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The Mediterranean Recluse Spider, Loxosceles rufescens (Dufour):
An Abundant but Cryptic Inhabitant
of Deep Infrastructure in the Washington, D.C. Area
(Arachnida: Araneae: Sicariidae)
Albert Greene, Nancy L. Breisch, Thomas Boardman, Benedict
B. Pagac Jr., Edward Kunickis, Randall K. Howes, and Paul V. Brown
ABSTRACT: Loxosceles rufescens (Dufour), a relatively cosmopolitan, synanthropic species commonly known as the Mediterranean
recluse spider, inhabits numerous government buildings in the Washington, D.C. area. Like the closely related brown recluse
spider (L. reclusa Gertsch and Mulaik) in the south-central United States, L. rufescens can be extremely abundant within a structure. Unlike L. reclusa, D.C. populations of L. rufescens are essentially troglophilic, concentrated mainly in basements, foundation walls,
and other man-made subterranean habitats, typically in close association with Periplaneta americana (L.) and/or Reticulitermes
spp. It has not been observed either outdoors or in smaller, residential buildings. Since this spider is often misidentified as L.
reclusa by entomologists who are unaware of L. rufescens’ widespread distribution and potential for persistent and dense local
populations, we present photographs to aid in distinguishing the adults of these two similar species.
L
oxosceles rufescens (Dufour), commonly known as the Mediterranean recluse spider, is a sporadically cosmopolitan species
that is native to the Europe-North African region but has
spread to various other countries by means of human activity. By far
the most widespread member of its genus (for which it is the type
species), it occurs from the southern Mediterranean area and Middle
East to at least as far north as the United Kingdom and western Russia, and has been introduced to Madagascar, southeast Asia from
India to Japan, Australia, and numerous Atlantic and Pacific islands
including four in the Hawaiian archipelago. In North America, it has
been recorded in at least 22 of the United States, widely scattered
from California to Florida and north to Michigan, as well as Toronto,
Ontario. Several South American records are either erroneous or
have yet to be confirmed (Gertsch 1967, Southcott 1976, Gertsch and
Ennik 1983, Roth and Nishida 1997, Binford and Wells 2003, Vetter
et al. 2003, Vetter and Swanson 2007, Vetter 2008).
Although L. rufescens is frequently found outdoors in all but the
northernmost parts of its Old World range, all confirmed North
American collections have so far been from inside structures, mostly
institutional (e.g. governmental, academic, museums) or commercial. A
typical state or city record involves one or a small number of specimens
encountered in a single building, and often initially misidentified as the
well-known brown recluse spider, L. reclusa Gertsch and Mulaik. They
are invariably regarded as representing isolated introductions rather
than as a predictable component of the local urban ecosystem (Gertsch
and Ennik 1983; Edwards 2001; Vetter 2005, 2008).
158
In recent years, we have become aware that the occurrence of
L. rufescens in Washington, D.C. does not conform to the “single
pinpoint” model, but rather is an area-wide phenomenon. This
report has three objectives: 1) to document our observations of
this spider and—considering the extreme (and often unjustified)
medical notoriety of its genus—emphasize that its secretive
behavior and the remoteness of its primary habitat ensures it
is not a significant public health concern; 2) to publicize to the
entomological and pest management communities in the United
States that a synanthropic species of Loxosceles almost identical
in appearance to L. reclusa is widespread and may potentially
be encountered in a structural environment virtually anywhere
in the country; 3) to assist non-arachnologists in distinguishing
the two species.
Materials and Methods
Discovery of L. rufescens at all sites was an ancillary result of
routine glue trap monitoring or visual inspections for other common
structural pests by government or commercial pest management
personnel. For reasons of security and confidentiality, specific buildings are identified only by numbers assigned in chronological order of
spider discovery. Macrophotos of L. rufescens from Washington, D.C.
and L. reclusa from Lenexa, KS were taken with the Auto-MontageTM
system from Syncroscopy. Voucher specimens of L. rufescens from
several collection sites have been deposited in the United States
National Museum (USNM), Washington, D.C.
American Entomologist • Fall 2009
Results
Specimens of L. rufescens were obtained from 14 federal government buildings in the Washington, D.C. area during the 10-yr period
from 1998 to 2007. Eleven of the structures are relatively close to
the National Mall in the city’s downtown core, scattered throughout
a rectangular area of about 4.0 km east-west and about 1.5 km northsouth. Three additional buildings in which the spiders were found are
located about 4.0, 4.5, and 6.0 km from the center of this core area.
The greatest distance between buildings is about 9.0 km.
Basic characteristics of the collection sites are presented in Table
1. The buildings ranged in size from 1,250 to > 93,000 gross m2 (=
13,460 to well over 1 million gross ft2), and in age from 19 to 134 yr
( x = 74 yr). All but two sites involved areas either on the first floor
(= ground level) or below. The exceptions were on the second and
sixth floors. Habitat type varied widely and included offices (n=6);
storage, utility, and mechanical rooms (n=10); and tunnels, chases, or
crawl spaces (n=4) (several sites had more than one type of habitat
where specimens were collected).
Initial detection of the spiders in eight of the buildings was by glue
trap captures, typically involving only one or two specimens (Fig. 1).
In the remaining six structures, detection was by chance observation
of a single adult (n=3) or a single exuvia (n=3) (Fig. 2).
Fig. 2.
Wandering
adult male
Loxosceles
rufescens,
Bldg. 8, 1st
floor wire
closet.
Fig. 3. Bldg. 1 mechanical room.
Fig. 1. Adult male Loxosceles rufescens on glue trap with Supella longipalpa, Bldg. 8, 2nd floor office.
Subsequent inspection at five sites revealed areas with numerous
adults and immatures: Bldg. 1. In 1998, specimens of L. rufescens were discovered
on glue traps placed in two adjacent ground floor utility rooms to
monitor for cockroaches (Periplaneta americana (L.) and Supella
longipalpa (F.)) and ants. Dozens of adults and immatures were
eventually captured on traps deployed at the door thresholds. In
2000, adult and immature spiders were collected together with
Reticulitermes sp. workers behind a baseboard in a third room on
the same floor. The baseboard, which was heavily damaged by the
termites, had been removed for replacement.
No further spiders were recorded in this space following treatment with sprayed pyrethroids, and the rooms were subsequently
eliminated in a major reconfiguration of the building. In December
2007 and January 2008, L. rufescens (primarily early-instar juveniles)
began to be trapped on glue boards in four newly renovated mechanical rooms about 40 m away from the original site. Untrapped speciAmerican Entomologist • Volume 55, Number 3
mens were also observed and collected, including one adult male
and one gravid adult female. The rooms were simple, clean, brightly
lit, well air-conditioned enclosures with concrete floors and block
walls, containing only new switchgear (electrical transformer) and
HVAC equipment (Fig. 3). Hairline cracks between slab and support
columns were enabling the access of large numbers of Reticulitermes
alates into one room, and it is likely that many of the younger spiders
were also entering this way. It was determined that a steam tunnel
ran underneath these rooms and the rooms where the spiders had
appeared 10 yr earlier.
