Comb Size Research Articles

The female red jungle fowl (Gallus gallus gallus) reproductive investment stimulated by male attractiveness

Abstract. Lelono A, Riedstra B, Groothuis T. 2024. The female red jungle fowl (Gallus gallus gallus) reproductive investment stimulated by male attractiveness. Biodiversitas 25: 2931-2936. To maximize their capacity for reproduction, mothers are expected to modify their investment in offspring based on the quality of their mates. A recent study showed that females in female-care only species do so by investing more in egg mass when mated with attractive males rather than in other reproductive traits. In our study, we investigated how red jungle fowl (Gallus gallus gallus) mothers invest in clutch production based on the size of the male's comb, a trait signaling attractiveness. We randomly paired 14 females with 14 males of either large or small combs and monitored their egg laying, clutch completion, and brood rearing. Following the initial clutch, we exchanged male partners and permitted females to establish up second generation. We found that females who were partnered with males who had bigger combs laid down their eggs earlier after pairing compared to those paired with males with smaller combs. However, there were no variations in egg mass or clutch size that we could find. Furthermore, the size of the male's comb influenced the growth and body condition of female chicks, with those sired by males with larger combs being heavier and in better condition at twenty-four weeks old. These data support the premise of the positive Differential Allocation (DA) hypothesis, where maternal investment varies with mate quality, rather than the negative DA, where females more investment in offspring from lower quality mates.

Comb size, shape complexity and laterality of laying hens reared in environments varying in resource choice

The comb is an ornament involved in signalling condition in domestic fowl. We hypothesised that comb size, comb shape complexity (i.e., rugosity, the comb perimeter jaggedness), and comb laterality of laying hens would be influenced by the degree of environmental enrichment experienced during juvenile development in the form of resource choice. We conducted a 2 × 2 factorial crossover experiment with pullets reared in pens containing four perches of equal length and four litter areas of equal size. Pullets were exposed to a single choice vs multiple choices of perch and litter types (i.e., all the same vs all different) during Weeks 1–4 (Period 1) and/or Weeks 5–15 (Period 2) of rearing (n = 4 pens/treatment combination) prior to transfer to standard adult laying pens for Weeks 16–27 (Period 3). In Week 27, combs were photographed, and comb laterality (hanging on left or right side) was noted. Using a custom-made image analysis programme, we captured comb area (mm2), perimeter length (mm), and rugosity ((perimeter length – horizontal length) / horizontal length) from comb photographs of 6–7 randomly selected hens/pen. We predicted that hens reared in the multi-choice environment during Periods 1 and 2 would have larger, more complex, and left-side-biased combs than those in the other treatment groups, reflecting lower allostatic load. The predicted comb side bias was based on a possible bias in head posture/movements associated with greater right eye/ear use and left-brain hemispheric dominance. Contrary to our predictions, we detected an overall right-side bias in comb laterality, and no associations between resource choice treatment in Period 1 or Period 2 and comb area, perimeter length, rugosity, or laterality of the adult hens. Thus, variation in allostatic load resulting from the rearing treatments was insufficient to modify the trajectory of comb morphological development, possibly due to a ceiling effect when comparing environmental treatments on the positive end of the welfare spectrum. We found that left-lopping combs had shorter perimeters than right-lopping combs. However, among hens with left-lopping combs, those with larger combs were heavier and had less feather damage, while among hens with right-lopping combs, those with longer-perimeter combs were heavier and tended to have less comb damage. In conclusion, comb characteristics were related to physical condition at the individual level but did not serve as sensitive integrated indicators of hen welfare in response to basic vs enhanced resource choice during rearing.

The Effect of Comb Cell Size on the Development of Apis mellifera Drones.

