RNA Viruses Responsible for European Honeybee Colony Collapse Disorder Found in other Hymenoptera, with Pollen as the Medium for Inter-Species Transmission

© 2010 Peter Free

 

29 December 2010

 

 

An elegant research article by Rajwinder Singh et al.

 

European honeybee Colony Collapse Disorder has greatly concerned scientists and agriculturalists.  Now a research group indicates that the responsible RNA viruses are simultaneously attacking other pollinating insects, apparently through the medium of mutually available plant pollen.

 

Rajwinder Singh et al. have written an exceptionally well-presented (understandable) paper regarding their findings.

 

 

Citation

 

Rajwinder Singh et al., RNA Viruses in Hymenopteran Pollinators: Evidence of Inter-Taxa Virus Transmission via Pollen and Potential Impact on Non-Apis Hymenopteran Species, Public Library of Science [PLoS ONE] 5(12): e14357, doi:10.1371/journal.pone.0014357 (22 December 2010)

 

 

Shared food source permits transmission of RNA viruses via pollen between Hymenoptera species

 

 

The research group reported that:

 

(1) Infected insects spread can spread their RNA viruses to pollen.

 

(2) Collected pollen can spread these viruses to other Hymenoptera.

 

(3) The viruses remain infectious after the pollen is collected.

 

(4) These viruses can infect multiple pollinator species during the contamination-transmission process.

 

(5) The phenomenon may partially explain why pollinator populations have been declining for the past two decades.

 

 

From the abstract

 

Here’s an example of the clarity that characterizes the group’s paper:

 

For the first time, we report the molecular detection of picorna-like RNA viruses (deformed wing virus, sacbrood virus and black queen cell virus) in pollen pellets collected directly from forager bees.

 

Pollen pellets from several uninfected forager bees were detected with virus, indicating that pollen itself may harbor viruses.

 

The viruses in the pollen and honey stored in the hive were demonstrated to be infective, with the queen becoming infected and laying infected eggs after these virus-contaminated foods were given to virus-free colonies.

 

These viruses were detected in eleven other non-Apis hymenopteran species, ranging from many solitary bees to bumble bees and wasps.

 

This finding further expands the viral host range and implies a possible deeper impact on the health of our ecosystem.

 

Phylogenetic analyses support that these viruses are disseminating freely among the pollinators via the flower pollen itself.

 

In containment greenhouse experiments, IAPV [Israeli Acute Paralysis Virus] moved from infected honey bees to bumble bees and from infected bumble bees to honey bees within a week, demonstrating that the viruses could be transmitted from one species to another.

 

This study adds to our present understanding of virus epidemiology and may help explain bee disease patterns and pollinator population decline in general.

 

© 2010 Rajwinder Singh et al., RNA Viruses in Hymenopteran Pollinators: Evidence of Inter-Taxa Virus Transmission via Pollen and Potential Impact on Non-Apis Hymenopteran Species, Public Library of Science [PLoS ONE] 5(12): e14357, doi:10.1371/journal.pone.0014357 (22 December 2010) (paragraph split)

 

 

Not so trivial a potential impact

 

The Singh group notes that pollinators account for more than $225 billion in global crops each year.

 

In the United States, honey bees (Apis mellifera L.) alone are responsible for pollinating more than $15 billion in agriculture.  Another $3 billion here comes from non-Apis Hymenopteran pollinators.

 

There are less obvious, but potentially even more significant, ecological impacts outside agriculture.

 

 

Seeing ecology with clearer eyes

 

So now, when we look at pollinators feeding on goldenrod and clover, we can envisage the spread of viral disease between the different Hymenoptera species that traffic there.  And we can imagine the radial ecologic transmission of these RNA rascals outward from these sample plants, and the billions like them, all over the world.

 

We’re all connected.  In one (often painful) way or another.