20th International Congress of Arachnology

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DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
20th International Congress of Arachnology
limit (digging males: 0.33±0.09, n=14, non-digging
males: 0.42±0.16, n=10; p=0.08). We are increasing
sample sizes to confirm whether male burrow digging
implies an energetic cost in this species, or if it is exclu-
sively performed by males with good body condition, for
whom digging causes no impact in immune responses.
Keywords: lytic activity, immune functions, trade-off,
burrows
Oral presentation
Complex mating, high male sperm effort
and strong female control in a wolf spider
Maria J. Albo, Fernando G. Costa
Laboratorio de Etología, Ecología y Evolución, Insti-
tuto de Investigaciones Biológicas Clemente Estable.
Montevideo, Uruguay
Post-copulatory sexual selection is often expected in poly-
androus species and it is especially promising to study in
species with complex mating patterns. In the wolf spider
Schizocosa malitiosa males perform two different consec-
utive copulatory patterns, which are characterized mainly
by different number of pedipalp insertions. The full mating
last 100 min, 80% of total insertions occur in pattern 1 and
20% in pattern 2. Both patterns produce similar number of
offspring, but pattern 1 induce higher female reluctance
to remating than pattern 2. By interrupting matings after
pattern 1 and then offering the male a second female,
which received only pattern 2, we investigated if the
complex copulatory patterns are related to male sperm
investment and sperm storage by females. We hypothesized
that males strategically allocate the sperm during pattern
1 causing female reluctance. Second, by mating males
with recently thawed, dead females we tested the possible
active roles of females in sperm storage. Our findings show
that males transfer in total 71% of the sperm available in
their pedipalps, being higher but not significant in pattern
1 than pattern 2. Females drastically reduced the amount
of sperm stored in their spermathecae and such control is
stronger in pattern 1 compared to pattern 2. We propose
that cryptic female choice is a main factor driving male
sperm effort, and differences in copulatory patterns among
males would result in wide variation in their reproductive
success. Receptive inhibiting substances rather than the
sperm itself may be acting during pattern 1, but active
female reduction in the amount of ejaculate that reaches
her spermathecae most probably help to reduce her reluc-
tance to remating.
Keywords: copulatory patterns, cryptic female choice,
sexual behavior, wolf spiders
Poster presentation
The fear of spiders: the effect of a single
talk on school children
Maria J. Albo1 , Laura Montes de Oca1 and Ignacio
Estevan 2
1Laboratorio de Etología, Ecología y Evolución, Instituto
de Investigaciones Biológicas Clemente Estable (IIBCE),
Montevideo, Uruguay; 2Instituto de Fundamentos y
Métodos en Psicología, Facultad de Psicología, Universi-
dad de la República, Montevideo, Uruguay
Loved and feared, spiders have been always mysterious
animals for human societies. The majority of species are
harmless, but probably due to their venom they are gener-
ally feared and disliked in many cultures. However, spiders
use the venom to capture prey or defend themselves
from predators, while only 1% are fatally dangerous for
humans. In this project we were interested in examining
children’s knowledge and attitudes about spiders as well
as in measuring the impact of our talks on their point
of view and behavior. We surveyed 172 children from 9
school groups (10 and 11 years old) visiting the Institute
(IIBCE) in 2015. We performed a multiple choice survey
before any knowledge was given, including identification
of native animals (particularly arachnids), whether they
are afraid or not to spiders, if they like them or not, and
what is their reaction if they spot one nearby. Afterwards,
we divided them in two groups: children receiving a talk
about spiders and other arachnids (spider group), chil-
dren receiving a talk in another topic (control group).
The same survey was repeated 30 days later at school by
their own teacher. We compared pre and post-responses
both within and between treatment groups. The results