Constant fluctuating asymmetry but not directional asymmetry along the geographic distribution of Drosophila antonietae (Diptera, Drosophilidae)

ABSTRACT The population dynamics of a species tends to change from the core to the periphery of its distribution. Therefore, one could expect peripheral populations to be subject to a higher level of stress than more central populations (the center–periphery hypothesis) and consequently should present a higher level of fluctuating asymmetry. To test these predictions we study asymmetry in wing shape of five populations of Drosophila antonietae collected throughout the distribution of the species using fluctuating asymmetry as a proxy for developmental instability. More specifically, we addressed the following questions: (1) what types of asymmetry occur in populations of D. antonietae? (2) Does the level of fluctuating asymmetry vary among populations? (3) Does peripheral populations have a higher fluctuating asymmetry level than central populations? We used 12 anatomical landmarks to quantify patterns of asymmetry in wing shape in five populations of D. antonietae within the framework of geometric morphometrics. Net asymmetry – a composite measure of directional asymmetry + fluctuating asymmetry – varied significantly among populations. However, once net asymmetry of each population is decomposed into directional asymmetry and fluctuating asymmetry, most of the variation in asymmetry was explained by directional asymmetry alone, suggesting that populations of D. antonietae have the same magnitude of fluctuating asymmetry throughout the geographical distribution of the species. We hypothesize that larval development in rotting cladodes might play an important role in explaining our results. In addition, our study underscores the importance of understanding the interplay between the biology of a species and its geographical patterns of asymmetry.

Broilers'toes asymmetry and walking ability assessment

Brazilian poultry production nowadays occupies important position in world's economy due to its technological advancement, which associated to the development of genetic strains of high growth may cause deviation in the growth rate and harm production. Morphological asymmetry has been pointed as an indicator of welfare, as maintained the pattern that leads to balance, the broiler chicken would have its normal locomotion characteristics, freely reaching water and feed. Thus, the objective of this research was to verify the possibility of using morphological asymmetry for evaluating walking ability of broiler chicken. The research was done in the Technology Center, at UNICAMP. The experiment was made using biomechanics analysis and following, the toes were measured. Results found did not show asymmetry useful for determining the locomotion ability of broiler chicken. New studies are recommended in order to search for other correlations that might help to estimate at field level, the locomotion difficulties of broiler chicken.

Effect of aerobic training on EEG alpha asymmetry and depressive symptoms in the elderly: a 1-year follow-up study

The effect of physical exercise on the treatment of depressive elderly adults has not been investigated thus far in terms of changes in cortical hemispheric activity. The objective of the present study was to identify changes in depressive symptoms, quality of life, and cortical asymmetry produced by aerobic activity. Elderly subjects with a diagnosis of major depressive disorder (DSM-IV) were included. Twenty patients (70% females, 71 ± 3 years) were divided into an exercise group (pharmacological treatment plus aerobic training) and a control group (undergoing pharmacological treatment) in a quasi-experimental design. Pharmacological treatment was maintained stable throughout the study (antidepressants and anxiolytics). Subjects were evaluated by depression scales (Beck Depression Inventory, Hamilton Depression Rating Scale, Montgomery-Asberg Depression Rating Scale) and the Short Form Health Survey-36, and electroencephalographic measurements (frontal and parietal alpha asymmetry) before and after 1 year of treatment. After 1 year, the control group showed a decrease in cortical activity on the right hemisphere (increase of alpha power), which was not observed in the exercise group. The exercise group showed a significant decrease of depressive symptoms, which was not observed in the control group. This result was also accompanied by improved treatment response and remission rate after 1 year of aerobic exercise associated with treatment. This study provides support for the effect of aerobic training on alpha activity and on depressive symptoms in elderly patients. Exercise facilitates the treatment of depressive elderly adults, leading to clinical and physical improvement and protecting against a decrease in cortical activity.