Fig. 4. Bldg. 2 steam tunnel.
159
Fig. 5. Adult Loxosceles rufescens feeding on Periplaneta americana,
Bldg. 2 steam tunnel.
Bldg. 2. In spring 1999, L. rufescens were discovered on glue
traps placed in basement office, utility, and mechanical rooms to
monitor for P. americana. In October, an inspection was made of a
short steam tunnel that connected to an adjacent building. About 18
m long and 1.5 m wide, the tunnel was filled with trash and debris
such as doors, insulation, cardboard boxes, and cinder blocks (Fig.
4). Adult and immature spiders were extremely abundant on the unfinished masonry walls and cement floor, as well as in and under the
debris. P. americana were also numerous, and several observations
were made of L. rufescens feeding on nymphs (Fig. 5). The following
month, much of the clutter was removed, vacuuming and extensive
caulking were performed, and the tunnel was treated with sprayed
pyrethrin and pyrethroid products as well as a pyrethrin/silica gel
dust. Subsequent monitoring failed to detect any spiders for several
months. Presently, an occasional specimen appears on glue traps
maintained at the site.
Bldg. 5. In spring 2004, L. rufescens were discovered on glue
traps placed in a basement storage area to monitor for P. americana
and other pests. Additional traps deployed throughout the facility
indicated that an adjacent switchgear room was a primary source
Fig. 6. Bldg. 5 switchgear room.
160
of the specimens. Unlike the newer mechanical space in Bldg. 1,
this room was not air-conditioned and had walls of the building’s
original brick foundation (Fig. 6). Although the room was free of
clutter, adults and immatures were flushed with a pyrethrin aerosol
from cracks in the walls, beneath equipment, and behind sheets of
plywood mounted on the walls to attach electrical panels.
A broader search revealed that the spiders had colonized two
additional basement mechanical rooms and occasionally appeared
on glue traps in several locations on the first floor. The number of
specimens collected annually over the next 4 yr on about 30 glue
traps maintained (and replaced as necessary) throughout the affected
space were 33, 48, 37, and 14. Treatments with sprayed pyrethroids
and pyrethrin/silica gel dust are carried out periodically to unoccupied areas where the spiders are most prevalent.
Bldg. 9. In June 2005, two adult males of L. rufescens were discovered on a glue trap placed in a ground floor room to monitor for P.
americana. Numerous sow bugs (Isopoda) had also been captured on
the trap. On 4 April 2007, during a brief inspection of a crawl space
(= pipe basement) under the building, a single male L. rufescens was
collected under a wooden box. The unventilated, unlighted space,
Fig. 7. Bldg. 9 crawl space.
measuring about 25 x 30 m, had unfinished walls of crumbling masonry and a dry dirt floor strewn with pieces of cardboard, rubble,
and debris (Fig. 7). Many P. americana adults and older nymphs were
observed, principally in the vicinity of leaking sewage pipes. Sections
of termite-damaged structural wood were also present.
Six days later, an inspection of the crawl space specifically to
search for L. rufescens confirmed that the spiders were extremely
abundant and were readily observed under virtually every object
that could be moved. On 3 May 2007, three people collecting for one
hr captured 46 specimens: 28 immatures, 12 adult females, and 6
adult males. Many additional individuals, particularly very small immatures, were observed. Most of the latter were in or under material
toward the center of the space; most adults were either in crevices
in the walls or in concrete rubble next to the walls.
Two days afterwards, the crawl space was extensively treated with
a microencapsulated pyrethroid spray. The applicators reported that
the spiders were very numerous on the walls during the treatment. One month later (7 June 2007), no spiders had been captured on a
series of 20 glue boards that had been placed one week after the
spraying. However, by nearly three months after the treatment (29
American Entomologist • Fall 2009
August 2007), 17 spiders of all ages had been captured on 10 of the
same traps.
Bldg. 12. This structure was originally built as a warehouse
that was later converted to a vehicle maintenance facility. Its slab
floor and block walls are in relatively poor condition, with numerous cracks and other damage. Although the presence of L. rufescens
was first revealed by an adult female and very young immature on a
glue board in a peripheral air-conditioned office, spiders were only
found in abundance in a service bay used primarily for storage in the
main, non-air-conditioned open area. Most individuals were under
or behind boxes, debris, wooden pallets, and shelving. The first
eight spiders observed during a 15-min period were collected; all
were immatures. Occasional remains of P. americana were observed
throughout the building.
Discussion
Distribution, Habitat, and Behavior. The occurrence of the
Mediterranean recluse spider in the continental U.S. can be characterized as widely distributed but rarely encountered. In Gertsch and
Ennik’s (1983) survey of museum specimens, 65% (11/17) of the
state records were represented by collections from a single locality;
23% (4/17) were represented by two localities, and 12% (2/17,
Texas and Louisiana) by three localities. Multiple specimens were
recorded in only 27% (7/26) of the total collection sites. Vetter’s
(2005) Internet offer to identify any U.S. spider perceived to be a
brown recluse yielded only three specimens of L. rufescens from two
states out of a total of 1,773 arachnid specimens from 49 states.
Much of our experience with L. rufescens in the Washington,
D.C. area reflects this pattern in microcosm: at 79% (11/14) of the
collection sites, the spider’s presence was revealed by an initial discovery of only one or two specimens, either on a single glue trap or
by observation of a nontrapped individual or an exuvia. All of these
initial discoveries were a byproduct of routine inspections for other
pests; in this regard, the well-known ability of glue traps to disclose
the existence of infrequent or furtive arthropods was responsible
for 57% (8/14) of the discoveries. In 64% (9/14) of the collection
sites—i.e. all buildings other than those where numerous spiders
were observed—either no further specimens (n=7) or a single additional specimen (n=2) have been collected (Table 1).
The prevalence of these types of records is curious, since populations of Loxosceles spp. tend to be extremely dense in favorable
habitats. Abundance within structures is best known in L. reclusa
and two synanthropic South American species, L. laeta (Nicolet)
and L. intermedia Mello-Leitão (Hite et al. 1966, Schenone et al.
1970, Vetter and Barger 2002, Fischer and Vasconcellos-Neto 2005,
Sandidge and Hopwood 2005), but has been noted for L. rufescens
as well (Vetter 2005, 2008).
Our observations of five Washington, D.C. sites where L. rufescens
was plentiful suggest that one reason for the characteristically low
numbers of collected specimens is because the species is strongly
troglophilic in the urban environment. The two areas where adults
and immatures were most numerous and readily observed with a
minimum of habitat disturbance were a steam tunnel and a crawl
space (Figs. 4 and 7) sharing the following features: 1) non-air-conditioned, rarely illuminated basement or sub-basement space that
is physically secluded and inaccessible to all but a small number of
personnel; 2) surrounded by a relatively old, deteriorating masonry
foundation; 3) filled with stored or discarded items; and 4) occupied
by American cockroaches and/or subterranean termites. Presenting
American Entomologist • Volume 55, Number 3
Table 1. Characteristics of L. rufescens collection sites in the
Washington, D.C. area.
