Hunting and Nesting Phenology Influence Gobbling of Wild Turkeys

Wild turkeys (Meleagris gallopavo) use a polygynous mating system whereby males engage in multiple courtship behaviors, including vocalizations (gobbling) to attract females and compete with other males for breeding opportunities. Males must balance the risk of courtship behaviors with the reproductive potential of each courtship behavior. Male turkeys are primarily hunted during the reproductive period, so the associated risk of courtship behaviors is increased. Many state agencies attempt to set hunting season frameworks that maximize hunter satisfaction by allowing hunting when gobbling activity is greatest and most females are theoretically incubating nests, but the relationship between gobbling activity and nesting phenology is unclear. We used autonomous recording units and global positioning system transmitters to monitor gobbling activity by male turkeys and reproductive behaviors of female turkeys in the Piedmont region of Georgia, USA. We used 13,177 gobbles, behavioral data from 82 females during the reproductive season, and daily estimates of harvest of males by hunters to examine relationships between daily gobbling activity, cumulative removal of males, and reproductive behaviors (laying, incubating) of females during 2017–2018. We observed a weak negative relationship between daily gobbling activity and gobbling activity the following day. As the reproductive season progressed, gobbling activity decreased. As the proportion of females engaged in laying or incubating behaviors increased, expected daily gobbling activity increased. Conversely, we observed that hunting and removal of males had a negative effect on daily gobbling activity, and this effect was disproportionately greater than the positive effect of female reproductive behaviors. Our findings suggest that hunting and removal of males are important determinants of gobbling activity, and that corresponding reductions in gobbling activity may have mediating effects on the mating system of wild turkeys. © 2019 The Wildlife Society.     

Male courtship preferences demonstrate discrimination against allopatric colour morphs in a cichlid fish

Whether premating isolation is achieved by male‐specific, female‐specific or sex‐independent assortative preferences often depends on the underlying evolutionary processes. Here we test mate preferences of males presented with females of different allopatric colour variants of the cichlid fish Tropheus sp., a Lake Tanganyika endemic with rich geographical colour pattern variation, in which the strength of sexual isolation varies between populations. We conducted two‐way mate choice experiments to compare behaviour of males of a red‐bodied morph (population Moliro) towards females from their own population with behaviour towards females from four allopatric populations at different stages of phylogenetic and phenotypic divergence. Males courted same‐population females significantly more intensely than females of other populations, and reduced their heteromorphic courtship efforts both with increasing genetic and increasing phenotypic distinctness of the females. In particular, females of a closely related red‐bodied population received significantly more courtship than either genetically distinct, similarly coloured females (‘Kirschfleck’ morph) or genetically related, differently coloured females (‘yellow‐blotch’ morph), both of which were courted similarly. Genetically and phenotypically distinct females (Tropheus polli) were not courted at all. Consistent with previous female‐choice experiments, female courtship activity also decreased with increasing genetic distance from the males’ population. Given successful experimental and natural introgression between colour morphs and the pervasive allopatry of related variants, we consider it unlikely that assortative preferences of both sexes were driven by direct selection during periods of secondary contact or, in turn, drove colour pattern differentiation in allopatry. Rather, we suggest that sexual isolation evolved as by‐product of allopatric divergence.     

Male and Female Soldier Beetles Relax Choice for Mate Quality Across Daily Courtship Periods

Mutual mate choice occurs when members of each sex will reject some potential mates in efforts to encounter better prospects later. The decision to reject may represent the interaction between mate preferences, mate availability, and temporal constraints. Theory predicts that mutual mate choice will favor relaxed choosiness as mate availability and time for courtship decline. We explored mutual mate choice in the soldier beetle, Chauliognathus pennsylvanicus (Cantharidae), where courtship consisted of males attempting to secure evasive females. We employed field observations, laboratory experiments, and stochastic simulations to investigate the decline in choosiness over the daily courtship period, during which individuals can mate at most once. We found that reproductive success of males and females increases with mate size and mating frequency. Females biased copulations toward larger mates by attempting to evade suitors, while males biased copulations by releasing the smaller females they capture. However, late in the day males and females may increase reproductive success by accepting rather than rejecting lower quality mates to maintain high mating rates. Stochastic simulations indicated that reproductive success, the product of mating frequency and mean mate size, was maximized in males and females by incrementally reducing mate standards across daily courtship periods. In the field, large males who rejected small females early in the daily courtship period rarely did so later. Large females used less effective evasive maneuvers later in the courtship period, resulting in copulations with progressively smaller males. These results support models of mutual mate choice that predict that individuals of high quality will maximize reproductive success by relaxing choosiness as the courtship period wanes.     

