20th International Congress of Arachnology

197 / 232

aversion to another component of the signal (color). Such
synergistic effects on predator psychology have received
little attention in invertebrate predators. We address this
gap by asking how multimodality affects attack rates in a
voracious jumping spider (Habronattus trimaculatus ).
Spiders were given the choice between red or black prey
(artificially colored termites) in either the presence or
absence of odor from a chemically defended coreid bug
(Acanthocephala femorata). We found that when the
scent was present, spiders were significantly more likely to
avoid red termites compared with when absent. Interest-
ingly, this pattern only held up when the scent was novel;
subsequent exposure to the scent did not have the same
effect on color preference. We discuss these findings in the
broader context of predator psychology and argue that
spiders may provide novel insights for the field.
Keywords: Salticidae, multimodality, aposematic, foraging
Student - poster presentation
Duplication and concerted evolution of
MiSp-encoding genes underlie the mate-
rial properties of minor ampullate silks of
cobweb weaving spiders
Jannelle Vienneau-Hathaway1, Elizabeth Brassfield1,
Amanda Kelly Lane1, Matthew Collin2, Sandra Correa-
Garhwal2 , Thomas H. Clarke1,2, Evelyn Schwager3, Jessica
E. Garb3, Cheryl Y. Hayashi 2, Nadia A. Ayoub1
1Department of Biology, Washington and Lee University,
Lexington, VA, USA; 2Department of Biology, University of
California, Riverside, CA, USA; 3 Department of Biological
Sciences, University of Massachusetts, Lowell, MA, USA
Orb-web weaving spiders and their relatives use mul-
tiple types of task-specific silks. The majority of spider
silk studies have focused on the ultra-tough dragline
silk synthesized in major ampullate glands, but all silk
types have impressive material properties. For instance,
minor ampullate silks of orb-web weaving spiders have
lower strength but higher extensibility than draglines.
Differences in material properties between silk types
result from differences in their component proteins,
which are members of the spidroin (spider fibroin) gene
family. However, the extent to which variation in mate-
rial properties within a single silk type can be explained
by variation in spidroin sequences is unknown. Orb-web
weavers use minor ampullate silk to form the auxiliary
spiral of the orb-web, while cobweb weavers use it to
wrap prey, suggesting that selection pressures on minor
ampullate spidroin (MiSp) sequences may differ between
the two groups. Here, we characterize complete or nearly
complete MiSp sequences from five cobweb weaving spider
species in three genera and measure material properties
of minor ampullate silks in a subset of these species. We
also compare MiSp sequences and silk properties of our
cob-web weavers to published data for orb-web weavers.
We demonstrate that all our cobweb weavers possess mul-
tiple MiSp loci and that one locus is more highly expressed
than the other in at least two species. We also find that the
proportion of β-spiral-forming amino acid motifs in MiSp
positively correlates with minor ampullate silk extensibil-
ity. Our sequences thus provide templates for recombinant
silk proteins with tailored properties.
Keywords: concerted evolution, minor ampullate
spidroin, cobweb weavers, physical properties
Oral presentation
Another bloody Australian in New Zealand:
The invasive spider Latrodectus hasseltii
Cor J. Vink
Canterbury Museum, Rolleston Avenue, Christchurch
8013, New Zealand
Latrodectus hasseltii , the Australian redback, is
an invasive spider that has been established in
New Zealand since 1980. As well as its medical
importance, L. hasseltii is a conservation threat to
threatened endemic chafer beetles, skinks and New
Zealand’s endemic widow spider, Latrodectus katipo.
This unwelcome Australian spider has the capabil-
ity to spread further than its current range in New
Zealand and can also spread to other parts of the world.
However, there is hope for controlling it biologically
using a volatile organic compound.
Keywords: invasive species, Latrodectus, New Zealand
196 DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Cushing