Building
Yeara
Building Building
Sizeb
Agec
1
1998
> 93,000
55
4
2003
39,204
134
84,270
69
2
3
5
6
7
1999
2000
2004
2004
2004
4,512
> 93,000
> 93,000
38,249
8
2005
69,038
10
2007
1,250
9
2005
8,063
89
64
Level d
Specimense
Basement
Numerous
1st Floor
Basement
Basement
1st Floor
105
88
6 Floor
th
1st & 2nd Floors
88
Numerous
Basement
1♀
13
2007
1,755
19
1st Floor
52,713
2♂
1st Floor
Basement
2007
2 Specimens
1 Exuvia, 1 ♂
35
14
1♂
Basement
20,290
5,323
1 Exuvia
86 1 Floor & Basement Numerous
st
2007
2007
1 Exuvia
93 1st Floor & Basement Numerous
11
12
Numerous
56
55
1♂
1♂
First year spiders were observed.
b
Gross m2 (= total area of all floors, including basement levels and vertical penetrations).
c
Building age at time of first spider observation.
d
“1st floor” = ground level; “Basement” = any floor below ground level.
e
Total collections through 2007. “Numerous” = abundant adults and immatures of all ages.
a
a highly stable microclimate with an abundance of food and shelter,
these anthropogenic “caverns” served as remote, subterranean
breeding sites for populations that, except for immediately adjacent
areas, exhibited relatively low levels of dispersal into the sections of
the built environment where most human activity occurs.
The susceptibility to L. rufescens colonization of any sort of interior space contiguous with such primary population loci is demonstrated by the essentially barren (clutter-free) mechanical rooms at
two other sites, none of which appear capable of supporting large
numbers of any invertebrate. However, the basement switchgear and
mechanical rooms of Bldg. 5 (Fig. 6) meet the first two conditions
described above and are routinely invaded by P. americana from the
surrounding infrastructure. The ground floor machine rooms of Bldg.
1 (Fig. 3) are far more microenvironmentally hostile, but constructed
immediately over a steam tunnel that presumably is the source
of the continuing L. rufescens immigration (as well as occasional
specimens of P. americana). Warmth from the tunnel undoubtedly
also accounted for the midwinter swarming of termite alates from
beneath the floor slab.
With its high ceiling and extensive, open space, the garage that
constitutes the fifth site of spider abundance is superficially distinct
in appearance from the others. However, the infested storage bay
shares some of the first condition as well as the second and third,
with the structure’s poorly sealed envelope allowing entry of ample
prey from outdoors in addition to the ubiquitous P. americana.
In fact, the discovery of L. rufescens in Washington, D.C. conforms
to a now-familiar scenario for urban colonization by both this species
and another anthropochorous (readily transported by man) congener. In 1960, a single adult male of L. laeta was collected in the basement
storage space of Harvard University’s Museum of Comparative Zoology
in Cambridge, MA. After a second individual was found the following
year, a systematic search revealed that the spiders were numerous
161
(with “loose boards, and cardboard or wood containers” as their
preferred cover) and may well have been present for at least 20 yr. A
fourth floor room had also been colonized (Levi and Spielman 1964).
Nearly identical circumstances were described for a building at the
University of Helsinki, Finland, in which, following sporadic collections
of isolated L. laeta individuals for 8 yr, it was finally recognized that the
entire ground floor and parts of the basement were infested (Huhta
1972). The most extensive example of long-term establishment of
this species outside of its native range began in 1968 with the chance
collection of a single individual from a building in a Los Angeles suburb
(Waldron 1969, Hebert 1993). By 3 yr later, it had been documented
in 127 buildings up to 18 km apart – twice as wide as the Washington,
D.C. cluster. Based on dense accumulations of exuviae and webbing,
the spider had evidently been present in the area for many years and
could have been introduced “at any time during the history and growth”
of southern California (Waldron et al. 1975).
Similar accounts of cryptic structural populations exist for L.
rufescens. In December 1996, a single specimen was noticed on a
glue trap in a ground floor storage room of a museum in Philadelphia,
PA. Subsequent trapping revealed that the spiders were abundant
in that room, adjacent switchgear space, and areas in the basement
and the second floor. Steam conduits leading into the building were
believed to be the source of the infestation, as well as an accompanying population of P. americana (V. Greene, personal communication). A parallel case of a long-standing L. rufescens colonization in
a sub-basement and adjoining greenhouse that was revealed by a
single collected individual was reported for a building on the Ohio
State University campus in Columbus, OH (Berry and Venard 1970).
Parker (2002) described additional infestations in basement habitats
in Philadelphia and New York City.
It is noteworthy that, unlike L. reclusa, L. rufescens in North
America has been almost exclusively associated with larger masonry
buildings or their subterranean infrastructure. Vetter (2005) observed that “virtually all locales” of specimens sent to him “have been
municipal, commercial, or university-related structures.” Gertsch
and Ennik’s (1983) survey of collection sites in the continental U.S.
specified 10 such buildings as opposed to one “house.” Other than
records of single individuals discovered in shipped material (Madon and Hall 1970, Unzicker 1972) and a specimen in the USNM
collection from a home in Beltsville, MD, we are aware of only one
instance where multiple specimens were found in a residential unit
in the U.S. (a house in Florida and initially assumed to be L. reclusa
– Harbison 2007a, 2007b). Almost the same constancy of niche is
shown by L. laeta outside of its native range. Although the southern
California population occasionally occupies attics as well as basement areas, the structures themselves are mostly older concrete
and brick commercial buildings within business districts (Waldron
et al. 1975, Hebert 1993).
Loxosceles colonization of cavern-like habitats has ample precedent: numerous species have been collected in and nearby natural
caves, and there are several that are found nowhere else (Newlands
1975, Gertsch and Ennik 1983, Griffin 1998, Ferreira et al. 2005,
Gonçalves-de-Andrade et al. 2007). L. rufescens in particular has
shown a markedly troglophilic tendency throughout its range, and
has gained notoriety for competing with (and apparently preying
on) an endangered indigenous species of troglobitic wolf spider in
volcanic caves on the Hawaiian island of Kauai (USFWS 2006). Moreover, L. rufescens on Kauai “has been observed to become a dominant
member in caves where conditions appear to be sub-optimal (i.e.,
162
reduced relative humidity) for native cave-dwelling animals” (USFWS
2006). However, L. rufescens is also well documented as frequently
occurring under cover in non-enclosed habitats as well, including in
Hawaii (Gertsch and Ennik 1983). In Israel, in addition to the species
being “fairly common in houses and cellars” (Shulov et al. 1960), it
has also been reported as the dominant spider in two citrus groves,
hiding in moist leaf litter and old egg cartons placed under trees to
soften the fall of ripe fruit (Borkan et al. 1995). In Australia, it has
been recorded as living beneath bark or under rocks as well as in
residences (Brunet 2000), and on the island of Saint Helena it is found
“under rocks in flax plantations” (Ashmole and Ashmole 2004).