Female goats use courtship display as an honest indicator of male quality

Due to the differential cost of reproduction in promiscuous species, like domesticated goat(s) (Capra hircus), it is expected that females should mate with higher quality males, while males should mate with a greater number of females. Females may use conspicuous secondary sexual characteristics of males such as courtship display to distinguish among high and low quality males. Testosterone (T) controls a large suite of secondary sexual characteristics and variation in T concentrations may account of differences in courtship rates. Two studies were conducted to examine the relationship between T concentrations and courtship rate and its role in mammalian female mate choice. Experiment 1 utilized bucks (intact males) and Experiment 2 utilized T-replaced wethers (castrated pre-pubertally). During the first year of Experiment 2, T-replaced wethers received either vehicle control (CON), 25 mg or 100 mg testosterone propionate (TP). During the second year of Experiment 2, T-replaced wethers were treated with either 5 mg, 15 mg or 25 mg TP. For all experiments, mean courtship rates and circulating T concentrations were measured, as well as female preference for males displaying different courtship frequencies. T concentrations and courtship rate were positively correlated for bucks and estrous females preferred high courting bucks. Males receiving 25 mg and 100 mg TP courted females at a similar rate, but both were significantly higher than courtship rates of the CON wethers. Courtship rates of the 25 mg, 15 mg and 5 mg TP-treated males were all significantly different. Females did not show a preference between the 100 mg or 25 mg TP-treated wethers, however both were preferred in comparison to the CON wethers. Females did not show preference between the 25 mg or 15 mg TP-treated wethers, however both were preferred in comparison to the 5 mg TP-treated wethers. Taken together, these studies suggest that courtship rate is T-dependent. Further, females can use courtship rate to distinguish among males.     

Offspring viability benefits but no apparent costs of mating with high quality males

Traditional models of sexual selection posit that male courtship signals evolve as indicators of underlying male genetic quality. An alternative hypothesis is that sexual conflict over mating generates antagonistic coevolution between male courtship persistence and female resistance. In the scarabaeine dung beetle Onthophagus taurus, females are more likely to mate with males that have high courtship rates. Here, we examine the effects of exposing females to males with either high or low courtship rates on female lifetime productivity and offspring viability. Females exposed to males with high courtship rates mated more often and produced offspring with greater egg-adult viability. Female productivity and lifespan were unaffected by exposure to males with high courtship rates. The data are consistent with models of sexual selection based on indirect genetic benefits, and provide little evidence for sexual conflict in this system.     

Uninformative polymorphisms bias genome scans for signatures of selection

Background

A female preference for intense sexual visual signals is widespread in animals. Although the preferences for a signal per se and for the intensity of the signal were often regarded to have the identical origin, no study has demonstrated if this is true. It was suggested that the female fiddler crabs prefer males with courtship structures because of direct benefit to escape predation. Here we tested if female preference for both components (i.e. presence and size) of the courtship structure in Uca lactea is from the sensory bias to escape predation. If both components have the identical origin, females should show the same response to different-sized courtship structures regardless of predation risk.

Results

First, we observed responses of mate-searching female U. lactea to courting males with full-sized, half-sized and no semidomes which were experimentally manipulated. Females had a directional preference for males with bigger semidomes within normal variation. Thereafter, we tested the effect of predation risk on the female bias in the non-courtship context. When threatened by an avian mock predator, females preferentially approached burrows with full-sized semidomes regardless of reproductive cycles (i.e. reproductive periods and non-reproductive periods). When the predator cue was absent, however, females preferred burrows with semidomes without discriminating structure size during reproductive periods but did not show any bias during non-reproductive periods.

