A scientific note on DNA fragmentation rates in sperm collected from drones and spermathecae of queens of different age, with possible implications on the scattered brood phenomenon

International audienceNo abstract availabl

A review of some issues in the ethological studies of beekeeping

W artykule omówiono ważne zagadnienia z zakresu etologii stosowanej w pszczelarstwie, takie jak: zachowania obronne, zachowania higieniczne, zbieranie nektaru i pyłku, opisano kilka przykładów komunikowania się pszczół, omówiono biologiczne sensory pszczół umożliwiające orientacje przestrzenną oraz omówiono zachowania rozrodcze. Opisano metody testowania zachowania obronnego przy pomocy "ball testu", którym zbadano agresywność pszczół afrykańskich sprowadzonych do Brazyli. Import pszczół afrykańskich miał na celu zwiększenie wydajności miodowej miejscowych pszczół. Jednak wzrosła tylko agresywność pszczół miejscowych, co dało początek pszczołom zafrykanizowanym. Odsklepianie, a następnie usuwanie z plastrów zainfekowanego/martwego czerwiu jest sposobem unikania przez pszczoły infekcji bakteryjnych. Selekcja w kierunku tego zachowania poprzez zwiększanie zdolności rodzin do samowyleczenia ma pozwolić w przyszłości na zredukowanie ilości środków chemicznych (leków) wprowadzanych do ula, a tym samym, wpłynie na poprawienie jakości produktów pszczelich. Przedstawiono metody badań nad zachowaniem higienicznym pszczół, które polegają na ocenie szybkości usuwania zabitego czerwiu z plastrów. Opisano alternatywną metodę przydatną w testowaniu zachowania higienicznego. Zamiast uśmiercać czerw i określać szybkość jego usuwania, można pszczołom podawać tekturę i określić szybkość usuwania tektury z rodziny pszczelej. Przybliżono strategie zbierania nektaru i pyłku przez pszczoły. Zbieraczki wylatujące po nektar, kierują się długoterminową maksymalizacją zysku. Oznacza to, że czy jest zapotrzebowanie/bodźce, czy też go nie ma, pszczoły i tak zbierają nektar, który w dłuższej perspektywie czasu będzie im potrzebny. Zbieraczki wylatujące po pyłek kierują się celem krótkoterminowym, czyli podejmują tę pracę wtedy, kiedy jest taka potrzeba/bodziec. Zbiór pyłku stymulują: duża ilość czerwiu niezasklepionego i brak zapasów pierzgi (zakonserwowanego pyłku), a hamują: brak miejsca w plastrach, brak czerwiu i duże zapasy pierzgi. Dodatkowo zbieraczki pyłku cechuje określona strategia i jest ona związana z jakością pyłku, a tym samym preferowaniem wybranych roślin. Przypomniano klasyczne badania Karla von Frischa nad tańcami pszczół, którymi pszczoły porozumiewają się i są w stanie wskazać kierunek pożytku. Dzięki intensywności wykonywanego tańca przez zbieraczki, pszczoły w ulu są w stanie wybrać obfitsze/lepsze źródło pożytku. Pszczoły zapamiętują położenie ula względem punktów orientacyjnych w terenie np. drzewa, krzewy. Orientację umożliwia im również zdolność rozpoznawania kolorów wylotów uli. W artykule omówiono haplo-diploidalny typ determinacji płci u pszczół. Wyjaśniono, jak dochodzi do lotów godowych matek pszczelich z trutniami. Matka, po locie godowym, plemniki przechowuje w zbiorniczku nasiennym, dlatego przez całe swoje życie może składać jaja zapłodnione i niezapłodnione. Liczba składanych jaj na dobę może dwukrotnie przekraczać masę ciała matki, a uzależnione jest to od pielęgnacji i odżywiania mleczkiem pszczelim podczas składania jaj.The article discusses several important issues in the ethological studies of beekeeping including defense behaviour, hygienic behaviour, foraging for nectar and pollen, some aspects of communication, spatial orientation and sensory biology, and reproductive behaviour. It describes methods of testing defense behaviour using the ball test. This test has been applied to examine the aggression in African bees brought to Brazil. The import of African bees was aimed at increasing the honey yield of local honey bees. This, however, resulted in enhanced aggressiveness of the native bees, and gave rise to the emergence of Africanised bees. The uncapping and removing of infected/dead brood from the honeycomb is the way bees try to eliminate infection. Selection for the uncapping and removing behaviour, will enhance the self-healing abilities of bee families. The quantities of chemicals (drugs) introduced into beehives in the future may then be reduced. The quality of bee products will also improve. When studying bee hygienic behaviour, it is necessary to check the rate of the removal of dead brood from combs. There is an alternative method that is useful for testing hygienic behaviour: instead of killing the brood and then determining the brood removal rate, bees can be supplied with cardboard. The cardboard removal rate in bee colonies may then be estimated. Strategies of nectar and pollen hoarding used by bees, have been presented. Foragers flying out to collect nectar are guided by long-term profit maximization. Therefore, irrespective of the presence of demand/stimulus, bees collect nectar which they will ultimately need. Foragers flying out to collect pollen have a short-term goal, i.e., they collect pollen when there is a need/stimulus. Collection of pollen is stimulated by a large number of open brood cells, and lack of bee bread (preserved pollen); it is inhibited by lack of space in the honeycombs, lack of brood, and sufficient bee bread stocks. Additionally, pollen foragers may employ various strategies related to the quality of pollen and a preference for particular plants. In the article, Karl von Frisch's classic study of the bee dance is also mentioned. Dancing bees are able to communicate the direction of nectar sources to their nestmates. The bees in the hive are able to choose a more abundant/better source of nectar flow on the basis of the intensity of the dance performed by foragers. Bees remember the location of the hive in relation to landmarks on the ground, such as trees or shrubs. Bee orientation is facilitated by the ability to distinguish the colours of the hive entrances. The article also discusses haplo-diploid sex determination in bees. After the mating flight, the queen stores the sperm in the spermatheca. The queen is then able to lay fertilized and unfertilized eggs throughout her life. The number of eggs laid daily may be twice as high as the queen's body weight. It depends on the care and nutrition of royal jelly provided by worker bees during oviposition

