Why do female mice mate with multiple males?

Females often show multi-male mating (MMM), but the adaptive functions are unclear. We tested whether female house mice (Mus musculus musculus) show MMM when they can choose their mates without male coercion. We released 32 females into separate enclosures where they could choose to mate with two neighboring males that were restricted to their own territories. We also tested whether females increase MMM when the available males appeared unable to exclude intruders from their territories. To manipulate territorial intrusion, we introduced scent-marked tiles from the neighboring males into males' territories, or we rearranged tiles within males' own territories as a control. Each female was tested in treatment and control conditions and we conducted paternity analyses on the 57 litters produced. We found that 46 % of litters were multiply sired, indicating that multiple paternity is common when females can choose their mates. Intrusion did not increase multiple paternity, though multiple paternity was significantly greater in the first trial when the males were virgins compared to the second trial. Since virgin male mice are highly infanticidal, this finding is consistent with the infanticide avoidance hypothesis. We also found that multiple paternity was higher when competing males showed small differences in their amount of scent marking, suggesting that females reduce MMM when they can detect differences in males' quality. Finally, multiple paternity was associated with increased litter size but only in the intrusion treatment, which suggests that the effect of multiple paternity on offspring number is dependent on male–male interactions.     

Allocation in reproduction is not tailored to the probable number of matings in common toad (<Emphasis Type="Italic">Bufo bufo</Emphasis>) males

The theory of life history evolution assumes trade-offs between competing fitness traits such as reproduction, somatic growth, and maintenance. One prediction of this theory is that if large individuals have a higher reproductive success, small/young individuals should invest less in reproduction and allocate more resources in growth than large/old individuals. We tested this prediction using the common toad (Bufo bufo), a species where mating success of males is positively related to their body size. We measured testes mass, soma mass, and sperm stock size in males of varying sizes that were either (1) re-hibernated at the start of the breeding season, (2) kept without females throughout the breeding season, or (3) repeatedly provided with gravid females. In the latter group, we also estimated fertilization success and readiness to re-mate. Contrary to our predictions, the relationship between testes mass and soma mass was isometric, sperm stock size relative to testes mass was unrelated to male size, fertilization success was not higher in matings with larger males, and smaller males were not less likely to engage in repeated matings than larger males. These results consistently suggest that smaller males did not invest less in reproduction to be able to allocate more in growth than larger males. Causes for this unexpected result may include relatively low year-to-year survival, unpredictable between-year variation in the strength of sexual selection and low return rates of lowered reproductive investment.     

Accumulation of selected metals and concentration of macroelements in liver and kidney tissues of sympatric golden jackal (Canis aureus) and red fox (Vulpes vulpes) in Somogy County,Hungary

Environmental Science and Pollution Research - This study examined the concentrations of Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn in the liver and kidney samples of golden jackals (n =...     

Yttrium Normalisation: a New Tool for Detection of Chromium Contamination in Soil Samples

The measurement of chromium and yttrium concentration could give a chance to detect 5–10 times less chromium contamination in soil by using the yttrium normalisation method. The principle of the method is the following: elements such as chromium and yttrium exist naturally in the soil in a strongly bonded form. Therefore, in a noncontaminated area there should be a close correlation between the yttrium and chromium concentrations. If the measured Cr concentration in a sample is not on the Cr–Y trend line then the distance of plotted point from the line indicates the amount of anthropogenic chromium. Anthropogenic chromium can be detected only in the case when the contamination does not contain yttrium. This theory was tested in an agricultural–toxicological field experiment where Cr(VI) was added to the soil. Applying the yttrium normalisation method a much smaller anthropogenic effect was detected than by other evaluation methods.     