It is therefore puzzling that such an adaptable species has thus far
been apparently so constrained in its habitat throughout the warmer
parts of North America, particularly in areas where there are no native Loxosceles that might serve as close competitors. There is only a
single, anomalous record of an outdoor collection of L. rufescens in the
U.S.: the holotype of L. marylandicus Muma, which was synonymized
as L. rufescens by Gertsch (1958). Muma (1944) noted that the male
specimen was “collected on a log, April 9, 1941” in College Park,
Maryland. Local temperatures on that date rose to a maximum of
20.6° C (National Climatic Data Center, NOAA Satellite and Information Service, online data for College Park Weather Station), so there
is no obvious meteorological reason why an individual could not have
crawled to an exposed location. However, since this type of site has
not been recorded elsewhere in the United States for L. rufescens, and
since decades of intensive entomological collecting at College Park
(which includes the University of Maryland campus) have failed to
produce a second documented specimen, it is likely the account is
not representative of normal L. rufescens behavior in this vicinity. Nevertheless, no systematic survey efforts have been carried out in
the surrounding landscapes of buildings harboring L. rufescens, which
might reveal dispersion into nonstructural microhabitats.
Considering the increasing rate of discovery of this spider in
Washington, D.C. buildings over the past 10 yr, two additional
questions come to mind. The first is whether these accumulating
records reflect a relatively recent spread of L. rufescens throughout
the city or are simply the result of a recently enhanced search image among pest management personnel. We assume the latter, and
wish to emphasize the similarity of our delayed recognition of the
spider’s abundance with previous accounts of L. rufescens and L.
laeta discoveries in other locations cited earlier. In this regard, one
of us (A.G.) observed what was apparently a live male L. rufescens in
a Bldg. 5 stairwell in 1989, about 15 yr before its presence in that
structure was positively confirmed by a glue trap capture. It should
also be noted that the widespread use of glue traps by pest management personnel throughout the city only began in the early 1990’s, a
methodological transition recorded by Greene and Breisch (2002). Older L. rufescens records for the area include specimens collected in
1925, 1933, and 1936 from a Washington, D.C. building that was not
one of our collection sites (USNM collection) and the 1941 specimen
from a nearby location in Maryland (Muma 1944).
The second question is whether the occurrence of L. rufescens
throughout the Washington, D.C. area has resulted mainly from
multiple introductions from foreign locations, active dispersal of the
spiders through the subterranean infrastructure of the city, or passive
dispersal as concealed hitchhikers in locally transported material. We favor the last explanation due to the high turnover rate (“churn”)
of personnel and associated boxed files, furniture, and equipment in
the area’s government office buildings. (Waldron et al. 1975 observed
American Entomologist • Fall 2009
Los Angeles County L. laeta specimens in cartons of merchandise
and church rummage sale items.) Although our captures of isolated
specimens that have wandered away from population centers (Figs.
1 and 2) indicate some degree of active dispersal is taking place that
might well affect contiguous structures, Loxosceles spp. seem to display remarkably limited vagility in the absence of human assistance
(Newlands 1981; Vetter 2005, 2008).
One consequence of L. rufescens’ troglophilic behavior in Washington, D.C. is a relatively limited suite of coexisting prey species
that are sufficiently abundant to sustain dense spider populations.
P. americana occurred in all 12 of the basement and first floor collection sites, with zones of greatest concentration closely overlapping
those of the spiders. One of the world’s most widespread species,
this cockroach has been recorded in virtually all of the mainland and
island locations where L. rufescens has been found, including the
caves of Kauai (USFWS 2006). Perhaps coincidentally, the smaller
brownbanded cockroach, S. longipalpa, was abundant at both of our
sites where individual spiders were collected above the first floor
(Fig. 1), as well as in the original Bldg. 1 rooms.
The occurrence (or evidence) of Reticulitermes sp. at five L. rufescens collection sites is noteworthy, not only because the spiders
readily fed on the workers in the laboratory (Fig. 8), but because two
of us (A.G. and N.L.B.) have observed Loxosceles adults (probably L.
arizonica Gertsch and Mulaik) preying on termites (probably Heterotermes aureus (Snyder)) in a Tucson, AZ storage cubicle. The web
of one female spider beneath a termite-occupied piece of wooden
furniture contained numerous discarded worker bodies.
A third potential source of reliably encountered food for L.
rufescens in Washington D.C. is the firebrat, Thermobia domestica
(Packard). This insect has been recorded as prey for L. rufescens in
Pennsylvania (Luke and Snetsinger 1971) and Levi and Spielman
(1964) speculated that a firebrat infestation in the museum basement
at Harvard University might have been brought under control by L.
laeta. Although individual firebrats were only occasionally noticed in
our basement and first floor collection sites, they occur in very high
numbers at certain locations within the city’s steam tunnel systems
(A.G., unpublished data), which might therefore coincide with some
L. rufescens population loci.
Public Health Implications and Pest Management. Spiders
in the genus Loxosceles are well known for possessing venom that
Fig. 8. Immature Loxosceles rufescens feeding on Reticulitermes sp.,
laboratory culture.
American Entomologist • Volume 55, Number 3
can cause severe skin necrosis in some individuals and in rare cases
even life-threatening systemic effects, although typical symptoms
are relatively minor (Futrell 1992, Anderson 1998, Sandidge and
Hopwood 2005, Vetter and Isbister 2008). The statement that
“rufescens is reputed to have a far less dangerous venom than that
of laeta, reclusa, and some other species” (Gertsch and Ennik 1983,
p. 349) has been widely repeated throughout the literature, despite
several lines of evidence suggesting this assumption is erroneous. Laboratory studies, both in vitro and with controlled bites or spider
body extract injections in mice or rabbits, have demonstrated that
enzymatic activity and resulting hemorrhagic/necrotizing ability
of L. rufescens venom are comparable to that of other Loxosceles
spp. (Shulov et al. 1960, Smith and Micks 1968, Young and Pincus
2001, Binford and Wells 2003). Clinical reports of L. rufescens bites
corresponding to those reported for other Loxosceles spp. and confirmed with either a collected specimen (Efrati 1969, White et al.
1995, Stefanidou et al. 2006) or ELISA (Akdeniz et al. 2007) have
been documented in Israel, Australia, Greece, and Turkey. A unique
account of multiple L. rufescens envenomations involved personnel
in an Israeli citrus grove who were bitten while crawling on densely
infested leaf litter under trees (Borkan et al. 1995).
Reflecting decades of accumulated data, Vetter’s (2005) comment that “all Loxosceles spiders should be considered potentially
capable of producing dermonecrosis to some extent” expresses a
longstanding consensus among spider venom specialists (Gorham
1968, Barbaro et al. 1996, Gomez et al. 2001, Young and Pincus 2001,
Binford and Wells 2003). Nevertheless, one of the more consistent
and dismaying aspects of the pathology known as “necrotic arachnidism” or “loxoscelism” is the substantial number of diagnoses by
medical professionals that are totally unsupported by confirmatory
data. In the United States, where L. reclusa has been regarded as by
far the most likely source of structural Loxosceles envenomation, the
principal reasons for skepticism in the absence of a victim-collected,
expert-determined specimen are 1) the high incidence of reported
bites outside the relatively limited native range of L. reclusa, which,
contrary to a prevailing misconception, only rarely occurs in states
where it is not endemic, 2) the secretive and nonaggressive behavior
of this species, and 3) the numerous other possible causes of similarappearing necrotic skin lesions (Anderson 1998, Vetter and Barger
2002, Vetter et al. 2003, Vetter 2005, Swanson and Vetter 2005, Vetter
and Swanson 2007, Vetter and Isbister 2008).
