Variation in circadian rhythms is maintained among and within populations in Boechera stricta

Circadian clocks have evolved independently in all three domains of life, and fitness benefits of a functional clock have been demonstrated in experimental genotypes in controlled conditions. Still, little is known about genetic variation in the clock and its fitness consequences in natural populations from heterogeneous environments. Using Wyoming populations of the Arabidopsis relative Boechera stricta as our study system, we demonstrate that genetic variation in the clock can occur at multiple levels: means of circadian period among populations sampled at different elevations differed by less than 1 h, but means among families sampled within populations varied by as much as 3.5 h. Growth traits also varied among and within populations. Within the population with the most circadian variation, we observed evidence for a positive correlation between period and growth and a negative correlation between period and root‐to‐shoot ratio. We then tested whether performance tradeoffs existed among families of this population across simulated seasonal settings. Growth rankings of families were similar across seasonal environments, but for root‐to‐shoot ratio, genotype × environment interactions contributed significantly to total variation. Therefore, further experiments are needed to identify evolutionary mechanisms that preserve substantial quantitative genetic diversity in the clock in this and other species.     

Resemblance for Body Mass Index in Families of Obese African American and European American Women

Objective: We determined the levels of resemblance in body mass index (BMI) in large samples of families selected through obese African American and European American women. Research Methods and Procedures: We examined correlations among relatives in 1185 European American and African American families ascertained through age-matched obese women (BMI ≥ 30 kg/m²). A subset of 801 families were ascertained through extremely obese women (BMI ≥ 40 kg/m²). Results: Parent-offspring and sibling correlations ranged from 0.19 to 0.15, suggesting a moderate level of heritability in both groups. Mean BMI values for female relatives were lower for European Americans than for African Americans even though probands were matched, perhaps because the European American relatives regress to a lower population mean. We found significantly higher family correlations for height in European Americans, suggesting greater environmental variability among African Americans for factors affecting growth and physical development. Discussion: Our results suggest a similar level of heritability of BMI in families of obese African American and European American women. Other genetic studies will be needed to determine the extent to which the same or different genes and environmental conditions contribute to an overall similar heritability in the two racial groups.     

Breeding success and lutein availability in great tit (Parus major)

The relationship among temporal variation in the availability of carotenoid-rich food, tissue carotenoid levels and breeding success are poorly known. We studied how diet quality and quantity affect the carotenoid profile and fledging success of great tit (Parus major) nestlings along a pollution gradient. We found declining seasonal trend in lutein concentration of caterpillars, which may be the explanation for the declining trend in nestlings' lutein concentration of plasma with season, despite the increase in caterpillar biomass. This may be because the biomass of most lutein-rich caterpillars (autumnal moths) decreased and less lutein-rich caterpillars (sawflies) increased during the breeding season. The temporal difference in occurrence of different caterpillar species means that peak lutein availability does not coincide with peak caterpillar abundance. However the positive association between total larval biomass and the number of great tit fledglings may suggest that fledging success depends more on total caterpillar availability than on lutein concentration of caterpillars.     

QUANTITATIVE VARIATION OF PROGENY FROM CHASMOGAMOUS AND CLEISTOGAMOUS FLOWERS IN THE GRASS DANTHONIA SPICATA

Progeny from chasmogamous (CH) and cleistogamous (CL) flowers of the grass Danthonia spicata were raised in their native habitat and in the greenhouse in order to determine how genetic variation was distributed among families and between CH and CL progeny within families. Twelve quantitative characters were measured on clones from individuals known to have arisen from either CH or CL flowers on a particular plant. Significant genetic variation existed for all characters measured. Most genetic variation was between families and two morphologically similar groups of families were identified. Relatively little genetic variation was found within families (approximately 5% of the total phenotypic variance). In field-raised plants, variance component analysis suggested that CL progeny were genetically more similar to each other than were CH progeny from the same plant. Levene's test of the average deviation of CH and CL progenies from their group means was nonsignificant but suggested there was a trend (0.05 < P < 0.10) for CH progeny to be more variable than CL progeny in the field but less variable in the greenhouse. The amount and distribution of genetic variation in the study population indicates that selective differentials would be larger among families than within families.     

