20th International Congress of Arachnology

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collective outcomes when keystone individuals are the first
to acquire it. We trained keystone or generic individuals to
attack or avoid novel stimuli and implanted these trained
individuals within groups of naive colony-mates. We
subsequently tracked how quickly groups learned about
their environment in situations that matched (accurate
information) or mismatched (inaccurate information) the
training of the trained individual. We found that colonies
with just one accurately informed individual were quicker
to learn to attack a novel prey stimulus than colonies with
no informed individuals. However, this effect was no more
pronounced when the informed individual was a keystone
individual. In contrast, keystones with inaccurate infor-
mation had larger effects than generic individuals with
identical information: groups containing keystones with
inaccurate information took longer to learn to attack/avoid
prey/predator stimuli and gained less weight than groups
harbouring generic individuals with identical information.
Our results convey that misinformed keystone individu-
als can become points of vulnerability for their societies.
Keywords: behavioral syndrome, leadership, learning,
personality, social spider, temperament
Student - oral presentation
Efficiency of paternal care on egg protec-
tion in the harvestman Poassa limbata
(Opiliones): do females help caring too?
*Rosannette Quesada-Hidalgo1, Diego Solano2 , Gustavo
Requena1 and Glauco Machado1
1Instituto de Biociências, Universidade de São Paulo,
São Paulo, Brazil; 2Escuela de Biología, Universidad
de Costa Rica, San José, Costa Rica
Parental care usually increases offspring protection
against predators and pathogens. Although paternal
care is widespread in harvestmen, only two studies have
investigated the benefits of male care in terms of offspring
protection. Here we tested the efficiency of parental care
in the harvestman Poassa limbata Roewer 1943¸ whose
males build cup-like mud nests used as oviposition sites.
Given that some females stay for long periods in the vicin-
ity of nests where they oviposit, we also tested whether
these resident females played a role in protecting the
offspring. During four consecutive days we monitored
40 nests and recorded the presence of caring males and
the position and behavior of all nearby females. We then
removed the caring males from 24 nests and monitored
all nests for the following four days. Predation events were
observed only in nests without males, performed mainly
by conspecifics and ants. Ten unprotected nests were
adopted by other males. Three resident females occupied
unprotected nests and no predation events were recorded
while present. These results show that paternal protection
is crucial for offspring survival and that resident females
may take care of unprotected eggs if caring males desert
or die. Additional information is required to assess whether
this is the first case of biparental care in harvestmen.
Keywords: parental care, sex role reversal, sexual selec-
tion, mud-nest harvestmen
Poster Presentation
Weather conditions affect developmental
decision in a common wolf spider species
Zoltán Rádai1, Balázs Kiss2, Ferenc Samu2
1Department of Evolution, Zoology and Human Biology,
University of Debrecen, Debrecen, Hungary; 2Plant
Protection Institute, Centre for Agricultural Research,
Hungarian Academy of Sciences, Budapest, Hungary
Cohort splitting is a unique life history characteristic
of the Central European agrobiont wolf spider, Pardosa
agrestis, and was suggested to be an adaptation to tempo-
rally variable environments by allowing the coexistence of
parallel cohorts with differential success in given environ-
mental conditions. We have tested whether the emergence
of rapidly and slowly developing cohorts (due to the
asynchronous development of first generation spiderlings)
depends on environmental, in particular weather condi-
tions during the season. We put forward three hypotheses
regarding the effect of weather. The first proposed that
weather conditions have no differential effect on the two
cohorts or different life stages. The other two hypotheses
devised that weather conditions may act as cues, based on
which plastic developmental decisions of choosing rapid
156 DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Cushing