Galleria mellonella larvae spin protective tubes, which they use until they finish feeding, when they spin cocoons. A feeding choice experiment showed that some of the silk produced by feeding larvae was consumed in addition to the standard diet (STD). To determine the effect of feeding on silk, last instar larvae were fed for 24 h on foods based on STD but modified by replacing the dry milk component (10% of the diet) with equal amounts of different kinds of silk. While each control larva consumed 21 ± 0.5 mg of the STD and produced 4.5 ± 0.1 mg of silk, larvae that ate the food that contained larval silk consumed 10 ± 0.4 mg of food and produced 6.1 ± 0.1 mg silk; the percentage ratio of silk produced to diet consumed was 21% and 61%, respectively. A more pronounced reduction in food consumption occurred when larvae were supplied with Galleria "cocoon" silk or the sericin fraction of such silk, and only 3.8 mg/larva was ingested of the diet containing Bombyx mori cocoon silk or its sericin fraction. Silk production expressed in terms of percentage of diet consumed was always higher than that recorded for larvae fed STD. We conclude that G. mellonella larvae recycle part of the silk that they produce during feeding. Presence of silk in the diet reduces food intake but increases the ratio of silk production to diet consumption. Sericin fraction of the cocoon silk seems to deter feeding., Haq Abdul Shaik, Archana Mishra, František Sehnal., and Obsahuje bibliografii
Male dimorphism in insects is often accompanied by alternative mating tactics, which may, together with morphological traits, determine fitness of the different male morphs. Fitness consequences of male head horn size, male-male competition and male nest-staying behaviour were experimentally assessed in Copris acutidens, in which major and minor males can co-occur in nests. Possible differences in their reproductive behaviour and breeding success were assayed in a breeding experiment, in which females were paired with one major male, one minor male, or a pair of major and minor males. The advantage of major males staying in a nest along with a rival male is that major males are reproductively more successful than minor males in this species. The weight of dung transported into nests was significantly less in rearing containers containing two males than in those with a single male of either morph, although it did not differ between major and minor males when kept alone. The results indicate that the presence of a rival male negatively affects male provisioning due to interference from rival males. In contrast, in the present study, an increased incidence of male nest-staying behaviour was recorded in the two- male and one minor male treatment than in the one major male treatment. These results indicate that because of the risk of sperm competition, major males stay longer in nests if a rival male is present. Furthermore, minor males (which are subject to a higher risk of sperm competition) stay longer than major males in nests without a rival male. In other words, the present study revealed an alternative behaviour during the post-copulatory stage associated with horn dimorphism and the presence or absence of a rival male., Mayumi Akamine., and Obsahuje bibliografii
The ongoing process of climate change will result in higher temperatures during winter and therefore might increase the survival of overwintering invertebrates. However, the process may also lead to a reduction in snow cover and expose overwintering invertebrates to lower temperatures, which could result in higher mortality. During a field experiment, I investigated the effects of a reduction in snow cover on the survival of the ant Temnothorax crassispinus, which overwinters in nests located on the ground. Ant colonies differed in the survival rate of the workers in the experimental (from which snow cover was removed) and control group. In the control group, the survival rate was unrelated to colony size. However, in the experimental group, from which snow was removed after each heavy snowfall, worker survival was lower in small colonies. Such colony size related mortality may affect the fusion of colonies before winter. and Sławomir Mitrus.
Pro rok 2013 se stal evropským pavoukem roku sklípkánek hnědý (Atypus affinis). Jde o jednoho ze tří druhů sklípkanů vyskytujících se v České republice. V článku popisuji morfologii, způsob života, stanovištní nároky a rozšíření sklípkánka hnědého. Je naším nejhojnějším zástupcem rodu, vyskytuje se na suchých osluněných kamenitých stráních s řídkou stromovou vegetací. Jeho stanoviště nejsou bezprostředně ohrožena sílícím zarůstáním krajiny., The Purse-Web Spider (Atypus affinis) became the European Spider of the Year 2013. The genus Atypus comprises three species in Europe. The morphology, natural history, habitat requirements and distribution of A. affinis are described. In Central Europe, it is the most common Atypus species and it occurs on dry sunny rocky slopes with sparse woody vegetation. These habitats do not tend to be overgrown by expansive tree or grass species., and Milan Řezáč.
