Alexandre A.L. Menezes

Effect of abiotic factors on seasonal population dynamics of Lutzomyia longipalpis (Diptera: Psychodidae) in northeastern Brazil.

Abstract The resurgence of visceral leishmaniasis in Brazil increases the need for studies to elucidate the spatial and temporal dynamics of Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae), the vector of Leishmania infantum, the causative agent of visceral leishmaniasis in Brazil. Sand flies were captured in peridomestic habitats biweekly for 3 yr. Cross-correlation tests and spectral analysis were used to analyze the simultaneous and lag-time correlations between Lu. longipalpis population densities and abiotic factors of temperature, relative humidity, wind velocity, and rainfall. Distinct seasonal patterns were observed for males and females, with intervals of 6 mo between population peaks for males and 12 mo for females. Peak female population densities lagged 3 mo behind the maximum annual temperature. Female population density was negatively correlated with relative humidity. An increase in average wind velocity was followed by a decrease in the number of females for 2 wk. Understanding the relationship between the seasonal population dynamics of Lu. longipalpis and abiotic factors will contribute to the design of better control measures to decrease transmission of L. infantum and consequently the incidence of leishmaniasis.

Latitude and Social Habits as Determinants of the Distribution of Morning and Evening Types in Brazil

Previous application of a Portuguese version of the Horne and Ostberg (H&O) questionnaires in Brazil showed a displacement of the distribution of Morningness/Eveningness (M/E) types towards morningness, demanding a reclassification of the scores limits for each of the 5 possible M/E types. Among city, age and sex, city was the only factor determining significant group differences. In the present paper, the same version of the H&Os questionnaire was applied to a distinct population of 260 adults, balanced according to age, sex and city. Data were collected from October to December, to control the effect of the photoperiod. City remains the only factor determining significant group differences (p <0.001). Moreover, there does not appear a coherent latitude trend that could explain differences among cities as a function of photoperiod. Local social habits could probably explain our results, suggesting further investigations of peculiar temporal patterns.

Circadian rhythm of motor activity of the Brazilian rock cavy (Kerodon rupestris) under artificial photoperiod

Abstract Kerodon rupestris, a Brazilian caviidae rodent, lives in dry stony places. In a first experiment, seven animals were kept in LD (250:0 lux and 400:0 lux) during 40 days in each condition. In the second, four animals were kept in LD (470 lux: red dim light) for 47 days, then in LL (470 lux) for 18 days and in DD (red dim light) for 23 days. Motor activity was continuously recorded by infrared sensors. Animals showed entrained rhythms to the LD cycle being light and dark active, with higher values in phase transitions. When the light intensity was increased, four animals increased and two reduced the activity. In LL, three animals expressed an endogenous tau of 24.4, 26.5 and 24.6 h and one was arrhythmic; in DD, two expressed tau of 23.6 and 23.7 h and one was arrhythmic. Results indicate that Kerodon rupestris circadian rhythm is affected by light intensity but it is not yet possible to determine its habit.

INFLUENCE OF SEASONALITY ON CIRCADIAN MOTOR ACTIVITY RHYTHM IN COMMON MARMOSETS DURING PUBERTY

The effect of puberty on circadian rhythmicity in nonhuman primates has been little studied, even though it has been demonstrated that puberty-related changes in circadian activity rhythm occur in a number of species, including humans. To characterize the motor activity rhythm during puberty in common marmosets (Callithrix jacchus), six animals was continuously monitored by actimeters between their 5th and 12th months of age. The animals were housed with their families in outdoor cages under seminatural conditions. Onset of puberty was determined from fecal estrogen and progesterone levels in females and androgen levels in males. The spectral power of the circadian component stabilized later in the last two animals to enter puberty. The bimodal characteristic of the active phase in this species became progressively more apparent over the course of the months in which the mean temperature was highest, irrespective of the animals age. Although the onset of activity advanced after entry into puberty, this parameter showed a strong correlation with sunrise, indicating that seasonality influences this variable. Neither age nor climatic factors included in the regression model influenced the differences in phase angles between sunrise and onset of activity, and between sunset and offset of activity. Total activity was the only parameter influenced by age in the regression model, showing an increase after entry into puberty. Despite the evidence of pubertal influence on both the circadian component and total activity, under seminatural conditions seasonal factors may have a more important effect on motor activity rhythm in common marmosets. (Author correspondence: E-mail: carolina@cb.ufrn.br)

