42 research outputs found
Utjecaj veliÄine tijela i obojenosti prilikom odabira partnera kod prugastog smrdljivca (Graphosoma lineatum L.) (Hemiptera: Pentatomidae)
Female as well as male mate choice has already been recognized in many insects. The traits responsible for the mate choice in a striped stink bug (Graphosoma lineatum L.) are not yet explored. This works concentrates on few possible traits responsible for mate choice in a striped stink bug. For this analysis free living copulating individuals as well as the single ones were collected. On two different locations animals were collected and their body length, pronotum broadness and coloration were measured. No differences were found in all measured traits between copulating and control individuals, showing no preferences when choosing copulation partner. Results also show no evidence of assortative mating, referring to the body length and the pronotum broadness of both sexes. All three measured traits seem not to have an influence on the mate choice of both sexes. Further experimental testing is needed to fully excluded importance of body size and coloration in mate choice of a striped stink bug.Odabir partnera od strane ženke, kao i mužjaka, veÄ je prepoznat kod mnogih kukaca. Evoluirale su razliÄite strategije odabira partnera na temelju veliÄine tijela i zabilježene su kod mnogih vrsta kukaca, ukljuÄujuÄi i neke smrdibube (Hemiptera: Pentatomidae). Osim veliÄine tijela kod kukaca je zabilježen i utjecaj obojenosti na odabir partnera. Osobine odgovorne za odabir partnera prugastog smrdljivca (Graphosoma lineatum L.) nisu detaljno istražene. Ovaj se rad usredotoÄuje na utjecaj veliÄine tijela i obojenosti oba spola kod odabira partnera prugastog smrdljivca. Ukupno 10 dana su na dvije lokacije prikupljane kopulirajuÄe jedinke, kao i slobodne (nekopulirajuÄe) jedinke. Životinjama je determiniran spol, izmjerena duljina tijela, Å”irina pronotuma i zabilježena boja. Jedinke u kopulaciji su brojevno oznaÄene u svrhu izuzimanja iz analize podatke ponovljenih parenja. Podaci ukljuÄuju ukupno 65 razliÄitih kopulacijskih kombinacija, 44 jedinki kontrolnih ženki i 53 kontrolna mužjaka. Za sve tri mjerene osobine nisu pronaÄene statistiÄki znaÄajne razlike izmeÄu kopulirajuÄih i kontrolnih (nekopulirajuÄih) jedinki, Å”to ukazuje da ne utjeÄu na preferencije prilikom odabira partnera. Rezultati takoÄer ne pokazuju dokaze asortativnog parenja, barem Å”to se tiÄe duljine tijela i Å”irine pronotuma. Kod oba spola Äini se da sve tri mjerene osobine nemaju utjecaja na izbor partnera. UnatoÄ dobivenom, potrebna su daljnja ispitivanja kako bi se u potpunosti iskljuÄila važnost veliÄine tijela i boje u odabiru partnera prugastog smrdljivca, kao i ispitivanja vezana uz moguÄi utjecaj kemijskih i vibracijskih signala
Besiedlungsstrategien von Pionierarten der Arvicolidae auf Fluss-Inseln, unter besonderer BerĆ¼cksichtigung des PhƤnomens der Ćberflutung
Innerhalb von sieben Jahren wurde die Populationsdynamik der KleinsƤugetiere auf zwei Fluss- Inseln untersucht. In den ersten Jahren vernichteten Winter-Ćberflutungen die Inselfauna. Es wanderten aber in jedem Jahr wieder bis zu 5 KleinsƤugetierarten auf die Inseln. In den letzten zwei Jahren blieben die Ćberflutungen aus, so dass KleinsƤugetiere auf den Inseln Ć¼berwinterten und sich jeweils im nƤchsten FrĆ¼hjahr Populationen aufbauten. Diese Gelegenheiten und ein Wiederansiedlungsprojekt der Sumpfmaus Microtus oeconomus im selben Gebiet ermƶglichten Vergleiche. Die erfolgreichsten Pionierarten waren die Feldmaus Microtus arvalis und die Erdmaus Microtus agrestis. Deren Populationswachstum begann im FrĆ¼hjahr mit einer Verzƶgerungsphase, an die sich eine exponentielle Dichtezunahme anschloss. Wie das Experiment der