We are aware that our observations of L. rufescens in Washington,
D.C. may dilute the logical strength of the first argument, particularly
for lay audiences. Broader recognition of a widespread Loxosceles
species that can colonize structural locations is likely to complicate
the efforts of entomological and arachnological professionals in
counteracting unreasonable perceptions of risk. We strongly emphasize that the remoteness of this spider’s typical habitat combined
with their extreme shyness makes human contact with L. rufescens
exceedingly unlikely in most circumstances. None of us have been
informed of any claimed necrotizing bites by an occupant of any
of the buildings in which we conduct pest management activities. Moreover, we have never encountered any personnel who work in
or close to the areas of greatest L. rufescens abundance who had even
been aware that the spiders were present.
Naturally, there are rare circumstances in which risk of envenomation would be elevated. For example, a plumber fixing the sewage
pipe leaks in the Bldg. 9 crawl space prior to spider control efforts
would essentially be the structural counterpart of workers in the
163
infested citrus grove described by Borkan et al. (1995). For this
reason, our policy as either pest managers or consultants is that all
confirmed and accessible population centers of L. rufescens should
be the focus of ongoing mitigation efforts.
Loxosceles spp. are among the most difficult structural pests to
control on a sustainable basis: they can enter a building through a
multitude of narrow crevices, build up extremely dense but cryptic
populations that harbor in concealed and well-protected microhabitats, survive for extraordinarily long periods of time indoors with
limited or no food and water, and at least one species (L. reclusa) can
scavenge on insects that have been dead for as long as one month
(Hite et al. 1966, Horner and Stewart 1967, Elzinga 1977, Eskafi et al.
1977, Lowrie 1980, Sandidge 2003). Although extensive deployment
of glue traps, sealing of access points, and minimization of clutter
have been shown to reduce their numbers, there is no evidence that
these measures alone can typically achieve what most clients would
consider to be an adequate level of suppression (Hedges and Lacey
1995, Merchant 2001, Sandidge and Hopwood 2005, Holper 2007,
Townsend and Potter 2007). The most critical factor for managers of
public buildings in the Washington, D.C. area is that the small number
of L. rufescens individuals invading occupied space represent continuing and inevitable “leakage” from largely inaccessible population
loci that cannot be completely sealed off from the remainder of the
(a)
(b)
(a)
Fig. 10(a). Loxosceles reclusa, right male palpus, exterior lateral view. (b).
Loxosceles rufescens, right male palpus, exterior lateral view.
(b)
Fig. 9(a). Loxosceles reclusa, male carapace. (b). Loxosceles rufescens,
male carapace.
164
structure. Greene and Breisch (2002) noted that situations “where
externally breeding pest species are continually generated from an
immutable, decaying infrastructure, create ‘pesticide sinks’ in structural IPM programs that may persist until cost-effective alternate
control technologies become available.” Although there have been
investigations of the biological control potential of geckos (Ramires
and Fraguas 2004) and other spider species (Sandidge 2004), as well
as preferred components of artificial refugia that might be used to
enhance the attractiveness of traps (Vetter and Rust 2008), the current reality is that no nonchemical methodologies currently match
the effectiveness of pesticides for recluse spider management.
Since direct contact at the time of application by either a sprayed
or aerosolized formulation is unlikely to affect the majority of a target
population sheltered deep in walls, foundations, and other protected
hollow spaces, the selected product(s) should ideally have a high
residual effect. Limited laboratory test data and anecdotal accounts
from commercial treatments of residential L. reclusa infestations, as
well as our own experiences in Bldgs. 1, 2, 5, and 9, suggest that liquids,
aerosols, and dusts containing pyrethroids (i.e. the dominant class of
insecticides currently available for indoor use), as well as silica gel
dusts, provide locally effective but temporary control until populations
gradually reestablish by immigration from surrounding harborages
(Hedges and Lacey 1995, Merchant 2001, Holper 2007, Townsend and
American Entomologist • Fall 2009
(a)
(b)
Fig. 11(a). Loxosceles reclusa, tarsus and apex of tibia, right male palpus, dorsal view. (b). Loxosceles rufescens, tarsus and apex of tibia, right
male palpus, dorsal view.
Potter 2007). We currently assume that—as with their Periplaneta
and Reticulitermes prey—permanent eradication of L. rufescens is
infeasible in most of the locations where we have found them and that
monitoring of known habitats must continue indefinitely.
Distinguishing L. rufescens from L. reclusa
It is virtually impossible to tell specimens of L. reclusa and L. rufescens apart by casual observation—they are essentially the same size,
shape, and color. As seen in Figs. 9-12, some sclerotized parts of L.
reclusa adults tend to be more deeply pigmented than in L. rufescens,
but variation among individuals renders this character unreliable. (Gross dissimilarities in hair and setae between the paired specimens
in the figures only reflect differences in abrasion.) Other than the
anterior carapace margins, the following descriptions of diagnostic
features are annotations of Gertsch and Ennik’s (1983) discussions
of the characters commonly used to distinguish between the two
species of Loxosceles most likely to be found in a structural habitat
throughout the U.S. and Canada. They are intended only as a point of
departure for interested entomologists and pest managers. Since all
other native species of the genus (as well as non-native synanthropic
species such as L. laeta) may also potentially be encountered in a
building, examination by an experienced arachnologist is essential
American Entomologist • Volume 55, Number 3
(a)
(b)
Fig. 12(a). Loxosceles reclusa, spermathecae, ventral view of eviscerated abdomen. (b). Loxosceles rufescens, spermathecae, ventral view of
eviscerated abdomen.
to confirm the identity of any specimen.
Eyes. The eyes of adult L. reclusa are proportionally somewhat
larger than those of L. rufescens, are arranged in a less recurved row
(termed the “anterior row” by Gertsch and Ennik (1983)), and the
three dyads are closer together (Fig. 9.). Gertsch and Ennik (1983)
defined these differences with more precise measurements for both
species, but we feel that the eyes by themselves are of limited use for
nonspecialists; the disparity in their size and arrangement are best
appreciated when known specimens of both species are available. Carapace. The anterior carapace margins of L. reclusa, from the
clypeus to the rear eye dyads, are approximately parallel (Fig. 9a);
those of L. rufescens diverge posteriorly at about a 45° angle (Fig.
9b). This previously unpublished character is constant with adult
specimens examined by us during the course of this study, but has
not been vetted over the years by multiple arachnologists as have
the other diagnostic features discussed here.