The growth and development of honeybees are influenced by many factors, one of which is the cell size of the brood comb. Larger worker bees can be obtained by being raised in bigger cells. However, whether cell size has the same effect on drone development is still unknown. Here, using 3D-printed foundations, we observed the development of drones kept in comb cells of different sizes from the late larval stage through eclosion. The results showed that drones in larger cell-size combs had heavier body weights, longer body lengths, and larger head widths, thorax widths, and abdomen widths compared to those in smaller cell-size combs. Furthermore, regardless of developmental stages, the drones' body weights increased linearly with the comb's cell size. However, the other morphological changes of drones in different developmental stages were out of proportion to the cell-size changes, resulting in smaller cells with a higher fill factor (thorax width/cell width). Our findings confirm that comb cell size affects the development of honeybees; drones become bigger when raised in large cells.

Research Note: A validation of an image-based method to estimate chicken comb size

Chicken combs carry important information about the individual, especially the size has been related to sexual reproduction, health, and social signaling. Comb size is usually estimated by weighing removed combs or by calculating the product of the comb's longest and highest dimensions (LHA) to approximate comb area based on measures of a ruler or caliper. These methods have several shortcomings including invasiveness or imprecision. As a result, more recent efforts have employed pixel-based approximations of comb area (PBA) from images. However, the validity of PBA to estimate comb area and how the approximation compares to previous approximation methods, such as LHA, is unknown. Therefore, we developed an apparatus for taking standardized images of the head position of the hens and then applied PBA using the software ImageJ. The hens were each photographed 3 times by 2 different handlers. We first tested the accuracy of the pixel-based area approximation on 3 geometric shapes of known area. Second, we tested the precision of PBA of 15 hens (Dekalb White), evaluated as within-image and within-individual hen precision. Furthermore, we compared the PBA with the LHA based on measures of a caliper. The PBA was both accurate and precise, whereas the LHA overestimated comb area with increasing overestimation for larger combs. Due to the greater accuracy of the PBA, as well as future possibilities of automation and inclusion of further measures, we suggest PBA as a more reliable approach to estimate comb area than LHA. Additionally, our results demonstrate that the outcomes of LHA should be evaluated on an ordinal scale level only.

Phenotypic characterization and genetic diversity of indigenous chickens of Jordan in comparison with native and commercial breeds ‎for conservation and breeding purposes

Indigenous chickens of Jordan are facing extinction and need genetic conservation because they were unable to commercially compete in poultry industry because of low genetic ability ‎compared to commercial layers. The study aimed to investigate phenotypic and genetic diversity ‎of village chickens in the Jordan using discriminant analyses procedures to provide a basis for ‎sustainable genetic conservation and utilization program to overcome any possible extinction. The ‎sampled chicken population of 578 one-year old chickens (125 males and 433 females) was ‎phenotypically characterized for 15 biometric and plumage traits from major cities of the three ‎regions; Middle, North, and South. The traits variations within and between breeds were detected ‎statistically by stepwise discriminant and canonical-discriminant of uni- and multivariate analyses. ‎The results showed the sampled population as village chickens in Jordan is comprised of ‎indigenous (Baladi) breed (85%) and few exotic and commercial breeds. The breeds were distinct ‎and differentiated based on phenotypic traits indicating high genetic variability. The major ‎phenotypic traits that showed significant power to differentiate breeds were comb type, body ‎weight, comb size, earlobe color, wattle size, face color and breast size in males and comb type and ‎size, body weight, face and breast size, leg color and wattle size in females. Recent and past ‎crossings, admixture or migration from exotic and commercial breeds were noted. Moreover, low ‎levels of phylogeographic structure were observed across the studied breeds. In conclusion, there is need to conserve the indigenous breed in situ and in vivo for its adaptive gene pool in coming ‎days of persisted climate change and diseases threats.