Wiederansiedlung der Sumpfmaus zeigte, lag auch ohne eine Flutkatastrophe eine Dichte-Depression im Winterhalbjahr. Aus dieser geringen Dichte heraus entwickelte sich im folgenden FrĆ¼hjahr ein Populationswachstum. Daraus kann geschlossen werden, dass die Pionierarten in der Lage sind, mit wenigen immigrierten fortpflanzungsaktiven Tieren individuenreiche Populationen aufzubauen. Diese Kenntnisse sind von Bedeutung, um einschƤtzen zu kƶnnen, welche Erfolge die Ćberflutungen zur Vernichtung von KleinsƤugetieren haben, um PrƤdatoren der WiesenbrĆ¼ter zu vergrƤmen. Offensichtlich kann mit dieser Methode ein Populationsaufbau der Pionierarten nicht verhindert sondern nur verzƶgert werden. Diese Verzƶgerung fĆ¼hrt zu einer GefƤhrdung der Bruten der WiesenbrĆ¼ter, da aufgrund der geringen Nagetierdichten im zeitigen FrĆ¼hjahr die PrƤdatoren wƤhrend der Nahrungssuche hƤufiger auf WiesenbrĆ¼ter als auf WĆ¼hlmƤuse treffen. Es sollte daher zukĆ¼nftig in der Managementplanung mehr das Nahrungssuchverhalten der PrƤdatoren und die Populationsdynamik der Beutetier-Populationen berĆ¼cksichtigt werfen.Within a period of 7 years, the settlement of small mammals has been monitored on two islands formed by the connection of old branches of the river Hase (Lower Saxony, Germany). In the first 5 years the islands have been flooded by water columns of up to one meter during each winter which killed all individuals. However, up to five small mammal species colonized the islands soon after the end of the winter inundations. In the last two winters the islands remained dry which allowed wintering and subsequently re-establishing of populations by the residents. The present situation in combination with a reintroduction experiment (translocation of Root voles, Microtus oeconomus, from the River Oder, Brandenburg, to the Hase Brook valley) allows drawing conclusions on the population dynamics of these species. Species composition of small mammals frequently changed within the years, but Common voles (Microtus arvalis) and Field voles (Microtus agrestis) were the most successful pioneer species. In spring the populations of both species started to increase exponentially after a short period of consolidation. This pattern of population growth even occurs when there hasnāt been any winter inundations as the reintroduction of Root voles has shown. They frequently increased in numbers after a winter depression. These findings indicate that in voles a few reproductive individuals are capable to build up large populations after they have colonized a suitable habitat. The present results are important for the evaluation of measures designed to reduce vole densities by winter inundations in order to prevent clutches and chicks of meadowbirds from predation. It is obvious that winter inundations cannot stop immigration and population growth of r-strategic pioneers like in our case Microtus species. However, winter inundations might retard the growth of vole populations which subsequently affect the survival of clutches and chicks of meadowbirds via an increasing predation risk. It is argued that management schemes designed to sustain meadowbird habitats require more information on the foraging behaviour of predators and their prey species
Forest Residue Management Impact on Rodent (Rodentia: Murinae, Arvicolinae) Damage in Pedunculate Oak (Quercus robur L.) Forests in Croatia
Small rodents (Rodentia, subfam. Murinae: real mice, Arvicoline voles) greatly affect natural
regeneration, stability and dynamics of forest communities worldwide. Every 3ā4 years rodent
damage in Croatian state forests is the most severe in forest regeneration stands, especially in
pedunculate oak (Quercus robur L.) and narrow-leaved ash (Fraxinus angustifolia Vahl.)
