20th International Congress of Arachnology

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predators indirectly influence leaf litter through trophic
interactions affecting decomposition rates. Numerous
studies have shown wandering spiders (Lycosidae) can
affect decomposition rates with varying magnitude and
direction. It is hypothesized that spiders consuming
Collembola has impacts on fungal communities, which
drives the changes in decomposition rates. And so with
changing abiotic environments and conditions, the
fungal community health is a key factor in how spiders
will impact this cascade. However, limited studies have
investigated the fungal communities in response to spider
presence or absence. Here I present the results of a labo-
ratory mesocosm study, investigating the “triangle” of
decomposition, measuring the spider-Collembola-fungus
interactions. Mesocosm treatments were a factorial design
of presence/absence of wolf spider (Schizocosa) and Col-
lembola (Sinella). Decomposition rates were measured
and fungal communities were assessed using phospho-
lipid fatty-acid (PLFA) analyses and mass spectrometry.
Keywords: Collembola, decomposition, fungus, phospho-
lipid fatty-acid, Schizocosa
Student - oral presentation
Exploring behavior and neurochemistry in
the polyphenic spider, Anelosimus studio-
sus (Araneae: Theridiidae)
*Jennifer B. Price, Thomas C. Jones
East Tennessee State University, Department of Biologi-
cal Sciences, Box 70703, Johnson City, TN, 37614, USA
The importance of social behavior is evident in human
society, but there are both costs and benefits associated
with cooperation and sociality throughout the animal
kingdom. At what point do the benefits outweigh the
costs, and when do selective pressures favor sociality and
colonization over solitude and independence? To investigate
these questions, we have focused on an anomalous species
of spider, Anelosimus studiosus, also known now as the
northern social spider. Throughout its broad range, A.
studiosus is solitary and aggressive, but recently, colonies
of cooperative and social individuals have been observed at
northern latitudes. This leads to two research questions: 1)
what characteristics differentiate the two variants behavior-
ally, and 2) how are they different physiologically? Colonies
and individuals were collected from multiple populations
throughout the Tennessee River watershed area and main-
tained in a laboratory environment for quantitative and
qualitative assessment of behavioral traits as well as spe-
cific neurochemical analysis by high performance liquid
chromatography with electrochemical detection. I looked
at the influence of factors such as age, reproductive state,
nutritional state, and time of day on behavior and neuro-
physiology. I found correlations between social behaviors
and serotonin, aggressive behaviors and octopamine
(invertebrate counterpart of norepinephrine), and several
other compounds associated with an increase or decrease in
aggression. These studies combine techniques from multi-
ple disciplines to contribute to the greater understanding of
the proximate control of social and aggressive behaviors as
well as the factors influencing the evolution of sociality.
Keywords: social behavior, neurochemistry, ontogeny,
aggression, reproductive state, circadian rhythm
Oral presentation
Male polymorphism in bird-associated
mites (Acariformes: Astigmata)
Heather Proctor
Department of Biological Sciences, University of
Alberta, Edmonton, Alberta, Canada, T6G 2E9
Male polymorphism is common in mites from the cohort
Astigmata. The best studied cases involve combat-related
morphology in mites associated with stored products, such
as Sancassania berlesei, in which some males have legs
modified for attacking rivals (heteromorphs) while others
have female-like walking legs (homeomorphs). In these
free-living species, induction of the hetermorphic state
can be environmentally or genetically determined. Poly-
morphism is even more commonly observed in astigmatan
mites associated with birds. Male nest mites from the dust-
mite family Pyroglyphidae can show strong variation in the
degree of hypertrophy of their forelegs. Male feather mites
from the superfamily Analgoidea often display homeo- and
heteromorphic states, which can be further complicated by
154 DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Cushing