20th International Congress of Arachnology

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poorly studied, and ongoing habitat alteration and
human population expansion has created an urgent need
to understand and begin to conserve this biota. Prelimi-
nary results show that spider in Central Africa are more
abundant and diverse in monodominant than in the
mixed forest. But on both continents, the same families
(Theridiidae, Thomisidae, Salticidae, and Oonopidae)
dominate (10–28% of communities) both ground and
aerial samples. Rare families (less than 2% of the assem-
blage), including Anapidae, Clubionidae, Ctenidae, and
Tetragnathidae, are rare in all our sites. Some families
have medium abundance (2–10%) in all sites, includ-
ing Linyphiidae and Gnaphosidae. A major result is that
family-level spider diversity in our Central Africa samples
(368 adult specimens collected, belonging to 25 families)
is very similar to sites in Central America (265 adult
specimens, 24 families). This similarity on two continents
requires our attention, for conservation. Moreover, some
families can be considered as indicators, because of their
scarcity in the populations. But this research needs to be
continued. This study has enhanced collaboration between
our American and African institutions, and promises to
open a new era of scientific exchange between us.
Keywords: rapid assessment protocol, Afrotropics,
Neotropics, spider communities, biodiversity
Oral presentation
Assessment strategies in male-male con-
tests of jumping spiders
Rowan H McGinley1,2, John Prenter 1,3, Phillip W Taylor1
1Department of Biological Sciences, Macquarie Univer-
sity, Sydney, Australia; 2School of Biological Sciences,
University of Nebraska-Lincoln, Lincoln, Nebraska,
USA; 3 St Mary’s University College, Belfast, UK
Animal contests are usually resolved when one opponent
makes the decision to withdraw. This decision may be influ-
enced by diverse sources of information available during a
contest. Animals may reduce the costs of fighting by assess-
ing the quality of their opponent and withdrawing when
they determine that the opponent is superior (“mutual
assessment”). However, as assessment itself may be costly
or difficult, animals may adopt an alternative strategy of
persisting until they reach a cost threshold (“self assess-
ment”). We conducted a series of experiments to examine
the sources of information that influence decision-making
during male-male contests of the jumping spider Servaea
incana. We considered both maximum level of escalation
and duration as measures of contest costs and also exam-
ined assessment strategies used at different stages within
a contest. There is substantial variation in body size in
S. incana males and body size was a strong predictor of
contest outcome. Despite the high acuity vision of jumping
spiders and their dynamic, ritualized, displays, we found
little evidence that S. incana males assess the size of their
opponents during staged contests. Smaller spiders were less
willing to escalate, regardless of opponent size, consistent
with a self-assessment strategy. Despite an apparent lack of
mutual assessment during contests between live pairs, S.
incana males did exhibit an ability to discern ‘opponent’
size in video playback experiments. The probability of dis-
playing was determined by an interaction between the size
of an individual and its video opponent. An additional set
of experiments reveal that hunger also influences contest
behaviour and may blur the distinction between “contests”
and “predator-prey interactions” in jumping spiders. We
discuss both the limitations of correlative studies in study-
ing assessment strategies and why spiders may not use
information about an opponent during live contests.
Keywords: agonistic signalling, animal contests, assess-
ment strategies, body size, intrasexual competition,
Salticidae, visual displays
Poster presentation
Relationships between whole-organism
performance, morphology and behaviour
in spiders
Rowan H. McGinley, J. Colton Watts, Eileen A. Hebets
School of Biological Sciences, University of Nebraska-
Lincoln, Lincoln, Nebraska, USA
Studies of whole-organism performance can assist in
interpreting relationships between morphology and
behaviour and how these in turn contribute towards
134 DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Cushing