All red widow images © DT Almquist 2015, all rights reserved
This beautiful specimen posing at The Nature Conservancy's Disney Wilderness Preserve after being
disturbed in her retreat is a female red widow spider (Latrodectus bishopi), a rarely encountered species of spider that
is closely related to black widows (L.
mactans and L. variolus). Although they are believed to be as venomous
as black widows, very few bites and no deaths have ever been attributed to them. Red widow spiders
are one of 16 rare spider species tracked by FNAI, and they have a conservation
rank of G2G3, meaning that they are imperiled to vulnerable over their entire
range.
This species is endemic to the Florida peninsula, but even
there it is only known from relatively few places (see the red stars on the map
above), with almost all populations being on the Lake Wales Ridge and a few on
the Atlantic Coastal Ridge. It lives primarily in scrub and scrubby flatwoods habitats, of
which much has been destroyed. Remaining areas of appropriate habitat that are not properly protected
for conservation purposes are threatened by development and poor management. Red widow populations appeared to be unaffected by fire in at least one study (Carrel
2001), but they very likely receive some "...benefit from fire because they nest
almost exclusively in palmettos that are only 1-1.5 m high, the sort that are
found naturally only in recently burned scrub" (Carrel pers. comm.).
Females construct a very distinctive retreat--where they
hide, mate, and guard their eggs--by binding together palmetto leaves with silk. The above female was very protective of her two egg sacs,
although not actually aggressive.
Like many spiders, red widows eat mostly insects and catch them
in a web. One study found that in the
spring they feed primarily on nocturnal beetles, such as the above glowing
click beetle, Deilelater sp., but
that later in the year diurnal bees and wasps become more important as prey
items. Overall, five species of endemic
scarab beetles, which also live primarily in scrub habitat, make up most of
their diet (Deyrup
and Carrel 2014).
As shown above, the males are smaller and more slender than the female and they usually eat prey that the females capture, although males are
capable of capturing their own meal.
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