Ant Mimicry Lessens Predation on a North American Jumping Spider by Larger Salticid Spiders

2011 ◽  
Vol 40 (5) ◽  
pp. 1223-1231 ◽  
Author(s):  
Caitlin A. Durkee ◽  
Martha R. Weiss ◽  
Divya B. Uma
2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Ximena J. Nelson

Among spiders, resemblance of ants (myrmecomorphy) usually involves the Batesian mimicry, in which the spider coopts the morphological and behavioural characteristics of ants to deceive ant-averse predators. Nevertheless, the degree of resemblance between mimics and ants varies considerably. I usedPortia fimbriata,a jumping spider (Salticidae) with exceptional eyesight that specialises on preying on salticids, to test predator perception of the accuracy of ant mimicry.Portia fimbriata’s response to ants (Oecophylla smaragdina), accurate ant-like salticids (Synageles occidentalis), and inaccurate ant-like salticids (females ofMyrmarachne bakeriand sexually dimorphic males ofM. bakeri, which have enlarged chelicerae) was assessed.Portia fimbriataexhibited graded aversion in accordance with the accuracy of resemblance to ants (O. smaragdina>S. occidentalis> femaleM. bakeri> maleM. bakeri). These results support the hypothesis that ant resemblance confers protection from visual predators, but to varying degrees depending on signal accuracy.


PLoS ONE ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. e0189482 ◽  
Author(s):  
Joseph S. Wilson ◽  
Aaron D. Pan ◽  
Erica S. Limb ◽  
Kevin A. Williams

1959 ◽  
Vol 36 (4) ◽  
pp. 654-664 ◽  
Author(s):  
D. A. PARRY ◽  
R. H. J. BROWN

1. Photographs of the jumping spider Sitticus pubescens (Salticidae) show that the jump is almost entirely due to the sudden straightening of the fourth pair of legs. Multiple-image photographs show the importance of a silk drag-line in controlling the jump. 2. The torques at the leg joints have been estimated. Extension torques occur at the two hinge joints although these lack extensor muscles. 3. The erection of leg spines at the moment of the jump provides direct evidence that hydraulic forces are involved in the jump. This view is supported by estimates of the pressures involved, which fall within a factor of about two of those previously measured in the legs of the spider Tegenaria.


2010 ◽  
Vol 278 (1710) ◽  
pp. 1356-1364 ◽  
Author(s):  
Jin-Nan Huang ◽  
Ren-Chung Cheng ◽  
Daiqin Li ◽  
I-Min Tso

Many spiders possess myrmecomorphy, and species of the jumping spider genus Myrmarachne exhibit nearly perfect ant mimicry. Most salticids are diurnal predators with unusually high visual acuity that prey on various arthropods, including conspecifics. In this study, we tested whether predation pressure from large jumping spiders is one possible driving force of perfect ant mimicry in jumping spiders. The results showed that small non-ant-mimicking jumping spiders were readily treated as prey by large ones (no matter whether heterospecific or conspecific) and suffered high attack and mortality rates. The size difference between small and large jumping spiders significantly affected the outcomes of predatory interactions between them: the smaller the juvenile jumping spiders, the higher the predation risk from large ones. The attack and mortality rates of ant-mimicking jumping spiders were significantly lower than those of non-ant-mimicking jumping spiders, indicating that a resemblance to ants could provide protection against salticid predation. However, results of multivariate behavioural analyses showed that the responses of large jumping spiders to ants and ant-mimicking salticids differed significantly. Results of this study indicate that predation pressure from large jumping spiders might be one selection force driving the evolution of nearly perfect myrmecomorphy in spiders and other arthropods.


2020 ◽  
Vol 29 (2) ◽  
pp. 259-264 ◽  
Author(s):  
Hasan K. Saleh ◽  
Paula Folkeard ◽  
Ewan Macpherson ◽  
Susan Scollie

Purpose The original Connected Speech Test (CST; Cox et al., 1987) is a well-regarded and often utilized speech perception test. The aim of this study was to develop a new version of the CST using a neutral North American accent and to assess the use of this updated CST on participants with normal hearing. Method A female English speaker was recruited to read the original CST passages, which were recorded as the new CST stimuli. A study was designed to assess the newly recorded CST passages' equivalence and conduct normalization. The study included 19 Western University students (11 females and eight males) with normal hearing and with English as a first language. Results Raw scores for the 48 tested passages were converted to rationalized arcsine units, and average passage scores more than 1 rationalized arcsine unit standard deviation from the mean were excluded. The internal reliability of the 32 remaining passages was assessed, and the two-way random effects intraclass correlation was .944. Conclusion The aim of our study was to create new CST stimuli with a more general North American accent in order to minimize accent effects on the speech perception scores. The study resulted in 32 passages of equivalent difficulty for listeners with normal hearing.


Sign in / Sign up

Export Citation Format

Share Document