Individual study: Periods of artificial light stimulate egg-laying in buff-tailed bumblebee queens Bombus terrestris; laboratory experiments at the French National Institute for Agricultural Research (INRA), Poitou-Charentes, France.
(1994) Effect of different narcosis procedures on initiating oviposition of pre-diapausing Bombus terrestris queens. Entomologia experimentalis et applicata, 72, 273-279
Bumblebees Bombus spp. are declining in Europe, and captive rearing could be used to augment or re-establish populations. This study tests the effect of different rearing procedures on egg-laying in buff-tailed bumblebee queens Bombus terrestris, in a laboratory study at the French National Institute for Agricultural Research (INRA), Lusignan, Poitou-Charentes, France.
Five days after mating, 200 laboratory-reared B. terrestris queens (not hibernated) were cooled to 3-4°C, then anaesthetized in plastic boxes with 99.9% CO2 for two periods of 10 minutes, 24 hours apart. Between the periods of ‘narcosis’ queens were kept at 23-24°C.
The only experimental treatment that increased the chances of a queen laying eggs, and made her lay more quickly, was eight hours of artificial light during rearing.
Queens exposed to light were more likely to survive and lay eggs (73%) than those kept in the dark (67%) and laid eggs more quickly (21.1 days on average, compared to 38.9 days to lay eggs in the dark).
A period of high temperature, narcosis at a greater age, or for a shorter time did not affect the percentage of queens that laid eggs (65-68%) or the amount of time before egg-laying (36-40 days), compared to the standard treatment.
Without narcosis, 7 of 13 queens (53%) survived and laid eggs, but took a similar amount of time to lay eggs as queens given 10 minutes of narcosis (average 17.3 – 19.8 days). There was no significant difference between the proportion of queens surviving and the time taken to lay eggs, between the five and 10 minute narcosis treatments.
Note: If using or referring to this published study, please read and quote the original paper, the abstract of which is available at: http://www3.interscience.wiley.com/journal/117984720/home