Does testis weight decline towards the Subarctic? A case study on the common frog, Rana temporaria

Interpopulation comparisons of variation in resource availability and in allocation patterns along altitudinal and latitudinal gradients allow insights into the mechanisms shaping the life history of animals. Patterns of between-population differences in female life history traits have been studied intensively across a wide range of taxa, but similar investigations in males have remained scarce. To study if testis weight—a measure of reproductive investment—varies on a geographical scale in anurans, we focussed on the variation in relative testis weight (RelTW) and asymmetry in 22 populations of the common frog Rana temporaria along a 1,600-km latitudinal transect across the Scandinavian peninsula. We found that RelTW decreased towards the north. Body mass and body length both had independent positive effects on testes mass. We found evidence for directional asymmetry (DA) in testis weight with the right testis being larger than the left. The level of DA in testis weight was not related to latitude, but both body mass and testes mass had independent positive effects on asymmetry. We discuss the northwards decrease in RelTW in terms of a decreased reproductive investment as a possible consequence of harsher environmental conditions, and perhaps also, weaker sexual selection in the north than in the south.     

The potential application of red mud and soil mixture as additive to the surface layer of a landfill cover system

Red mud, the by-product of aluminum production, has been regarded as a problematic residue all over the world. Its storage involves risks as evidenced by the Ajka red mud spill,an accident in Hungary where the slurry broke free, flooding the surrounding areas. As an immediate remediation measure more than 5 cm thick red mud layer was removed from the flooded soil surface. The removed red mud and soil mixture(RMSM) was transferred into the reservoirs for storage. In this paper the application of RMSM is evaluated in a field study aiming at re-utilizing waste, decreasing cost of waste disposal and providing a value-added product. The purpose was to investigate the applicability of RMSM as surface layer component of landfill cover systems. The field study was carried out in two steps: in lysimeters and in field plots. The RMSM was mixed at ratios ranging between 0 and 50% w/w with low quality subsoil(LQS) originally used as surface layer of an interim landfill cover. The characteristics of the LQS + RMSM mixtures compared to the subsoil(LQS) and the RMSM were determined by physical–chemical, biological and ecotoxicological methods. The addition of RMSM to the subsoil(LQS) at up to 20% did not result any ecotoxic effect, but it increased the water holding capacity. In addition, the microbial substrate utilization became about triple of subsoil(LQS) after 10 months. According to our results the RMSM mixed into subsoil(LQS) at20% w/w dose may be applied as surface layer of landfill cover systems.     

Effects of leaching from alkaline red mud on soil biota: modelling the conditions after the Hungarian red mud disaster

A soil column experiment was set up to investigate the effect of red mud from Ajka (Hungary) on a typical soil profile from the affected area. The chemical changes caused by the red mud leachate and the effects of these changes on living organisms were assessed. Ecotoxicological tests were performed with Vibrio fischeri, Sinapis alba and Folsomia candida and the number of aerobic heterotrophic microorganisms was determined. The total, plant-available, exchangeable and water-soluble fractions of Na, Mo, Cu and Cr increased in the soil, mostly owing to their leaching from the red mud layer, but partly to the increase in the pH and DOC concentration. The chemical changes only had significant effects on the test organisms in the 0–30 cm soil layer, except for F. candida, which also had a lower survival rate in the 30–50 cm soil layer. No severe toxic effects were detected in the test organisms; in fact a stimulating effect was revealed for the aerobic heterotrophic cell number and for S. alba germination. However, the red mud itself was toxic, so the ecotoxicological tests justified the removal of red mud from the soil surface after the disaster.     

Nanobioaerosols--reconsidering agricultural irrigation in a warming world

Nanobacteria are best described as 60-300 nm nanovesicles. In the body they collect calcium and phosphate to form apatite, adhere to cells, or invade them--processes regulated by a slime based on proteins (primordial proteins). A versatile functionality realized with a minimum of properties equips nanobacteria with a unique survival potential. They were identified in humans, animals, wastewater and the stratosphere. In South Africa they were detected in people infected with HIV. Models indicate that they boost the genetic diversity of the HIV-1 virus. Experiments showed that they are excreted via urine, explaining their presence in the environment. Eradication would be virtually impossible if they had an extraterrestrial origin, implying a permanent bombardment from space. Whereas the biological status of nanobacteria is still not clarified, we postulate here that the native habitat of nanobacteria are mammals, suggesting that at least modern species have their origin on Earth. The thesis results from mapping functions and properties of the slime, and could facilitate the localisation of nanobacterial reservoirs, identification of local distribution routes and tracking of global transport cycles. Agricultural irrigation with water containing excreta from humans infected with nanobacteria could be a central disseminator of the nanobioaerosols.