Until recently, the Canadian distribution of the blueberry maggot, Rhagoletis mendax Curran (Diptera: Tephritidae), was restricted to Nova Scotia, Prince Edward Island and New Brunswick. The insect was first mentioned in southern Quebec in 1996 and, to date, it has not reached the Lac St-Jean region, where 34% of Canadian blueberry acreage is located. Two questions concerning the northern limit of distribution of the blueberry maggot in Quebec were addressed. First, are wild plants suitable hosts for larval development? We collected the fruit of five wild plants, (e.g. Vaccinium corymbosum, Vaccinium angustifolium, Vaccinium myrtilloides, Gaylussacia baccata, and Aronia melanocarpa) growing in southern Quebec and allowed larvae to complete their development into pupae. Blueberry maggot pupae were recovered from Vaccinium corymbosum, Vaccinium angustifolium, and Gaylussacia baccata, indicating that these plants are suitable for larval development. Second, are harsh winter temperatures a factor limiting the northern distribution of the blueberry maggot? Pupae collected in Quebec and Nova Scotia were put in the soil in the fall and were brought back to the laboratory to determine their supercooling points at different times during winter. The supercooling points of pupae collected in Quebec and Nova Scotia averaged -22.6°C. In natural conditions, air temperatures <-20°C are frequently observed in Quebec in January, February and March. However, due to snow cover, soil temperatures are rarely <-12°C. If -22.6°C constitutes the lower limit for the survival, then winter temperatures are probably not a limiting factor to its northern distribution in Quebec, because blueberry maggot pupae overwinter in the soil., Charles Vincent, Pierre Lemoyne, Sonia Gaul, Kenna Mackenzie., and Obsahuje bibliografii
Thrips are important agricultural pests and accurate identification is important for their effective management. In order to determine species, however, they need to be mounted on slides and the traditional process is time-consuming. The aim of this paper is to describe a simple and fast method to prepare temporary slides for the routine identification of thrips, which is not dependent on their colour and hardness. Four species of thrips of different colours were used in the preparations: Frankliniella occidentalis (yellow with brown tergal markings), Frankliniella schultzei (entirely brown), Haplothrips gowdeyii (dark brown to carmine) and Caliothrips phaseoli (brown to black). Slides of each species were prepared using three different methods: traditional (3 days), simplified (6 h) and fast method (10 min). The thrips on the resulting slides were observed under a microscope and important structures used in their identification were compared. The quality of the slides prepared using the traditional method was superior to those prepared using the other two methods if only the transparency and general position of the insects on the slides were considered. The transparency of the slides prepared using the simplified method was also good, but only for the pale coloured species (yellow and grey-brown). The fast method, on the other hand, was very efficient for routine identification since it resulted in slides of sufficient quality for identifying species regardless of their colour. It is important, however, to stress that the fast method is only suitable for preparing temporary slides for routine identification and is not a substitute for the traditional method of preparing permanent slides., Luís C.P. Silveira, Marcelo M. Haro., and Obsahuje bibliografii
Faunistika není mrtvý obor zoologie. V prvním dílu diskutujeme záludnosti faunistiky a rozdíly mezi faunistikou a sběratelstvím. Měkkýši byli vybráni jako modelová skupina organismů, na nichž ukazujeme historii vývoje oboru v Českých zemích a vývoj měkkýší faunistiky., Faunistics is not a dead subject of zoology. The challenges of faunistics and the difference between faunistics and collecting are discussed. Molluscs were chosen as a model group to show the history of the subject in the Czech Republic and the development of mollusc faunistics., and Vojen Ložek, Lucie Juřičková.
Detailní výzkum recentní fauny umožňuje srovnání s výskytem jednotlivých druhů v období od glaciálu, přes oteplení na počátku holocénu, klimatické optimum holocénu i s nástupem zemědělství až po zhoršení podmínek v mladším holocénu. Fosilní záznamy mohou pomoci při vysvětlení absence konkrétních druhů na určitém místě v současnosti. Autoři článku také diskutují vliv ekologických fenoménů na lokální druhovou diverzitu - některé z nich druhovou bohatost zvyšují (říční, krasový a vrcholový fenomén), jiné ji snižují (hadcový a pískovcový fenomén). Faunistický výzkum musí probíhat ruku v ruce s taxonomickými studiemi. I v tak malakologicky prozkoumaných zemích, jako je Česká republika, jsou stále objevovány pro dané území nové druhy, včetně invazních – žádné území není prozkoumané jednou provždy. Článek zmiňuje některé důležité faunistické objevy na území České republiky, tak připomíná zásadní význam tohoto dnes podceňovaného oboru a nastiňuje také jeho výhled do budoucnosti., It is important to study the occurrence (presence vs. absence) of extant species; fossil records can help explaining the patterns. The role of ecological phenomena on local species diversity is discussed. The impact of ecological phenomena on local species diversity is discussed – some of them increase (river, karst and hilltop phenomena), while others decrease the species diversity (serpentine and sandstone phenomena). Faunistic research must go hand in hand with taxonomic research. Even in a well-explored country such as the Czech Republic, new species for this area are constantly being discovered including some invasive species, making faunistic research a never-ending story., and Lucie Juřičková, Vojen Ložek.