Male Palpus. The adult male palpus is quite distinct between the
two species. In L. reclusa, the tibia swells like a vase from a relatively
narrow, almost stalk-like base, and the embolus is much longer than
the width of the oval bulb (Fig. 10a). Viewed from above, the tarsus
is broader than long and noticeably asymmetrical, with a prominent
165
lobe on its interior side (Fig. 11a). In L. rufescens, the tibia does not
have such a prolonged, narrow base and the embolus is only about
as long as the width of the relatively globular bulb (Fig. 10b). Viewed
from above, the tarsus is about as long as broad and not laterally
developed (Fig. 11b).
Spermathecae. Although Gertsch and Ennik (1983) used the
term “epigynum” as a synonym for female spider genitalia, modern
convention restricts it to the external sclerotized structures associated with the genital opening, which are not present in haplogyne
families such as the Sicariidae (Cushing 2005). The primary character
used to distinguish adult Loxosceles females is the paired spermathecae (= “seminal receptacles” of Gertsch and Ennik 1983), which
are internal and thus not as conveniently observed as the male palpi. Examination entails removing sufficient surrounding tissue to expose
the structures, either by cutting through the overlying integument
and folding it back (Cushing 2005) or by simply eviscerating the abdomen from the dorsal side. As with the males, the female genitalia
of the two species are very different. In L. reclusa, the spermathecae are moderately separated at the midline and characterized by
a single, narrow, finger-like lobe and often additional smaller and
more rounded lobes toward the outside (Fig. 12a). Due in part to
its pronounced sclerotization, this feature is often partially visible
through the ventral abdominal wall of undissected specimens. In L.
rufescens, the spermathecae are close together at the midline and
characterized by a single lobe that is large and rounded (Fig. 12b).
They are typically not visible through the abdominal wall unless the
specimen has been eviscerated.
Acknowledgments
Many thanks to Rick Vetter for generously providing specimens
of L. reclusa, a review of this manuscript, and much fruitful discussion about Loxosceles in general and L. rufescens in particular. Rick
also pointed out the utility of the anterior carapace outline in distinguishing between adults of L. reclusa and L. rufescens. We would
also like to extend our appreciation to Virginia Greene for providing
a detailed account, as events unfolded, of the discovery and management response to a L. rufescens infestation in Philadelphia, PA; Jon
Coddington for graciously retrieving early Washington D.C. area L.
rufescens specimens in the USNM collection; Wayne Olson, reference
librarian extraordinaire (National Agricultural Library, Beltsville,
MD) for tracking down a little-known L. rufescens reference that has
been mis-cited (and thus functionally unavailable) in the literature
for many years; Allison Dineen for skillfully detecting L. rufescens
harborage at one of our primary observation sites; and Zollie Fogg
and Gholam Azarion for diligently maintaining many thousands of
glue traps each year in about 100 federal facilities throughout the
Washington, D.C. area.
7
References Cited
Akdeniz, S., J. A. Green, W. V. Stoecker, H. F. Gomez, and S. U. Keklikçi.
2007. Diagnosis of loxoscelism in two Turkish patients confirmed with
an enzyme-linked immunosorbent assay (ELISA) and non-invasive tissue sampling. Dermatol. Online J. 13(2): 11. (http://dermatology.cdlib.
org/132/case_reports/spider/akdeniz.html)
Anderson, P. C. 1998. Missouri brown recluse spider: a review and update.
Miss. Med. 95: 318-322.
Ashmole, P., and M. Ashmole. 2004. Guide to invertebrates of Prosperous
Bay Plain, St Helena and illustrated account of species found on the
Eastern Arid Area (EAA), including Prosperous Bay Plain, Holdfast Tom
and Horse Point Plain. Kidston Mill, Peebles, Scotland.
Barbaro, K. C., M. V. Sousa, L. Morhy, V. R. D. Eickstedt, and I. Mota. 1996.
166
Compared chemical properties of dermonecrotic and lethal toxins from
spiders of the genus Loxosceles (Araneae). J. Prot. Chem. 15: 337-343.
Berry, R. L. and C. E. Venard. 1970. Loxosceles rufescens found in Columbus,
Ohio. Ohio J. Sci. 70: 128.
Binford, G. J., and M. A. Wells. 2003. The phylogenetic distribution of
sphingomyelinase D activity in venoms of haplogyne spiders. Comp.
Biochem. Physiol. B 135: 25-33.
Borkan, J., E. Gross, Y. Lubin, and I. Oryan. 1995. An outbreak of venomous
spider bites in a citrus grove. Am. J. Trop. Med. Hyg. 52: 228-230.
Brunet, B. 2000. Spiderwatch: a guide to Australian spiders. Reed New
Holland, Sydney, Australia.
Cushing, P. E. 2005. Introduction, pp. 1-17. In Ubick, D., P. Paquin, P. E.
Cushing, and V. Roth (eds.), Spiders of North America: an identification
manual. American Arachnological Society (www.americanarachnology.
org).
Edwards, G. B. 2001. The present status and a review of the brown recluse
and related spiders, Loxosceles spp. (Araneae: Sicariidae), in Florida. Fla.
Dept. Agric. Con. Serv., Div. Plant Ind., Entomol. Circ. 406: 1-6.
Efrati, P. 1969. Bites by Loxosceles spiders in Israel. Toxicon 6: 239-241.
Elzinga, R. J. 1977. Observations on the longevity of the brown recluse spider,
Loxosceles reclusa Gertsch & Mulaik. J. Kans. Entomol. Soc. 50: 187-188.
Eskafi, F. M., J. L. Frazier, R. R. Hocking, and B. R. Norment. 1977. Influence of environmental factors on longevity of the brown recluse spider.
J. Med. Entomol. 14: 221-228.
Ferreira, R. L., X. Prous, S. F. Machado, and R. P. Martins. 2005. Population dynamics of Loxosceles similis (Moenkhaus, 1898) in a Brazilian
dry cave: a new method for evaluation of population size. Rev. Bras.
Zoociên. 7: 129-141.
Fischer, M. L., and J. Vasconcellos-Neto. 2005. Microhabitats occupied
by Loxosceles intermedia and Loxosceles laeta (Araneae: Sicariidae) in
Curitiba, Paraná, Brazil. J. Med. Entomol. 42: 756-765.
Futrell, J. M. 1992. Loxoscelism. Am. J. Med. Sci. 304: 261-267.
Gertsch, W. J. 1958. The spider genus Loxosceles in North America, Central
America, and the West Indies. Am. Mus. Nov. 1907: 1-46.
Gertsch, W. J. 1967. The spider genus Loxosceles in South America (Araneae,
Scytodidae). Bull. Am. Mus. Nat. Hist. 136: 117-174.
Gertsch, W. J., and F. Ennik. 1983. The spider genus Loxosceles in North
America, Central America, and the West Indies (Araneae, Loxoscelidae).
Bull. Am. Mus. Nat. Hist. 175: 264-360.
Gomez, H. F., M. J. Miller, M. W. Waggener, H. A. Lankford, and J. S. Warren. 2001. Antigenic cross-reactivity of venoms from medically important North American Loxosceles spider species. Toxicon 39: 817-824.
Gonçalves-de-Andrade, R. M., F. D. Pretel, and D. V. Tambourgi. 2007.
