Terms Of Ecological Factors Research Articles

Serological Evidence of Contrasted Exposure to Arboviral Infections between Islands of the Union of Comoros (Indian Ocean).

A cross sectional serological survey of arboviral infections in humans was conducted on the three islands of the Union of Comoros, Indian Ocean, in order to test a previously suggested contrasted exposure of the three neighboring islands to arthropod-borne epidemics. Four hundred human sera were collected on Ngazidja (Grande Comore), Mwali (Mohéli) and Ndzouani (Anjouan), and were tested by ELISA for IgM and/or IgG antibodies to Dengue (DENV), Chikungunya (CHIKV), Rift Valley fever (RVFV), West Nile (WNV), Tick borne encephalitis (TBEV) and Yellow fever (YFV) viruses and for neutralizing antibodies to DENV serotypes 1–4. Very few sera were positive for IgM antibodies to the tested viruses indicating that the sero-survey was performed during an inter epidemic phase for the investigated arbovirus infections, except for RVF which showed evidence of recent infections on all three islands. IgG reactivity with at least one arbovirus was observed in almost 85% of tested sera, with seropositivity rates increasing with age, indicative of an intense and long lasting exposure of the Comorian population to arboviral risk. Interestingly, the positivity rates for IgG antibodies to DENV and CHIKV were significantly higher on Ngazidja, confirming the previously suggested prominent exposure of this island to these arboviruses, while serological traces of WNV infection were detected most frequently on Mwali suggesting some transmission specificities associated with this island only. The study provides the first evidence for circulation of RVFV in human populations from the Union of Comoros and further suggests that the virus is currently circulating on the three islands in an inconspicuous manner. This study supports contrasted exposure of the islands of the Comoros archipelago to arboviral infections. The observation is discussed in terms of ecological factors that may affect the abundance and distribution of vector populations on the three islands as well as concurring anthropogenic factors that may impact arbovirus transmission in this diverse island ecosystem.

Differences in the nesting sites microhabitat characteristics of two syntopic species of Messor harvester ants in a phytosociological homogeneous grassland area

Physiological tolerance of species to temperature, moisture or chemical-physical properties of the soil could be important in determining the distribution and abundance of ant nests. In the present study we investigated the possible differences in the nesting site microhabitat characteristics of two syntopic species of harvester ants of the genus Messor living in a Mediterranean homogeneous grassland area belonging to a single phytosociological association known as “Vulpio ligusticae-Dasypyretum villosi”. We tested to see whether the activity of the colonies of the two species directly altered the microhabitat characteristics of the nesting sites. Microhabitat characteristics were assessed quantifying several abiotic factors (light, temperature, soil moisture, soil pH, nitrogen) by means of the Ellenberg Bioindication Model. The model represents a simple way of interpreting the vegetation pattern in terms of ecological factors from the perspective of the plants and can be considered an effective and promising approach to link animal and plant ecology. Our data showed significant differences in the nesting site microhabitat characteristics partially due to a different capacity of the two species to alter nesting site proprieties. Possible differences in the physiological tolerance of these species to moisture gradients could be crucial in determining the distribution and abundance of their nests.

Ecotoxicological effects of Methyl parathion on living things and environment

Methyl parathion; is an insecticide which is commonly used in our country in the aim of agriculture and it is known that some environmental problems arise due to the chronical usage of this pesticide. For this reason, it is very important to raise the awareness the public in terms of the risk factors because of the usage of methyl parathion. The researches showed that methyl parathion inhibits cholinesterase enzyme in the human brains, cause genotoxic effect in mammalian somatic cells in culture medium and increase the anormalities in chromosomal structure. It was determined that this insecticide causes a decrease in the body weights of experimental animals and an increase in the weight of liver, cellular damages in the livers, various neurological problems by affecting reproduction, nervous and cardiovascular systems. Since methyl parathion causes the formation of a toxic medium for human beings, birds, fresh water fish, other hydrophilous organisms as well as sea organisms by mixing to air, soil and water, it is well known that the usage of methyl parathion as an insecticide is a threatening factor for the ecosystem. The usage of methyl parathion has been forbidden in EU (European Union) countries since 2003 and some restrictions have been applied in United States of America. There is no limiting or forbidding enforcement related with the usage of methyl parathion which is in the 3rd order among commonly used pesticides in our country. To bring new arrangements for the usage of methyl parathion which constitutes various risk factors in terms of ecological factors may minimize the ecotoxicological effects of this pesticide. Key words: Methyl parathion, insecticide, ecotoxicological effect.

Sexual Difference in Color Sense in a Lycaenid Butterfly, Narathura japonica

The spectral sensitivity of a lycaenid butterfly, Narathura japonica, was investigated by electroretinography using an integrating sphere that could illuminate the compound eye from almost all directions. Samples were collected from three locations. Butterflies from different locations showed a similar pattern; the first, second, and third peaks (or a shoulder) were located at about 380, 460, and 560 nm, respectively. Males clearly showed the highest sensitivity at the first peak point. In contrast, females showed a higher relative sensitivity than males at the second and third peak points in all samples, and showed broad spectral sensitivity. This male-specific UV-sensitivity is discussed in terms of ecological factors.

