Stickers: hanging on for dear life

Call it tenacity, perseverance or dedication but these creatures have the unique ability to adhere to all kinds of surfaces

By Lee Kong Chian Natural History Museum

Lee Kong Chian Natural History Museum

Helmet Urchin (Colobocentrotus atratus) (2011-03-24) by Heok Hui TanLee Kong Chian Natural History Museum

Helmet Urchin
Colobocentrotus atratus (Linnaeus, 1758)

The Helmet Urchin is unique in that the spines facing away from its mouth are short and smooth. Most urchins are covered in spines that are of even length over their entire surface. Scientists have long thought that this adaptation would minimise the force of waves pulling the Helmet Urchin away from the surface it is attached to. To study this, researchers studied the Helmet Urchin and three other species of urchins that naturally occur with it.

Helmet Urchin (Colobocentrotus atratus) (2010-02-03) by Yoshihisa FujitaLee Kong Chian Natural History Museum

Their results showed that the Helmet Urchin was the best sticker among the four species. The reason for this was not due to the shape and length of the spines but rather to the number of feet that the Helmet Urchin was able to use to grasp the surface. It is now thought that the shape and short spines of this species are instead an adaptation to either disperse the direct crashing force of waves (as opposed to the tugging counter-current) or to minimise desiccation when they are exposed. This species is found in the Indian and Pacific Oceans from Sri Lanka to Hawaii. Within the ASEAN region, this species is known from Indonesia and Thailand.

Auricularia auricula-judae by Keng Soon ChuaLee Kong Chian Natural History Museum

Auricularia auricula-judae (Bull.) J. Schröt.

The genus name Auricularia denotes things “of the ear” in Latin while the species name means “Judas’ ear” in reference to the Biblical character Judas Iscariot. All these references to the ear come from the ear-like appearance of the fruiting bodies of this species, which look like ears sticking to wood. This species (and its relatives) can be found growing in the forest on dead or dying tree branches, tree trunks and rotting logs.

Auricularia auricula-judae by Keng Soon ChuaLee Kong Chian Natural History Museum

The fruiting bodies are fleshy, jelly-like to cartilaginous in texture, ear-shaped and translucent in appearance, and reddish brown to black in colour. This species is known to have been cultivated in China during the Tang Dynasty over a thousand years ago. This species is very widespread globally and is almost certainly found across ASEAN.

Neogastromyzon brunei (2017-10-16) by Heok Hui TanLee Kong Chian Natural History Museum

Neogastromyzon brunei Tan, 2006

This species belongs to a group of fishes called torrent loaches. They are able to adhere to the bottom of freshwater habitats not by using their mouths but by using their pectoral and pelvic fins as well as body to form a suction cup. This species was the first species of Neogastromyzon to be found in northern Borneo. This species is not found outside of the ASEAN region and is only known from Brunei.

Tokay Gecko (Gekko gecko) (2003-07-26) by Heok Hui TanLee Kong Chian Natural History Museum

Tokay Gecko
Gekko gecko (Linnaeus, 1758)

The Tokay Gecko gets its name from the noise it makes. Like other species of geckos, the Tokay Gecko is able to adhere to most surfaces and at most angles. Researchers have found that this ability is due to the presence of spoon-like bristles (“spatulae”) at the end of the setae that cover their feet.

Tokay Gecko (Gekko gecko) by Mary-Ruth LowLee Kong Chian Natural History Museum

The stickiness is therefore due to physical forces and is not generally affected by the chemical composition of the surface. This discovery has led to the potential development of dry glues. The Tokay Gecko is found across much of South and Southeast Asia. Within the ASEAN region, it is found in Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Thailand and Vietnam.

Caymanostella sp. (2018-03-25) by SJADES 2018Lee Kong Chian Natural History Museum

Caymanostella sp.

During the SJADES 2018 Expedition, numerous specimens of a peculiar sea star were found on pieces of wood and even on pieces of coal. These specimens were collected at between 500 and 1,200 metres. They were initially identified as species from the genus Xyloplax.

Caymanostella sp. (2018-03-25) by SJADES 2018Lee Kong Chian Natural History Museum

Images of these sea stars were posted online and a world authority on this group of sea stars sent an email to the expedition (yes, even at sea) identifying them as species of Caymanostella instead. This species is possibly new and undescribed. This species is only known from the ASEAN region in deep water off Java, Indonesia.

Striped Sticky Frog (2009-08-14) by Somsak PanhaLee Kong Chian Natural History Museum

Striped Sticky Frog
Kalophrynus interlineatus (Blyth, 1855)

This species of frog is called a sticky frog because glands in its skin exude a sticky yellowish secretion when it is touched. This frog is quite widely distributed and is found in northern peninsular Myanmar, northern Thailand, Laos, Cambodia, and Vietnam, Peninsular Malaysia, and also in southern China.