The spider Loxosceles adelaida GERSTCH, 1967 (Araneae, Sicariidae) in
the karstic area of Ribeira Valley, PETAR, São Paulo, Brazil. J. Entomol.
4: 46-50. Gorham, J. R. 1968. The brown recluse spider Loxosceles reclusa and necrotic spiderbite – a new public health problem in the United States. J.
Env. Health 31: 138-145.
Greene, A., and N. L. Breisch. 2002. Measuring integrated pest management programs for public buildings. J. Econ. Entomol. 95: 1-13.
Griffin, R. E. 1998. Species richness and biogeography of non-acarine
arachnids in Namibia. Biodiver. Conserv. 7: 467-481.
Harbison, B. 2007a. Brown recluse spider confirmed in Florida. PCT
Online News, 6/7/2007. (http://www.pctonline.com/news/news.
asp?ID=5080)
Harbison, B. 2007b. Update: brown recluse found in Florida not native,
spider expert reports. PCT Online News, 6/13/2007. (http://www.
pctonline.com/news/news.asp?ID=5090)
Hebert, B. 1993. Ouch! Pest Control Technol. 21(10): 72-74.
Hedges, S. A., and M. S. Lacey. 1995. Field guide for the management of
urban spiders. Franzak & Foster, Cleveland, OH.
Hite, J. M., W. J. Gladney, J. L. Lancaster, Jr., and W. H. Whitcomb. 1966.
Biology of the brown recluse spider. Univ. Arkansas Agr. Exp. Sta. Bull.
711: 1-26.
Holper, J. 2007. What can brown do for you? Pest Control Technol. 35(4):
86, 88-90.
Horner, N. V., and K. W. Stewart. 1967. Life history of the brown spider,
Loxosceles reclusa Gertsch and Mulaik. Texas J. Sci. 19: 333-347.
Huhta, V. 1972. Loxosceles laeta (Nicolet) (Araneae, Loxoscelinae), a venomous spider established in a building in Helsinki, Finland, and notes on
American Entomologist • Fall 2009
American Entomologist • Volume 55, Number 3
Vetter, R. S., and M. K. Rust. 2008. Refugia preferences by the spiders
Loxosceles reclusa and Loxosceles laeta (Araneae: Sicariidae). J. Med.
Entomol. 45: 36-41.
Vetter, R. S., and D. L. Swanson. 2007. Of spiders and zebras: publication
of inadequately documented loxoscelism case reports. J. Am. Acad.
Dermatol. 56: 1063-1064.
Vetter, R. S., P. E. Cushing, R. L. Crawford, and L. A. Royce. 2003. Diagnoses
of brown recluse spider bites (loxoscelism) greatly outnumber actual
verifications of the spider in four western American states. Toxicon
42: 413-418.
Waldron, W. G. 1969. Loxosceles laeta (Nicolet), an introduced species in
Los Angeles County. Bull. Entomol. Soc. Am. 15: 377-379.
Waldron, W. G., M. B. Madon, and T. Suddarth. 1975. Observations on the
occurrence and ecology of Loxosceles laeta (Araneae: Scytodidae) in Los
Angeles County, California. Calif. Vector Views 22: 29-36.
White, J., J. L. Cardoso, and H. W. Fan. 1995. Clinical toxicology of spider
bites, pp. 259-329. In J. Meier and J. White (eds.), Handbook of clinical
toxicology of animal venoms and poisons. CRC Press, Boca Raton, FL.
Young, A. R., and S. J. Pincus. 2001. Comparison of enzymatic activity from
three species of necrotising arachnids in Australia: Loxosceles rufescens,
Badumna insignis and Lampona cylindrata. Toxicon 39: 391-400. Al Greene serves as Entomologist and National Pest Management Coordinator for the Public Buildings Service, U.S. General Services Administration,
Washington, D.C., with responsibility for technical policy, contract administration, and interagency liaison. Nancy L. Breisch is an urban entomologist
in the Department of Entomology, University of Maryland, College Park, MD.
Tom Boardman serves as Staff Entomologist for the Pentagon. Ben Pagac
is a medical entomologist working on arthropod-related health issues for
the Department of the Army. Ed Kunickis is an entomologist with the
Smithsonian Institution’s Horticulture Services Division and the technical
representative for the Institution’s structural IPM program. Randy Howes
and Paul Brown are pest management specialists in the U.S. General Services
Administration’s (National Capital Region) IPM program.
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some other synanthropic spiders. Ann. Entomol. Fenn. 38: 152-156.
Levi, H. W., and A. Spielman. 1964. The biology and control of the South
American brown spider, Loxosceles laeta (Nicolet), in a North American
focus. Am. J. Trop. Med. Hyg. 13: 132-136.
Lowrie, D. C. 1980. Starvation longevity of Loxosceles laeta (Nicolet) (Araneae). Entomol. News 91: 130-132.
Luke, J. E., and R. Snetsinger. 1971. Fiddleback spiders natural predators
of firebrats, a relative of the silverfish. Sci. Agric. (Penn. St. Univ., Agric.
Exp. Sta.) 18(4): 7.
Madon, M. B., and R. E. Hall. 1970. First record of Loxosceles rufescens
(Dufour) in California. Toxicon 8: 91-92.
Merchant, M. 2001. Control of brown recluse spiders. (http://citybugs.
tamu.edu/FastSheets/Ent-1004.html)
Muma, M. H. 1944. A report on Maryland spiders. Am. Mus. Nov. 1257:
1-14.
Newlands, G. 1975. A revision of the spider genus Loxosceles Heinecken &
Lowe, 1835 (Araneae: Scytodidae) in southern Africa with notes on the
natural history and morphology. J. Entomol. Soc. S. Afr. 38: 141-154.
Newlands, G. 1981. A new violin spider from Johannesburg with notes on its
medical and epidemiological importance. Z. Angew. Zool. 68: 357-365.
Parker, T. A. 2002. Recounting recluses. Pest Control Technol. 30(7): 12.
Ramires, E. N., and G. M. Fraguas. 2004. Tropical house gecko (Hemidactylus mabouia) predation on brown spiders (Loxosceles intermedia). J.
Venom. Anim. Tox. Incl. Trop. Dis. 10: 185-190.
Roth, V. D., and G. M. Nishida. 1997. Corrections and additions to the spider
fauna of Hawaii. Bishop Mus. Occas. Pap. 49: 41-48.
Sandidge, J. S. 2003. Arachnology: scavenging by brown recluse spiders.
Nature 426: 30.
Sandidge, J. 2004. Predation by cosmopolitan spiders upon the medically
significant pest species Loxosceles reclusa (Araneae: Sicariidae): limited
possibilities for biological control. J. Econ. Entomol. 97: 230-234.
Sandidge, J. S., and J. L. Hopwood. 2005. Brown recluse spiders: a review
of biology, life history and pest management. Trans. Kans. Acad. Sci.
108: 99-108.
Schenone, H., A. Rojas, H. Reyes, F. Villarroel, and G. Suarez. 1970.
Prevalence of Loxosceles laeta in houses in central Chile. Am. J. Trop.
Med. Hyg. 19: 564-567.
