Arachnids in Produce

Arachnids in Produce
with an emphasis on
Black Widows in Grapes
Chris Newman
November 2002
The Black Widow
Family
Genus
Species
Theridiidae
Latrodectus
hesperus
Californian Table Grape
Market
During the 2007 season 22.4 million boxes of
grapes were exported.
United Kingdom/Ireland imported 796,197 boxes
valued at $17.2 million.
In the 1988/89 investigation up to 10% of boxes
entering the UK contained spiders.
Issues
Latrodectus bites can be fatal
The good news is only about 4% of untreated
bites are fatal.
The bad news is bites are often painless, and
symptoms can take 24/48 hours to develop.
Therefore a person bitten may not know they
have been bitten by a spider and not receive the
appropriate treatment!
International
Recluse Spider
Family
Sicariidae
Genus Loxosceles
Species laeta - reclusa
Origin
Americas
Issues
Bites of recluse spiders can be fatal
Bites can be difficult to diagnose, like bites from
Latrodectus they are often painless and
symptoms may take hours or even days to
develop.
Bites although not often fatal can be very
debilitating, sometimes resulting in loss of limbs!
Other spiders
Cupiennius salei
Heteropoda
venatoria
Avicularia
Phoneutria fera
Issues
Between 2000 & 2005 at least 4 people have
been bitten and hospitalized by Phoneutria in the
UK.
None of the bites were fatal.
All bites were associated with spiders found in
bananas.
Scorpions
Centruroides gracilis
Tityus melanostictus
Issues
Scorpions can cause fatalities
Scorpions are mostly associated with banana
imports.
Numbers imported appear to be high.
There are reports of both workers and members
of the public being stung.
Discussion
It is known that since at least 1988, during the
Californian Table Grape season, May to December,
black widow spiders enter the UK concealed within
produce. What we do not know is how many?
During the 1988 season shipments of grapes usually
consisted of 5,000 boxes per consignment. The most
contaminated consignment contained 100’s of spiders
(at least 500). Other consignments contained no
discernible spiders.
In the worst case scenario the number of spiders
entering the UK annually could be as high as 100,000
or as low as perhaps 20. The actual figure is
unknown, but likely to be in the high 100’s to low
1,000’s!
Questions
Do we consider any of this as an issue?
Do we know how or why these infestations occur?
Why we do not see Latrodectus entering the UK
contained within grapes grown in other countries?
Are harmful arachnids entering the UK by means
other than concealed within consignments of produce?
Should measures be put in place to monitor and/or
address these issues?
Could/are any of these species established in the UK?
Recommendations
Take the issue seriously
Mandatory reporting
Recording and monitoring
Evaluation
Eradication