Lateral asymmetry of voluntary attention orienting

We recently demonstrated that automatic attention favors the right side of space and, in the present study, we investigated whether voluntary attention also favors this side. Six reaction time experiments were conducted. In each experiment, 12 new 18-25-year-old male right-handed individuals were tested. In Experiments 1, 2, 3 (a, b) and 4 (a, b), tasks with increasing attentional demands were used. In Experiments 1, 2, 3a, and 4a, attention was oriented to one or both sides by means of a central spatially informative visual cue. A left or right side visual target appeared 100, 300, or 500 ms later. Attentional effects were observed in the four experiments. In Experiments 2, 3a and 4a, these effects were greater when the cue indicated the right side than when it indicated the left side (respectively: 16 ± 10 and 44 ± 6 ms, P = 0.015, for stimulus onset asynchrony of 500 ms in Experiment 2; 38 ± 10 and 70 ± 7 ms, P = 0.011, for Experiment 3a, and 23 ± 11 and 61 ± 10 ms, P = 0.009, for Experiment 4a). In Experiments 3b and 4b, the central cue pointed to both sides and was said to be non-relevant for task performance. In these experiments right and left reaction times did not differ. The most conservative interpretation of the present findings is that voluntary attention orienting favors the right side of space, particularly when a difficult task has to be performed.

Isokinetic dynamometry of knee flexors and extensors: comparative study among non-athletes, jumper athletes and runner athletes

Participation in intensive sports activities leads to muscular specializations that may generate alterations in involved articular forces and cause static (posture) and dynamic changes (alterations of articular stability, coordination, etc.). Prevention of injury requires specific functional muscular evaluation in all athletes and for any kind of sport. OBJECTIVE: To dynamically evaluate, through isokinetic tests, the peak torque, total work, and average power of the knee flexor and extensor muscles of jumper and runner athletes and compare them to those of a non-athletic population, evaluating dominance and balance between agonistic and antagonistic muscle groups. RESULTS: In the non-athlete group, we noted a higher asymmetry between the dominant and nondominant members. The jumpers had the highest values of the evaluated parameters of all groups, whereas parameters for the runners were intermediate between non-athletes and jumpers.

Sexing the human skull through the mastoid process

OBJECTIVE: The purpose of this study was to evaluate the significance for sex determination of the measurement of the area formed by the xerographic projection of 3 craniometric points related to the mastoid process: the porion, asterion, and mastoidale points. METHOD: Sixty skulls, 30 male and 30 female, were analyzed. A xerographic copy of each side of the skull was obtained. On each xerographic copy, the craniometric points were marked to demarcate a triangle. The area (mm²) of the demarcated triangle for each side of the skull (right (D) and left (E) sides) was determined, and the total value of these measures (T) was calculated. RESULTS: Concerning the right area of the male and female skulls, 60% of the values overlapped; for the left area, 51.67% overlapped, and for the total area, 36.67% overlapped. The analysis of the differences between the sexes in the areas studied was significant for the 3 areas. Regarding the total area, which is the preferred measurement because of the asymmetry between the sides of the skull, the value of the mean was 1505.32 mm² for male skulls, which was greater than the maximum value obtained in the female skulls. The value of the mean for female skulls was 1221.24 mm², less than the minimum value obtained for the male skulls. CONCLUSIONS: This study demonstrates a significant result in the 3 studied areas, (D), (E), and (T). The total area values show less overlapping of values between the sexes, and therefore can be used for sexing human skulls. For the population studied, values of the total area that were greater than or equal to 1447.40 mm² belonged to male crania (95% confidence). Values for this area that were less than or equal to 1260.36 mm² belonged to female crania (95% confidence).

