Hi all
Today's NY Times has the article: "Are Your Sperm in Trouble?" by Nicholas Kristof
These days, scientists say, an increasing proportion of sperm — now about 90 percent in a typical young man — are misshapen, sometimes with two heads or two tails. Sperm counts also appear to have dropped sharply in the last 75 years, in ways that affect our ability to reproduce.
One recent study found that of sperm donor applicants in Hunan Province, China, 56 percent qualified in 2001 because their sperm met standards of healthiness. By 2015, only 18 percent qualified. "The semen quality among young Chinese men has declined over a period of 15 years," concluded the study, which involved more than 30,000 men.
Perhaps even more alarming, Canadian scientists conducted a seven-year experiment on a lake in Ontario, adding endocrine disrupting chemicals and then observing the impact on fathead minnows. The chemicals had a devastating impact on males, often turning them into intersex fish, with characteristics of both sexes but incapable of reproducing.
Back to bees:
The adverse sublethal effects of PPPs [plant protection products] on non-target invertebrate species, including the honey bee, are a major concern, but they remain difficult to assess. In this context, we have developed tools that can be used to take into consideration a portion of the potential hazard posed by PPPs to honey bee reproduction.
In this study, we reared drones using different methods using bees that were or were not exposed to a relevant concentration of the insecticide Fipronil, which has been previously shown to have effects on drone fertility under SF [semi-field] conditions and on the reproductive potential of the queen ... the exposed drones presented impaired semen quality, which was attributed to a decrease in the amount of spermatozoa and an increase in the spermatozoa mortality rate.
Fipronil did not affect survival rates, maturity rates or semen volumes, whereas it did affect fertility by inducing a decrease in spermatozoa quantity that was associated with an increase in spermatozoa mortality.
Kairo, Guillaume, et al. "Assessment of the toxicity of pesticides on honey bee drone fertility using laboratory and semi‐field approaches: A case study of fipronil." Environmental Toxicology and Chemistry (2017).
http://onlinelibrary.wiley.com/doi/10.1002/etc.3773/pdf
submitted for review purposes only by PLB
***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
|