Socially Adjusted Synchrony in the Activity Profiles of Common Marmosets in Light-Dark Conditions

Synchronized state of activity and rest might be attained by mechanisms of entrainment and masking. Most zeitgebers not only act to entrain but also to mask circadian rhythms. Although the light-dark (LD) cycle is the main zeitgeber of circadian rhythms in marmosets, social cues can act as weaker zeitgebers. Evidence on the effects of social entrainment in marmosets has been collected in isolated animals or in pairs where activity is not individually recorded. To characterize the synchronization between the daily activity profiles of individuals in groups under LD conditions, the motor activity of animals from five groups was continuously monitored using actiwatches for 15 days during the 5th, 8th, and 11th months of life of juveniles. Families consisting of twins (4 ♂♀/1 ♂♂) and their parents were maintained under controlled lighting (LD 12:12 h), temperature, and humidity conditions. Synchronization was evaluated through the synchrony between the circadian activity profiles obtained from the Pearson correlation index between possible pairs of activity profiles in the light and dark phases. We also calculated the phase-angle differences between the activity onset of one animal in relation to the activity onset of each animal in the group (ψon). A similar procedure was performed for activity offset (ψoff). By visual analysis, the correlation between the activity profiles of individuals within each family was stronger than that of individuals from different families. A mixed-model analysis showed that within the group, the correlation was stronger between twins than between twins and their parents in all families, except for the family in which both juveniles were males. Because a twin is an important social partner for juveniles, a sibling is likely to have a stronger influence on its twin’s activity rhythm than other family members. Considering only the light phase, the second strongest correlation was observed between the activity profiles of the individuals in the reproductive pair. Regarding the parameters ψon and ψoff, the juvenile/juvenile dyad had lower values than the other dyads, but these differences did not reach statistical significance in relation to all dyads. Comparing the results of the ψon and ψoff, and correlation indices, we suggest that the latter could detect differences between the animals that were not observed in the results of the phase-angle differences. These differences could be related to changes that occur during the active phase but not only in a particular phase, such as the temporal changes during the activity phase that characterize unimodal or bimodal patterns. Based on the differences in the correlations between individuals subjected to the same LD routine, we suggest that social cues modulate the circadian activity profiles of marmosets as a result of interactions between the animals within each group. Future studies are necessary to characterize the mechanisms of synchronization that are involved in this social modulation. (Author correspondence: carolina@cb.ufrn.br)

Encoding, storage and retrieval processes of the memory and the implications for motor practice in stroke patients

This study intended to evaluate the influence of stroke on memory processes (encoding, storage and retrieval) of visual and verbal stimuli and its implications to the motor practice. Twelve patients (6 with right and 6 with left brain lesions; 6-36 months post-lesion) and 12 healthy subjects, 45-65 years old from both sexes were studied. The encoding and storage processes were evaluated during test sessions where each subject had three attempts to identify two lists with 10 stimuli each (10 figures and 10 words referring to animals and objects). The retrieval process was evaluated by immediate free retrieval and by recognition tests. Data were analyzed by Mann-Whitney test. Performance was worse in patients (encoding - visual: p=0.0001 and verbal: p=0.0001; storage - verbal: p=0.0001) and those with right lesions had worse performance in visual encoding (p=0.0005) and those with left lesions had in verbal storage (p=0.0246) and retrieval (p=0.0001). According to results it is suggested that the patients were not able to adequately codify and store the information, however, they were adequately able to recover by recognition and this implicates the necessity to make a observational, distributed and varied practice in cerebrovascular disease patients therapy.

The influence of social cues on circadian activity rhythm resynchronisation to the light–dark cycle in common marmosets Callithrix jacchus

The influence of a previously synchronised conspecific of the same sex on the circadian activity rhythm resynchronisation rate to the LD cycle was assessed in five adult male marmosets during a 6 h LD cycle delay, followed by a 6 h advance, in the absence and presence of a donor. After phase delay with donor, activity onset and offset were resynchronised in fewer days. During the transients, the occurrence of a mid-activity delay, an activity increase in the L-phase and a decrease in the D-phase indicates a faster resynchronisation. After phase advance, activity onset resynchronised promptly and the number of transients for the offset and mid-activity during the transients did not differ. Daily activity increased at phase shifts. Social cues may influence photic synchronisation in marmosets, probably due to direct effects of socially-induced arousal on the circadian pacemaker or by indirect effects, thus increasing photic input or masking.

