20th International Congress of Arachnology

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very common species. However, it is still unclear, whether
the newly founded populations in mountain regions in
the south or in harsh climatic conditions of north-eastern
Poland are unstable and vulnerable to fluctuations, which
hinders effective colonization. In expansive species, data
about the genetic diversity and gene flow between local
populations are important in predicting the longevity of
the population, especially in newly colonized areas. The
main goal of the research was to analyze genetic structure
and to estimate a migration level of the wasp spider in
Poland. Over 600 specimens we obtained from 24 sites. The
genetic variability of the species and genetic differentiation
among populations was estimated using 19 microsatellite
loci. We found that in Poland A. bruennichi presents low
level of genetic variability. Most of local populations were
not in Hardy-Weinberg equilibrium. Genetic structure was
weakly pronounced but some division of populations into
geographical groups was supported by genetic data. We
suggest that observed pattern of distribution of genetic
diversity could be a consequence of rapid expansion and
result of founder effect in the newly colonized areas.
Keywords: gene flow, dispersal, habitat fragmentation,
population structure, isolation by distance.
Student - oral presentation
A first glance at the coupled genitalia of
the harvestmen Phalangium opilio(Eupnoi)
*Rachel M. Werneck1, Abel Pérez-González2 , Gabriele Uhl3
1Museum Alexander Koenig, Bonn, Germany;
2División Aracnología, Museo Argentino de Ciencias
Naturales “Bernardino Rivadavia”, Buenos Aires,
Argentina; 3Zoological Institute and Museum, Univer-
sity of Greifswald, Greifswald, Germany
Harvestmen genital morphology has long been described
mainly for taxonomic purposes, but genital coupling
interactions remain largely unknown. Male genital
functioning was generally inferred by artificial hydraulic
expansion, since interactions between male genital parts
(as well as their possible movements) were never seen.
This is a huge information deficit for a better understand-
ing of genital interactions in harvestmen, a group in
which complex genital morphology suggests functions
beyond gamete transfer/oviposition. Previously, we studied
a Laniatorean species’s coupled genitalia in some detail
(unpublished data). Here we present the first observations
for the suborder Eupnoi. Three pairs of Phalangium
opilio in copula were freeze-fixed with liquid nitrogen.
One pair was submitted to microCT scan and the others
photographed, since they were clearly in early stages
of penetration: beginning of penetration, and mouth
rubbing. The images show interesting new facts, e.g.,
pre-penetration interaction, depth of penis penetration,
stylus location in relation to seminal receptacles, penis
and ovipositor contact regions. These results, even though
preliminary, contribute to fill the gap in harvestmen func-
tional genital morphology, and also provide consistent
data for sexual selection hypotheses formulation.
Keywords: Opiliones, genital coupling, genital morphology,
mating
Student - poster presentation
Anti-predator submersion behavior: a
coevolutionary arms race between two
species of wolf spiders?
*John A. Whitinger1 , Alex N. Mullins1, Matt M. Steffenson1,
Chris A. Brown2
1Adams State University, 208 Edgemont Blvd Almosa,
CO 81101, USA; 2Tennessee Tech University, 1 William
L Jones Drive, Cookeville, TN 38505, USA
Spiders exhibit a wide range of anti-predatory defenses
that affect their overall behavior. The Red Queen
hypothesis predicts situations in which interactions with
predators can result in a coevolutionary arms race. We
examined the predator-prey interactions between two
species of semi-aquatic wolf spiders from Arizona. In these
interactions, the smaller prey species will dive under the
water to escape the larger species, however the larger
species has also evolved a diving behavior. We compared
the submersion tolerance and morphological characters
that may influence such aquatic anti-predator behavior
to determine if a coevolutionary arms race may be occur-
ring. Results indicated that the prey species had a faster
198 DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Cushing