forests, where rodents can seriously impede natural regeneration by damaging seeds, stems
and roots of saplings. These negative interactions are an even bigger challenge nowdays as
pedunculate oak and narrow-leaved ash have become more vunerable in the last decades and
are known as the most sensitive species of lowland forests in Croatia due to microclimatic and
macroclimatic changes and the unfavourable interaction of a whole series of anthropogenic,
abiotic and biotic factors. In the last 40 years, in Croatian state forests, rodent management
consisted of monitoring and mainly rodenticide use. Trying to implement IPM (Integrated
Pest Management) postulates into practice over the years, different prevention methods against
small rodents were tested, but not many came to use. The aim of this research was to look into
different logging residue management approaches and their effect on the rodent damage in two
pedunculate oak forest regeneration stands in central Posavina in Croatia. Rodent damage on
stem and root of tree saplings was recorded by visual inspection on three plots (5x5 m) with
scattered logging residue, and one plot (5x5 m) with no residue at one micro-depression site
(95 m a.s.l.), and on one micro-elevation (99 m a.s.l.) site. Plots with scattered logging residue
represented a type of forest residue management in which logging debris (branches) is cut to
smaller lengths and distributed evenly at the forest regeneration stand. Plot with no logging
debris represented a residue management method in which wood mass is completely removed
from the regeneration stand after felling. We counted, determined and inspected tree saplings
found at chosen plots for rodent damage (on stem and roots) and also determined the average
weight and moisture content of logging residue (branches around 5ā7 cm in diameter) found
at the site. In spring 2017, 3380 tree saplings (2978; 81% pedunculate oak, 7; 0.2% narrowleaved
ash and 395; 11.7% other deciduous species) were inspected for rodent damage. At
micro-depression site, on a plot with no logging residue, only 13.4% of the saplings were
damaged, while the average share of damaged saplings on three plots with scattered residue
was more than six times higher; 87.8%. The average mass of the logging residue weighed at
site with scattered residue was 10.14 kg kg/m2 and moisture content was 19.2%. At microelevation
site, 25.4% of the saplings were damaged on a plot with no logging residue, while
the average share of damaged saplings on three plots with scattered residue was two times
higher; 51.4%. The average mass of the logging residue weighed at SRP 1ā3 was 5.1 kg/m2.
We also determined moderately strong positive correlation (R=0.69133) between the mass of
logging residue and rodent damage and strong negative correlation (R=ā0.89598) between
wood moisture content of the logging residue and rodent damage. In years ahead, with unpredictable
climate effects and potentially very variable small rodent dynamics, removing
the logging residue after the felling could represent a residue management that contributes to
a more effective and ecologically based rodent management. It could also become a usable
preventive method within IPM and help prevent sever rodent damage, even during the outbreaks
in pedunculate oak regeneration stands
MALL RODENT DAMAGE ON STEM AND ROOT OF PEDUNCULATE OAK (Quercus robur L.)
Sitni glodavci iz podporodica Murinae (pravi miÅ”evi) i Arvicolinae (voluharice) u Å”umama hrasta lužnjaka (Quercus robur L.) tijekom godina masovne pojave otežavaju prirodnu obnovu Å”uma, uzrokujuÄi Å”tete na sjemenu, stabljici i korijenu mladih hrastovih biljaka. U okviru istraživanja provedenih od 2011. g. do 2013. g. na podruÄju Å”umarije Lipovljani utvrÄena je relativna brojnost glodavaca zajedno s udjelom dominantnih podporodica u populaciji te njihovim prostornim rasporedom. Analizirane su takoÄer Å”tete od glodavaca na stabljici i korijenu lužnjakovog pomlatka, u okviru Äega je provedena morfoloÅ”ka obrada oÅ”teÄenoga i neoÅ”teÄenoga korijenja te njihova usporedba. UtvrÄeno je da pri relativno niskoj brojnosti glodavaca (0ā16 %) viÅ”e od petine hrastova pomlatka (22 %) može biti uniÅ”teno zbog posljedica grizenja korijena, osobito ako u strukturi populacije glodavaca dominiraju voluharice. Nadalje, pokazalo se da hranjenje glodavaca korijenjem hrasta starosti do pet godina