Temporal variability of the ichthyofauna in a Northern Aegean coastal lagoon (Greece). Influence of environmental factors

The ichtyofauna of the Porto-Lagos Lagoon in northern Greece was sampled over 17 months, using a bag-seine net, to investigate factors influencing species seasonal composition and abundance. Of the 35 resident, migrant and straggler species caught, representing 22 families, the most numerically dominant species were Atherina boyeri (46.4% of total catch), which today is the most economically important species, followed by Pomatoschistus marmoratus (28% of total catch) and Aphanius fasciatus (9.1% of total catch). Mugilidae and Sparidae were the most diverse families. According to various diversity indices, the lagoon’s ichthyofauna was found to be most diverse in May 1990; taxonomic spread however, as shown by the taxonomic distinctness index (Δ*), was lowest in July 1990, when the greatest monthly water temperature range was observed (13.5 °C). Overall fish relative abundance was positively correlated with the maximum monthly water temperature (r²=0.32, p < 0.05). The NMDS and cluster analysis performed on the bag seine catches showed four groupings, based mainly on the life history of the species. The main group consisted of all the resident species of the lagoon and four mugilid species that were present throughout most of the sampling period. The second group consisted of marine migrant species that spent a short period of their life in the lagoon. Marine migrants and one marine straggler that were found once or twice formed the third group, while the fourth group consisted of species with casual presence. The importance of Porto-Lagos Lagoon as nursery and feeding area for marine species was confirmed by the catch of young individuals of several marine species.     

QUANTITATIVE VARIATION IN PHLOX: COMPARISON OF SELFING AND OUTCROSSING SPECIES

Variation of 20 quantitative characters was examined within and among 10 populations of the predominantly outcrossing Phlox drummondii and 4 populations of the predominantly selfing P. cuspidata grown in a greenhouse. Multivariate analysis of variance, considering all characters simultaneously, indicated that there were significant differences among populations in both species while analysis of individual characters demonstrated that there were significant population differences for 19 characters in P. drummondii and 13 characters in P. cuspidata. On average, 16% of the total phenotypic variation in P. drummondii occurred among populations compared to less than 4% of the total variation in P. cuspidata. In addition, P. drummondii exhibited significant differences among families within populations more frequently than P. cuspidata. Most observed variation in both species occurred within families where environmental and genetic sources of variation could not be partitioned. There was a trend for P. drummondii to have higher heritabilities than P. cuspidata for most characters even when assumptions about breeding systems were relaxed. Thus, the outbreeding species exhibited larger genetic differences among populations and among families within populations than the selfing species in the greenhouse environment. These data suggest that P. drummondii has the greater evolutionary potential of the two species and are consistent with the hypothesis that differences in population structure result from differences in the breeding systems of the two species.     

An assessment of the fish population of the lower reaches of the Sanyati River,Zimbabwe

The fish population of the lower reaches of the Sanyati River was studied using multifilament gillnets and monthly sampling was conducted over 13 consecutive months. A total of 15 fish species belonging to seven families were collected and variations in monthly catches and catch per unit effort and condition were observed. The five most common species exhibited a seasonal breeding pattern, with most breeding occurring in the rainy season. The exotic Nile tilapia Oreochromis niloticus was found to have established itself in the Sanyati River. The results of this study were compared with those of previous workers on Lake Kariba.     

Composition,Seasonal Dynamics,and Long-Term Fluctuations in the Density of Pelagic Polychaetes in Amurskii Bay,Sea of Japan

This is the first survey of the composition and seasonal density dynamics of the pelagic polychaete larvae in Amurskii Bay. This is a summary of the results of two years of observations (1996–1998). The larvae of 14 polychaete families have been recorded. The greatest number of species have been found in the family Spionidae. The most common were the larvae of Harmothoe imbricata (family Polynoidae) and Paraprionospio sp. (family Spionidae). The larvae of polychaetes have been found in plankton throughout the year and have two density peaks. The first peak was due to the spawning of H. imbricata; the second one was provided by representatives of several species of the family Spionidae, mostly Paraprionospio sp., Polydora ciliata, and P. caeca.     

Distribution and biology of marine cladocerans in the coastal waters of southern China

Geographical and seasonal distributions of marine cladocerans in the coastal waters of southern China were studied. Penilia avirostris was the most common species, followed by Evadne tergestina and Podon schmackeri. P. avirostris and E. tergestina were most common during summer. P. schmackeri, found only in a small bay northeast of Hong Kong, showed no clear seasonal pattern of occurrence. P. avirostris and E. tergestina were found at temperatures ranging from 16–32°C and salinity ranging from 7.3–37.2. P. schmackeri was restricted to a temperature range of 17–29°C and a salinity range of 31.0–37.2. No significant relationships between marine cladoceran abundance and chlorophyll a concentration were found in samples taken from Tolo Harbour. Parthenogenetic brood size of P. avirostris and E. tergestina ranged from 1 to 14, while P. schmackeri was found to carry up to 19 embryos per brood. No geographical trend in fecundity patterns was observed. No correlation was found between body length and brood size. The occurrence of females with resting eggs was rare.     