4-Second Exercise Test: Reference Values for Ages 18–81 Years

Background: Physiological reflexes modulated primarily by the vagus nerve allow the heart to decelerate and accelerate rapidly after a deep inspiration followed by rapid movement of the limbs. This is the physiological and pharmacologically validated basis for the 4-s exercise test (4sET) used to assess the vagal modulation of cardiac chronotropism. Objective: To present reference data for 4sET in healthy adults. Methods: After applying strict clinical inclusion/exclusion criteria, 1,605 healthy adults (61% men) aged between 18 and 81 years subjected to 4sET were evaluated between 1994 and 2014. Using 4sET, the cardiac vagal index (CVI) was obtained by calculating the ratio between the duration of two RR intervals in the electrocardiogram: 1) after a 4-s rapid and deep breath and immediately before pedaling and 2) at the end of a rapid and resistance-free 4-s pedaling exercise. Results: CVI varied inversely with age (r = -0.33, p < 0.01), and the intercepts and slopes of the linear regressions between CVI and age were similar for men and women (p > 0.05). Considering the heteroscedasticity and the asymmetry of the distribution of the CVI values according to age, we chose to express the reference values in percentiles for eight age groups (years): 18–30, 31–40, 41–45, 46–50, 51–55, 56–60, 61–65, and 66+, obtaining progressively lower median CVI values ranging from 1.63 to 1.24. Conclusion: The availability of CVI percentiles for different age groups should promote the clinical use of 4sET, which is a simple and safe procedure for the evaluation of vagal modulation of cardiac chronotropism.

Seasonal analysis of the number of aeropiles in Anocentor nitens (Neumann, 1897) (Acari: Ixodidae) from the State of Rio de Janeiro, Brazil

Variation between aeropile numbers of the right and left peritrematic plate in male and female Anocentor nitens (Neumann, 1897) is reported from a site in Brazil. From January to December 1998, 146 males and 247 females of A. nitens were recovered from Equus caballus L. in Silva Jardim District, State of Rio de Janeiro. Asymmetry of numbers of aeropiles between right and left plates occurred in 83.6% of the males and 82.2% of the females. Differences in the number of aeropiles between the sexes were not significant. Quantitative variation of aeropiles was correlated to the period of recovery, with significant asymmetry detected in August-September and November-December, mainly in males. Results suggest an adaptation, especially in the male ticks, that expresses itself as greater variation in the number of aeropiles in some periods of the year.

Morphometric analysis of Triatoma dimidiata populations (Reduviidae:Triatominae) from Mexico and Northern Guatemala

Triatoma dimidiata is one of the major vectors of Chagas disease in Latin America. Its range includes Mexico, all countries of Central America, Colombia, and Ecuador. In light of recent genetic analysis suggesting that the possible origin of this species is the Yucatan peninsula, we have analyzed populations from the state of Yucatan, San Luis Potosi, and Veracruz in Mexico, and a population from the southern region of the Yucatan peninsula located in Northern Guatemala, the region of El Peten. Classical morphometry including principal component, discriminant, sexual dimorphism, and wing asymmetry was analyzed. San Luis Potosi and Veracruz populations were indistinguishable while clearly separate from Yucatan and Peten populations. Despite important genetic differences, Yucatan and Peten populations were highly similar. Yucatan specimens were the smallest in size, while females were larger than males in all populations. Only head characters were necessary to distinguish population level differences, although wing fluctuating asymmetry was present in all populations. These results are discussed in light of recent findings suggesting genetic polymorphism in most populations of Triatoma dimidiata south of Chiapas to Ecuador.

Heterozigosidade e assimetria do número de hâmulos em operárias adultas de Apis mellifera (Hymenoptera, Apidae)

Heterozygosity and hammuli number asymmetry in adult workers of Apis mellifera (Hymenoptera, Apidae). Relationship between individual heterozygosity at particular loci (Mdh-1, Hk-1 ou Pgm-1) or average heterozygosity of the colony and asymmetry of the hammuli number of right and left wings was verified on adult workers of five Africanized and five European colonies of Apis mellifera. Our results demonstrated the importance of statistical tests to verify the type of asymmetry of the character studied and they did not validate the assumption that uni or multiloci heterozygosity has a positive effect on developmental stability.

