng/L TCS, and a more severe intersex induction and depressed mating behavior compared to those seen after exposure to only βE2 or TCS were observed. The adverse effects of TCS and binary mixtures with βE2 on testicular development and reproduction in fish at environmentally relevant concentrations are demonstra...

Effect of the age of ganders on reproductive behavior and fertility in a competitive mating structure

Abstract This paper presents the study on determination of gander-goose mating activity in relation to age and the position of gander in social hierarchic rank. Moreover, levels of fertility (F) and testosterone (T) in different gander age groups were analyzed. The study was carried out on one-year-old geese (N = 64) and one- or two-year-old ganders (N = 16; 1♂: 4♀). Observations of mating activity (MA) were conducted during the 3-h period of the daylight (10 h), 2-3 times per week (102 h/ group/34 days). The recording was done with a digital recorder connected to cameras. Agonistic behavioral interactions between ganders were noted to determine a social hierarchic rank. The MA was described by frequency of courtship displays, copulation attempts, successful copulation (SCop), and interaction disrupted (DMI) with agonistic behavior. Fertility was evaluated after the artificial incubation (1×/week) in a commercial hatchery. The frequency of SCop, DMI, and T concentration were higher (P&lt;0.05) for two- than one-year-old ganders. Moreover, F was higher by 11.2% for group of geese kept with two-year-old ganders. There was an effect of the gander’s rank in social hierarchy on the frequency of MA. For dominant ganders, frequency of courtship displays (1.0/times/3 h) and copulation attempts (0.8/times/3 h) were lower (P&lt;0.05), but SCop (1.5/times/3 h) was higher (P&lt;0.05) than for subordinate ones. Thus, in domestic goose flocks reproductive success was associated with age of ganders used in competitive mating system. This is probably a multifactor effect of interaction between sexual/social experience, T-dependent mating motivation, and efficiency of MA. It is recommended to keep one-year-old geese with older ganders (after sexual reactivation) for optimal fertility results with sex ratio adjusted to gander-gander antagonistic interaction dynamic.

Role of intratumoral expression of thymidylatesynthase in patients with pancreatic cancer on adjuvant gemcitabine and tegafur regimen

We measured frequency and duration of different courtship activities of male guppies (especially the simoid display) at different temperatures, by means of direct observations, and video-recorder. We observed that the animals undergoing long-term temperature adaptation show nearly an independence of courtship frequency to the influence of temperature within the range of 20° to 30°C. After transfer to higher or lower temperatures, the frequency of the sigmoid behaviour was diminished. Afterwords, temperature compensation took place. The duration of the sigmoid display was temperature dependent. We concluded that certain fin movements during the sigmoid display were directly temperature dependent, and that lowering the temperature acted as a stressor on sexual motivation. After adaptation to the new temperature (which lasted 4–5 days) the fish were able to show a complete cycle of 5.5 dorsal fin movements per sigmoid display in temperatures between 20° and 30° C.

Effects of the social environment during adolescence on the development of social behaviour, hormones and morphology in male zebra finches (Taeniopygia guttata)

BackgroundIndividual differences in behaviour are widespread in the animal kingdom and often influenced by the size or composition of the social group during early development. In many vertebrates the effects of social interactions early in life on adult behaviour are mediated by changes in maturation and physiology. Specifically, increases in androgens and glucocorticoids in response to social stimulation seem to play a prominent role in shaping behaviour during development. In addition to the prenatal and early postnatal phase, adolescence has more recently been identified as an important period during which adult behaviour and physiology are shaped by the social environment, which so far has been studied mostly in mammals. We raised zebra finches (Taeniopygia guttata) under three environmental conditions differing in social complexity during adolescence - juvenile pairs, juvenile groups, and mixed-age groups - and studied males’ behavioural, endocrine, and morphological maturation, and later their adult behaviour.ResultsAs expected, group-housed males exhibited higher frequencies of social interactions. Group housing also enhanced song during adolescence, plumage development, and the frequency and intensity of adult courtship and aggression. Some traits, however, were affected more in juvenile groups and others in mixed-age groups. Furthermore, a testosterone peak during late adolescence was suppressed in groups with adults. In contrast, corticosterone concentrations did not differ between rearing environments. Unexpectedly, adult courtship in a test situation was lowest in pair-reared males and aggression depended upon the treatment of the opponent with highest rates shown by group-reared males towards pair-reared males. This contrasts with previous findings, possibly due to differences in photoperiod and the acoustic environment.ConclusionOur results support the idea that effects of the adolescent social environment on adult behaviour in vertebrates are mediated by changes in social interactions affecting behavioural and morphological maturation. We found no evidence that long-lasting differences in behaviour reflect testosterone or corticosterone levels during adolescence, although differences between juvenile and mixed-age groups suggest that testosterone and song behaviour during late adolescence may be associated.