Reproduction and Growth Performance of Kampung Unggul Balitbangtan (KUB) Chicken Cross

In Indonesia, one of the sources of regional livestock genetic diversity is the kampung chicken. This study aimed to assess the development and reproductive potential of F1 Kampung Unggul Balitbangtan (KUB) crosses (KUB roosters with different types of combs crossed to layer chickens). This research was conducted at a private chicken company in Gunungkidul regency using 40 KUB roosters and 320 layer chicks. The KUB roosters were separated into four groups based on their comb types: single, walnut, and double. Each set of ten males was housed in a single cage, with a male-to-female ratio of one to eight (male and female). Observed reproductive variables included egg weight (EW), hatch weight (HW), fertility, hatchability, number of eggs, number of day-old chicks (DOCs), and number of saleable chicks. The body weight (BW) of the offspring at ages ranging from DOC, 4, 8, to 12 weeks of age is one measure of their growth characteristics. The analysis of variance using a one-way design and the DMRT test were performed to describe the difference in growth and reproductive performance across groups. As a result, each comb type revealed a significant difference in EW, HW, fertility, hatchability, egg and chick production, DOC, and saleable chick production (P<0.05). Compared to other combs, the single comb performed the best in terms of EW, HW, fertility, number of eggs, and number of DOC. The most hatchable and sellable chicks were from walnut comb. Therefore, comb size has a positive correlation with chicken reproduction and productivity. Comb type groups have no effect on BW at 12 weeks (P>0.05), while they significantly affect BW for DOC at 4 and 8 weeks (P<0.05). The rose comb shows BW at its maximum point. In conclusion, the rose comb has the biggest body weight and the single comb has the best reproductive performance in comparison to other comb types.

Genomic and gene expression associations to morphology of a sexual ornament in the chicken.

How sexual selection affects the genome ultimately relies on the strength and type of selection, and the genetic architecture of the involved traits. While associating genotype with phenotype often utilizes standard trait morphology, trait representations in morphospace using geometric morphometric approaches receive less focus in this regard. Here, we identify genetic associations to a sexual ornament, the comb, in the chicken system (Gallus gallus). Our approach combined genome-wide genotype and gene expression data (>30k genes) with different aspects of comb morphology in an advanced intercross line (F8) generated by crossing a wild-type Red Junglefowl with a domestic breed of chicken (White Leghorn). In total, 10 quantitative trait loci were found associated to various aspects of comb shape and size, while 1,184 expression QTL were found associated to gene expression patterns, among which 98 had overlapping confidence intervals with those of quantitative trait loci. Our results highlight both known genomic regions confirming previous records of a large effect quantitative trait loci associated to comb size, and novel quantitative trait loci associated to comb shape. Genes were considered candidates affecting comb morphology if they were found within both confidence intervals of the underlying quantitative trait loci and eQTL. Overlaps between quantitative trait loci and genome-wide selective sweeps identified in a previous study revealed that only loci associated to comb size may be experiencing on-going selection under domestication.

Automated image analysis to assess hygienic behaviour of honeybees.

Focus of this study is to design an automated image processing pipeline for handling uncontrolled acquisition conditions of images acquired in the field. The pipeline has been tested on the automated identification and count of uncapped brood cells in honeybee (Apis Mellifera) comb images to reduce the workload of beekeepers during the study of the hygienic behavior of honeybee colonies. The images used to develop and test the model were acquired by beekeepers on different days and hours in summer 2020 and under uncontrolled conditions. This resulted in images differing for background noise, illumination, color, comb tilts, scaling, and comb sizes. All the available 127 images were manually cropped to approximately include the comb area. To obtain an unbiased evaluation, the cropped images were randomly split into a training image set (50 images), which was used to develop and tune the proposed model, and a test image set (77 images), which was solely used to test the model. To reduce the effects of varied illuminations or exposures, three image enhancement algorithms were tested and compared followed by the Hough Transform, which allowed identifying individual cells to be automatically counted. All the algorithm parameters were automatically chosen on the training set by grid search. When applied to the 77 test images the model obtained a correlation of 0.819 between the automated counts and the experts' counts. To provide an assessment of our model with publicly available images acquired by a different equipment and under different acquisition conditions, we randomly extracted 100 images from a comb image dataset made available by a recent literature work. Though it has been acquired under controlled exposure, the images in this new set have varied illuminations; anyhow, our pipeline obtains a correlation between automatic and manual counts equal to 0.997. In conclusion, our tests on the automatic count of uncapped honey bee comb cells acquired in the field and on images extracted from a publicly available dataset suggest that the hereby generated pipeline successfully handles varied noise artifacts, illumination, and exposure conditions, therefore allowing to generalize our method to different acquisition settings. Results further improve when the acquisition conditions are controlled.

