Related Experiment Video
Updated: Jun 1, 2026
09:47
Microdissection of Black Widow Spider Silk-producing Glands
Published on: January 11, 2011
Arachnids secrete a fluid over their adhesive pads
Anne M Peattie1, Jan-Henning Dirks, Sérgio Henriques
1Department of Zoology, University of Cambridge, Cambridge, United Kingdom. apeattie@gmail.com
Plos One
|June 4, 2011
Summary
Spiders and other arachnids use fluid secretions, not just dry adhesion, for climbing. This discovery challenges the long-held belief that their adhesive pads work solely through intermolecular forces, impacting synthetic adhesive design.
Area of Science:
- Biophysics
- Materials Science
- Zoology
Background:
- Arachnids like spiders and geckos utilize adhesive pads for locomotion and prey capture.
- These pads feature a branched, hairy structure, theoretically enabling dry adhesion via intermolecular forces.
- Previous research suggested spiders and solifugids adhere without secretions.
Purpose of the Study:
- To investigate the adhesive mechanisms of spiders, solifugids, and mites.
- To determine if fluid secretions are involved in arachnid adhesion.
- To compare the adhesive properties of spider setae with those of geckos.
Main Methods:
- Interference reflection microscopy to detect thin liquid films in the adhesive contact zone.
- Observation of fluid footprints left by arachnids on glass surfaces.
- Measurement of attachment forces of individual spider setae using a bending beam apparatus.
Main Results:
- All studied arachnids (spiders, solifugids, mites) left hydrophobic fluid footprints on glass.
- Fluid secretion was intermittent, indicating potential for both wet and dry adhesion.
- Individual spider setae exhibited lower static friction than gecko setae, possibly due to fluid lubrication.
Conclusions:
- Tarsal secretions are present in major terrestrial arthropod groups with adhesive pads.
- The presence of liquid affects attachment performance, enhancing adhesion on rough surfaces and introducing rate-dependent effects.
- Geckos and anoles appear to be the only known examples of truly dry adhesive pads in nature.
Related Concept Videos
01:23Surface Appendages of Archaea
Archaeal surface appendages are highly specialized structures essential for environmental adaptation, encompassing roles in adhesion, biofilm formation, and motility. Among these appendages, pili and archaella stand out for their distinct morphologies and functionalities, enabling archaea to thrive in diverse and often extreme environments.Pili: Adhesion and Biofilm FormationPili are filamentous structures assembled from pilin protein subunits, primarily contributing to adhesion and biofilm...
01:47Osmoregulation in Insects
Malpighian tubules are specialized structures found in the digestive systems of many arthropods, including most insects, that handle excretion and osmoregulation. The tubules are typically arranged in pairs and have a convoluted structure that increases their surface area.
01:08Exocrine Glands: Methods of Secretion
Exocrine glands are those that release their secretions through ducts. Based on their mode of secretion, they can be classified into merocrine, apocrine, and holocrine.
Merocrine Secretion
Merocrine secretion is the most common type of exocrine secretion. The secretions are enclosed in vesicles and moved to the cell's apical surface, where the contents are released by exocytosis. For example, mucous, a watery secretion rich in the glycoprotein mucin, is a merocrine secretion. The eccrine glands...
Merocrine Secretion
Merocrine secretion is the most common type of exocrine secretion. The secretions are enclosed in vesicles and moved to the cell's apical surface, where the contents are released by exocytosis. For example, mucous, a watery secretion rich in the glycoprotein mucin, is a merocrine secretion. The eccrine glands...
01:39Mechanism of Filopodia Formation
Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
02:40Epiphytes, Parasites, and Carnivores
Plants often form mutualistic relationships with soil-dwelling fungi or bacteria to enhance their roots’ nutrient uptake ability. Root-colonizing fungi (e.g., mycorrhizae) increase a plant’s root surface area, which promotes nutrient absorption. While root-colonizing, nitrogen-fixing bacteria (e.g., rhizobia) convert atmospheric nitrogen (N2) into ammonia (NH3), making nitrogen available to plants for various biological functions. For example, nitrogen is essential for the biosynthesis of the...
01:31Mechanism of Lamellipodia Formation
Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...