Residence advantage in heterospecific territorial disputes of Erythrodiplax Brauer species (Odonata, Libellulidae)

Residence advantage in heterospecific territorial disputes of Erythrodiplax Brauer species (Odonata, Libellulidae). Territories are the outcome of interactions determining where and how long individuals settle. To odonate species, aggressive disputes are not so common since the outcome can be predetermined by advantages such as residency, age, and body size. However, it is possible to predict that at heterospecific disputes, larger body-sized or more aggressive species have some profits overcoming these individual advantages, generating patterns of species hierarchy. Here, I studied the aggressiveness of five Erythrodiplax species (Odonata, Libellulidae) during territorial disputes and verified if larger body-sized species are more aggressive than smaller ones or if the residence advantage prevails on the heterospecific disputes. Larger species were not more aggressive than smaller ones and winners of intra- and interspecific territorial disputes were defined mainly by the residence. So, the residence advantage between heterospecific opponents appears to prevail over any other asymmetry among these species. This pattern may occur because, despite the territorial behaviour in dragonfly males, heterospecific disputes may not increment male reproductive success because it may not increase their access to females.

Are larger and/or more symmetrical Drosophila melanogaster (Diptera, Drosophilidae) males more successful in matings in nature?

Are larger and/or more symmetrical Drosophila melanogaster (Diptera, Drosophilidae) males more successful in matings in nature? Sexual selection in Drosophila melanogaster, related to body size and fluctuating asymmetry in wing length and number of sex comb teeth in males, was tested in natural conditions. Males collected in copula were significantly larger than those collected as a single, while no difference in mean number of sex comb teeth between copulating and single males was observed. On the other hand, single males had greater asymmetry both for wing length and number of sex comb teeth than their mating counterparts. It looks like that symmetry of these bilateral traits also may play a role in sexual selection in this dipteran species in nature.

Register of a gynandromorph of Euglossa pleosticta Dressler (Hymenoptera, Apidae)

Register of a gynandromorph of Euglossa pleosticta (Hymenoptera, Apidae). Here we provide a description of a gynandromorph of Euglossa pleosticta with partial bilateral phenotypic asymmetry. The specimen was collected by cineol baittrap at Parque Estadual São Camilo, a conservation unit in western Paraná. The bee has mostly a female phenotype, except by the right half of its head, including the presence of 11 flagellomeres, ivory markings on scape and parocular area, by the pilosity of the right galea, and by deformed male characteristics on mid and hind tibiae of right legs.

Chromosome characterization of two varieties of Mangifera indica L.¹

Chromosome studies were performed in two varieties of Mangifera indica L. (mango), 'IAC-140 Espadona' and in its progenitor 'Espada Stahl'. Both varieties showed 2n=40 chromosomes though the karyotype formulae were 8m + 10sm + 2sm s for 'Stahl' and 7m + 11sm + 2sm s for 'IAC-140'. The varieties showed moderate karyotype asymmetry which was estimated according to four different indices. Both varieties exhibited three chromosome pairs with silver impregnation after NOR-banding. The number of nucleoli within interphase cells varied from one, the commonest, to eight. The nucleolus persistent phenomenon was observed in more than 22% of metaphase cells of both varieties, seeing that in 'Stahl', up to two nucleoli were evidenced. This variety also showed one nucleolus in several anaphase cells. The studies were suitable for evidencing diversity at chromosomal level between these two varieties.

Karyotype and NOR-banding of mitotic chromosomes of some Vitis L. species

Chromosome studies were performed in V. champinii, V. cinerea, V. girdiana, V. labrusca, V. rotundifolia, V. rupestris and V. vinifera with the purpose of species characterization using chromosome morphometric data and NOR banding. A median ideogram was obtained for each species. The karyotype formula obtained varied from 7m + 12sm to 9m + 11sm. The species showed moderate chromosome asymmetry values according to TF% form, Stebbins, Romero Zarco and Paszko indices. V. champinii and V. girdiana were apart from the other species by CVcl and CVci graphic representation and also formed a group apart in the dendrogram based on Euclidian distances. The chromosome pair number 3 harbors the secondary constriction and a satellite segment in all species analyzed with Giemsa staining and it may be the same observed after NOR banding technique. It seems that the process of speciation in the North American Euvitis species studied involved some discrete changes in chromosome morphometry which have been reflected in the asymmetry index.