scholarly journals Thermal preferences of two spider species: an orb-web weaver and a synanthropic funnel-web weaver

2021 ◽  
Vol 88 (1) ◽  
pp. 824-836
Author(s):  
T. Napiórkowska ◽  
J. Templin ◽  
P. Grodzicki ◽  
J. Kobak
Keyword(s):  
Spider Species ◽  
Orb Web ◽  
Thermal Preferences

Analysis of transcriptomes of three orb-web spider species reveals gene profiles involved in silk and toxin

2013 ◽  
Vol 21 (6) ◽  
pp. 687-698 ◽  
Author(s):  
Ying-Jun Zhao ◽  
Yan Zeng ◽  
Lei Chen ◽  
Yang Dong ◽  
Wen Wang
Keyword(s):  
Spider Species ◽  
Web Spider ◽  
Gene Profiles ◽  
Orb Web

scholarly journals Adhesion modulation using glue droplet spreading in spider capture silk

2017 ◽  
Vol 14 (130) ◽  
pp. 20170228 ◽  
Author(s):  
Gaurav Amarpuri ◽  
Ci Zhang ◽  
Todd A. Blackledge ◽  
Ali Dhinojwala
Keyword(s):  
Crack Propagation ◽  
Stimuli Responsive ◽  
Droplet Spreading ◽  
Droplet Shape ◽  
Spider Species ◽  
Environmental Humidity ◽  
Orb Web ◽  
Orb Web Spiders

Orb web spiders use sticky capture spiral silk to retain prey in webs. Capture spiral silk is composed of an axial fibre of flagelliform silk covered with glue droplets that are arranged in a beads-on-a-string morphology that allows multiple droplets to simultaneously extend and resist pull off. Previous studies showed that the adhesion of capture silk is responsive to environmental humidity, increasing up to an optimum humidity that varied among different spider species. The maximum adhesion was hypothesized to occur when the viscoelasticity of the glue optimized contributions from glue spreading and bulk cohesion. In this study, we show how glue droplet shape during peeling contributes significantly to capture silk adhesion. Both overspreading and underspreading of glue droplets reduces adhesion through changes in crack propagation and failure regime. Understanding the mechanism of stimuli-responsive adhesion of spider capture silk will lead to new designs for smarter adhesives.

Spiral geometry in the garden spider's orb web

1985 ◽  
Vol 72 (12) ◽  
pp. 666-667 ◽  
Author(s):  
F. Vollrath ◽  
W. Mohren
Keyword(s):  
Spiral Geometry ◽  
Orb Web

scholarly journals Shifts in morphology, gene expression, and selection underlie web loss in Hawaiian Tetragnatha spiders

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Cory A. Berger ◽  
Michael S. Brewer ◽  
Nobuaki Kono ◽  
Hiroyuki Nakamura ◽  
Kazuharu Arakawa ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Adaptive Traits ◽  
Deep Time ◽  
Selective Pressures ◽  
Silk Production ◽  
Silk Glands ◽  
Genetic Mechanisms ◽  
Orb Web ◽  
Short Time ◽  
Web Building

Abstract Background A striking aspect of evolution is that it often converges on similar trajectories. Evolutionary convergence can occur in deep time or over short time scales, and is associated with the imposition of similar selective pressures. Repeated convergent events provide a framework to infer the genetic basis of adaptive traits. The current study examines the genetic basis of secondary web loss within web-building spiders (Araneoidea). Specifically, we use a lineage of spiders in the genus Tetragnatha (Tetragnathidae) that has diverged into two clades associated with the relatively recent (5 mya) colonization of, and subsequent adaptive radiation within, the Hawaiian Islands. One clade has adopted a cursorial lifestyle, and the other has retained the ancestral behavior of capturing prey with sticky orb webs. We explore how these behavioral phenotypes are reflected in the morphology of the spinning apparatus and internal silk glands, and the expression of silk genes. Several sister families to the Tetragnathidae have undergone similar web loss, so we also ask whether convergent patterns of selection can be detected in these lineages. Results The cursorial clade has lost spigots associated with the sticky spiral of the orb web. This appears to have been accompanied by loss of silk glands themselves. We generated phylogenies of silk proteins (spidroins), which showed that the transcriptomes of cursorial Tetragnatha contain all major spidroins except for flagelliform. We also found an uncharacterized spidroin that has higher expression in cursorial species. We found evidence for convergent selection acting on this spidroin, as well as genes involved in protein metabolism, in the cursorial Tetragnatha and divergent cursorial lineages in the families Malkaridae and Mimetidae. Conclusions Our results provide strong evidence that independent web loss events and the associated adoption of a cursorial lifestyle are based on similar genetic mechanisms. Many genes we identified as having evolved convergently are associated with protein synthesis, degradation, and processing, which are processes that play important roles in silk production. This study demonstrates, in the case of independent evolution of web loss, that similar selective pressures act on many of the same genes to produce the same phenotypes and behaviors.

scholarly journals Does Hyperoxia Restrict Pyrenean Rock Lizards Iberolacerta bonnali to High Elevations?

