A possibility of using synthetic analogues of juvenile hormone (juvenoids) to disrupt imaginal diapause of the apple blossom weevil, Anthonomus pomorum females was demonstrated. Out of three preparations tested (methoprene, fenoxycarb and W-328) methoprene and fenoxycarb appeared to be effective. Sensitivity to juvenile hormone analogues develops early after imaginal emergence (even before the female starts to feed) and lasts throughout the whole aestivo-hibernation dormancy. Although the juvenoids could stimulate the onset of oogenesis at any time during diapause, the propensity of the ovaries to form normal eggs developed only during hibernation part of the dormancy; in earlier stages of diapause accumulation of yolk was observed but matured eggs were not produced. Methoprene treatment caused marked increase of locomotory activity accompanied with decrease of dry weight, increase of water content, depletion of trehalose resources, decrease of cold hardiness and, finally, 100% mortality within four weeks in the weevils treated during their feeding or aestivation stages. Although similar changes were observed in the treated pre-feeding weevils, they later recovered and survived until next spring without apparent loss of cold hardiness. A possibility of designing a control method based on this principle is discussed and the results of small-scale field trials that support its plausibility are reported.
This paper describes the first study of the diatom assemblages in caves in the Czech Republic. The study focused on subaeric habitats: rock faces within caves, walls at cave entrances and “lampflora” assemblages, in three cave systems, Mladeč, Javoříčko and Zbrašov, all in central Moravia. The morphological and cytological variability, ecology and life strategies of diatoms were studied in fresh samples, in Naphrax preparations, in cultures grown on agar plates and in monoclonal cultures. A total of 22 diatom species was identified, mostly aerophytic species and tolerant of low light intensities. Luticola and Diadesmis species complexes are discussed. Taxa D. gallica and L. paramutica var. binodis are new for the Czech Republic. Sexual reproduction was observed in L. mutica and Orthoseira roeseana.
Metaschistura cristata is a small nemacheilid loach species found at a few localities only in Turkmenistan and Iran. The present study reports, for the first time, data on its biology, based on 747 specimens collected from the River Zanglanlou in north-eastern Iran. Specimens were collected at monthly intervals over two reproductive seasons from February to June 2007 and 2008. Maximum age, based on opercula readings, was 4+ years for both sexes. Specimens ranged in size from 25 to 87 mm total length and weighed from 0.09 to 4.91 g. Length-weight relationships implied positive allometric growth for both sexes and the sex ratio was 1 : 1.2 in favour of females. The Gonadosomatic indicated that peak reproduction occurred during April and May, with highest average values of 1.473 ± 0.99 for males and 12.9 ± 7.14 for females in April. Oocyte diameter ranged from 0.53 to 1.46 mm, with a mean value of 0.943 mm. Absolute and relative fecundity ranged between 114-1246 eggs and 79.47-1285.71 eggs/g, respectively. Absolute fecundity and oocyte diameter to fish size (length and weight) were directly correlated, while the relationship between relative fecundity and fish size (length and weight) showed an inverse power function.
The multicoloured Asian lady beetle Harmonia axyridis (Coleoptera: Coccinellidae) may potentially exploit a range of "alternative" food sources. The nutritional value of three common non-prey food groups, i.e. fruit, fungi and pollen, is examined in this study. Development, reproduction and survival of the species were assessed in the laboratory on diets of apple, pear and raspberries and the fungi Oidium lycopersicum, Botrytis cinerea, Sclerotinia sclerotiorum and Rhizoctonia solani. When fed exclusively on these foods this ladybird failed to complete its development or reproduce. However, larval and adult survival was prolonged by 4 to 8 days and 55 to 67 days, respectively, when fruit was offered compared with only water. During a field study H. axyridis adults were collected monthly from March to October at two locations near Ghent, Belgium. Gut analysis demonstrated that, despite the continued presence of aphids, over 90% of all the adults collected contained pollen throughout the year. The pollen belonged to 53 different pollen types. Monthly average numbers of pollen grains in the gut varied from 5 to 233 grains. In contrast, there were about 35,000 grains in the guts of H. axyridis females that successfully developed and reproduced in the laboratory on diet that consisted of only pollen. This suggests that in the field in the majority of cases pollinivory mainly only provided complementary nutrients for this coccinellid. The use of alternative non-prey foods like pollen and fruit may play a role in sustaining populations of this coccinellid at times when the optimal prey is absent.
