BackgroundIn addition to their general role in the hydrolysis of storage lipids, bumblebee lipases can participate in the biosynthesis of fatty acids that serve as precursors of pheromones used for sexual communication.ResultsWe studied the temporal dynamics of lipolytic activity in crude extracts from the cephalic part of Bombus terrestris labial glands. Extracts from 3-day-old males displayed the highest lipolytic activity. The highest lipase gene expression level was observed in freshly emerged bumblebees, and both gene expression and lipase activity were lower in bumblebees older than 3 days. Lipase was purified from labial glands, further characterized and named as BT-1. The B. terrestris orthologue shares 88% sequence identity with B. impatiens lipase HA. The molecular weight of B. terrestris lipase BT-1 was approximately 30 kDa, the pH optimum was 8.3, and the temperature optimum was 50°C. Lipase BT-1 showed a notable preference for C8-C10 p-nitrophenyl esters, with the highest activity toward p-nitrophenyl caprylate (C8). The Michaelis constant (Km) and maximum reaction rate (Vmax) for p-nitrophenyl laurate hydrolysis were Km = 0.0011 mM and Vmax = 0.15 U/mg.ConclusionThis is the first report describing neutral lipase from the labial gland of B. terrestris. Our findings help increase understanding of its possible function in the labial gland.

S u m m a r ySeveral methods for stimulating nest initiation (particularly the use of the Bombus terrestris cocoon) in queen bumblebees of the species B. lapidarius and B. hortorum were compared. For B. lapidarius, it was determined that the percentage success rate for establishing the fi rst egg cell on a cocoon of B. terrestris is similar to that on a conspecifi c cocoon. Nest establishment, however, was signifi cantly slower on the cocoon of B. terrestris. Moreover, it was determined that queens of B. lapidarius are able to initiate a nest without hibernation. Queens hibernated in the laboratory displayed a similar percentage success rate in establishing an egg cell during stimulation with the cocoon of B. terrestris as did the outdoor queens, but the lab queens established it signifi cantly more slowly. Queens of B. hortorum did not incubate the cocoon of B. terrestris, nor did they establish an egg cell on it.

BUČÁNKOVÁ, A., KOMZÁKOVÁ, O., CHOLASTOVÁ, T., PTÁČEK, V.: Notes on distribution of Bombus cryptarum (Hymenoptera, Apoidea) in Moravian territory (Czech Republic) and its laboratory rearing. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 6, pp. 69-74 B. cryptarum and B. magnus are among the so-called cryptic species whose identifi cation is very diffi cult due to high interspecifi c variability of their morphological characteristics. This greatly limits possibilities for studying their biology, bionomics and ecology. The aim of this research was to contribute to knowledge about distribution of B. cryptarum in Moravia (Czech Republic) and to verify the possibility of its laboratory rearing. During 2006During -2009 collections were performed at Moravian localities. Of the 17 specimens that were assigned to B. cryptarum or B. aff . cryptarum based on morphology, the molecular analysis of mtDNA RFLP confi rmed the identifi cation of 10 speciemens. The molecular analysis even assigned to B. cryptarum one specimen determined morphologically as B. aff . magnus. Of four queens captured in spring, and while applying a laboratory method used for breeding of B. terrestris, two complete nests were successfully reared, including queens of the 2nd generation that then set up their own brood. Species identifi cation of these queens as B. cryptarum was confi rmed by both molecular analysis and analysis of the marking pheromones of males among their off spring. A single B. terrestris worker was able to raise young queens of B. cryptarum of the brood.

The consumption of sugar is an important part of the energy intake of social insect. Its monitoring provides information regarding the costs and efficiency of energy flow in a colony. This study aims at tracking the sugar flow from a sugar source to artificial bumblebee micro-colonies and at quantifying the amount of sugar consumed by the larvae. We developed a new method of sugar tracking that utilises an inert lanthanide complex (GdDOTA) dissolved in an aqueous sugar solution. The delayed defecation of bee larvae enabled the collection of all faeces from a cocoon. The amount of digested sugar corresponded to the amount of the lanthanide in the faeces, which was quantified using inductively coupled plasma spectrometric techniques. We highlight the possibility of the novel developed method to be extended for tracking the energy flow within a colony using up to 15 different metal markers without the necessity of killing individuals.