posljediÄno znaÄi gubitak do 77 % volumena korijena, 96 % korijenovih vrhova te smanjenje duljine korijena i do 97 %, Äime je potvrÄeno da je preživljavanje oÅ”teÄenih biljaka potpuno onemoguÄeno. Hranjenje glodavaca korom stabljike za posljedicu je imalo stvaranje grizotina povrÅ”ine od 16,5 mm2 do 766,5 mm2 i to prosjeÄno na 1,6, a najviÅ”e na pet mjesta na stabljici. UtvrÄeno je da su Å”tete na korijenu i stabljici rasle sa staroÅ”Äu biljaka. Usporedbom prosjeÄnih vrijednosti volumena, duljine i broja vrhova korijena oÅ”teÄenih i neoÅ”teÄenih biljaka, ustanovljeno je da su razlike meÄu njima statistiÄki znaÄajne kod gotovo svih visinskih kategorija biljaka i debljinskih kategorija korijena za koje je provedena usporedba. Ovim je istraživanjem dobiven kvalitativni nalaz Å”teta od glodavaca na korijenu hrastova pomlatka, te je potvrÄeno da je sustavno praÄenje dinamike, ali i udjela podporodica u strukturi populacija sitnih glodavaca, zajedno s evidentiranjem staniÅ”nih prilika i prouzroÄenih Å”teta, preduvjet ekoloÅ”ki i ekonomski odgovornoj zaÅ”titi Å”uma.Small rodents from subfamilies Murinae (real mice) and Arvicolinae (voles) during the years of their mass occurrence can impede natural regeneration of pedunculate oak (Quercus robur L.) forests by causing damage to seeds, stem and roots of young plants.. Such damage on different tree species is being recorded throughout Europe periodically. In Croatian forestry an area size on which rodent damage occures in the years of their high abundance extends on 4500 hectars on average. The mere observing of the damage and of rodent presence is the most common method of evaluating rodent abundance while thorough analysis of the two is generally missing.The aim of this research was to conduct qualitative and quantitative analysis of rodent damage made to stem and root system of pedunculate oak saplings in accordance to rodent abundance, dynamics and population structure in young-growth pedunculate oak forest (Genisto elatae ā Quercetum roboris Ht. 1938) situated within the region of Central Posavina (Lipovljani, Opeke). Quantitative analysis included monitoring of rodent abundance (linear transect method, three transects, 112 snap traps) and counting oak saplings on five experimental plots (5m 5m) where saplings that had gnawing marks on their stem or roots were sampled and counted as damaged. Qualitative analysis included measuring dimension of gnawing marks (widh x hight) along with scaning, analysing and comparing damaged and undamaged root systems of sampled oak saplings. The latter was done using scaner Epson Expression 10000 XL while the WinRhizo software was used to determine root varables: lenght, volume and the number of root tips. Data classification of the root lenght and number of root tips was made in accordance to four categories depending on the diamentar of root sections: 0ā1 mm, 1ā2 mm, 2ā5 mm, > 5 mm. Roots of 115 damaged and 33 undamaged oak saplings was sampled, scaned and sorted into three categories depending on a plant hight: <40 cm, 40ā80 cm, >80 cm. Plant and rodent sampling were done in November 2011, April 2012 and in May 2013. Morphological determination of rodents was done according to Niethammer and Krapp. Georeferencing of trapped animals was made using the GPS (Garmin Oregon 450). Collected data was analysed using Garmin MapSource ver. 6.16.3., Microsoft Office Excel 2007 and STATISTICA 8. Differences between undamaged and damaged roots of the saplings were tested by Student t-test, or in case of inhomogeneous variences, by nonparametric Mann-Whintey U-test. In all the analyzes 5 % error was considered statistically significant. Monitoring of the rodent population showed that in period from November 2011 till May 2013 rodent abundance varied from 0 % to 16 % and that ratio of subfamilies Arvicolinae and Murinae changed seasonally (Graph 1). Analysis of the rodent spatial distribution showed that most of real mice were trapped on transect covered by dense vegetation, while voles were mostly trapped on other two transects with less vegetation coverage. Quantitative analysis showed that the ratio of damaged pedunculate oak saplings varied from 0,0 % to 42,05 % within individual experimental plots, while the highest overall recorded ratio was 22 %. Qualitative analysis showed that the extent of damage made by rodents increased with the age of oak