Drosophila melanogaster males evolve increased courtship as a correlated response to larval crowding

A competitive resource-based environment such as larval crowding is an important stress factor in the life history of holometabolous insects such as Drosophila melanogaster and can have major consequences for adult fitness through its direct effects on body size. We investigated precopulatory sexual behaviour, which is an important subset of adult fitness, using D. melanogaster populations adapted to larval crowding for 100+ generations. We found that selected males evolved significantly higher courtship frequency than their ancestral controls. While we found a negative correlation between larval density and adult courtship frequency using low, moderate and high larval rearing densities, we also found that supplementation of live yeast, which is an important dietary component in their life cycle, caused a significant rise in courtship frequency. We further dissected out the male and female behavioural components that contribute to overall courtship activity by factorially combining selected and ancestral male and female types, reared in both low and high larval densities, and found that courtship frequency of selected males was higher with selected females than with control females. We also quantified the mating frequency, a crude measure for mating success, and found that increased courtship frequency in selected populations did not lead to increased mating success. From the results of this and a previous study, we conclude that precopulatory sexual activity in these populations is not traded for life span.

An integrative multidisciplinary approach to understanding cryptic divergence in Brazilian species of theAnastrepha fraterculuscomplex (Diptera: Tephritidae)

An integrative multidisciplinary approach was used to delimit boundaries among cryptic species within the Anastrepha fraterculus complex in Brazil. Sexual compatibility, courtship and sexual acoustic behaviour, female morphometric variability, variation for the mitochondrial gene COI, and the presence of Wolbachia were compared among A. fraterculus populations from the Southern (Vacaria, Pelotas, Bento Goncalves, Sao Joaquim) and Southeastern (Piracicaba) regions of Brazil. Our results suggest full mating compatibility among A. fraterculus populations from the Southern region and partial pre-zygotic reproductive isolation of these populations when compared with the population from the Southeastern region. A. fraterculus populations from both regions differed in the frequency of courtship displays and aspects of the calling phase and mounting acoustic signal. Morphometric analysis showed differences between Southern region and Southeastern region samples. All populations analyzed were infected with Wolbachia. The trees generated from the COI sequencing data are broadly congruent with the behavioural and morphometric data with the exception of one Southern population. The likely mechanisms by which A. fraterculus populations might have diverged are discussed in detail based on behavioural, morphometric, molecular genetics, and biogeographical studies.

Sexual Receptivity and Mating Behavior ofDiaeretiella rapae(Hymenoptera: Aphidiidae)

Sexual receptivity and mating behavior of the cabbage aphid parasitoid Diaeretiella rapae McIntosh were studied under laboratory conditions. When male and female D. rapae were paired females, males actively courted females, while females kept themselves away from males and displayed grooming behavior. Males became sexually active immediately after emergence and made mating attempts, whereas females took longer to become receptive to mating. Virgin males quickly detected female presence, resulting in a significant increase in the frequency of male courtship. Males encountered females within 5 min of pairing, and 90% of the males displayed courtship behavior by fanning their wings and chasing the female for mating. Before successful mating, males tended to approach females more often than females approached males. The time between pairing and mating in newly emerged females was longer than in 1-d-old females. The overall mating success in D. rapae was about 70%, and successful mating was largely dependent on females’ decision to mate. Unlike females, males remained sexually receptive after mating.

Testing the adaptive significance of sex-specific mating tactics in collared lizards (Crotaphytus collaris)

We tested whether territorial defence is adaptive in male collared lizards by examining the extent to which territory owners monopolize females. We also tested whether females benefit by mating with multiple males using alternative tactics when local sex ratios varied. Surprisingly, neither the number of offspring that males sired, nor the number of females that males mated with varied as a consequence of highly variable local sex ratios. Moreover, both the number of offspring sired and the number of female mates were independent of male social status. Courtship frequency was under positive directional sexual selection for mating success for territorial males. None of the phenotypic traits that we examined were targets of sexual selection in nonterritorial males. Although offspring survivorship decreased with the degree of multiple mating, females mated multiply with similar numbers of territorial and nonterritorial males during all three seasons. Females did not obtain material or genetic benefits that balanced the apparent offspring survival cost imposed by mating with multiple males. Instead, females appeared to be ‘making the best of a bad job’, perhaps because the abundance of hiding places used by subordinate males makes it difficult for females to avoid male harassment. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, ••, ••‐••.

Involvement of different mesotocin (oxytocin homologue) populations in sexual and aggressive behaviours of the brown anole.