A numerical analysis of metrological properties of Venturi tube in the air-coal particle mixture flow measurement in power industry

The main topic of the study is to evaluate the effect of particle concentration and fractional composition on the differential pressure in the Venturi tube during the measurement of flow rate of the gas-particle mixture. Gas phase flow was described by Euler method, while particles movement by Lagrange method. Calculations were performed using ANSYS Fluent Package. A series of numerical calculations were carried out on the particle loading ratio Y ≤ 2 and their diameters of 10 μm ≤ dp ≤ 200 μm. It has been found that, except for the Y concentration loading ratio, the increase in the differential pressure in the venturi tube also affects the Stokes number. It depends on the flow conditions and particles diameter. A correction function has been proposed to determine the effect of particles diameter on the results of the mixture flow measurement. The results of the calculations were compared with the Lee and Crowe experimental data. A good comparison of calculation results to measurement results was found

Prospects and Validity of Laboratory Cage Tests Conducted in Honeybee Research Part Two: New Possibilities for Use of Laboratory Cage Tests in Response to Challenges Revealed at the Turn of the 20th and 21st Centuries

Nowadays, cell cultures are a standard tool in animal biotechnology, but the problem with honeybees is the constant lack of appropriate cell lines to be used in in vitro research. Until the imperfections of bee tissue cultures are resolved, researchers have to conduct experiments on bees in laboratory cage tests (LCTs)

Modification of the inlet to the tertiary air duct in the cement kiln installation

Rotary kiln installation forms a very complex system, as it consists of various components which affect cement production. However, some problems with particle settling are encountered during operation of tertiary air installation. This paper reports on the results of a study into gas-particle flow in a tertiary air duct installation. This flow was calculated using Euler method for air motion and Lagrange method for particle motion. The results in this paper demonstrate that study focus on the tertiary air installation is a practical measure without the analysis of other processes in the rotary kiln. A solution to this problem offers several alternatives of modifying the inlet to the tertiary air duct. As a result of numerical calculations, we demonstrate the influence of geometry of a rotary kiln modification on the number of large particles transported in the tertiary air duct. The results indicate that in order to reduce large particles, rotary kiln head geometry needs to be modified, and a particle settler should be installed at its outlet

Dead Brood of Apis mellifera Is Removed More Effectively from Small-Cell Combs Than from Standard-Cell Combs