saplings (1ā5 years), both on the root system (Graphs 2ā6) and on the stam. Feeding on the stems of the saplings resulted in gnawing marks that varied from 16,5 mm2 to 766,5 mm2 in size and were 182,5 mm2 on average. Number of gnawing marks recorded on individual plant varied from one to five and was 1,6 on average. Rodent feeding on root system resulted in loss of 57ā77 % of root volume, 71 %ā97 % of root lenght and 65 %ā96 % of root tips of pedunculate oak saplings depending on the hight of a plant. Statistically significant difference in volume, rooth lenght and number of root tips between damaged and undamaged oak saplings within almost all high and root categories was determened. This research confirmed that rodent abundance and population structure varies seasonally and is therefore important to be aware of it while it provides basic information for predicting the damage made by rodents on the pedunculate young-growth. It also showed that, in accordance to root volume, lenght and number of root tips of pedunculate oak saplings damaged by rodents ā that were measured for the the first time within this research ā the plant itself cannot recover from the loss
No Influence of Indy on Lifespan in Drosophila after Correction for Genetic and Cytoplasmic Background Effects
To investigate whether alterations in mitochondrial metabolism affect longevity in Drosophila melanogaster, we studied lifespan in various single gene mutants, using inbred and outbred genetic backgrounds. As positive controls we included the two most intensively studied mutants of Indy, which encodes a Drosophila Krebs cycle intermediate transporter. It has been reported that flies heterozygous for these Indy mutations, which lie outside the coding region, show almost a doubling of lifespan. We report that only one of the two mutants lowers mRNA levels, implying that the lifespan extension observed is not attributable to the Indy mutations themselves. Moreover, neither Indy mutation extended lifespan in female flies in any genetic background tested. In the original genetic background, only the Indy mutation associated with altered RNA expression extended lifespan in male flies. However, this effect was abolished by backcrossing into standard outbred genetic backgrounds, and was associated with an unidentified locus on the X chromosome. The original Indy line with long-lived males is infected by the cytoplasmic symbiont Wolbachia, and the longevity of Indy males disappeared after tetracycline clearance of this endosymbiont. These findings underscore the critical importance of standardisation of genetic background and of cytoplasm in genetic studies of lifespan, and show that the lifespan extension previously claimed for Indy mutants was entirely attributable to confounding variation from these two sources. In addition, we saw no effects on lifespan of expression knockdown of the Indy orthologues nac-2 and nac-3 in the nematode Caenorhabditis elegans
ANALYSIS OF BEAVER (Castor fiber L.) MORTALITY IN CROATIA AND SERBIA
U sklopu monitoringa dabrova u Hrvatskoj i Srbiji nakon njihove reintrodukcije, evidentiraju se gubici dabrova prema mjestu i vremenu uginuÄa, uzroku, spolu i starosti jedinke. Podaci se prikupljaju pomoÄu mreže suradnika, odnosno po evidenciji dogaÄaja. Na temelju analize prikupljenih podataka o stradanju dabrova u proteklih 18 godina, uoÄava se porast stradalih dabrova, posebice nakon porasta populacije i prostornog Å”irenja dabrova, odnosno 10 godina nakon ispuÅ”tanja u Hrvatskoj. U promatranom razdoblju u Hrvatskoj je evidentirano ukupno 111 gubitaka dabrova, dok je u Srbiji taj broj znatno manji i iznosi 36 jedinki. U Srbiji nije primjetan proporcionalni porast stradanja dabrova u odnosu na dinamiku populacije. NajviÅ”e dabrova stradava u prometu, 40 % u Hrvatskoj i 17 % u Srbiji, te nezakonitim lovom i ribolovom 22 % u Hrvatskoj i 19 % u Srbiji. Iznimku Äini jedna jedinka koja je stradala uslijed pada stabla na odraslog dabra. Äesto se kod pronalaska leÅ”ine ne može utvrditi uzrok uginuÄa 21 % u Hrvatskoj i 28 % u Srbiji. U Srbiji je utvrÄen znaÄajan udio uginuÄa zbog bolesti, Äak 25 % evidentiranih gubitaka. Å to se tiÄe starosne strukture stradalih dabrova, najveÄim dijelom stradavaju adultne jedinke a potom subadultne, dok je, s obzirom na brojne nepotpune informacije, Äesto starost nepoznata. Kada se analizira spol stradalih