Vybrat vhodnou metodu sběru hmyzu tak, aby byla efektivní a přitom poskytovala relevantní data, není vůbec snadné. Na základě rozsáhlého datového souboru se ukázalo, že zemní pasti, standardně používaná metoda při ekologickém výzkumu epigeických členovců, zaznamenaly jen polovinu druhů střevlíků ve srovnání s metodou individuálního sběru. Výrazně se lišily i vlastnosti zaznamenaných druhů, v pastech převládaly druhy velké, kdežto ve vzorcích z individuálního sběru druhy drobné. Ale i metoda individuálního sběru má své mouchy, protože její účinnost do značné míry závisela na terénních zkušenostech sběratele. Ideálním řešením zajišťujícím co nejkompletnější záznam společenstev střevlíků se zdá být kombinace obou metod sběru dat., The selection of a proper sampling technique for ecological research into insect assemblages is a tough nut to crack. Based on extensive field study, I have shown that the commonly employed "pitfall trapping" technique recorded just half the number of carabid species compared to the individual collection technique. There were also differences in species trait representation in samples originating from each particular technique. Pitfall traps efficiently recorded large species but missed smaller ones, which were frequently recorded by individual collection. The main shortcoming of the individual collection technique is the dependence of its efficiency on the field experiences of each particular researcher. A combination of both investigated sampling techniques seems to be the best way to gain as complete records of carabid assemblages as possible., and Michal Knapp.
Reflex bleeding is one of the many anti-predation behavioural tactics used by insects. This behaviour is recorded widely in several insect taxa and provides scientists with an interesting opportunity for easily obtaining samples of haemolymph for physiological experiments. However, there is no good evidence that haemolymph and reflex blood have the same characteristics. In this study, we compared three basic characteristics of reflex blood and haemolymph collected from the body cavity, of three species of ladybirds: Harmonia axyridis, Coccinella septempunctata and Ceratomegilla undecimnotata. In the reflex blood we recorded the same concentration of haemocytes and total protein, and level of antimicrobial activity against Escherichia coli as in samples of haemolymph collected from within the body cavity. Therefore, reflex blood is a promising source of haemolymph for use in many physiological and immunological studies. It is the best way of collecting haemolymph if one wants to avoid challenging the immune system and concurrently also enables one to repeatedly collect haemolymph from one individual without injuring it, which would initiate repair mechanisms. The interspecific comparison indicates significant differences among the species studied in three characteristics measured. Interestingly, the native species Ceratomegilla undecimnotata has nearly as effective immune system as the invasive Harmonia axyridis based on the level of antibacterial activity against Escherichia coli.
Pitfall trapping is the most frequently used sampling technique for epigeal arthropods. Trap design could significantly affect the catch so the results of studies using different trap designs may be difficult to compare. Although species composition is frequently investigated in ecological studies, however when pitfall trapping is employed, the effect of trap design on the recorded species composition is rarely considered. In the present study, we investigated the effect of trap construction (funnel or cup trap) and the preservative used (formaldehyde or propylene glycol) on total catch, catch of particular species, species richness and species composition of the ground beetle assemblage sampled. We were interested in the extent to which trap design could bias these characteristics. Total catch was significantly affected by trap construction and preservative used, with the effect of the latter being the stronger. Species richness was only slightly affected by trap design when assemblages caught by traps of a particular type were corrected for unequal sample size. Moreover, we show that the traps of different designs differ in their efficiency for catching particular species of carabid and thus the composition of assemblages recorded using pitfall traps is affected by trap construction and the preservative used. We conclude that to assess the full significance of the effect of pitfall trap design on the results of ecological studies on epigeal arthropods it is necessary to simultaneously use traps of various designs., Michal Knopp, Jan Růžička., and Obsahuje seznam literatury