Conclusions

Results indicate that selection for the size of courtship structures in U. lactea may have an origin in the function to reduce predation risk, but that the preference for males with structures may have evolved by female choice, independent of predation pressure.     

The influence of increasing density on body weight, kid production, home range and winter grouping in roe deer (Capreolus capreolus)

In this paper, we present an analysis of the consequences of increasing density, over a period of nine years (from 1980 to 1988), on the dynamics, and the social and spatial organization of a forest roe deer population. Hunting of this population ceased in 1979, after which time there was a significant increase in population density, with three distinct periods easily identified: 1980–1983 (PI), immediately following cessation of hunting, characterized by a relatively low density (d = 5–7 animals/100 ha), 1984–1985 (P2), a period of rapid population growth, and 1986–88 (P3), a period of high density (d = 25 animals/100 ha). During PI, the population was irregularly distributed across the study site but, as density increased, distribution became more uniform, and eventually covered the whole of the available area. Home-range structure and shape remained unchanged from PI to P3 but, by the end of the study, average range size was 30% lower for adult males only, and the period prior to subadult males, but not females, establishing a permanent home range had increased from c. 18 month to c. 30 months. Winter group size increased overall from PI to P3 with, for the first time, observations of groups of five or more animals and a reduction in the frequency of observations of solitary females, with does more commonly observed in pairs or small groups; the proportion of solitary males, however, did not change between the two periods. The mean number of kids per female declined significantly from PI to P3 and body weights recorded for juveniles of both sexes and for adult males were also significantly lower during the period of relatively high density (P3). However, for adult females, absolutely no body weight change was observed. This divergence between the sexes of response to increasing density is discussed.     

Female Sexual Interference in the Smooth Newt,Triturus vulgaris vulgaris

Competition between unmated females for males was observed in the smooth newt, T. vulgaris, during the early part of the breeding season. Females interfered at the spermatophore-transfer stage of courtship, preventing a rival female from picking up the sperm mass. Interference often resulted in the rival female abandoning the courtship encounter. In many of the encounters (70%), the interfering female was inseminated. However, interference between females was not observed after the commencement of ovulation. By contrast, the incidence of sexual interference between males was low during the preovulatory period and increased significantly post-ovulation. Sexual interference in newts and salamanders has previously only been observed between males. During the greater part of the breeding season, when females are ovipositing, eggs are the limiting resource and males compete for access to receptive females. However, this study suggests that early in the breeding season, prior to commencement of ovulation, the limiting resource may temporarily be sperm, due to the physiological constraint of spermatophore production. This may lead to female competition for mates.     

Male displays and female preferences in the courtship of a gregarious cricket

The courtship of males of the gregarious cricket Amphiacusta maya involves a variety of signals. The quantitative aspects of both successful and unsuccessful courtship sequences were examined to determine whether certain aspects of male displays were correlated with female mating preferences regardless of which male performed them. Although variability among males was high for most courtship components measured, I found no evidence of female choice with respect to the courtship variables studied. About 35% of the duration of each male courtship sequence is devoted to chirping, but there were no differences in either the likelihood of copulation or the latency to copulation between normal males and experimentally silenced males. The possibility that intrinsic differences in male quality explained the variability in courtship duration was examined with a two-way analysis of variance. The variance in courtship duration was attributable to variance among females, not to variance among males. Thus the courtship behaviour of male A. maya is variable enough to allow females to exert stabilizing or disruptive selection on displays, but there is no evidence that females use the available information.     

Courtship Solicitation by Females of the Barred Sulphur Butterfly (<Emphasis Type="Italic">Eurema daira</Emphasis>) (Lepidoptera: Pieridae)

Virgin females of the subtropical pierid butterfly Eurema daira were observed to actively solicit male courtship. The resulting interactions involved both aggressive contact with male individuals and elaborate female posturing. Cage-based trials showed that there was a direct relationship between the frequency of courtship solicitation attempts and female age. Virgin females under 3 days old showed little or no interest in initiating courtship. By contrast, 23.2 percent of the virgin females over three days old actively solicited available males with peak solicitation behavior exhibited from five day old individuals.     

