Thanks to a reader, here is another of our occasional updates on the rattus rattus situation in mainland southeast Asia. IRIN News reports that owls are being recruited to the fight against rats in northern Laos. As in other parts of the region, bamboo flowering is blamed for high rat numbers:
Experts attribute the unusually large number of rodents to bamboo flowering: As the availability of bamboo seeds – a popular food for rats – increases, so too does the rats’ fertility. Rattus rattus, the rat responsible for the outbreak, has decimated rice crops in many villages. Seventy-four percent of interviewed households reported 50-100 percent losses; 100 percent rice losses were common, the WFP survey said. “I’ve lost about a third of my total paddy rice crop and 80 percent of my entire upland rice crop,” Bounfaeng Leukai, a villager in Xay District said, describing the situation as the worst he has seen in more than two decades. “Seventy to 80 percent of my other crops – sesame and maize – are also gone,” he said.
3 responses so far ↓
1 jeplang // Jul 23, 2009 at 3:55 am
A Review of the Biology and Management of
Rodent Pests in Southeast Asia
Grant R. Singleton and David A. Petch
Australian Centre for International Agricultural Research
Canberra 1994
p13
After visiting the areas affected by the 1991
plague and talking to government officials and
villagers, we were not convinced of this link be-
tween the bamboo flowering and rodent outbreaks.
The story appears to have developed only over the
last ten years or so and may have come across from
northern Thailand (Walter Roder, pers. comm.) One
would expect that if there were a well established
relationship between bamboo flowering and the
appearancc of rodent plagues, then the story would
be enshrined within the folklore of the local people.
They are very careful observers of the environment
and it is extremely unlikely that such an important
relationship would have gone unnoticed prior to the
past decade. It may be that the bamboolrodent story
p16
is an argument of convenience, deflecting the blame
to an act of nature rather than to the fa& manage-
ment of the hill tribes. However it is difficult to be
definitive when reviewing the cause of an outbreak
that occurred two years earlier and when so little is
known about the animals involved.
There is much work to be done to ascertain
whether any of these stories about the relationship
between rodent plagues and bamboo flowering are
true. There is so little known about the biology of
the rodents that even the identity of the main pest
species is uncertain. From talking to farmers and
officers of the Agricultural Services and Extension
Agency, it appears that there are three sizes of pest
rodents. The largest one is assumed to be a bandi-
coot, probably the great bandicoot, Bandicota
indica, the middle sized one the ricefield rat, Rattus
argentiventer, and the smallest probably a species of
Mus (M. caroli or M. cervicolor).
2 jeplang // Jul 23, 2009 at 4:04 am
Always exercise caution when attempting to explain animal population cycles.
Correlation does not necessarily imply causation.
3 Basil // Jul 23, 2009 at 7:03 pm
Driving back from Nakhon Sawan to BKK a few weeks ago, it was clear from the number of roadside sellers offering said rodent for human consumption that many Thais ‘care for a rat’. There is even a special symbol that they erect up the road from their stalls to show drivers that they are selling this apparent delicacy.
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