jedinki, takoÄer je nepoznato najviÅ”e zastupljeno, Å”to je donekle razumljivo jer ne postoji kod dabra izraženi spolni dimorfizam, a kod utvrÄenog spola neznatno viÅ”e stradava mužjaka. S obzirom na vrijeme stradavanja, najviÅ”e jedinki je evidentirano u proljeÄe i jesen, dok najmanje dabrova stradava tijekom zime. Kao mjere zaÅ”tite dabrova u prvom redu poziva se na poÅ”tivanje zakonskih propisa vezano za ilegalni lov i ribolov, a stradavanju u prometu moguÄe je smanjiti ili ponegdje u potpunosti sprijeÄiti postavljanjem žiÄane ograde uz prometnicu na problematiÄnim prijelazima. TakoÄer se mogu uspjeÅ”no sprijeÄiti gubici kod radova na vodotocima u podruÄju koje nastanjuju dabrovi, da se struÄno i tehniÄko osoblje koje obavlja zahvat na ureÄenju vodotoka educira i orijentira na mjere zaÅ”tite dabrova kod izvoÄenja radova (zaÅ”tita nastambi i jedinki od radnih strojeva). Takozvani āopasniā objekti u koje dabrovi mogu upasti i u njima stradati, mogu se prilagoditi na naÄin da se dabrovima onemoguÄi ulazak u takav prostor ili da se osigura moguÄnost izlaska iz takovog prostora. U biti, zaÅ”tita dabrova provodi se dobrom medijskom prezentacijom i informiranjem javnosti o dabru i njegovom naÄin života, mjerama zaÅ”tite i edukacijom graÄana. Takva izravna komunikacija omoguÄava i jednostavnije prikupljanje podataka o dabrovima, ukljuÄujuÄi i podatke o stradalim ili uginulim jedinkama.Population monitoring of beavers in Croatia and Serbia is being continuously run since the first release of beavers in 1996. in Croatia(GrubeÅ”iÄ i Krapinec, 1998, GrubeÅ”iÄ, 2014). Serbia has started with monitoring in 1999. When the first beak has been registered in the north of Vojvodina and it has been intensified since 2004. when they started with inhabitation ā reintroduction (ÄiroviÄ, 2010). As a part of monitoring beavers in Croatia and Serbia since their reintroduction, beaver losses are being recorded by place and time of death, cause, sex and age of individuals. Information is being gathered with help of a network of associates, and by evidence of events. Based on the analysis of gathered information on beaver killings in the past 18 years a growth of killed beavers has been noticed, especially after the population growth and territorial expansion of beavers, and 10 years after the release in Croatia. In the observed period in Croatia a total of 111 beaver losses have been registered, while in Serbia this number is significantly lower and amounts to 36 individuals. Based on registered beaver losses a significant rise in beaver losses in the past 7 years has been noticed on the territory of Republic of Croatia. Actually the number of killed individuals has risen significantly when the beaver population has stabilized and increased its numbers and after 10 years since the inhabitation. In Serbia, despite the stabilization and territorial expansion, registered losses are relatively small, and stagnation or slight drop in killed or died animals has been noted. The main factor of mortality in Croatia and Serbia has been traffic. About one third of beavers (50 individuals) have been killed in traffic accidents. Traffic share in beaver mortality is equal or even somewhat smaller when compared to results from some parts of Germany, where this share is from 50 % to even 86,5 % (Pokorny and associates 2014., Muller 2014).Strangulation in fishing nets has been the second most significant beaver loss in populations on the territory of Posavina and Podravina (22 beavers ā 15 %). Autopsy unquestionably proved that 17 beavers (11.6 %) died from illness. For 33 of them (22,4 %), due to untimely findings or delivery to autopsy, a precise cause of death could not have been determined. When we look at beaver loss causes on the territory of Republic of Croatia traffic absolutely dominates, followed by unknown causes, and in third place illegal hunting and fishing (especially gillnets). In Serbia alongside unknown causes significant influences have diseases. From all 147 losses, only one beaver has been killed underneath a tree. Even though it has been noted he has been ākilled at workā the position of the beavers body and tree points that the killing was not a consequence of knocking down the tree in question (Picture 1 and 2), but that the tree fell on the beaver as it has been passing by, most likely as a consequence of wind blowing the bitten tree