Male Courtship Pheromones Affect Female Behaviour in the Swordtail Characin (Corynopoma riisei)

Pheromones constitute an important cue used by both males and females during courtship. Here, we investigate the effect of male pheromones on female behaviour in the swordtail characin (Corynopoma riisei), a species of fish where males have a caudal pheromone gland which has been suggested to affect female behaviour during courtship. We subjected female C. riisei to male courtship pheromones and investigated the effect on both female behaviour and brain serotonergic activity levels compared to a control group. While no difference in serotonergic activity was found, the pheromone‐treated females showed lower stress levels compared to the control group. Furthermore, pheromone‐treated females increased locomotor activity over time, while a decrease in locomotor activity was observed in the control group. These results suggest that the male courtship pheromones may serve to reduce female stress and increase female activity, possibly to aid males in gaining access to females and facilitating sperm transfer.     

Evolutionary significance of courtship conditioning in Drosophila melanogaster

Males of the fly Drosophila melanogaster initially court mated, unreceptive females but later develop an avoidance reaction against them and even become temporally unresponsive to virgin females. This conditioned inhibition has been described as an associative process, the conditioned stimulus being a mixture of pheromones on the female's cuticle. To assess the evolutionary significance of courtship conditioning we recorded and analysed the male's behaviour during the conditioning process. The time traces of individual males were marked by an abrupt behavioural change. The time he spent courting suddenly decreased, and the frequency of ‘turn-away’ events at the same time sharply increased. Thus, the gradual decline of courtship observed as a group average does not reflect a slow change in motivation of the individual male but rather the interindividual differences of an active, experience-guided all-or-none decision to stop courting and to avoid the female. Three recently collected D. melanogaster strains were each maintained under two distinct mating conditions. Males were kept together with females for either ca. 2 weeks or 18 h. After 21 generations males of the two regimes differed markedly in their behaviour towards mated females. With long interaction periods between males and females, selection favoured courtship conditioning, while with short periods no such selection was observed. Slowly recovering receptivity of mated females may be needed for the maintenance of courtship conditioning. Courtship conditioning in D. melanogaster appears to be a fitness-relevant behaviour adapted to high-density populations with females mating a second time.     

韭菜迟眼蕈蚊成虫行为活动昼夜节律

【目的】本研究旨在明确韭菜迟眼蕈蚊Bradysia cellarum成虫行为活动的昼夜节律,为其室内饲养、行为学研究和研发精准、高效的监测与防控新技术提供依据。【方法】室内系统观察记录了韭菜迟眼蕈蚊成虫羽化盛期求偶、交配、产卵、移动与静息等行为的昼夜节律,分析了其特定行为的时间分配特征。【结果】韭菜迟眼蕈蚊成虫的运动行为和静息行为白天和黑夜均有发生,夜间的繁殖行为(求偶、交配和产卵)频次高于白天的,各时间点的移动、静息和繁殖行为频次占比间均具有显著性差异。韭菜迟眼蕈蚊雌雄成虫的求偶节律相同,一天中求偶有两次高峰,分别出现在3:00和7:00。韭菜迟眼蕈蚊雌雄成虫的交配节律与雌成虫的产卵节律相似,雄成虫移动行为频次占比的峰值时刻均出现在3:00时,雌成虫移动行为频次占比的峰值时刻则出现在19:00时。雌雄成虫静息行为的频次占比均无明显昼夜节律高峰。在日时间分配上,雌、雄成虫以静息行为的时间占比最多,分别为89.53%和89.90%;求偶行为的时间占比最少,分别为0.56%和0.89%。雌雄成虫各行为的日时间占比差异不显著。【结论】韭菜迟眼蕈蚊成虫的求偶、交配、产卵、移动和静息行为具有明显...     