The oxytocin (OT) family of neuropeptides are known to modulate social behaviours and anxiety in mammals and birds. We investigated cell numbers and neural activity, assessed as Fos induction, within magnocellular and parvocellular populations of neurons producing the OT homologue mesotocin (MT, Ile(8)-oxytocin). This was conducted within the male brown anole lizard, Anolis sagrei, following agonistic or courtship encounters with a conspecific. Both neurons colocalizing and not colocalizing corticotropin-releasing factor (CRF) were examined. Parvocellular neurons of the paraventricular nucleus exhibited a positive correlation between courtship frequency and Fos colocalization, regardless of whether they produce just MT or MT + CRF. Magnocellular populations showed only trends towards positive relationships with courtship and no cell populations showed aggression-related Fos induction. These findings are novel because they demonstrate the involvement of MT neurons in male social behaviour, especially in reptiles for whom the involvement of MT in social behaviour was previously unknown.

Resistance of morphological and behavioral sexual traits of the palmate newt (Lissotriton helveticus) to bacterial lipopolysaccharide treatment

Infectious diseases are considered as a significant factor in the global decline of amphibians. In some vertebrates, the assessment of the individual sexual traits can be useful for assessment of their health status and immunocompetence due to trade-off between them and investment in the immune system. Our aim here was to determine whether the trade-off between the expression of sexual morphological and behavioral traits and investment in the immune system is present in an urodele, the Palmate newt (Lissotriton helveticus). The groups of males were injected by solutions of proinflammatory agent, lipopolysaccharide (LPS) from Escherichia coli serotype O:55:B5, at dosages toxic to vertebrates (2 and 10 mg/kg of body mass) or by saline solution only (control groups). They were subsequently measured for variations in body condition and expression of both morphological (filament length, hind-foot-web, crest) and behavioral (courtship frequency) sexual traits. The injection of either LPS or saline solution did not cause any adverse effect on health in any male of all groups. No significant differences in any of the sexual traits were observed between two groups of males injected by LPS and control groups of males indicating the absence of a trade-off between immune response and expression of sexual traits. Our result suggests that measuring morphological or behavioral sexual traits may not be a useful method for monitoring emergence of infectious diseases in the palmate newt.

异色瓢虫不同光环境下的交配行为

光照条件是影响昆虫生长发育及生理行为变化的重要环境因子之一.以重要的捕食性天敌异色瓢虫为研究对象,借助动物行为自动观察系统对其在不同光照强度、光周期和光波长下的交配行为及繁殖力进行了分析研究.结果显示:(1)异色瓢虫的各交配行为和繁殖能力在有光和黑暗处理间具有显著差异;(2)异色瓢虫的求偶行为不受光照强度变化的影响,而交配持续时间及交配间隔时间在高光照强度下均显著短于低光照强度.尽管异色瓢虫的累积产卵量在不同光照强度间未见显著性差异,但是其幼虫孵化率随光照强度的增强显著降低;(3)异色瓢虫在光照时间较长的条件下表现出较高的交配求偶欲望,交配持续时间及交配间隔时间随光照时间的延长而缩短,其累积产卵量和幼虫孵化率均随光照时间的延长而显著增加;(4)不同环境颜色对异色瓢虫的求偶行为没有显著影响,但是其交配持续时间及交配间隔时间随照射光波长的增加而显著降低,雌虫的累积产卵量和幼虫孵化率均在黄色(575 nm)和绿色(510 nm)条件下最高,且显著大于其它处理.结果表明异色瓢虫的交配受光照条件影响极为显著,为进一步深入研究异色瓢虫环境适应性及提升其在生物防治中大规模饲养中的扩繁效率提供了重要的理论依据.;As one of the most important environmental factors, the light condition may influence the performance of development and physiological behavior in insect. The variation of light environment could induced many negative phenomenon, such as diapause, courtship inhibition and lower food consume. The intensive research on the light influences may promote the efficiency in massive rearing and population manipulation of the natural enemy. We focused on the key predacious natural enemy coccinellid<em> Harmonia axyridi</em>s, which has been utilized as efficacious biological control agent to suppress various arthropod herbivores at present study to reveal the influences of light intensity, photoperiod and wavelength to the copulatory behavior and fertility by using an animal behavior automatic observation monitoring system. Totally 3 illuminative factors and 17 treatments, included light intensity (600 lx、900 lx、1200 lx、1500 lx、1800 lx及2100 lx), photoperiod (light: dark=0:24、6:18、12:12、18:6 and 24:0), and light wavelength (violet (395 nm), blue (480 nm), green (510 nm), yellow (75 nm), orange (610 nm) and red (685 nm)) were set as different environment conditions respectively. By reviewing the video records, the results showed that: (1) There are significant differences of each copulatory behavior and fertility between light and dark conditions of <em>H. axyridis</em>; (2) the courtship behavior was not influenced by light intensity but showed significant shorter in high intensity (in 1800 lx and 2100 lx) of copulation and interval duration that darker conditions (600 lx and 900 lx). We also did not find some significant influences by the variation of light intensity on pre-duration of mating. The offspring hatchability decreased with the increasing of light intensity although we did not find some differences of accumulation fecundity; (3) Long photoperiod and full day-light environment may enhance the courtship frequency. The ladybird couples showed significantly shorter pre-duration of mating in full-dark and short photoperiod conditions. The copulation and interval duration decreased with the prolonging of photoperiod but showed increasing in accumulated fecundity and offspring hatchability; (4) The light wavelength did not show significant influences to the courtship of male. Similarly, all couples in all colored conditions represented no different in pre-duration of mating. The mating duration and intervals duration decreased with the increasing of light wavelength. Both accumulative fecundity and larvae hatchability were showed significant highest in yellow (575 nm) and green (510 nm) conditions than rest colored treatments. The results of present study indicated the significant influences of light variation to the mating process in <em>H. axyridis</em> and it provided theoretical values for our continuous work on the environmental fitness and enhancement of plasticity adaption in biological control processes of <em>H. axyridis</em>. It indicated high illuminative intensity, long day-light photoperiod and in moderate colored (light wavelength) conditions could benefit the predacious ladybird <em>H. axyridis</em> in both massive rearing or in inoculative releasing via augmentative biological control application in greenhouse or other agroecosystem. Our study have provided the empirical witness of the value in light manipulation in insect conservation and augmentation system.

