Effect of Endosulphan insecticide on Lepidoptera

[krushnamegh at mail.utexas.edu]

some comments about the endosulphan business that was brought up recently:

i am not sure that paul's interpretation is right ("If you are seeing 
hundreds of butterflies dying despite many years of using of 
endosulphan then it would appear that butterflies have remained 
abundant despite it's use."). butterflies move about quite a lot, and 
if endosulphan is killing local butterflies, then the butterflies you 
see there are originating from neighboring areas. besides, from what 
i gather from a previous email, endosulphan is sprayed in this area 
thrice a year, which leaves the area some opportunity to receive 
immigrants from neighboring areas and for the new immigrants to breed 
there between the spraying episodes. the danaine migrations in this 
area confounds the whole thing further (see below). so, the local 
populations may not have persisted in abundance *in spite* of years 
of spraying, but because of immigrants.

there is nothing in endosulphan that would selectively kill pest 
species, so i would take the reports claiming that endosulphan does 
not affect non-target species extremely suspiciously (besides 
checking funding sources of the investigators). i just do not see any 
way the chemical would kill the pests but not wasps and ladybirds and 
butterflies.

however, what kishen reported may not even be related to the use of 
endosulphan. this part of the western ghats (mountain range in SW 
india) and coastal areas receive millions of butterflies as part of 
the annual danaine migrantion from the eastern part of southern 
india. i worked in the anamalai mountains close by on butterfly 
communities and this danaine migration, from which i know that the 
danaines arrive in this area by the end of october or in november, 
and remain in very large groups (tens of thousands of butterflies) 
until the beginning of january. they roost mainly on the high 
branches of big trees in the evergreen and semi-evergreen forests. 
some predators (i haven't figured out which ones) prey on the 
roosting butterflies. i have often seen the forest floor strewn with 
butterfly wings during these periods (in fact, almost seven years ago 
i found my first post-migration danaine roost in the anamalais 
because i noticed a high density of butterfly-wings on the floor and 
looked up to find branches almost as loaded with several species of 
danaines as you see at monarch roosts). so, what kishen is describing 
may be evidence of predation on the roosting butterflies, not the 
effect of endosulphan. if you noticed, all but two species he 
mentioned are danaines, three of them (T. septentrionis, E. sylvestor 
and E. core, in that order) make up the bulk of the danaine migratory 
swarms in southern india. out of the two Papilios he mentioned, one 
is known to migrate in loose groups (P. hector). i think this 
representation indicates something else.

anyway, someone should study whether the butterflies really died of 
endosulphan or not. so much pesticide in the western ghats is 
certainly a bad idea, there are too many butterflies, many of them 
endemic, endangered and beautiful, there.

cheers,

At 12:35 PM -0800 12/21/05, Paul Cherubini wrote:
>If you are seeing hundreds of butterflies dying despite
>many years of using of endosulphan then it would appear
>that butterflies have remained abundant despite it's use.
>
>Here is one university website that says endosulphan "is
>relatively nontoxic to beneficial insects such as parasitic wasps, lady
>bird beetles, and some mites"
>http://extoxnet.orst.edu/pips/endosulf.htm
>
>Paul Cherubini
>
>Kishen.Das at gxs.com wrote:
>
>>  For last few months we are seeing hundreds of butterflies
>>  dying in the kerala state of India in a Mango Plantation.Here they are
>>  using Endosulphan extensively. The species which are affected
>>  are Euploea core, Euploea sylvester, Tirumala limniace, Tirumala
>>  septentrionis, Pachliopta hector, Papilio polymnestor and Danaus
>  > genutia.

-- 
Krushnamegh.

--------------------------------
Krushnamegh Kunte
Doctoral Student (Gilbert and Juenger Labs).
University of Texas at Austin,
Section of Integrative Biology,
1 University Station C 0930,
Austin, Texas 78712-0253.

Office: (512) 471-8240
Cell: (512) 577-1370
Fax: (512) 471-3878
Email: krushnamegh at mail.utexas.edu

 
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