Short‐Term Nutritional Limitation Affects Mating Behaviour and Reproductive Output in Dwarf Spiders

Mating decisions can vary considerably depending on individual experience, mate availability and nutritional status. Here, we applied short‐term dietary restrictions to adult female spiders that were well fed during the juvenile stage in an effort to understand whether and how brief periods of food shortage can influence male and female mating decisions and mating behaviour. To assess whether responses vary between closely related species, we conducted the same experiment on the dwarf spiders Oedothorax retusus and O. apicatus. During courtship and mating, males of both species offer secretion to females from glandular tissue in their prosoma. Females were subject to food shortage over a period of 3 wks (‘low‐diet’ treatment, LD) or fed regularly (‘high‐diet’ treatment, HD). We compared courtship probability, mating probability/behaviour, and reproductive output between dietary groups and species. In both Oedothorax species, females in the LD treatment were less likely to mate and more aggressive towards males. Furthermore, LD females produced egg sacs that were significantly lighter than were those of the HD females. Effects of food deprivation on copulation duration, gustatory behaviour and oviposition latency differed between species. Our study shows that short periods of dietary restriction during the adult stage can strongly affect mating behaviour and reproductive output with differences between closely related species.     

Female Choice and the Consistency of Courtship Feeding in Black-horned Tree Crickets Oecanthus nigricornis Walker (Orthoptera: Gryllidae: Oecanthinae)

Courtship feeding in insects is often strongly correlated with insemination duration and therefore provides a potential postcopulatory episode of sexual selection. We tested whether courtship feeding and other courtship traits in the black-horned tree cricket Oecanthus nigricornis showed sufficient consistency potentially to respond to sexual selection by testing whether they differed significantly among males. Duration of courtship feeding differed among males when measured repeatedly and this caused significant differences in the duration of spermatophore attachment, a trait that determines the maximum duration of insemination and thus has important fitness consequences in crickets. We also partitioned variance in courtship behaviour between the sexes to test whether differences in courtship behaviour were attributable primarily to males, females or both sexes. Duration of spermatophore attachment was controlled by females and therefore represents a mechanism of female mate choice. Significant variation in duration of spermatophore attachment was associated with differences between individuals of both sexes. Differences among males indicate that females agree in their preference of certain males whereas differences among females indicate that females differ in their receptivity to postcopulatory courtship and insemination. The fact that differences among males in duration of spermatophore attachment were due to significant differences solely in the period of courtship feeding indicates that postcopulatory female choice was mediated through courtship feeding. Whether males manipulate female choices by allocating more or fewer resources requires further testing, but we found that males court some females more vigorously than others after females dismount. The number of previous mates had opposite effects on the duration of courtship feeding for the sexes, decreasing it for males but increasing it for females, and we discuss the possible causes of these results.     

Do Male Veiled Chameleons,Chamaeleo calyptratus,Adjust their Courtship Displays in Response to Female Reproductive Status?

Variation in male courtship behavior may be due to inherent differences among males or may arise from males adjusting their courtship displays according to female responsiveness. Female veiled chameleons, Chamaeleo calyptratus , exhibit two distinctive suites of body coloration and behavior patterns that vary according to receptive and non-receptive stages of their reproductive cycle. We presented male chameleons with both receptive and non-receptive females, and recorded differences in their mating frequency, courtship intensity and courtship behavior patterns. As expected, males were more likely to court and attempt mating with receptive females. Although fewer males courted non-receptive females, their courtship displays were significantly longer than those directed towards receptive females. Males also adjusted the contents of their displays according to female reproductive condition. Certain behavior patterns were unique to courtship displays directed towards each class of females. Males exhibited the behavior pattern `head roll' only when paired with receptive females, and `chin rub' was displayed only during courtship of non-receptive females. We hypothesize that these differences in male courtship frequency, intensity and content reflect differences in female reproductive value. Although males may benefit from mating with both receptive and non-receptive females, the costs associated with courtship may depend on female responsiveness. Thus, males adjust their courtship tactics accordingly.     