Shulov, A., M. Ickowicz, and H. Pener-Salomon. 1960. Observations on
the influence of the venom of Loxoscelis rufescens (Sicariidae, Araneina)
(Dufour 1820) on white mice. Proc. XI Int. Congr. Entomol., Vienna, 2:
499-501.
Southcott, R. V. 1976. Spiders of the genus Loxosceles in Australia. Med.
J. Aust. 1: 406, 408.
Smith, C. W., and D. W. Micks. 1968. A comparative study of the venom
and other components of three species of Loxosceles. Am. J. Trop. Med.
Hyg. 17: 651-656.
Stefanidou, M. P., M. Chatzaki, K. G. Lasithiotakis, D. J. Ioannidou, and
A. D. Tosca. 2006. Necrotic arachnidism from Loxosceles rufescens harboured in Crete, Greece. J. Eur. Acad. Dermatol. Venereol. 20: 486-487.
Swanson, D. L., and R. S. Vetter. 2005. Bites of brown recluse spiders and
suspected necrotic arachnidism. N. Engl. J. Med. 352: 700-707.
Townsend, L., and M. Potter. 2007. Brown recluse spider. (http://www.
ca.uky.edu/entomology/entfacts/ef631.asp)
Unzicker, J. D. 1972. The first record of the spider Loxosceles rufescens
(Dufour) in Illinois. Entomol. News 83: 119-120.
(USFWS) U.S. Fish and Wildlife Service. 2006. Recovery plan for the Kauai
cave arthropods: the Kauai cave wolf spider (Adelocosa anops) and the
Kauai cave amphipod (Spelaeorchestia koloana). USFWS, Portland, OR.
Vetter, R. S. 2005. Arachnids submitted as suspected brown recluse spiders
(Araneae: Sicariidae): Loxosceles spiders are virtually restricted to their
known distributions but are perceived to exist throughout the United
States. J. Med Entomol. 42: 512-521.
Vetter, R. S. 2008. Spiders of the genus Loxosceles (Araneae, Sicariidae):
a review of biological, medical and psychological aspects regarding
envenomations. J. Arachnol. 36: 150-163.
Vetter, R. S., and D. K. Barger. 2002. An infestation of 2,055 brown recluse
spiders (Araneae: Sicariidae) and no envenomations in a Kansas home:
implications for bite diagnoses in nonendemic areas. J. Med. Entomol.
39: 948-951.
Vetter, R. S., and G. K. Isbister. 2008. Medical aspects of spider bites. Ann.
Rev. Entomol. 53: 409-429.
167
The 57Th AnnuAl MeeTing of The
enToMologicAl SocieTy of AMericA
Celebrate Entomology:
Colleagues, Science,
and Ideas
December 13 – 16, 2009 | indianapolis, indiana
The 2009 ESA Annual Meeting will
celebrate entomology with more
scientific presentations, new special
plenary sessions, and new virtual
posters.
Plenary Sessions
The Opening Plenary Session, on Sunday,
December 13, will feature Dr. Edward D.
Walker, who will deliver the Founders’
Memorial Award lecture.
Dr. Walker, professor, Department of
Entomology and the Department of
Microbiology and Molecular Genetics,
Michigan State University, will honor
Dr. George B. Craig, Jr.
In 1958, ESA established the Founders’
Memorial Award to honor scientists
whose lives and careers enhanced
entomology as a profession, and, who
made significant contributions to the
field in general and in their respective
subdisciplines.
Walker
Craig
For full speaker
descriptions and other
meeting details visit:
www.entsoc.org/am
In addition, this Annual Meeting will
have three Special Plenary Sessions.
Colonel Richard Johnson, Ph.D., of
the Uniformed Services University of
the Health Sciences, will be speaking on
Monday, December 14. Col. Johnson will
be addressing military entomology from a
historical perspective, and will explain the
roles military entomologists are playing in
Iraq and Afganistan.
Johnson
Dr. Mark Moffett, a Harvard-trained
ecologist and nationally-known National Geographic
photographer, is one of only a handful of people to earn a
Ph.D. under the world’s most famous
ecologist, E. O. Wilson. Dr. Moffett will
be speaking on Tuesday, December 15.
Using the unique perspectives he gained
studying insects below sea level and more
than 200 feet above the forest floor, Dr.
Moffett wrote The High Frontier (Harvard
University Press), comparing terrestrial,
marine, and microbial ecosystems, which
Moffett
challenged prevailing trends in the field of
ecology.
Dr. Peter H. Raven, president of the
Missouri Botanical Garden and George
Engelmann Professor of Botany at
Washington University in St. Louis,
is one of the world’s leading botanists
and advocates of conservation and
biodiversity. He is scheduled to speak
Wednesday, December 16, and will
focus on biodiversity and a sustainable
environment.
Raven
Scientific Presentations
There will be 68 symposia, with more than 500 presentations.
Topics range from bioenergy to insect molecular physiology.
In addition, there will be more than 400 ten-minute papers
and more than 400 posters.
An important part of the scientific program is the student
competition. This year more than 450 student papers will be
featured.
Virtual Posters
Social Mixers; Networking Opportunities
For the first time, scientists from outside North America will
have the opportunity to present their posters virtually. Using
the latest technology, attendees at the Annual Meeting will be
able to view posters electronically and chat with presenters
online.
Get ready to ignite new friendships and rekindle old ones,
discuss ideas with other professionals who have similar
concerns, and get new insights that could help you achieve
long-term success — all in a fun, relaxing atmosphere.
ESA Exposition
Explore new products and services in the exposition, which
will feature entomological equipment, supplies, and reference
materials, as well as offer the opportunity to purchase gifts for
friends and family.
Student Activities
In addition to the Student Competition, there are several
other events planned for student attendees. These include the
Student Debate, the Linnaean Games, and the Student Mixer.
In addition, there are volunteer opportunities that will help
students defray the cost of their expenses.
Registration Fees
Even with an expanded program and new activities,
registration fees are the same as last year. Complete
registration information can be found on the ESA website
at www.entsoc.org/am.
¼ If you are not already an ESA member,
become one and take advantage of lower
registration rates, as well as a host of other
valuable benefits. To view full member benefits
visit: www.entsoc.org/membership.
Students are also eligible to attend a special tour of Dow
AgroSciences’ facilities and R&D buildings on Tuesday,
December 15. Buses will leave the Indiana Convention
Center at 1:00 p.m. (lunch provided) and return by 5:30 p.m.
The tour will include informational stops throughout the
R&D laboratories and training facilities. At each stop guests
will learn more about DAS research programs, including
insecticide discovery/development, biotechnology/transgenic
crops, and formulations/delivery systems. A special session
that describes career opportunities for entomologists at DAS
will also be offered.
Awards and Honors
ESA will honor new Fellows, the Comstock Award winners,
and the recipients of many other awards during the Opening
Session. The Opening Session will also feature the first ever
Stingers, honoring the winners of the first YouTube “Your
Entomology” contest and premiering the winning video clips.
Entomological Society of America
2009 Annual Meeting
Indianapolis, Indiana
December 13–16, 2009
Registration is now open — Visit www.entsoc.org/am to register today!