20th International Congress of Arachnology

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placed along a grid pattern within a farm-scape in the
Tift county area. Spiders were later removed, preserved in
alcohol, and counted and identified to lowest taxon pos-
sible. Species data were compiled and correlated with the
four selected attributes using multivariate methods and
geospatial statistics. Preliminary analysis shows at least 12
different species of spiders present across the contrasting
cotton farm-scapes, and one bioenergy feedstock, Miscan-
thus giganteus. The wolf spiders (Lycosidae) numerically
dominated the communities. Further identification of
spiders and more in-depth analysis of the data will allow
for greater exploration of the relationship between spider
abundance, diversity, and the farm-scape’s geospatial
attributes. Ultimately, the results should help growers
identify potential spider hotspots within their farm-scapes,
which could then be maintained to promote healthy popu-
lations of these beneficial predators.
Keywords: agroecosystems, bioenergy feedstocks,
biophysical environment, natural enemies
Oral presentation
Who eats whom—life history strategies of
the vinegaroon Mastigoproctus giganteus
Justin Schmidt
Southwestern Biological Institute, 1961 W. Brichta
Dr., Tucson, Arizona 85745, USA
Little is known about the life history or biology of
vinegaroons (Thelyponida). They are perhaps best-known
for their vinegary smelling defensive spray that functions
as a powerful defense against would-be predators. The
chemistry of the spray of Mastigoproctus giganteus is well
characterized and likely is similar throughout the order.
Vinegaroon natural history is terra incognita and lacking
even basic information including life spans, predators, prey,
and whether individuals tend to be cannibalistic. Through
an extensive series of field observations and experiments
both in the field and the lab, I report on the acceptable
prey, potential predators, and highlight the weaknesses
or limitations of the different links of the life cycle M.
giganteus . A teaser: they are not naturally cannibalistic.
Keywords: predation, prey, life history, cannibalism, defense
Student - poster Presentation
Influence of web in prey detection: a com-
parison of four tarantula species
*Sarah E Schrader, Cara Shillington
Department of Biology, Eastern Michigan University,
Ypsilanti, Michigan 48197, USA
Tarantulas are primarily sit-and-wait predators that do
not rely on a web to capture prey. In many species, silk
structures do not extend much past retreat entrances. There
are species however that construct extensive sheets of web
interconnected by silken tubes. Four species that build
this type of retreat were chosen for this study: Heterothele
gabonensis, H. villosella, Holothele incei and Oligoxystre
diamantensis. Previous observations have shown that the
Heterothele species react to prey more quickly and have
a higher capture success rate in home containers with
intact webs than in bare arenas. The goal of this study was
to further examine how this network of web influences
prey detection and capture behavior in other species of
tarantula, and the impact of web removal. Feeding trials
were conducted in situ, with each species divided into two
treatment groups: one where the web was left intact, and
the other had webbing removed 24 hours before the trial
began. We hypothesized that spiders with intact webbing
would capture prey faster and exhibit bolder behaviors.
Each week, spiders were fed a single, live cricket weigh-
ing 80% of the spider’s weight. Across six trials, latency
to capture was recorded and analyzed using a three-way
mixed ANOVA. Prey capture behaviors, particularly failed or
aborted grabs, were recorded and ranked in terms of bold-
ness. Web structure and percent coverage of the housing
containers were also recorded and compared between
species.
Keywords: Theraphosidae, tarantula, prey capture, web
Student - poster presentation
Male black widows decrease competition
via web reduction
*Catherine Scott1,2, Devin Kirk1 , Sean McCann1,
Gerhard Gries1
1Simon Fraser University, 8888 University Drive,
170 DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Cushing