The efficiency of the hygienic behaviour in bee colonies towards dead brood was assessed in small-cell combs (SMCombs) and in standard-cell combs (STCombs). Each colony had both types of combs in the nest on a permanent basis. Simultaneous keeping of a colony on standard- and small-cell combs is a novel approach to the use of small-cell combs in beekeeping. The number of killed pupae removed within 24 h was the measure of the hygienic behaviour efficiency. Regardless of the year, the brood in the SMCombs was uncapped and removed significantly more efficient (p ≤ 0.01) than in the STCombs (number of non-uncapped cells: in 2020 SMCombs = 3.79, STCombs = 11.62; in 2021 SMCombs = 2.34, STCombs = 5.28 and completely removed cells: in 2020 SMCombs = 87.46, STCombs = 80.04; in 2021 SMCombs = 96.75, STCombs = 92.66). In colonies kept simultaneously on standard- and small-cell combs, the width of the comb cells has a significant effect on the efficiency of removal of dead brood, which is removed more efficient from small-cell combs than from standard-cell combs

Prospects and Validity of Laboratory Cage Tests Conducted in Honeybee Research Part one: Main Directions of Use of Laboratory Cage Tests in Honeybee Research

For more than forty years, laboratory cage tests (LCTs) have been used in honeybee research. These tests facilitate the control of elements of the environment present in the laboratory, which allows the minimization of the impact of the changing environmental conditions and conditions in the bee colony nest on the studied features. Therefore, it is possible to estimate the content of the genetic component of a particular trait and to assess the impact of a specific substance or tested agent on the traits of bees

Possibility to change the body size in worker bees by a combination of small-cell and standard-cell combs in the same nest

International audienceThe aim of the study was to investigate the impact of the combination of the colony type (kept on small-cell or standard-cell combs) and the width of worker comb cells (small-cell or standard-cell combs) on the body weight and morphometric traits of worker bees. The values of morphometric parameters of worker bees changed within a substantially lower range than the width of their rearing cells. This indicates that the worker body size is relatively constant, and manipulation with the cell width is not a good method for modeling the body size of workers. The reduction in the thorax weight was proportional to the decrease in the comb cell width, and this part of the body proved to be most susceptible to weight reduction caused by the use of small-cell combs. The rearing of workers in small-cell combs in the colony kept on standard-cell combs resulted in an increase in the value of the fill factor (thorax width to cell width ratio). The relatively constant body size of workers in combination with the use of small-cell combs resulting in an increase in the fill factor may be one of the determinants of increased resistance of the insects to Varroa destructor. The values of the morphometric traits commonly used for identification of honeybee subspecies, i.e., the length of the fore wing, the sum of the widths of 3rd and 4thth tergites, and the proboscis length, were inconsiderably altered vs. the changes in the comb cell width, which confirms their high suitability for identification of honeybee subspecies

Nosema ceranae Infection Promotes Proliferation of Yeasts in Honey Bee Intestines.

BACKGROUND:Nosema ceranae infection not only damages honey bee (Apis melifera) intestines, but we believe it may also affect intestinal yeast development and its seasonal pattern. In order to check our hypothesis, infection intensity versus intestinal yeast colony forming units (CFU) both in field and cage experiments were studied. METHODS/FINDINGS:Field tests were carried out from March to October in 2014 and 2015. N. ceranae infection intensity decreased more than 100 times from 7.6 x 108 in March to 5.8 x 106 in October 2014. A similar tendency was observed in 2015. Therefore, in the European eastern limit of its range, N. ceranae infection intensity showed seasonality (spring peak and subsequent decline in the summer and fall), however, with an additional mid-summer peak that had not been recorded in other studies. Due to seasonal changes in the N. ceranae infection intensity observed in honey bee colonies, we recommend performing studies on new therapeutics during two consecutive years, including colony overwintering. A natural decrease in N. ceranae spore numbers observed from March to October might be misinterpreted as an effect of Nosema spp. treatment with new compounds. A similar seasonal pattern was observed for intestinal yeast population size in field experiments. Furthermore, cage experiments confirmed the size of intestinal yeast population to increase markedly together with the increase in the N. ceranae infection intensity. Yeast CFUs amounted to respectively 2,025 (CV = 13.04) and 11,150 (CV = 14.06) in uninfected and N. ceranae-infected workers at the end of cage experiments. Therefore, honey bee infection with N. ceranae supported additional opportunistic yeast infections, which may have resulted in faster colony depopulations