Subject: Re: Yellowjackets vs. butterflies(?)

From: Patrick Roper <[email-masked]>
Date: Sat, 17 Jun 1995 18:29:13 +0100

>        It seems probable that the yellowjackets were responsible for the
>decrease in butterfly numbers in the Fairbanks area. Can anyone come up with
>a similar case--or with another explanation for the situation? Note that
>last winter in Fairbanks was milder than usual, with a somewhat lighter
>snowpack than average--but similar winters in the past had no such effects.

In Britain a new social wasp (? yellowjacket) from mainland Europe called
Dolichovespula media was first recorded about 10 years ago and has spread
northwards and westwards for  hundreds of miles/kilometers.  In many places
it is now quite common.  It is substantially larger than the other British
Dolichovespula  and Vespula species, though not as big as our hornet, Vespa
crabro gribodoi (now a rare and declining insect).

D. media must have a substantial appetite and it is a worry that it may be
consuming large quantities of lepidopterous larvae.  However, it is very
difficult to prove anything conclusively and butterflies do not appear to
have declined proportionately in the areas it has colonised.

One area you may get information from is New Zealand.  I believe European
wasps (Vespula and/or Dolichovespula) have been introduced there and have
had a very damaging effect on native invertebrates.

Patrick Roper
Butterfly Conservation (UK)
============================================================
South View, Sedlescombe, Battle, East Sussex TN33 0PE, UK
Telephone:  (01424) 870208; Fax: (01424) 870208
Email: [email-masked]
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From: [email-masked] ("Colin Cracknell")
Date: Tue, 20 Jun 1995 23:38:53 GMT

Apart from size, is there a convenient way of distinguishing 
Dolichovespula from Vespula?