Parent-offspring conflict in the evolution of vertebrate reproductive mode.

We propose and evaluate the hypothesis that parent-offspring conflict over the degree of maternal investment has been one of the main selective factors in the evolution of vertebrate reproductive mode. This hypothesis is supported by data showing that the assumptions of parent-offspring conflict theory are met for relevant taxa; the high number of independent origins of viviparity, matrotrophy (direct maternal-fetal nutrient transfer), and hemochorial placentation (direct fetal access to the maternal bloodstream); the extreme diversity in physiological and morphological aspects of viviparity and placentation, which usually cannot be ascribed adaptive significance in terms of ecological factors; and divergent and convergent patterns in the diversification of placental structure, function, and developmental genetics. This hypothesis is also supported by data demonstrating that embryos and fetuses actively manipulate their interaction with the mother, thereby garnishing increased maternal resources. Our results indicate that selection may favor adaptations of the mother, the fetus, or both in traits related to reproductive mode and that integration of physiological and morphological data with evolutionary ecological data will be required to understand the adaptive significance of interspecific variation in viviparity, matrotrophy, and placentation.

Parenting style and adolescent depressive symptoms, smoking, and academic achievement: ethnic, gender, and SES differences.

This paper examines whether the relationship between parenting style and adolescent depressive symptoms, smoking, and academic grades varies according to ethnicity, gender, and socioeconomic status. Four parenting styles are distinguished, based on patterns of parent-adolescent decision making: autocratic (parents decide), authoritative (joint process but parents decide), permissive (joint process but adolescent decides), and unengaged (adolescent decides). The sample included 3993 15-year-old White, Hispanic, African-American, and Asian adolescents. Results are generally consistent with previous findings: adolescents with authoritative parents had the best outcomes and those with unengaged parents were least well adjusted, while the permissive and the autocratic styles produced intermediate results. For the most part, this pattern held across ethnic and sociodemographic subgroups. There was one exception, suggesting that the relationship between parenting styles, especially the unengaged style, and depressive symptoms may vary according to gender and ethnicity. More research is needed to replicate and explain this pattern in terms of ecological factors, cultural norms, and socialization goals and practices.

Peer interaction in Andalusia and Holland: A comparative study

The relative scarcity of studies of cultural variations in peer interaction served as impetus for the present study. In this investigation, differences in peer interaction (child age: about 5 years) in Andalusia and Holland were examined both in an urban and a rural settings. Observational data were analysed with special interest on the collectivism-individualism dimension. Results showed that Andalusian children displayed a stronger tendency than Dutch children to function as part of a social group. However, this tendency was more clearly present in the Andalusian rural than in the urban setting. No cultural differences were found with respect to sociometric ratings. Results were discussed in terms of ecological factors in cross-cultural research.

Chimpanzees' choices of prey between two sympatric species ofMacrotermes in the Campo Animal Reserve, Cameroon

Details are presented relating to chimpanzees' choices between two sympatric species of termites,Macrotermes lillijeborgi andM. vitrialatus, as food in the Campo Animal Reserve, southwest Cameroon, West Africa. An attempt was made to determine the various factors that affected such choices. The two species of termites seemed to have almost the same value in terms of ecological factors. However, chimpanzees fed almost exclusivelyonM. lillijeborgi, using digging sticks and fisching probes, during the study period which extended from the end of August to the middle of January, with their feeding activity showing peak at the beginning of the rainy season. By contrast,M. vitrialatus was rarely eaten in spite of the ease with which such prey could be obtained, namely, by desctruction of termite mounds by hand, without the need for tools. The reason that the chimpanzees discriminated between the two species of termite cannot be explained in terms of ecological factors such as size of prey, seasonal differences in termite activity, etc. Sticks used as tools were fairly uniform in size and character, mainly because of physical constraints related to the structure of termite mounds, and the brush-like ends of sticks seemed to be incidentaly byproducts of the chimpanzee's choice of plant species. Ecological factors could provide chimpanzees with a basis for the use of some kind of tool and help them modify it, while other factors, for example, something akin to leisure or the chimpanzee's interest in use of a tool, could provide an opportunity for inventing some tool-using behavior or for maintaining such behavior. These different factors, not being exclusive of one another, might affect the invention and maintenance of tool using-behavior at different phases. It is possible that chimpanzee's choice of prey may not always be the most efficient or appropriate in a given ecological situation.

Laboratory methods for the assessment of social dominance among captive squirrel monkeys

The utility of various techniques for assessing dominance relations within captive primate groups has been repeatedly debated. The present research compared status rankings derived from observations of spontaneous agonism with rankings based on success in experimental competitions within two groups of captiveSaimiri. Observation of social agonism revealed stable dyadic dominance relations in both groups. Status rankings derived from the competitive Water Dominance tests were neither temporally stable nor concordant with observational rankings. Thus the utility of the Water Dominance test as an index of dominance among captive squirrel monkeys seems questionable. Results are discussed in terms of ecological factors in group adaptation which lead to species-specific differences in the relationship between social conflict and competition.