20th International Congress of Arachnology

DENVER MUSEUM OF NATURE & SCIENCE

REPORTS

No. 3, July 2, 2016

International Congress of Arachnology

São Paulo, SP, Brazil; ²Instituto de Biociências da

Universidade de São Paulo. R. do Matão. 05508-090

- Butantã, SãoPaulo SP, Brazil

i.cizauskas@gmail.com

The diversity of spiders that occurs in caves in Brazil

is poorly known. Little is known about the diversity of

species and their distribution and, ecological aspects as

behavioral characteristics (e.g., maternal behavior, the

webs architecture) and the relationship of these species

with the cave environment are even less studied. In this

study, we intend to map the diversity of spiders in caves in

different karst regions in Brazil, as well as to record and

analyse ecological characteristics of these species. Our

study is based on a data-bank (still being update, 2009–)

with information from more than 3,100 caves, based on

standardized sampling. So far, we identified 35,674 adult

spiders from 51 families distributed in 391 spp. Among

these, 43 species, distributed in the families Ochyroc-

eratidae, Tetrablemmidae, Oonopidae, Prodidomidae,

Symphytognathidae, Caponiidae, Hahniidae, Corinnidae,

Pholcidae, Ctenidae, Microstigmatidae, Dipluridae and

Theraphosidae, have characteristics that indicate prefer-

ence or isolation in the hypogean environment. This

information has been ordered and will be presented in

an analysis of guilds. We also evaluated the richness and

abundance of species and related it with environmental

variables (e.g., different lithologies). Among the results

related to the ecology, species that carry their egg-sacs

with them seem to be particularly abundant in caves com-

munities. All information of distribution, taxonomy and

ecology of cave species of Brazil are being organized to be

available on a website still under construction.

Keywords: cave spiders, mapping, diversity and behavior

Student - poster presentation

Autotomized

Prionostemma

harvestmen

have equal mating success than intact

individuals

*Leticia Classen-Rodriguez

, Ignacio Escalante

Department of Environmental Science, University

of Puerto Rico–Rio Piedras, San Juan, Puerto Rico,

00928;

Department of Environmental Science,

Policy and Management, University of California–

Berkeley, 94720 Berkeley, California, USA.

bohiti.ki@gmail.com

By studying sexual behavior in animals, biologists can

understand how particular morphological and behav-

ioral traits have evolved. Furthermore, the importance

of certain defensive strategies associated with mating

can be addressed, for its impact on reproductive success.

Autotomy –the voluntary releasing of legs– is a common

strategy used as an anti-predator defense mechanism

among arachnids. Although it may ensure immediate

survival, it may convey long-term costs in courtship and

individual fitness. This would be especially relevant for

arachnids with behaviorally complex courtship that involve

using their legs. For instance, some species of Sclerosoma-

tidae harvestmen interact by doing leg-wrappings during

courtship, which is known to be crucial for the male’s

mating success. Many species of Sclerosomatidae have

high frequency of autotomy. For example, in a currently

undescribed species of

Prionostemma

in the Neotropical

rainforests of Costa Rica we observed that 61% of individu-

als, including males and females, were missing at least one

leg. Therefore, we tested the hypothesis that leg condi-

tion (intact or autotomized) had an effect on the sexual

behavior and consequently, mating success particularly of

males, when compared to females. We conducted 144 lab

mating trials using either autotomized males or females,

or both. Overall, we found no major differences in court-

ship behavior nor mating success between autotomized and

intact individuals (mating success average 38 ± 3%). We

also found a similar pattern for mating interactions when

compared with field observations. We also described for

the first time in Neotropical harvestmen the details of the

mating behavior. Compared to temperate zone Sclerosoma-

tidae,

Prionostemma

sp. males did not wrap the females’

legs with their own. These findings suggest that autotomy

does not interfere with mating success, potentially explain-

ing why it is so prevalent in in this genus. However, this

mechanism remains to be studied.

Keywords: Opiliones, sexual behavior, mating success,

daddy-longlegs, Neotropical harvestmen