The main characteristics of the Antimüllerian hormone from the points of view of biochemistry, molecular genetics, physiological functions and importance for diagnostics in reproductive endocrinology and related biomedical fields are reviewed. The role of the hormone in male and female development, its participation in oocyte maturation including selection of a dominant follicle are summarized, as well as its changes under various pathological situations in both sexes. The physiological changes of serum AMH leves in the life span in both sexes and their alterations under various pathological conditions are provided, too., R. Hampl, M. Šnajderová, T. Mardešić., and Obsahuje bibliografii a bibliografické odkazy
A laboratory study was conducted to examine tritrophic effects on the suitability of the peach-potato aphid, Myzus persicae (Sulzer), and tobacco aphid, Myzus persicae nicotianae (Blackman & Eastop), as prey for the two spot ladybird, Adalia bipunctata (L.), when the aphids were reared on either sweet pepper or tobacco. Significant host plant-aphid interactions were evident for every component of development (juvenile survival, developmental time, adult mass at emergence) and reproduction (pre-oviposition period, fecundity, fertility). By almost all measures, the suitability of each aphid species was improved by rearing on its host plant of origin and diminished by rearing on the alternative host plant. The symmetry of the interactions are suggestive of both positive and negative host plant effects on aphid suitability as prey. Whereas M. p. nicotianae may be better able than M. persicae to detoxify the nicotine that is likely responsible for the reduced suitability of M. persicae when reared on tobacco, it appears to have lower nutritive value for A. bipunctata than M. persicae when reared on pepper. Thus, population parameters (R0, rm, l and DT) derived from performance data indicated that M. persicae reared on sweet pepper was the most suitable prey and that the same species reared on tobacco was the least suitable, with other host plant-aphid combinations intermediate., Mohammad A. Jalali, J.P. Michaud., and Obsahuje seznam literatury
Duponchelia fovealis Zeller is a polyphagous insect that has been recently reported attacking strawberry plants (Fragaria x ananassa Duchesne). Despite its economic importance there are few studies on this pest because it is difficult to rear it in the laboratory. With a constant supply of insects, studies on alternative methods of pest control can be conducted. This study aimed at developing an artificial diet for rearing D. fovealis with biological characteristics similar to those reared on their natural diet. This study was carried out in a climate-controlled room (25°C ± 2°C, RH 70% ± 10%, and 14L : 10D). The natural diet consisted of 'San Andreas' strawberry leaves (D1), while the artificial diet (D2) was developed in which beans, casein, soy protein, yeast and wheat germ are used as sources of protein. Five instars were identified. D. fovealis completed its life cycle in 38 and 40 days when fed D1 and D2, respectively. Survival was highest for the larvae fed the artificial diet. Females fed D1 lay a mean of 300.2 ± 62.3 eggs, while those fed D2, 220.3 ± 41.8 eggs. The artificial diet is suitable for the continuous rearing of D. fovealis in the laboratory., Maria A. C. Zawadneak, Rodrimar B. Gonçalves, Alex S. Poltronieri, Bráulio Santos, Adélia M. Bischoff, Aline M. Borba, Ida C. Pimentel., and Obsahuje bibliografii
The hypothesis that small species of aphidophagous coccinellids need lower aphid population densities for reproduction than large species (Dixon, 2007) was tested in the field. In 2006 we compared seasonal changes in the oviposition behaviour of two coccinellid species regularly found in cereal stands in central Europe, the large Coccinella septempunctata L. and the small Propylea quatuordecimpunctata (L.). Adults of both species were collected at 2-3 day intervals from stands of winter wheat and spring barley, females were allowed to deposit eggs for 24 h following collection and the percentage that laid eggs and the number of eggs were recorded. Both species colonized the cereal crop simultaneously in the middle of May. After colonization of the crop, while the aphid density was still low, few females of C. septempunctata oviposited and laid only a few eggs. Oviposition increased up to a maximum c. 1 month later and was closely associated with prey abundance. Of the females of P. quatuordecimpunctata, whose mass is about one quarter of that of the former species, the percentage ovipositing and number of eggs laid varied less in time and was less associated with prey abundance than in C. septempunctata. As predicted by theory, the small P. quatuordecimpunctata was more effective at exploiting the lower prey densities as it produced proportionally more of its eggs during the early stages of the aphid infestation than the larger C. septempunctata.
The Cobitis hankugensis-Iksookimia longicorpa (formerly C. sinensis-C. longicorpus) complex in South Korea includes diploid and triploid forms of hybrid origin that are most often females. However, there are a few males that show no differences from the hybrid females in their general morphology except the presence of a lamina circularis on the pectoral fin. An examination of 354 adult hybrid specimens revealed that 3 % of the complex are male specimens. The testes of the rare males are normal in shape and external morphology. The gonadosomatic index of hybrid males is similar to that observed in males of the parental species and changes during the year in a similar pattern. However, the testicular cells differ from those of the parental species in their morphology. Especially sperm cells are very rare and show abnormalities in their morphology, therefore we conclude that the rare males are sterile. This result suggests that although males are present with a low frequency in the complex, this complex functionally is unisexual and depends on the males of the parental species for perpetuation.
In Central Europe, where most wolf populations persist in habitats altered by humans, the dynamics of these populations are significantly influenced by human activities. Our studies in the western-most part of the Polish Carpathian Mts, 1996–2003, revealed that the winter density of wolves varied in the region from 1.3–1.9 wolves/100 km2 (on average 1.6, SE=0.13). In late summer, the average number of wolves in a pack was 4.7 wolves (n=21, range 2–9, SE=0.4), while an average pack in winter consisted of 4.0 wolves (n=25, range 2–7, SE=0.3). The mean wolf territory covered an area of 158 km2 (SE=26.7, range 98–227 km2). In the Silesian Beskid Mountains, where no human hunting pressure occurred, the wolf population increased during the study period at a mean rate of 28% per year. However, in the Żywiecki Beskid Mountains, where wolves were subject to hunting management in the Slovakian parts of their territories, the population did not increase. The mean rate of increase of the wolf population in the entire study area was 8% per year. Wolf mating seasons began on February 13th and lasted until March 7th, with pups being born during the first ten days of May. Pup rearing places were located between 880 and 1290 m a.s.l. (average = 1009 m a.s.l., SE=34.5, n=11), in dense thickets or under roots of fallen trees and stumps. We did not find excavated dens. In late summer, we recorded an average of 1.9 pups per pack, but counted only 1.3 pups per pack the following winter. Reasons for death (n=18) included culls (83%), collisions with motor vehicles (11%), and sarcoptic mange (6%). In the Żywiecki Beskid Mountains we estimated the minimum mortality rate of 1.5 individuals/pack/year.