20th International Congress of Arachnology

200 / 232

199
DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
submersion recovery time and a higher density of longer
spines on their femurs when compared to the predator
species. This may allow the prey species to remain sub-
merged longer by way of a larger volume of trapped air,
resulting in the ability to evade predation. Further investi-
gation will determine whether the density of the hairs on
the abdomen differs between predator and prey, as well as
how the density of spines influences aquatic movement.
Keywords: anti-predator behavior, Red Queen hypoth-
esis, Lycosidae, submersion, tolerance
Student - oral presentation
Macronutrient effects on juvenile jumping
spider growth
*Will Wiggins, Shawn Wilder
Department of Integrative Biology, Oklahoma State
University LSW 501, Stillwater, OK 74078, USA
A large body size is important for many reasons, including
increases in viable eggs, decrease risk of cannibalism, and
increased success in male-male combat. However, building
a large body is costly and may require particular amounts
and ratios of nutrients. For many animals, especially
carnivores on which less is known of their nutritional
ecology, the balance of nutrients at which animals
maximize growth and body size remains unknown. We
manipulated the quantity and nutrient content of flies
as prey to test how the lipid and protein content of prey
affected the growth of spiders. We measured the body size
of 420 F1 jumping spiders, Phidippus audax, raised on
21 different diet treatments ranging from high protein to
high lipid across several prey quantities. The ratio of lipid
to protein in prey had the largest effect on spider growth
in the high prey abundance treatments. Overall, spiders
weighed more and had larger body size on diets that were
more lipid-biased. Our results suggest that spiders require
lipid rich prey for maximal growth. Previous work indi-
cates most prey in nature are lipid poor. Spiders should
then either select lipid rich prey over lipid poor prey or
find alternative energy sources, like extra floral nectar.
Keywords: nutrition, macronutrients, jumping spider,
growth, Phidippus audax
Oral presentation
Measuring the nutrient content of prey for
spiders
Shawn M. Wilder
Department of Integrative Biology, 501 Life Sciences West,
Oklahoma State University, Stillwater OK 74078, USA
Diet quality has long been known to have large effects on
the behavior, survival, growth and reproduction of spiders.
The main attributes of prey thought to be responsible for
these effects of diet quality are toxins and nutrients. For
decades, analysis of prey nutrient content have measured
nitrogen (N) and extrapolated to protein using an out-
dated conversion factor (6.25). Here, I test if N or protein
is a better measure of the nutrient content of the prey
of spiders. Overall, there was a poor correlation between
the N and protein content of a wide range of arthropods
and the estimated conversion factor was lower than the
traditional 6.25. Analyses of N also overestimated the
amount of protein left in prey remains after spiders fin-
ished feeding. The N content of prey remains is similar
too, if not higher than, whole prey items. Yet, almost no
protein is present in prey remains. Feeding experiments
demonstrated that analysis of the protein content in whole
prey items is a strong predictor of the amount of protein
consumed from prey by spiders. Assays of protein content
provide a more direct and cost effective method for mea-
suring the nutrient content of prey and the nutrients that
spiders consume from prey than the traditional method of
measuring N and multiplying by 6.25.
Keywords: foraging, nutrition, prey, protein
Oral presentation
Female mating status affects male mating tactic
expression in the wolf spider Rabidosa punctulata
Dustin J. Wilgers, S. Simon
McPherson College, 1600 E. Euclid Ave., McPherson,
KS 67460, USA
Males commonly alter the expression of alternative
mating tactics based on their condition, the environment
20th International Congress of Arachnology