Evolution of mate-harm, longevity and behaviour in male fruit flies subjected to different levels of interlocus conflict

BackgroundInterlocus conflict predicts (a) evolution of traits, beneficial to males but detrimental to females and (b) evolution of aging and life-span under the influence of the cost of bearing these traits. However, there are very few empirical investigations shedding light on these predictions. Those that do address these issues, mostly reported response of male reproductive traits or the lack of it and do not address the life-history consequence of such evolution. Here, we test both the above mentioned predictions using experimental evolution on replicate populations of Drosophila melanogaster. We present responses observed after >45 generations of altered levels of interlocus conflict (generated by varying the operational sex ratio).ResultsMales from the male biased (high conflict, M-regime) regime evolved higher spontaneous locomotor activity and courtship frequency. Females exposed to these males were found to have higher mortality rate. Males from the female biased regime (low conflict, F-regime) did not evolve altered courtship frequency and activity. However, progeny production of females continuously exposed to F-males was significantly higher than the progeny production of females exposed to M-males indicating that the F-males are relatively benign towards their mates. We found that males from male biased regime lived shorter compared to males from the female biased regime.ConclusionF-males (evolving under lower levels of sexual conflict) evolved decreased mate harming ability indicating the cost of maintenance of the suit of traits that cause mate-harm. The M-males (evolving under higher levels sexual conflict) caused higher female mortality indicating that they had evolved increased mate harming ability, possibly as a by product of increased reproduction related activity. There was a correlated evolution of life-history of the M and F-males. M-regime males lived shorter compared to the males from F-regime, possibly due to the cost of investing more in reproductive traits. In combination, these results suggest that male reproductive traits and life-history traits can evolve in response to the altered levels of interlocus sexual conflict.

Nitrate affects courting and breathing but not escape performance in adult newts

The increasing spread of contaminants in the environment affects the behaviour of individuals and can be predicted to modify population characteristics in the long run. It is thus crucial to investigate the effect of contaminants on fitness-related traits. Nitrate is a major pollutant that disrupts oxygen fixation and steroid metabolism and is expected to affect adult behaviour. In water breeding newts, reduced oxygen supply may increase predation risk by elevating surfacing rate and limiting the capacity to evade a predator. It may also reduce mating success by altering sexual behaviour. We assessed the effect of nitrate on fitness-related behavioural traits in male palmate newts Lissotriton helveticus. We measured courtship and breathing during sexual encounters and escape performance in exposed and non-exposed adults. Unexpectedly, exposed males courted females more often than control males. Body size and breathing rate were also positively related in control males but not in exposed males. Results only partially support the hypothesis of oxygen transfer disruption. Alternatively, exposed males seem to compensate their reduced olfactory attractiveness by decreasing surfacing and increasing courtship frequency. Surprisingly, nitrate did not affect escape performance possibly because anaerobic respiration supplies most of energy during unsustainable activity. Nitrate exposure altered time budget in exposed adults and shifted behavioural trade-offs between competing activities like breathing and courting. Ecological and evolutionary consequences, driven by changes on predation risk or sexual selection regimes, can be expected. This study calls for more attention on amphibian adult stages and the evolutionary response of populations in contaminated environments.