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 200
Author(s):  
Eric J. Gangloff ◽  
Sierra Spears ◽  
Laura Kouyoumdjian ◽  
Ciara Pettit ◽  
Fabien Aubret
Keyword(s):  
High Elevation ◽  
Conservation Strategy ◽  
The Novel ◽  
Thermal Physiology ◽  
Treatment Groups ◽  
Thermal Performance Curve ◽  
And Performance ◽  
Thermal Preferences ◽  
High Elevations ◽  
Intense Radiation

Ectothermic animals living at high elevation often face interacting challenges, including temperature extremes, intense radiation, and hypoxia. While high-elevation specialists have developed strategies to withstand these constraints, the factors preventing downslope migration are not always well understood. As mean temperatures continue to rise and climate patterns become more extreme, such translocation may be a viable conservation strategy for some populations or species, yet the effects of novel conditions, such as relative hyperoxia, have not been well characterised. Our study examines the effect of downslope translocation on ectothermic thermal physiology and performance in Pyrenean rock lizards (Iberolacerta bonnali) from high elevation (2254 m above sea level). Specifically, we tested whether models of organismal performance developed from low-elevation species facing oxygen restriction (e.g., hierarchical mechanisms of thermal limitation hypothesis) can be applied to the opposite scenario, when high-elevation organisms face hyperoxia. Lizards were split into two treatment groups: one group was maintained at a high elevation (2877 m ASL) and the other group was transplanted to low elevation (432 m ASL). In support of hyperoxia representing a constraint, we found that lizards transplanted to the novel oxygen environment of low elevation exhibited decreased thermal preferences and that the thermal performance curve for sprint speed shifted, resulting in lower performance at high body temperatures. While the effects of hypoxia on thermal physiology are well-explored, few studies have examined the effects of hyperoxia in an ecological context. Our study suggests that high-elevation specialists may be hindered in such novel oxygen environments and thus constrained in their capacity for downslope migration.

scholarly journals A survey on poorly known rainforest litter-dwelling spiders of Orchid Island (Lanyu, Taiwan) with the description of a new species (Araneae: Linyphiidae, Tetrablemmidae, and Theridiosomatidae)

Zootaxa ◽  
2021 ◽  
Vol 4927 (2) ◽  
pp. 197-208
Author(s):  
FRANCESCO BALLARIN ◽  
TAKESHI YAMASAKI ◽  
YONG-CHAO SU
Keyword(s):  
New Species ◽  
Endemic Species ◽  
Morphological Characters ◽  
Spider Species ◽  
Orchid Island ◽  
First Time ◽  
A New Species

Representatives of some poorly known spider species collected in the rainforest litter of the Orchid Island (Taiwan) are illustrated and discussed here. A new species, Brignoliella tao sp. nov. (Fam. Tetrablemmidae), endemic to Orchid Island, is described based on both sexes. The previously unknown female of Theridiosoma triumphale Zhao & Li, 2012 (Fam. Theridiosomatidae), is described for the first time. Zoma taiwanica (Zhang, Zhu & Tso 2006) comb. nov., from the same family, is illustrated and its transfer from the genus Theridiosoma O. Pickard-Cambridge, 1879 to Zoma Saaristo, 1996 is proposed on the basis of morphological characters. Habitus and genitalia of the endemic species Gongylidioides angustus Tu & Li, 2006 (Fam. Linyphiidae) are also illustrated. 

scholarly journals Thermal Preferences of Cowpea Seed Beetles (Callosobruchus maculatus): Effects of Sex and Nuptial Gift Transfers

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 310
Author(s):  
Dariusz Krzysztof Małek ◽  
Marcin Czarnoleski
Keyword(s):  
Water Balance ◽  
Callosobruchus Maculatus ◽  
Thermal Environment ◽  
Nuptial Gift ◽  
Thermal Preference ◽  
Nuptial Gifts ◽  
Insect Performance ◽  
Evaporative Water ◽  
Thermal Preferences ◽  
Seed Beetles

The thermal environment influences insect performance, but the factors affecting insect thermal preferences are rarely studied. We studied Callosobruchus maculatus seed beetles and hypothesized that thermal preferences are influenced by water balance, with individuals with limited water reserves preferring cooler habitats to reduce evaporative water loss. Adult C. maculatus, in their flightless morph, do not consume food or water, but a copulating male provides a female with a nuptial gift of ejaculate containing nutrients and water. We hypothesized that gift recipients would prefer warmer habitats than gift donors and that both sexes would plastically adjust their thermal preferences according to the size of the transferred gift. We measured the thermal preference in each sex in individuals that were mated once or were unmated. In the mated group, we measured the sizes of the nuptial gifts and calculated proportional body mass changes in each mate during copulation. Supporting the role of water balance in thermal preference, females preferred warmer habitats than males. Nevertheless, thermal preferences in either sex were not affected by mating status or gift size. It is likely that high rates of mating and gift transfers in C. maculatus living under natural conditions promoted the evolution of constitutive sex-dependent thermal preferences.

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