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
Keyword(s):  
North American ◽  
Jumping Spider ◽  
Salticid Spiders ◽  
Ant Mimicry

scholarly journals A Predator's Perspective of the Accuracy of Ant Mimicry in Spiders

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Ximena J. Nelson
Keyword(s):  
Batesian Mimicry ◽  
Sexually Dimorphic ◽  
Oecophylla Smaragdina ◽  
Jumping Spider ◽  
Behavioural Characteristics ◽  
Ant Mimicry ◽  
Signal Accuracy

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.

scholarly journals Comparison of African and North American velvet ant mimicry complexes: Another example of Africa as the ‘odd man out’

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

The Jumping Mechanism of Salticid Spiders

1959 ◽  
Vol 36 (4) ◽  
pp. 654-664 ◽  
Author(s):  
D. A. PARRY ◽  
R. H. J. BROWN
Keyword(s):  
Direct Evidence ◽  
Jumping Spider ◽  
Multiple Image ◽  
Extensor Muscles ◽  
The Moment ◽  
Salticid Spiders ◽  
Fourth Pair

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.

scholarly journals Salticid predation as one potential driving force of ant mimicry in jumping spiders

2010 ◽  
Vol 278 (1710) ◽  
pp. 1356-1364 ◽  
Author(s):  
Jin-Nan Huang ◽  
Ren-Chung Cheng ◽  
Daiqin Li ◽  
I-Min Tso
Keyword(s):  
Visual Acuity ◽  
Predation Risk ◽  
Driving Force ◽  
Mortality Rates ◽  
Predation Pressure ◽  
Size Difference ◽  
Jumping Spider ◽  
Jumping Spiders ◽  
Selection Force ◽  
Ant Mimicry

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.

Adaptation of the Connected Speech Test: Rerecording and Passage Equivalency

2020 ◽  
Vol 29 (2) ◽  
pp. 259-264 ◽  
Author(s):  
Hasan K. Saleh ◽  
Paula Folkeard ◽  
Ewan Macpherson ◽  
Susan Scollie
Keyword(s):  
Speech Perception ◽  
North American ◽  
First Language ◽  
Intraclass Correlation ◽  
Normal Hearing ◽  
Connected Speech ◽  
Internal Reliability ◽  
Speech Test ◽  
The Mean ◽  
Unit Standard

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.

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