The Effect of Zinc, Shell, and Fishbone Supplementations on Comb Width and Length of Bangkok Rooster

The Bangkok rooster is a prestigious ornamental bird in Indonesia. Zinc and shell have an aromatase blocker effect that results in testosterone elevations. Additionally, fishbone contains rich protein for optimum biological functions. Serum testosterone regulates comb size in the chicken. This study aimed to investigate the effect of natural aromatase blockers and protein in the comb of Bangkok roosters. This experiment divided thirteen Bangkok roosters into control and treatment groups with zinc, fishbone-shell, and fishbone supplementations. The weekly comb lengthening and widening were intervals between week 0 and the measurement week in this study. The results suggested that fishbone and fishbone-shell supplementations escalated the comb lengthening. Fishbone–shell treatment significantly increased the comb lengthening in the second and fourth weeks (p < 0.05). The significant elongation change in the fishbone group only appeared in the second week (p < 0.05). Otherwise, the treatments produced lower comb widening in the roosters. Fishbone and fishbone-shell supplementation significantly caused a lower widening in every measurement week (p < 0.05). This study uncovered the effects of zinc, shell, and fishbone supplementations on reproductive phenotype in Bangkok roosters.

Quiet flight, the leading edge comb, and their ecological correlates in owls (Strigiformes)

Abstract Owls have evolved sensitive hearing facilitated by a facial disc, and flight that is quieted in part by a leading-edge comb on their wing. This comb is a series of modified barbs, or serrations, which project up from the outermost primary feathers on the leading edge of the wing. Here we explore the evolution of comb and facial disc morphology. We measured leading-edge comb morphology on museum skins of 147 owl species, and facial disc morphology from photos, as well as ecological traits, on 66 species. The first principal component of comb morphology loaded on serration length, which varied between 0 and ~6 mm long in the species we sampled. Comb size (PC1) was correlated with relative facial disc size, suggesting that owls with good hearing also tend to have quiet flight. Two non-exclusive hypotheses for why quiet flight evolved are for stealth, allowing the owl to approach prey undetected; or to reduce self-masking, enabling the owl to hear prey better midflight. We examined whether ecological variables (prey type, active period and habitat) suggest whether stealth or self-masking better explain the evolution of comb size. Phylogenetic analyses suggested support for both the stealth and the self-masking hypotheses for the evolution of quiet flight.

Alternative wax recovery from Apis mellifera: Different combs size effect

The bee wax has great historical importance and has been present since the evolution of civilizations. Currently, besides several uses of the wax, its recovery is indispensable for the rational management of swarms by beekeepers. The wax can be recovered from the combs using different techniques, however the conditions of the pre-extraction combs, such as their size, can influence the wax yield. Thus, studies must still be carried out to standardize the techniques and processes for extracting the wax from the combs, in order to improve the wax yield. This study aimed to evaluate the recovery of Apis mellifera wax according to the size of the comb using an alternative extraction technique. First, the influence of the comb size on wax recovery was evaluated. We used brown color combs, which were broken down into four sizes, each size representing a treatment, namely: Treatment I - 25 cm2; Treatment II - 16 cm2; Treatment III - 9 cm2 and Treatment IV - 4 cm2. Combs were submitted to the "internal strain" technique for 30 minutes of extraction, after boiling the water. The wax recovery was superior in treatment III (P <0.05). Wax recovery from treatment IV was similar to treatment II, which, in turn, showed similar recovery to treatment I (P <0.05). Besides, the wax recovery using 9 cm2 combs was evaluated by the commercial technique of "steam extraction" and the alternative technique of "internal strain", for a period of 30 minutes. The “internal strain” technique showed greater wax recovery than the “steam extraction” technique (P <0.01). The use of alternative wax recovery together with 9 cm2 combs size may optimize the wax extraction process, in terms that it decreases the time of exposure of the wax to heat, and thus positively affect the quality of the final product.

