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.
Ray-finned fishes (Actinopterygii) are by far the most diversified group of vertebrates on Earth, and there are currently more than 32500 valid species in about 500 families and 72 orders. The diversity of ray-finned fishes has increased dramatically during their evolution, particularly in the modern group of Percomorpha. This also includes high morphological diversity of body shapes. However, in many cases similar morphological structures have evolved in different groups independently (by convergence). Recently, fish phylogeny has been reconstructed based on molecular genetic data, including whole genome sequencing. In this issue we present two articles on general relationships among the main lineages of fishes and the current version of the phylogeny of the ray-finned fishes. and Zuzana Musilová.
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.