The article presents the characteristic features of the worldwide wolf spider family (Lycosidae) and describes how its study has affected Czech arachnology, which takes credit for resolving several issues. Among the 38 families of spiders living in the Czech Republic, wolf spiders are remarkable for their ecology. Wolf spider vital signs are so prominent that every observer inevitably notices their constant movement. In addition to history of the research into the wolf spider family, some faunistic issues are also presented. and Jan Buchar.
The second part of this article on the wolf spider family (Lycosidae) and the importance of Czech arachnologists in its study deals with various questions involving the taxonomy, zoogeography, ecology, bioindications and protection of these spiders, as well as their etology and cytogenetics. and Jan Buchar.
Studie sociálního chování vlků arktických se zaměřuje především na etologii tohoto druhu, ale také na adaptaci přirozených vzorců chování na umělé podmínky. Poskytuje stručné informace o obecné hierarchii smečky, způsobu života a umožňuje náhled na jednotlivé projevy dominance a submise. Analýza byla prováděna na základě pozorování dvou smeček chovaných v Zoo Brno a Zoo Olomouc., This study of the social behaviour of Arctic Wolves (Canis lupus arctos) focuses on the ethology of this species, and the adaptation of its natural behaviour to artificial conditions. It provides brief information about the general hierarchy of a pack and its way of life and presents photographs of the individual manifestations of dominance and submission. The analysis is based on observations of two packs kept in Brno Zoo and Olomouc Zoo., and Dobromila Malíková.
Korbikula asijská (Corbicula fluminea) je jedním z nepůvodních a zároveň invazních druhů mlžů, které postupně dobývají území Evropy včetně České republiky. Korbikula pochází z jihovýchodní Asie, odkud byla introdukována zřejmě asijskými přistěhovalci do Severní Ameriky a z té po několika desítkách let (kolem r. 1980) doputovala lodní dopravou (pravděpodobně s balastní vodou) do Evropy. Na naše území pronikla Labem z Německa a byla zde poprvé zjištěna v r. 1999. V současnosti je známa z Labe, prozatím po Týnec nad Labem. Byla však již zaznamenána také v dolním toku Vltavy (po Nelahozeves, včetně plavebního kanálu Vraňany – Hořín) a Ohře (po Terezín) a překvapivě pozorována v některých menších přítocích Labe, jakým je např. potok Vlkava u Kostomlat nad Labem. Od r. 2009 je sledována neobvyklá lokalita na rozhraní středních a severních Čech, kde korbikula dosahuje zatím největší známé koncentrace na našem území. Jde o betonový kanál vedoucí vodu z odkališť Elektrárny Mělník do Labe jižně od obce Horní Počaply. Byla měřena koncentrace korbikuly na této lokalitě na několika plochách o rozměrech 50 × 50 cm a v přepočtu na 1 m2 kolísala hustota v rozmezí 1 045–4 224 živých jedinců, tedy výrazně vyšší než na jiných místech České republiky a srovnatelná s nejvyššími hustotami tohoto mlže nalezenými v Evropě., The Asian Clam (Corbicula fluminea) is native to the south-eastern part of Asia and has been introduced to other continents including Europe. In the Czech Republic it was found in 1999 and is currently known from the Elbe River and lower parts of several tributaries (Ohře, Vltava). An unusual site with the occurrence of this invasive bivalve was found in 2009. A concrete canal conducting water from the sedimentation basin of the Mělník coal power station is inhabited by a large population. The density of its population was estimated to 1 045 – 4 224 living specimens/1 m2., and Luboš Beran.