Associations between neck plumage and beak darkness, as well as comb size measurements and scores with ranging frequency of Sasso and Green-legged Partridge chickens

Despite the intensive genetic selection in modern poultry, variability of domestic fowl phenotypes has remained, especially in breeds adapted to local conditions. The relevance of this variability to the chicken outdoor ranging activities remains unknown. The aim of this study was to investigate if external features were associated with the ranging frequency of the 48 female chickens from each of the 2 breeds: Sasso and Green-legged Partridge. In each of 6 single-breed pens, 8 hens and 2 roosters were housed under conditions of EU requirements for organic meat chicken production, including free access to an outdoor range, from wk 5 to 10 of age. The birds were video-recorded during the experiment to obtain frequencies of individual birds' use of the ranges. Comb size (length and height) was measured using a digital ruler, while the sizes of the dark area of neck plumage and beak were processed and analyzed using ImageJ software. The same traits were scored using direct visual assessment by a trained observer on a scale of 1-3. In addition, the eye color of the bird was recorded. Statistical analysis was conducted independently for each breed using regression models, ANOVAs and Spearman correlations. Significant positive associations between neck plumage (P < 0.01), beak darkness (P = 0.03) measurements, comb length (P < 0.01) and comb height (P < 0.01) and frequency of range use were identified for Sasso. Sasso hens scored with darkest neck plumage (P = 0.03) and biggest comb size (P = 0.04) ranged the most, while their external features were significantly and positively correlated between each other, except beak darkness and comb length. No significant associations between ranging and external features were found in Green-legged Partridge birds, except that their comb height was significantly and positively correlated with neck plumage and beak darkness (r = 0.39 and 0.33, respectively). In some genetic strains, better understanding of the associations between chickens’ external features with ranging behavior could contribute to improve selection programs and bird welfare, assuring production of breeding stock suitable for outdoor conditions.

Sexual selection: Large sex combs signal male triumph in sperm competition

A new study using artificial selection reveals that the size of the sex comb on the legs of male flies is genetically correlated with their fertility success under conditions of sperm competition.

Separate weighing of male and female broiler breeders by electronic platform weigher using camera technologies

The body weight of breeding broiler chickens (broiler breeders) is an important control variable used to optimize the amount, quality and fertility of the eggs being laid. In modern breeding barns, the population of animals generally supports a female:male ratio of 10:1, wherein males and females each receive their own food supply. To control this supply the broiler breeders are weighed using automatic electronic platform weighers and the weights are then classified into cockerel and hen categories using theoretical growth curves. However, due to the non-uniform growth of the animals and replacement (called spiking) of cockerals this classification is not always correct, causing a risk of under/over feeding of the population. To overcome this challenge, in this study we have developed a system that integrates the electronic platform weigher with the low-cost 3D Kinect camera was employed to separate weigh male and female broiler breeders under commercial conditions. A novel image processing algorithm is proposed. The algorithm first constructed the Height Accumulating Image (HAI) using depth image to locate the region of interest (ROI) where a broiler breeder jumps onto the weigher, then the comb size was calculated on RGB image as the gender classifying feature, and finally, an adaptive classification threshold was determined by the kernel density estimation using the recent days comb size measurements. The results showed that enough measurements can be obtained for estimating overall weight expectation with the average acceptance rate of 77.32%. Based on these accepted measurements, the accuracy, sensitivity, precision, and specificity were 99.7%, 98.82%, 100% and 100% respectively.