down or exceptionally that an another individual knocked down the tree and it fell on the beaver passing by.Mostly adult individuals are being killed (Croatia 39, Serbia 14 beavers) which is linked to their increased activity in search for food and in moving about in general. Reasearch of other authors also shows that adult individuals are mostly being killed and mainly females (Pokorny and associates 2014).Sub adult individuals are being killed when exploring the territory (new locations) or when they inhabit a zone where the get killed easily, especially in traffic. This age group has mostly been killed in Serbia (15 beavers).In relation to sexual structure in Croatia and in Serbia a larger number of males were killed than females. Unfortunately, for half of killed beavers we were not able to tell the sex.If we look at beaver killing on a seasonal level, then two periods stick out, mostly spring then autumn. In spring beavers move more, especially the sub adult ones in search for foo and exploration of new habitats, while in autumn when they are more active in agricultural lands, they are being killed in traffic or in illegal hunting (this influence is most likely significantly bigger than the recorded one, but the prefix āillegalā points to unavailability of information and data on individuals killed this way).Illness for now are not a more significant cause of population loss, but in the future, especially in areas overcrowded by beaver, the might have a more significant role in the reduction of population, considering that we are dealing with a species (rodents) that are sensitive to certain diseases (leptospirosis, tularemia) (Parker and ass. 1951, Hopla 1974, Hornfeldti sur. 1986, Morneri sur., 1988, Wolli sur. 2012).Certain problems or flaws in delivering information on losses emerge due to associates not being educated; these are accidental findings by people who have seen this species most likely for the first time. Apart from that some information has been delivered without details that would give a clearer picture in determining a cause of death, age and sex.As a measure of protecting beavers first in line is respecting the legislation connected to illegal hunting and fishing, and the traffic killing might be decreased or somewhere completely prevented by setting up a wire fence alongside roads in troubling crosses. Also losses can be successfully prevented in watercourse construction in territories inhabited by beavers, that the personnel that is carrying out the construction is being educated and pointed to beaver protection measures while carrying out the work (lodge and animal protection from excavators). So called ādangerousā objects in which beavers can fall into and get hurt, can be adjusted in a way that beavers are enabled to get into such spaces but also to ensure the possibility of getting out from such a space. Beaver protection is being carried out by good media presentation and informing the public of beavers and their way of life, protection measures and citizen education. Such direct communication enables and simplifies information gathering on beavers, also including information on killed or died individuals
Mechanisms of Life Span Extension by Rapamycin in the Fruit Fly Drosophila melanogaster
The target of rapamycin (TOR) pathway is a major nutrient-sensing pathway that, when genetically downregulated, increases life span in evolutionarily diverse organisms including mammals. The central component of this pathway, TOR kinase, is the target of the inhibitory drug rapamycin, a highly specific and well-described drug approved for human use. We show here that feeding rapamycin to adult Drosophila produces the life span extension seen in some TOR mutants. Increase in life span by rapamycin was associated with increased resistance to both starvation and paraquat. Analysis of the underlying mechanisms revealed that rapamycin increased longevity specifically through the TORC1 branch of the TOR pathway, through alterations to both autophagy and translation. Rapamycin could increase life span of weak insulin/Igf signaling (IIS) pathway mutants and of flies with life span maximized by dietary restriction, indicating additional mechanisms
Influence of beech mast on small rodent populations and hantavirus prevalence in Nacional Park āPlitvice lakesā and Nature Park āMedvednicaā
