Animal Diseases: Symptoms of a Sick Planet?
It has been given the name White Nose Syndrome (WNS), a name that almost certainly describes a symptom and not the cause. This new disease of bats has been compared to the growing Colony Collapse Disorder (CCD) in bees, also a term that describes consequences–the best we can do–because we don’t understand why it is happening.
The media compares WNS to CCD which in turn is said to be like the AIDS of bees. There is so much we do not understand. One thing is “like” another. Metaphors give us false comfort. Our problems seem more manageable boiled down to a few letters.
Bats leave their caves too early in winter. They starve to death, their fat reserves burned up too soon. As immune protections weaken, unable to preen, white spores of an opportunistic fungus dusts their noses. Investigators use thermal imagery to study infected caves. Sick bats glow an eerie green, warmed for the last time by insects eaten on the wing months earlier.
WNS is spreading in New York and Vermont where it was first discovered last year. Springtime migration promises to carry it far off to other caves where the tiny flying mammals roost hundreds per square foot.
While it is likely that human cavers (perhaps wearing boots they wore days before in caves on another continent) brought the unknown organism into the first infected caves, the bats will pass it amongst themselves. Several species are already affected, including the endangered Indiana Bat.
Is the comparison of WNS to CCD warranted? Perhaps. CCD was first named in late 2006 so we’d have something to call the complex, alarming and previously unknown condition in the Western Honey Bee. Bees fly off from the hive and never come back.
The insects and other creatures that normally descend on an unprotected colony won’t go near the abandoned hive’s store of tainted honey and wax. At least a quarter of the 2.4 million bee colonies in the United States have disappeared since the fall of 2006. And like the bees from their hives, bats fly away from their warm caves and die. What is going on?
Bee scientists can’t help us much here. There is a fungus, Nosema ceranae and a virus–IAPV– first described in Israel. Persistent new pesticides in widespread agricultural and home use are neurotoxins called neonicitinoids. They produce loss of memory and make insects stop feeding. Are bees collateral damage?
All of these stressors are “associated” with collapsed colonies–white noses, if you will–but none a smoking gun to explain the cause or halt the loss of the the world’s honeybees. Yes, the world. China, Brazil, and at least nine European nations report increasing incidence of CCD.
The so-what? We stand to lose some portion of the enormously undervalued and unappreciated work provided by bees and bats. What happens if bees no longer adequately pollinate fruit, nut and vegetable crops (for humans or wildlife)? And will it matter if bat populations don’t control night-flying, crop-eating moths and beetles or a summer evening’s disease-carrying mosquitos?
Songbirds and salamanders, now bees and bats. It is not just species at risk but orders and classes of plants and animals. Can we continue to assume their colonies can collapse and ours stay habitable?