Effects of social experience, aggressiveness and comb size on contest success in male domestic fowl.

The ability to dominate conspecifics and thereby gain access to resources depends on a number of traits and skills. Experience of dominance relationships during development is a potential source of learning such skills. We here study the importance of social experience, aggressiveness and morphological traits for competitiveness in social interactions (contest success) in male domestic fowl (Gallus gallus domesticus). We let males grow up either as a single (dominant) male or as an intermediately ranked male in a group of males, and measured their success in duels against different opponents. We found that single-raised males had lower contest success than group-raised males, and that aggression and comb size correlated positively with contest success. This indicates that experience of dominance interactions with other males increases future success in duels. We similarly studied the consequences of growing up as a dominant or subordinate in a pair of males, finding no statistically significant effect of the dominance position on contest success. Finally, we found that males were consistent over time in contest success. We conclude that social experience increases contest success in male domestic fowl, but that certain behavioural and morphological characteristics have an equal or even stronger covariation with contest success.

Compact, High-Performance All-Polarization-Maintaining Er: Fiber Frequency Comb With Single Fiber Actuator

The large volume and weak environmental adaptability of fiber optical frequency combs (OFCs) have become the main obstacles for their applications in various fields. To address these issues, in this study, we present a compact, low-cost f -to-2 f interferometer and fiber actuator with a large tuning range and a high control bandwidth for a 200-MHz OFC that is based on a 1.5-μm all-polarization-maintaining fiber mode-locked laser. By employing customized fiber-coupled gradient index lenses, our f -to-2 f interferometer is encapsulated in a miniature tube with a diameter of only 4 mm and a length of 40 mm, which substantially reduces the optical section size of the frequency comb as compared to conventional devices. The carrier envelope offset beat with a signal-to-noise ratio of 40 dB is detected in a resolution bandwidth of 360 kHz. In addition, a laboratory-made piezoelectric transducer-driven mechanical actuator for repetition rate regulation exhibited a large tuning range of 106 kHz (corresponding to an effective temperature drift of 53 °C) and a high control bandwidth of approximately 1 kHz. This resulted in a robust repetition rate locking with an Allan deviation of 330 μHz at a gate time of 1 s and a residual integrated timing jitter of 418 fs [3 Hz to 1 MHz] when referenced to a hydrogen maser. Along with reducing the size and improving the environmental adaptability of the OFC, our design can also decrease the power consumption of the system significantly. Our findings provide a new direction to the development of OFCs for various applications.

Full spectra coloration and condition-dependent signaling in a skin-based carotenoid sexual ornament

AbstractCarotenoid-based traits commonly act as condition-dependent signals of quality to both males and females. Such colors are typically quantified using summary metrics (e.g., redness) derived by partitioning measured reflectance spectra into blocks. However, perceived coloration is a product of the whole spectrum. Recently, new methods have quantified a range of environmental factors and their impact on reflection data at narrow wavebands across the whole spectrum. Using this approach, we modeled the reflectance of red integumentary eye combs displayed by male black grouse (Lyrurus tetrix) as a function of ornament size and variables related to male quality. We investigated the strength and direction of effect sizes of variables at each waveband. The strongest effect on the spectra came from eye comb size, with a negative effect in the red part of the spectrum and a positive effect in ultraviolet reflectance. Plasma carotenoid concentration and body mass were also related to reflectance variance in differing directions across the entire spectra. Comparisons of yearlings and adults showed that the effects were similar but stronger on adult reflectance spectra. These findings suggest that reflectance in different parts of the spectrum is indicative of differing components of quality. This method also allows a more accurate understanding of how biologically relevant variables may interact to produce perceived coloration and multicomponent signals and where the strongest biological effects are found.