ObiÄna bukva (Fagus sylvatica L.) u Hrvatskoj ima najveÄi areal, najzastupljenija je vrsta na obraslom Å”umskom zemljiÅ”tu i pojavljuje se u velikom broju Å”umskih zajednica. Urod bukvice bilježi se kao bitan faktor porasta populacije sitnih glodavaca, koji su poznati prijenosnici niza zaraznih bolesti opasnih za Äovjeka. Cilj ovog istraživanja je praÄenje populacija sitnih glodavaca i hantavirusa u bukovim Å”umama. U okviru rada obavljen je izlov u periodu od 2011. do 2014. godine na ukupno 7 lovnih ploha rasporeÄenih na dva lokaliteta (NP PlitviÄka jezera i PP Medvednica). Ulovljene jedinke obraÄene su na prisutnost hantavirusa. Na lovnim plohama u NP PlitviÄka jezera mjeren je i urod bukvice. Rezultati ovoga rada pokazali su da u bukovim Å”umama dominiraju žutogrli Å”umski miÅ” i Å”umska voluharica te zajedno Äine 99 % ulova. Brojnost sitnih glodavaca karakterizirale su poviÅ”ene vrijednosti u 2012. godini i visoka brojnost (āmiÅ”ja godinaā) u 2014. godini, dok je 2011. i 2013. godinu karakterizirala niska brojnost. Kod obraÄenih glodavaca potvrÄena je prevalencija 3 vrste hantavirusa. Puumala virus bio je zastupljen u 50 % ulova Å”umske voluharice, Dobrava (DOBV) u 5 % ulova žutogrlog Å”umskog miÅ”a i hantavirus Seewis (SWSV) u jednoj od dvije ulovljene jedinke Å”umske rovke. Urod bukvice na lovnim plohama NP PlitviÄka jezera zabilježen je poviÅ”en u 2011. godini i obilan u 2013. godini. Iz podataka utvrÄujemo pozitivnu vezu izmeÄu koliÄine jesenskog uroda bukvice te porasta populacija sitnih glodavaca, porasta prevalencije hantavirusa i epidemije miÅ”je groznice u godinama nakon obilnog uroda.The European beech (Fagus sylvatica L.) is at present considered to be the most common economically important and widespread tree species in Europe. In contrast to other tree species and economically important species in Croatia European beech has the largest areal and can be found in variety of plant communities. As the most specious and widely distributed mammalian group, rodents are the wildlife reservoir for many zoonoses which can infect humans and other wildlife. Rodent outbreaks tend to follow years with increased seed production of oak and beech. Many authors have linked fluctuations in abundance of rodent reservoirs with increase of human zoonotic infections. Aim of this research is monitoring of rodent populations and hantaviruses in beech forests. At two locations (National park Plitvice lakes and Nature park Medvednica) seven trapping plots were set, each containing 1 or 2 grids size 100m x 100m (100 traps). Rodent capturing was done from year 2011 until 2014 in summer and autumn. Beech mast was recorded in NP Plitvice lakes each year in autumn. Trapped rodents were screened for hantaviruses. Results show two dominant rodent species, yellow-necked mouse (Apodemus flavicollis) and bank vole (Myodes glareolus) in beech forests of NP Plitvice and NP Medvednica. Both species make 99 % of total captures. Rodent abundance showed increase in year 2012 and outbreak in year 2014 measuring on one grid max abundance of 45 animals/ha, whereas year 2011 and 2013 had lowest abundance. In beech forests of National Park Plitvice lakes and Nature Park Medvednica 3 different hantaviruses were found within their typical rodent host species: Puumala (PUUV) in bank voles (Myodes glareolus), hantavirus Dobrava (DOBV) in yellow-necked mouse (Apodemus flavicollis) and Seewis (SWSV) in common shrew (Sorex araneus) which makes first molecular evidence of shrew-borne Seewis virus in Croatia. Highest infection rate was found in bank voles with 50 % of Puumala positive individuals. Dobrava was found in 5 % of trapped yellow-necked mouse. In 2011 there was slight increase in beech seed production reported in comparison to year 2012 and 2014. In year 2013 beech seed production was the highest with mean beech seeds/m2 23x higher than in year 2012. From the rodent abundance and beech mast data we see the trend of mast years being followed with high rodent abundance. Highest proportion of hantavirus positive rodents was found in year 2014 when their abundance was also reported highest. From this data the connection of beech mast year and rodent abundance following next year as well as high infection rates of rodents is confirmed. In same years with increased rodent abundance there was high number of human HFRS cases (hemorrhagic fever with renal failure syndrome)