Ecological diversity of edible insects and their potential contribution to household food security in Haut‐Katanga Province,Democratic Republic of Congo

Democratic Republic of the Congo (DR Congo) has a wide diversity of edible insects making it one of the most important biodiversity hot spots in Africa. The aim of this study was to give the first insight into the food plant range, seasonal availability of edible insects, community preference and willingness to consume them. The study revealed a list of eleven edible insect species belonging to four families. Twenty‐six plant species were recorded as food plants of nine edible caterpillar species. Seasonal availability of these insects coincided with the rainy season and was strongly linked to relatively high level of consumption. The caterpillars Elaphrodes lactea Gaede, Lobobunaea saturnus Fabricius and Cinabra hyperbius (Westwood) as well as the termites Macrotermes falciger Gerstäcker were the most dominant species of edible insects preferred and consumed among the different communities. Our study demonstrates that entomophagy is a common practice among the ethnic populations with married, tertiary and university‐level individuals recording significantly higher consumption of edible caterpillars. Populations between the ages of 18 and 45 years as well as the Bemba tribe were also more actively involved in entomophagy. Further research would be necessary to exploit edible insect biodiversity and ethno‐entomophagy and initiate actions for food plant conservation in DR Congo.     

Water availability and population origin affect the expression of the tradeoff between reproduction and growth in Plantago coronopus

Investment in reproduction and growth represent a classic tradeoff with implication for life history evolution. The local environment can play a major role in the magnitude and evolutionary consequences of such a tradeoff. Here, we examined the investment in reproductive and vegetative tissue in 40 maternal half‐sib families from four different populations of the herb Plantago coronopus growing in either a dry or wet greenhouse environment. Plants originated from populations with an annual or a perennial life form, with annuals prevailing in drier habitats with greater seasonal variation in both temperature and precipitation. We found that water availability affected the expression of the tradeoff (both phenotypic and genetic) between reproduction and growth, being most accentuated under dry condition. However, populations responded very differently to water treatments. Plants from annual populations showed a similar response to drought condition with little variation among maternal families, suggesting a history of selection favouring genotypes with high allocation to reproduction when water availability is low. Plants from annual populations also expressed the highest level of plasticity. For the perennial populations, one showed a large variation among maternal families in resource allocation and expressed significant negative genetic correlations between reproductive and vegetative biomass under drought. The other perennial population showed less variation in response to treatment and had trait values similar to those of the annuals, although it was significantly less plastic. We stress the importance of considering intraspecific variation in response to environmental change such as drought, as conspecific plants exhibited very different abilities and strategies to respond to high versus low water availability even among geographically close populations.     

Foraging activity and population estimation of Microtermes mycophagus Desneux (Isoptera: Termitidae: Macrotermitinae) in Multan,Punjab, Pakistan

The knowledge of the seasonal foraging activity and the numbers of foragers in a colony would be helpful for designing effective termite baiting programs. The current study presents the seasonal activity of Microtermes mycophagus Desneux in a tree plantation in Multan, Punjab, Pakistan, using silk cotton tree wood traps during 2011–2013. The population of M. mycophagus was also estimated using the constant removal method. The number of workers in the underground traps showed a seasonal trend with the highest capture rate occurring during summer and the lowest during winter. The peak in the population (1139 workers/trap) was observed in October after the rainy season. Positive and significant correlation was found between the mean air temperature and the numbers of M. mycophagus workers captured. The constant removal population estimates revealed 16 499–40 265 individuals in the colony of M. mycophagus. Our results suggest that for cost–effective management of the termite species, baiting programs should be started immediately after August when rapid increases in activity of M. mycophagus have been recorded.     

Seasonal dynamics in community structure,abundance, body size and sex ratio in two species of Neotropical annual fishes

Seven ephemeral pools on the coastal plain of southern Brazil were found to be inhabited by three annual and 22 non‐annual fish species. Two common annual species (Austrolebias minuano and Cynopoecilus fulgens) exhibited clear seasonal dynamics, with the appearance of young fishes in the austral autumn (May to June) and a decline in abundance over the seasonal cycle. The third annual species, Austrolebias wolterstorffii, was rare. No seasonal dynamics were observed in non‐annual fishes. The relative abundance of non‐annual fishes compared with annual fishes increased over the seasonal cycle, but they coexisted widely. The size structure of annual fishes suggested the presence of a single age cohort in most pools though a second age cohort was registered in one pool in August, coinciding with a large flooding. Strong sexual dimorphism in body size was found in C. fulgens throughout the seasonal cycle, while no sexual dimorphism in body size was found in A. minuano. Female‐biased sex ratios were recorded in both common annual fish species in the last three sampling dates (in spring), but not during the first two sampling dates (in winter). The natural lifespan of annual fishes was <8 months. Annual fishes disappeared before habitat desiccation in half of the pools, while non‐annual fishes were still present.     