Diurnal Variation in a Visual-Motor Coordination Test in Healthy Humans

Before a rehabilitation therapy, a variety of tests are used to investigate the sensory-motor system condition of the patient. Since some parameters evaluated by those tests exhibit temporal variations, this work was conducted to investigate the performance of healthy subjects at different times during the day in a visual-motor coordination test, consisting in perfectly drawing a diagonal in as many 1 × 1 cm squares as possible during a 1 min interval. The test was applied to 14 diurnally active subjects (7 men and 7 women; 18–25 years old) in sessions at 3 h intervals from 06:00 to 00:00 h during four days divided in two blocks of two days each. Oral temperature was digitally measured before each test session in order to check the synchronization of the subjects. The results showed a significant difference (Anova, p < 0.001) between sexes with women (122.4 ± 16.4 sq/min; x ± SD) being faster than men (110.1 ± 22.8 sq/min), although daily profiles for both sexes were quite similar with better performances occurring between 09:00 and 15:00 h. Single Cosinor analysis detected significant circadian rhythmicity for 5 individuals (1 men and 4 women) with acrophases distributed between 09:15 and 13:03 h. The profiles for oral temperature and test performance were very similar with significant correlation (R = 0.26, p = 0.0002) only for men. The variation coefficient shows lower values at 15:00 h for both sexes, suggesting this time as the appropriate moment to apply the test.

The temporal pattern of mating behavior of the fruit fly, Anastrepha zenildae in the laboratory.

Abstract The state of Rio Grande do Norte is an important fruit-producing and exporting area in northeastern Brazil. The success of this industry depends on fruit fly population control, especially in fly-free exporting zones. However, many fruits are not exported because of quarantine restrictions imposed by importing countries. A survey in the state has detected a considerable increase of the fruit fly, Anastrepha zenildae Zucchi (Diptera: Tephritidae), probably a result of the introduction of irrigated guava orchards that make fruit available all year. Knowledge of the sexual behavior of Tephritidae has great importance to pest control programs, particularly those that employ the Sterile Insect Technique. In order to characterize the reproductive behavior of A. zenildae, 32 individuals (16 males; 16 females) in each of six generations were submitted to an artificial 12:12 L:D cycle (750: < 1 lux, lights on 07:00–19:00) and observed over their lifetimes. The courtship and copulation occurred in leks and the episodes varied with the time of day, courtship being most frequent between Zeitgeber time (ZT) 3 and ZT 7, peaking at ZT 5–6. Copulations occurred between ZT 2 and ZT 8, with a higher frequency between ZT 5–7 and a peak at ZT 6. Mean duration was 0.28 ± 0.03 min/male (range: 5–163 min). Males in the leks attempted to copulate mainly between ZT 3 and ZT 7 with a peak at ZT 6, and males outside leks peaked at ZT 7. The different timing of sexual behaviors among related sympatric species, including A. zenildae, may contribute to species isolation.

Influence of different light intensities on the daily grooming distribution of common marmosets Callithrix jacchus.

The daily distribution of autogrooming was evaluated in adult marmosets submitted to different illumination intensities in the light phase of the light-dark cycle. Autogrooming and locomotor activity were monitored and the faecal cortisol level assessed as a stress indicator. The distribution of autogrooming showed two distinct tendencies: when the light intensity varied from 500 to 200 lux, a slight increase in frequency and duration was observed, while a significant decrease in both variables occurred at 10 lux. Varying light intensities did not inhibit rhythm synchronization. The daily profile of autogrooming was mainly unimodal with an acrophase in the first half of the light phase. Faecal cortisol levels tended to increase in animals submitted to 100 and 10 lux, but these results are not conclusive. We suggest keeping captive marmosets in light intensities of at least 200 lux in the light phase, allowing animals to maintain autogrooming levels in order to reduce the discomfort caused by captivity and isolation.