SIZE,SYMMETRY, AND SEXUAL SELECTION IN THE HOUSEFLY,MUSCA DOMESTICA

Relationships between measures of body size, asymmetry, courtship effort, and mating success were investigated in the housefly, Musca domestica (Diptera: Muscidae). A previous study indicated that both male and female flies with low fluctuating asymmetry enjoyed enhanced mating success. The aim of our investigations was to determine whether the greater success of symmetrical males is due to variation in male mating effort or to female choice and whether males exhibited mate choice. However, our study found directional rather than fluctuating asymmetry with both male and female flies having, on average, longer left wings than right. Also, asymmetry was not related to mating success in either sex. Rather, both males and females appeared to exhibit choice on the basis of the size of potential mates, with males preferring females with long bodies and females preferring heavy males. Possible benefits from choice of large mates are discussed. The initial mating strikes (in which the male leaps onto the back of the female) did not appear to be targeted according to female morphology, and their frequency did not vary according to male morphology. This indicates that mate choice by both sexes according to size probably occurs during the later stages of courtship, when the flies are in intimate contact. Possible reasons for the absence of choice according to asymmetry are discussed.     

Sex before or after blood feeding: Mating activities of Aedes aegypti males under conditions of different densities and female blood feeding opportunities

Blood feeding and mating are critical behaviors that regulate both mosquito population maintenance and disease transmission. However, our understanding of mosquito mating systems remains incomplete. One of the most critical issues is a lack of understanding regarding how and where males and females encounter one another. This study was performed to investigate changes in key mating behaviors of Ae. aegypti relative to female blood feeding opportunities, taking into account male density. We compared courtship latency and copulation activity between single and pooled males in a range of assays performed in the presence or absence of a blood source and after blood feeding. The time taken by grouped males to initiate courtship in the presence of a host was much shorter than that in single males. There was no significant difference in courtship latency between pooled and single males in the absence of a blood source or after blood feeding. At low male density, the presence of the host and blood meal ingestion provided better conditions for copulation. At high male density, however, copulation activity was decreased after blood feeding, but remained high regardless of the presence or absence of the host. In addition to providing insight into the mating ecology of Aedes aegypti, this study indicated that the presence of a blood source influences how males encounter and copulate with females. The observation that copulation activity decreases after blood feeding when males are numerous provides new avenues for improving mass release programs of sterile mosquitoes.     

Effect of Drosophila melanogaster Female Size on Male Mating Success

In this study, we examined the influence of female size on mating success in Drosophila melanogaster. The results that were obtained from experiments performed in mating chambers allowed us to confirm the results of previous studies, demonstrating higher mating success of larger D. melanogaster males, and to conclude that female size also affects mating success, either when considering a single male or two competing males. We observed that the advantage for larger males depends on their size relative to that of the female, demonstrating a previously unknown role for female size in mating behavior studies. This effect of female size on mating success depends on various factors: males take longer to initiate courtship toward larger females, large females receive more wing vibrations from males prior to mating, and large females tend to keep moving for longer periods during male courtship. The importance of this finding is discussed in the context of recent reports on sexual conflict in D. melanogaster, in which males were observed to depress fitness in females as a result of intercourse.     

An experimental investigation of patch use by female monarch butterflies,Danaus plexippus (L.)

Monarch butterflies, which breed throughout the year in southeastern Queensland, Australia, were studied in four dense milkweed patches during the winter months (June-August) 1983. The percentage of marked females recaptured was measured in each of four 15-day sampling periods. In patches where males were experimentally removed, female recapture rate decreased compared with patches which had the same density reduction but no change in sex ratio. There was a significant correlation between female recapture rate and the proportion of males in samples, but female recapture rate was not correlated with population density, the number of males, the number of females or the proportion of young butterflies in the samples. We propose that females assessed patch quality by the sex ratios, and left a patch sooner if encounter rate with males was low. Since males provide a nutrient ‘reward’ during copulation, they may be a limited resource for females during winter. An alternative interpretation, that females left a patch sooner when female density was higher, was not supported as strongly by the data.