DNA sequences repaired at pachytene exhibit strong homology among distantly related higher plants

Moderately repetitive DNA sequences in Lilium (cv Enchantment) which undergo a meiotic-specific repair synthesis during pachytene (P-DNA) were previously shown to exist as families of very low internal sequence divergence. The present study concerns P-DNA sequence preservation among higher plants. The relative abundance of these sequences in a variety of plant species and their divergence relative to Enchantment P-DNA was determined through C₀t analysis and thermal denaturation of hybrid duplexes. Nearly all of the P-DNA sequence families of Enchantment were found to be present in the genomes of a number of monocot species and the dicot Vicia faba. Sequence content is highly conserved, with less than 6% divergence between Lilium and distantly related species such as Zea mays and Secale cereale. However, the number of repeats per P-DNA family varies considerably in different species, being particularly low among the Poales. P-DNA differs from most high thermal stability (HTS) sequence families of Enchantment which, although exhibiting a high degree of internal homology, are not present as repetitive DNA in the genomes of the other species examined. For most HTS families, the lack of internal divergence probably reflects their fairly recent introduction into the moderately repetitive DNA class, while P-DNA sequences represent evolutionarily ancient families which are the products of strong selective pressure for an indispensable meiotic function.     

Converging prevalences of obesity across educational groups in Switzerland

Objective: To assess whether the rapid increase in obesity prevalence among persons with higher education levels observed in one U.S. study is also observed in a European adult population. Research Methods and Procedures: This study involved continuous surveillance of the adult population of Geneva, Switzerland (1993 to 2004), with annual random, independent, cross‐sectional, representative samples (6635 men and 6558 women, ages 35 to 74 years) and analysis of 12‐year trends in obesity prevalence across educational level subgroups. Results: Obesity prevalence in men had an upward trend in the medium education subgroup (p < 0.02), a borderline upward trend in the high education subgroup (p < 0.08), but no trend in the low education subgroup. There was a borderline trend interaction between the male low and medium education subgroups (p < 0.09). Obesity prevalence in women had a borderline increase in the low education subgroup (p < 0.08), an almost borderline increase in the high education subgroup (p = 0.11), but no significant trend in the medium education subgroup. There was no evidence of trend interaction between the female education groups. Discussion: In Geneva, as in the United States, the inverse association between education level and obesity rates has weakened over time among men, but, inconsistent with the U.S. findings, has persisted for women. Explanations may include more physically demanding occupations for men with low education levels and different attitudes toward body image between the sexes.     

Zooplankton dynamics in the upstream part of Stratos reservoir (Greece)

The investigation of the zooplankton community in the upstream part of Stratos reservoir during a 24 months survey (September 2004–August 2006) revealed 26 invertebrate species (14 rotifers, 6 cladocerans, 5 copepods and one mollusk larva). The mean abundance of the total zooplankton was higher in the first sampling period (2004–2005) and ranged between 8.81 and 47.74 ind. L⁻¹, than the second period (2005–2006) when fluctuated between 1.91 and 43.09 ind. L⁻¹. The seasonal variation was strongly influenced by the presence of rotifers, which accounting on average for 68.4% in total. Among them Keratella cochlearis and the order Bdelloidea were numerically the most important, while Macrocyclops albidus prevailed among the copepods and Bosmina longirostris among the cladocerans. Dreissena polymorpha was the only mollusk found in the zooplankton community. Rotifers, copepods and cladocerans showed a seasonal succession with the former preceding in the abundance having their first maximum in spring, while copepods and cladocerans followed, having peaks of abundance in early summer and in autumn, respectively. No seasonal succession among the cladoceran species was observed. The intense water flow in the upstream part of the reservoir, as well as temperature, conductivity, DO, pH, phosphates and silicates, were significant parameters controlling abiotic and biotic elements of the ecosystem and consequently influencing the seasonal variation and the dynamics of the zooplankton community.     