Variant forms of qualitative traits of indigenous chickens reared under extensive system in Tolon District, Ghana

Context Rural chicken production in most developing countries is based mainly on scavenging systems with indigenous chickens that have not been properly characterised and classified into well-defined breeds. Aims This study was conducted to identify the variant forms of qualitative phenotypic traits of local chickens in Tolon District, northern Ghana. Methods About 320 adult birds were sampled and data collected by using observation and a chicken colour chart. Traits included head shape; comb type, size and colour; feather distribution; and earlobe, eye, plumage, skin and shank colours. Chi-squared goodness of fit test was used to test whether variant phenotypes of each qualitative trait were equally distributed. The hypothesis of no associations between pairs of traits was tested by using Cramér’s V. Key results There were highly significant (P &amp;lt; 0.01) differences in the distributions of variant phenotypes of all traits. The main comb type observed was single (85.9%), followed by pea (8.8%) and rose (5.3%). A majority of birds had small combs (57.8%), although others had medium (28.4%) and large (13.8%) combs. Females had small to medium combs, whereas males had medium to large combs. A majority of the chickens had white earlobe colour (60.3%), followed by pied red and white (22.5%). Feather distributions observed were normal feathered (84.4%), naked neck (8.4%) and frizzled (7.2%). Five plumage colours were observed, although some were in combinations. White plumage was the most common (22.5%), followed by black (18.8%), with brown/ash the least common (0.03%). Community was significantly (P &amp;lt; 0.01) associated with comb type, size and colour, and eye, shank and skin colours. Also, comb size was significantly associated with sex and comb type. Conclusions Generally, local chickens exhibited heterogynous phenotypes for qualitative traits. Local chickens in the district could be described as normally feathered with wide variation in plumage colours and having mainly single comb type. Implications The knowledge of these variant phenotypes and their associations will serve as baseline information for the characterisation and conservation of local chicken types. It could also provide guidelines in selecting bird ecotypes and/or communities for breed improvement programs in the study area.

Design and Simulation Analysis of Mechanical Picking Comb Teeth of Artificial Finger Marigold Flowers

As the key component of mechanical picking device of marigold flower, the structure, size, strength and motion of comb are closely related to the reliability and the rate of picking. In this paper, a mechanical comb for marigold based on bionic finger is designed, and the parameters of structure, row, spacing and outside diameter are designed respectively. Then, the three-dimensional model is established with ANSYS/LS-dyna platform, and the design strength of the comb-type picking mechanism is checked. The results show that the maximum deformation of the comb with 2.3802mm occurs near the top of the tooth during the picking process, which is small and meets the design strength requirements. Finally, the picking process of the comb-type picking mechanism is simulated and the result shows that when the operating speed v is set to 3.0km/h and w is set to 30r/min, the picking effect is good. The above research provides a theoretical reference for the mechanical picking of marigold.

Dynamic phenotypic correlates of social status and mating effort in male and female red junglefowl, Gallus gallus.

Despite widespread evidence that mating and intrasexual competition are costly, relatively little is known about how these costs dynamically change male and female phenotypes. Here, we test multiple hypotheses addressing this question in replicate flocks of red junglefowl (Gallus gallus). First, we test the interrelationships between social status, comb size (a fleshy ornament) and body mass at the onset of a mating trial. While comb size covaried positively with body mass across individuals of both sexes, comb size was positively related to social status in females but not in males. Second, we test for changes within individuals in body mass and comb size throughout the mating trial. Both body mass and comb size declined at the end of a trial in both sexes, suggesting that mating effort and exposure to the opposite sex are generally costly. Males lost more body mass if they (a) were socially subordinate, (b) were chased by other males or (c) mated frequently, indicating that subordinate status and mating are independently costly. Conversely, females lost more body mass if they were exposed to a higher frequency of coerced matings, suggesting costs associated with male sexual harassment and female resistance, although costs of mating per se could not be completely ruled out. Neither competitive nor mating interactions predicted comb size change in either sex. Collectively, these results support the notion that sex‐specific costs associated with social status and mating effort result in differential, sex‐specific dynamics of phenotypic change.