Hillstream Catfish (Glyptothorax coracinus) by Heok Hee NgLee Kong Chian Natural History Museum

Hillstream Catfish
Glyptothorax coracinus Ng & Rainboth, 2008

Unlike suckerfishes (which use their mouths) and Neogastromyzon brunei featured earlier (that uses its fins and belly) species of the catfish genus Glyptothorax use specially pleated folds of skin and modified jaw and skull bones to form their sticking apparatus. The Hillstream Catfish is unusual in having a blackish-brown body with a pale running stripe down its sides. This species is only known from the ASEAN region from Cambodia.

Brown Peachia Anemone (Synpeachia temasek) by Ria TanLee Kong Chian Natural History Museum

Brown Peachia Anemone
Synpeachia temasek Yap, Fautin, Ramos & Tan, 2014

The archetypical sea anemones looks like a short and squat brightly-coloured bush of tentacles with the requisite anemonefish in attendance. The Brown Peachia Anemone looks nothing like this. Not short, not colourful and definitely no ‘Nemo’! In fact this species burrows deep into the bottom and emerges only between dusk and dawn, presumably to feed.

Brown Peachia Anemone (Synpeachia temasek) (2013-06-24) by Ria TanLee Kong Chian Natural History Museum

This species was first discovered in Singapore through the efforts of a group of citizen scientists nicknamed the “Anemone Army”. Researchers from Singapore and the USA described and named this species in 2014. The same researchers hypothesise that this species may be found in the Indian Ocean as well but this has not been confirmed. This species is currently only known with certainty from the ASEAN region from Singapore.

Frilly Gecko (Hemidactylus craspedotus) (2012-07-16) by Evan S. H. QuahLee Kong Chian Natural History Museum

Frilly Gecko
Hemidactylus craspedotus Mocquard, 1890

Like the Tokay Gecko, this species also has spatulae at the end of the setae on its feet that allow it to adhere to most surfaces. But whereas the Tokay Gecko is a brightly-coloured blue with orange spots, this species is the epitome of camouflage. Its colouration and textured skin help it blend with the bark of trees on which it is often found. It also has a flattened body with flaps of skin along its body, tail and feet to help reduce shadows. All this helps it to blend with its surroundings.

Frilly Gecko (Hemidactylus craspedotus) (2014-03-29) by Evan S. H. QuahLee Kong Chian Natural History Museum

When flipped over, however, the Frilly Gecko is an entirely different animal. The underside of the body is a spectacular yellow while the underside of the tail is orange-red. Nothing is known about the function of this secret and colourful B side. This species is only known from the ASEAN region from Indonesia, Peninsular Malaysia, Singapore and Thailand.

Caymanostella sp. (2018-03-25) by SJADES 2018Lee Kong Chian Natural History Museum

These creatures have adapted to never let go. And their persistence holds many potential lessons for man—one day we may well be using glues and adhesion devices inspired by their evolutionary innovations.

Credits: Story

Text:

Auricularia auricula-judae
Amy Choong
Keng Soon Chua
Clarisse Y. D. Tan
(National University of Singapore, Singapore)

Brown Peachia Anemone
Ria Tan
(Wild Singapore, Singapore)
Nicholas W. L. Yap
(National University of Singapore, Singapore)

Caymanostella sp.
SJADES 2018
(Indonesian Institute of Sciences, Indonesia and National University of Singapore, Singapore)

Frilly Gecko
Evan S. H. Quah
(Universiti Sains Malaysia, Malaysia)

Helmet Urchin
Hillstream Catfish
Peter K. L. Ng
(National University of Singapore, Singapore)

Neogastromyzon brunei
Tan Heok Hui
(National University of Singapore, Singapore)

Striped Sticky Frog
Somsak Panha
(Chulalongkorn University, Thailand)

Tokay Gecko
Wanwei Xu
(National University of Singapore, Singapore)


Images:

Auricularia auricula-judae
Keng Soon Chua
(National University of Singapore, Singapore)

Brown Peachia Anemone
Ria Tan
(Wild Singapore, Singapore)

Caymanostella sp.
SJADES 2018
(Indonesian Institute of Sciences, Indonesia and National University of Singapore, Singapore)

Frilly Gecko
Evan S. H. Quah
(Universiti Sains Malaysia, Malaysia)

Helmet Urchin
Yoshihisa Fujita
(Okinawa Prefectural University of Arts, Japan)
Heok Hui Tan
(National University of Singapore, Singapore)

Hillstream Catfish
Heok Hee Ng
(Singapore)

Neogastromyzon brunei
Heok Hui Tan
(National University of Singapore, Singapore)

Striped Sticky Frog
Somsak Panha
(Chulalongkorn University, Thailand)

Tokay Gecko
Mary-Ruth Low
(Rimba Research, Malaysia)
Heok Hui Tan
(National University of Singapore, Singapore)

Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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