Bombolitin is a venom peptide originally isolated from bumblebees and possesses various biological activities, including hemolytic activity. Bombolitins exhibit amphipathic α-helical structure in lipid-membrane-mimicking environments. To investigate their pharmacological and toxicological properties, anti-tumor, anti-microbial and cytotoxic activities of bombolitins from Bombus ardens and Bombus ussurensis were evaluated. Bombolitins of the two species exhibited extremely high anti-tumor activity against ovarian tumor cells SK-OV-3 and NIH; OVCAR-3 at 25-50 μM, which is 2-fold more potent than other wasp venom peptides studied to date (Yoon et al., 2015; Yoon et al., 2016). The two bombolitins showed significantly high antimicrobial activity. However, bombolotin of B. ussurensis showed no antimicrobial activity against Escherichia coli. In addition to their high levels of anti-tumor activity, bombolitins showed considerable levels of hemolytic activity. Thus, to utilize bombolitins as a potential candidate for anti-tumor peptide drugs, further studies for reducing cytotoxic properties of bombolitns is essential.

We cloned venom serine proteases from two bumblebee species, Bombus hypocrita sapporoensis and B. ardens ardens. We compared the predicted mature protein sequences of these serine proteasegenes to those previously reported from other bees. Using B. h. sapporoensis venom serine protease(Bs-VSP), we identify that Bs-VSP acts as a fibrin(ogen)olytic enzyme. Bs-VSP activates prothrombin and directly degrades fibrinogen into fibrin degradation products, as demonstrated for B. ignitus and B. terrestrisvenom serine proteases. Our results further define roles for bumblebee venom serine proteases as fibrin(ogen)olytic enzyme, providing strong evidence that bumblebee venom serine proteases are hemostatically active proteins that are potentially promising therapeutic agents.

Bumblebees are widely used to pollinate crops in greenhouses and fields. Here, we investigated whether different wake-up treatments during a short period of 1-3 days just before indoor rearing has any effects on oviposition and colony development of CO2-treated Bombus ignitus queens and artificially hibernated B. terrestris queens The wake-up regimes were defined as 16L for 1 day (16L-1), 16L per day for 3 days (16L-3), 24L for 1 day (24L-1), or 24D for 1 day (24D-1). Among these wake-up treatments, the oviposition rate and preoviposition period of B. ignitus queens reared at 24L-1 were 16.7-25.1% higher and 1.0-3.5 days shorter than other wake-up treatments. B. terrestris queens reared at 24L-1 also showed the best results for egg-laying characteristics, which were 8.9-18.8% higher for oviposition and 0.6-3.5 days shorter for preovipostion period than other wake-up treatments. Furthermore, B. terrestris queens reared at 24L-1 were 17.5% and 13.8% higher in rate of colony foundation and queen production, respectively, than other wake-up treatments. These results show that the most favorable wake-up treatment just before rearing for egg-laying and colony developmental characteristics of B. ignitus and B. terrestris queens was 24L-1. Overall, our findings indicate that a wake-up treatment just before rearing was effective for colony initiation and colony development of bumblebee queens.

We investigated the mating age for sexual maturity and sperm quality of the bumblebee Bombus terrestris queens and males. In the mating age of sexual maturity of queen, mating rate was 6.7% at just emergence, 85.0% at 10 days of emergence, and decreased thereafter. In case of mating age of sexual maturity of male, mating rate was 38.3% at just emergence and 62.5% to 75.0% at 7 days to 20 days of emergence. The colony development at aging of B. terrestris queen and male was a similar tendency to the mating age of sexual maturity. In case of multiple mating, B. terrestris male was mated by 4 times, which was 74.3% for one time, 50.0% for two times, 22.9% for three times and 8.6% for four times. The number of spermatozoa was increased as the age of male was older until 25days after emergence. The number of spermatozoa of non-mated males of one day and 3 days after emergence was higher at 1.2 and 1.7 times than that of mated males and 18.9 and 36.6 times than that in spermatheca of mated queen. Our results indicate that period favorable for artificial insemination of B. terrestris was from 6 days after emergence for queen and 7 days after emergence for male.

The large bumblebee, Bombus terrestris, which is indigenous to Europe and is used extensively for high-value crop pollination, has been artificially introduced throughout the world. Here we show the interspecific cross-mating between bumblebee species, B. terrestris and B. ignitus under laboratory conditions. The mating and oviposition rates of interspecific cross-mating of B. terrestris queen with B. ignitus male are higher than those of intraspecific matings of B. ignitus. Furthermore, the competitive copulation experiment indicates that cross-mating of a B. ignitus male with B. terrestris queen is 1.8-fold more frequent than with a B. ignitus queen. The cross-mated B. ignitus queen with B. terrestris male produced B. ignitus workers and B. ignitus male offspring, and the cross-mated B. terrestris queen with B. ignitus male produced both B. terrestris males and B. ignitus male offspring. The genetic tests using a portion of the mitochondrial COI gene for the parent and hybrid offspring indicate that mitochondrial DNA was maternally inherited. Our results indicate that interspecific cross-mating occurred between B. ignitus and B. terrestris, which suggests that the cross-mating is not an exclusive force against the negative impact of competition and genetic contamination on native bumblebees.

We compared colony development and survival rate after artificial hibernation between the bumblebees, Bombus terrestris, produced from domestic and foreign companies. The number of worker and queen produced from foundation colony of three domestic and one foreign companies was 232.4-270.8 and 62.0-181.8, respectively, but there was no statistical difference. in colony development of B. terrestris queens which were terminated diapause by CO₂ narcosis at different companies, oviposition rate, colony foundation and progeny-queen production of bumblebees produced from domestic companies were superior to those from foreign company. But foreign company in the number of worker and queen was superior to domestic companies. On the other hand, survival rate and colony development of B. terrestris queens, which were terminated diapause by artificial hibernation at three domestic and two foreign companies, were no significant differences. These results indicate that oviposition, colony foundation, progeny-queen production, and survival rate after artificial hibernation showed no differences between the bumblebees produced from domestic and foreign companies.

토종 호박벌(Bombusignitus)과 수입 서양뒤영벌(B. terrestris)의 냉장온도별 생존율과 실내사육에 의한 봉세발달을 비교 조사하였다. -2.5, 0, 2.5, 5등 4종류 냉장온도 중 호박벌과 서양뒤영벌 모두 2.5에서 생존율이 가장 높았으며, 냉장 3개월까지는 호박벌이, 냉장 4개월째는 서양뒤영벌의 생존율이 다소 높게 나타났다. 한산가스처리로 휴면을 타파한 여왕별의 봉세발달을 조사한 결과, 산란율은 호박벌이 72.5%로 서양뒤명벌보다 6.1% 높았고, 산란전기간도 17.4일로 7.4일 빨랐다. 일벌이 50마리 될 때까지의 봉군형성소요일수, 수벌 및 여왕벌출현소요일수 또한 호박벌이 각각 62.8일, 66.4일, 63.0일로 서양뒤명벌보다 2.1-29.5일 빨리 출현하였다. 그러나 일벌출현소요일수는 28.6일과 28.4일로 차이가 없었다. 반면에 우수봉군의 지표가 되는 봉군형성률 및 신여왕벌출현봉군율은 서양뒤영벌이 각각 14.2%, 13.6%로서 호박벌보다 3.8-5.7배 높게 나타났다. 성충출현수 역시, 서양뒤영벌이 일벌 104.2 마리, 수벌 317.9 마리, 여왕벌 27.1 마리로 호박벌보다 1.1-1.8배 많아 봉세 발달은 서양뒤영벌이 우수한 것으로 나타났다.