20th International Congress of Arachnology

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DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
20th International Congress of Arachnology
Oral presentation
Spiders attending sentinel egg masses
prefer landscapes comprising native not
exotic plants
Matthew H. Greenstone1 , Richard T. Olsen 2, Mark E. Payton 3,
Mary L. Cornelius1
1USDA-ARS Invasive Insect Biocontrol and Behavior
Laboratory, 10300 Baltimore Ave., Beltsville, MD
20705, USA; 2USDA-ARS US National Arboretum,
3501 New York Ave., NE, Washington, DC 20002,
USA; 3Department of Statistics, 301 MSCS Building
Oklahoma State University, Stillwater, OK 20705, USA
There is heightened interest in effects that the prov-
enance of plants in the landscape has on animals
inhabiting them. There is an increasing body of
research on insect herbivores, but less attention has
been paid to arthropod natural enemies. This question
is of great interest for designers of urban ornamental
landscapes, which tend to be mosaics of native and
exotic plants. Many commonly grown exotic woody
plants were missing from eastern North America for
millions of years prior to the arrival of Europeans.
We present the hypothesis that due to the lack of
a recent co-evolutionary history with these plants,
native natural enemies will be less well able to utilize
the resources–architectural features and nutritional
supplements–provided by exotic plants than they will
those of native plants, and hence will be less numerous
and diverse in landscapes dominated by exotic plants.
To test the hypothesis, we designed a replicated experi-
ment comprising 0.08 Ha plots planted to congeners of
16 genera of woody plants from either Eurasia or North
America. Spiders attending egg masses of the brown
marmorated stink bug, Halyamorpha halys, emplaced
on leaves of a subset of plant species known to be
attacked by this pest, were statistically less abundant in
the exotic plots, supporting the hypothesis.
Keywords: Anyphaenidae, predation, salticidae, urban
ornamental landscapes
Poster presentation
Morphology of setae on coxae and
trochanters of spiders Theraphosinae:
preliminary results
Jose Paulo Leite Guadanucci, Arthur Galleti Lima
UNESP Rio Claro, Instituto de Biociências, Depar-
tamento de Zoologia, Av 24A, 1515, Bela Vista, Rio
Claro, São Paulo, Brazil
Theraphosidae spiders, known as tarantulas, present
a homogeneous morphology. They have a diversity of
cuticular structures, such as stridulating, sensory and
adhesive setae that are used for systematics purposes. Many
genera of Theraphosinae are diagnosed by the presence of
stridulating apparatus, which can be formed by distinct
types of setae. These structures have never been examined
in a comparative approach in the subfamily. We aim to
describe, using SEM images, the diversity of setae, located
on coxae and trochanters of theraphosinae spiders, as
well as propose a terminology regarding the morphologic
variants. The presence of stridulating setae on prolateral
face of coxae I and II in spiders of the genus Lasiodora
is documented. These stridulating setae are character-
ized by a smooth base, mid region sparsely covered with
thin and long barbs and a spiniform apex. We found the
same plumose setae in the close related genera Vitalius,
Nhandu, Proshapalopus, Pterinopelma. These setae
were recorded on all coxae and trochanters, and they are
more numerous in males and on the front legs. Unlike of
the plumose setae of the group above, spiders of the clade
Acanthoscurria+Cyrtopholis, possess a stridulating clavi-
form setae, characterized by having a bulky appearance,
a smooth base, wide mid region densely barbed and a spi-
niform apex. Moreover, in some species of Acanthoscurria
(A. paulensis, A. natalensis and A. juruenicola) we also
recorded the stridulating plumose setae, similar to those in
Lasiodora and closely related genera. Note that in Acan-
thoscurria these setae occur only on the front legs and
are more numerous in males. Other theraphosine genera
were examined and only covering body setae were found.
Some other genera for which a stridulating apparatus has
been reported, such as Pamphobeteus, Grammostola,