20th International Congress of Arachnology

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sequence data. DNA extraction, amplification and data
analysis was conducted as per standard procedures.
Among the five mtDNA haplotypes identified, three haplo-
types were present in both Central WG and Northern WG
and two were present in Southern WG. The neighbour-
joining tree of the five haplotypes identified two distinct
clades of haplotypes: clade 1 and clade 2. Estimates of
gene flow show that there is little exchange between SWG
and other part of the Western Ghats, compared to
exchange among population within NWG and CWG
regions. The resulted MP tree showing two monophyletic
groups: one SWG group and CWG-NWG combined. The
consideration of local population differentiation is impor-
tant in deciding how to conserve a fragmented population.
Most measures of local distinctiveness will predominantly
reflect genetic variation between populations. Such varia-
tion can be regarded as indicating a departure from an
ideal panmictic system, although it may reflect long-term
evolutionary processes as well as recent disturbance.
Keywords: Western Ghats, biodiversity hotspot, popula-
tion structure
Student - oral presentation
Assessing fitness benefits of increased
sperm transfer in the copulatory silk wrap-
ping nursery web spider, Pisaurina mira
*Alissa Anderson, Eileen Hebets
University of Nebraska - Lincoln, School of Biological
Sciences, 325 Manter Hall, Lincoln, NE, 68588
Male fitness is largely dictated by his ability to fertilize
eggs and there is a plethora of male adaptations associ-
ated with increasing fertilization success. In the nursery
web spider, Pisaurina mira, males restrain females
prior to and during copulation by wrapping them with
silk. Previous research demonstrates that copulatory silk
wrapping reduces a male’s chance of being sexually can-
nibalized, and increases the number of sperm transfer
opportunities (termed insertions) that a male can achieve
within a mating. While avoiding cannibalism provides an
obvious survival benefit to males, the impact of insertion
number on male fitness remains unknown. This study
tested the hypothesis that the increased insertion number
realized through copulatory silk wrapping increases (a)
the quantity of sperm transferred and (b) fertilization
success. To accomplish this we directly quantified the
amount of sperm in male pedipalps (i.e. the male sperm
storage organ) before and after mating, and quantified
fertilization success when males were capable of obtain-
ing one versus two insertions within a mating. Pisaurina
mira exhibits a unique mating behavior that may reflect
an evolutionary history of conflicting reproductive strate-
gies between males and females. We hope this study will
begin to shed fundamental insights into the co-evolution-
ary dynamics between the distinct sexes.
Keywords: Pisauridae, sexual conflict, sexual selection,
mating systems, sperm competition
Student - oral presentation
Rapid diversification of spiders on islands
- insights from comparative and popula-
tion genomic inferences
*Ellie Armstrong1, Stefan Prost2 , Rosemary Gillespie3,
Dmitri Petrov1
1Stanford University Department of Biology 371 Serra
St. Stanford, CA 94305-5020; 2 University of California,
Berkeley Department of Environmental Science,
Policy, & Management, 130 Mulford Hall #3114,
Berkeley, CA 94720; 3University of California, Berkeley
Department of Integrative Biology, 4098 Valley Life
Sciences Building (VLSB) Berkeley, CA 94720-3140
Understanding the underpinnings of population diver-
gence and the early stages of species formation is one of
the new frontiers in evolutionary biology and has been
enabled by next-generation genomics. However, the
application of next-generation tools to arthropod systems
can be difficult, as the characteristics of these genomes
are relatively unknown. To address questions of early
population divergence in spiders, we have applied several
different methods, including ddRAD sequencing, de-novo
whole genome sequencing and assembly, and low-cover-
age re-sequencing of several of the spider lineages based
in the Hawaiian Islands. Although relatively few spider
40 DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Cushing