The importance of cultivated land for spreading of allergenic plants in Italy

We studied the ecological characteristics of the plants of Italian cultivated land that cause allergies in sensitized individuals. Differences between the allergenic flora of annual and perennial cultivations were found. Prevalence of annual therophytes was found in seasonal and annual crops subjected to soil tillage and to strong human disturbance. Plants growing in stable, moderately disturbed cultivations (citrus and olive groves, vineyards) were more often perennials. Allergenic species dispersed by wind and those endowed with multiple dispersal strategies (polychory) were well represented in seasonal and annual crops. The moderate height of these cultivations facilitates circulation of air, favouring the diffusion of anemochoric plants, which explains the abundance of the Poaceae and the Asteraceae families. The spreading of some allochthonous invasive allergenic species was ascertained. The entrance of allergenic plants from surrounding natural ecosystems increases the overall allergenicity of Italian cultivations. The results obtained pointed out a strong relationship between allergenic flora, human impact, and the structure of the cultivations. They point out the importance of knowledge about the ecological characteristics of the allergenic flora infesting the cultivations, which enables efficacious control of the diffusion of the most dangerous species.     

Seasonal patterns of reproductive activities among deep-sea benthic copepod species in the bathyal Sagami Bay, central Japan

Little is known about the life histories of the deep-sea metazoan meiobenthos. At a bathyal site (depth 1430 m) in Sagami Bay, central Japan, temporal changes in abundance and reproductive activity of deep-sea benthic copepods were investigated for eight abundant species that composed about 50% of total individuals, based on samples collected before fresh organic matter increased in the sediment (December 1996 and 1997), 1 month thereafter (June 1997 and May 1998), and a few months after the event (August 1997 and 1998). Densities of adults of these species fluctuated among samples (the total abundance was 5–30 individuals/10 cm²), but did not show any seasonal trend. Strong evidence for competitive relationships among species could not be detected, and there was no significant negative correlation in abundance between any species pair. The percentage of ovigerous females among total adult females of Schizopera sp. 1 differed significantly by month. Furthermore, the adult sex ratio of the species appeared to fluctuate temporally. These suggest a temporal change in reproductive activity and synchronized growth of Schizopera sp. 1. There was no temporal trend, however, in any parameter for the other species. Mean egg number per brood and egg diameter differed among species, but did not change seasonally in any species. Our study suggests the rarity of seasonal breeding species among the deep-sea benthic copepods, one of the major metazoan meiofaunal groups, as well as among other macro-megafaunal metazoans.     

THE SEASONAL DISTRIBUTION,ABUNDANCE AND DIVERSITY OF DESMIDS (CHLOROPHYTA) IN A SOFTWATER,NORTH TEMPERATE STREAM1

Suspended and benthic algal communities from a mildly acidic, third-order Rhode Island stream were examined to determine the seasonal distribution, abundance and diversity of the lotic desmids. Within a one-year sampling period, 148 species and 202 subspecific taxa of desmids were identified, representing 23 genera. Species of Cosmarium and Closterium accounted for approximately 70% of the desmids present, and were the most diverse and abundant taxa during all seasons except spring, when Hyalotheca dissiliens was the dominant desmid species. Average abundance and species richness generally were greatest during summer for both suspended and benthic desmids. Most desmids occurred in benthic habitats, and were randomly distributed among substrata. Average seasonal abundance was 7.4 × 10⁴ cells·g^?1 dry wt substratum, among 13 types of substrata. Highest desmid abundance was measured among substrata with intricate morphologies, such as Fontinalis spp., which was associated with 1.2 × 10⁶ desmid cells·g^?1 dry wt substratum, or 1.7 × 10³ cells·cm^?2 substratum. Cell division was observed for 70 desmid taxa, and average seasonal reproduction (based on cell numbers) among all substrata ranged from 4% in winter to 20% during summer. In addition, sexually produced zygospores were found occasionally for H. dissiliens. Desmids were distributed among most substrata examined in this stream, with abundance comparable to reported estimates from softwater lakes and acid bogs. In contrast to established dogma, lotic desmids are not incidental drift organisms, but rather comprise a viable and persistent component of the stream periphyton.     

Studies on the prevalence of tinea capitis infection in Ile-Ife,Nigeria

Investigations were carried out into the prevalence of tinea capitis infection among school children in Ile-Ife, Nigeria. The prevalence rate of clinical infection was found to be 14.02%. The infection was found to be more frequent among pupils between ages 5 and 10 years, and more prevalent among the poor than the rich (p<0.005). Families having between 1 and 4 children had lower prevalence than families having minimum of five children (p<0.10). Approximately one-third of the clinically infected children were not receiving any treatment while about two-thirds of the remaining two-thirds were using local native remedies, some of which had resulted in deaths of some children. The most common causative agent isolated from the lesions was Microsporum audouinii.