Flowers of dicotyledonous plants host communities of arthropod species. We studied the community associated with dandelion (Taraxacum section Ruderalia), a complex of apomictic micro-species abundant in central Europe. Identification of microspecies in the field was impracticable. These plants produce an abundance of flowers that host arthropod communities that are not yet fully documented. We investigated species occurrence, its diurnal and seasonal variation and some of the factors that determine the abundance of the dominant species. Insect and spiders were collected from 2010 to 2012 at a locality in Prague. Whole capitula were harvested at weekly intervals and resident arthropods were identified. Diurnal variation in insect presence and the effect of pollen and microclimate on some of the species were also examined. The insect community (> 200 species) consisted mainly of species of Hymenoptera (86 spp.), Coleoptera (56 spp.), Diptera (46 spp.) and Heteroptera (23 spp.). The most abundant were Thysanoptera (2 spp.). Pollen eaters/collectors and nectar feeders dominated over predators and occasional visitors. From April to mid-August, the insect community was dominated by Coleoptera, and later by Diptera and Hymenoptera. Except for Meligethes spp. and species breeding in the capitula, the insects occupied flowers during the daytime when the flowers were open (10-12 h in spring and only 2-4 h in late summer). The presence of Meligethes spp. in particular flowers was associated with the presence of pollen; the occurrence of Byturus ochraceus with pollen and flower temperature. Although pollination is not necessary, dandelion plants produce both nectar and pollen. The community of arthropods that visit dandelion flowers is rich despite their being ephemeral.The composition of local faunas of flower visitors, presence of floral rewards and flower microclimate are important factors determining the composition of the flower community., Alois Honěk, Zdenka Martinková, Jiří Skuhrovec, Miroslav Barták, Jan Bezděk, Petr Bogusch, Jiří Hadrava, Jiří Hájek, Petr Janšta, Josef Jelínek, Jan Kirschner, Vítězslav Kubáň, Stano Pekár, Pavel Průdek, Pavel Štys, Jan Šumpich., and Obsahuje bibliografii
Accurate Batesian mimicry is known to impose constraints on some traits of the mimic, such as foraging or reproductive behaviour. It is not known whether life-history traits of inaccurate Batesian mimics are constrained as well. We studied selected life-history traits of three spider species, Liophrurillus flavitarsis, Phrurolithus festivus (both Corinnidae), and Micaria sociabilis (Gnaphosidae), that are inaccurate mimics of ants. Namely, we were interested in how myrmecomorphy (ant-like resemblance) constrains their circadian activity, trophic niche and reproductive behaviour. The spiders were found to have diurnal activity like their models, whereas their close relatives have nocturnal activity. The three mimics do not catch ants, nor do they use food resources of ants, but catch various tiny invertebrates that occur in the vicinity of their models. Their trophic niche seems to be constrained by occurrence among ants. Absence of courtship and long lasting copulation, in a position that does not provide protective resemblance, do not seem to be constrained by mimicry in the three species. Comparative analysis of fecundity in mimetic and non-mimetic spiders showed that clutch size is also not constrained. Unlike in accurate mimics, life-history traits of inaccurate myrmecomorphs appear not to be constrained. and Stano Pekár, Martin Jarab.