We investigated the effect of the feeding behaviour of young larvae of Pieris rapae crucivora Boisduval (Pieridae) on parasitism by the parasitoid wasp, Cotesia glomerata (L.) (Braconidae). Young, 1st-3rd instar larvae used approximately three sites for feeding each day. When not feeding, they moved a short distance away from the feeding sites (= feeding marks) and rested. For first, second and third instar larvae, the distances from the new mark, made within 24 h, to larva at rest were, respectively, about 3.5 mm, 5 mm and more than 10 mm. To resume feeding, they moved back to one of the former feeding sites or a new site. The percentage of the feeding marks older than 24 h that attracted parasitoids was less than 50%. Time spent searching for hosts by a parasitoid was short. Larvae placed 5 mm or more from a feeding mark were less parasitized than the larvae placed near a mark. The number of feeding marks affected parasitism. When comparing single-marked and triple-marked leaves, the percentage parasitism of the larvae on the latter was significantly lower than that of the larvae on the former. On triple-marked leaves, parasitoids visited each mark unevenly. Accordingly, the time spent searching each mark differed significantly among the marks. Because of this confusing effect, hosts are considered to be reducing the risk of parasitism. Our results demonstrate that the feeding habits of young larvae of P. rapae crucivora are adaptive in terms of reducing the risk of parasitism by C. glomerata., Aya Nakayama, Keiji Nakamura, Jun Tagawa., and Obsahuje bibliografii
Haemadipsid leeches are among the most successful terrestrial invertebrates in Bornean rainforests. They are very common ectoparasites of vertebrates, and their abundance has facilitated the conduction of numerous projects in the fields of ecology, zoogeography and taxonomy. We undertook research on two species inhabiting lowland dipterocarp forest, Haemadipsa picta Moore, 1929 and Haemadipsa subagilis (Moore, 1929), in order to address the following questions: (a) is there a difference in leech abundance between trails and off-trails?; (b) is ambush location dependent on specimen size or is species-specific?; (c) is intra- and interspecific competition limited by differences in foraging behaviours or vertical niche partitioning? Our results clearly show that H. picta is more abundant on trails than on off-trails and is vertically dispersed within the understory; the size of a specimen is strongly correlated with plant height. Haemadipsa subagilis was found not to exhibit such patterns. We suggest a possible lowering of interspecific competition between these species as a result of: (i) size-dependent dispersion of H. picta (together with reduction of intraspecific competition); and (ii) habitat specialisation of H. subagilis. Moreover, we provide new observations on their foraging behaviour., Piotr Gąsiorek, Hanna Różycka., and Obsahuje bibliografii
Parasitoid females may adjust offspring sex allocation according to the number and quality of hosts available. Because in solitary species only one offspring survives per host, already parasitized hosts are of low quality and generally rejected. Superparasitism (i.e., sequential oviposition by the same or different females) results in aggressive interactions and competition for nutritional resources among larvae. We examined variations in the offspring sex ratio of Dendrocerus carpenteri (Curtis) (Hymenoptera: Megaspilidae), a solitary ectoparasitoid developing as a hyperparasitoid on the prepupae and pupae of primary aphid parasitoids inside mummified aphids. Mated females produced a female-biased sex ratio of 0.433 (proportion of sons) when caged singly and provided with 12 mummies for 2 h; they parasitized an average of four mummies/h and rarely superparasitized. Superparasitism increased when two females were caged together and provided with 12 mummies, from 1.18 to 1.24 and 1.38 eggs/host parasitized in 1, 2 and 3 h, respectively. The offspring sex ratio became increasingly more female-biased with increase in superparasitism; however, sex ratio variations were not correlated with cohort size. One mated and one unmated female provided with 12 mummies and caged together for 1 h produced a mean cohort sex ratio of 0.645, which differed from the one predicted (0.717) by an algebraic model incorporating the assumptions that both females contribute equal numbers of offspring and that the mated female does not change her offspring-sex allocation strategy. The observed shift in the cohort sex ratio to an increased female-bias indicates that mated females of D. carpenteri change their behaviour when encountering parasitized mummies or a conspecific competitor in the same patch. By depositing fertilized rather than unfertilized eggs, a female can increase the proportion of her daughters among parasitoids competing for a diminishing host supply., Manfred Mackauer, Andrew Chow., and Obsahuje bibliografii