Structure and development of bracteal nectary glands in Aphelandra (Acanthaceae)

A survey of bracteal (extrafloral) nectaries in species of Aphelandra (Acanthaceae) reveals substantial diversity. Each bracteal nectary is an aggregate of individual glands that vary in number, size, and structure among species. Glands contain three cell layers: a palisade-like secretory cell layer, a one-to-many-celled intermediate layer with thickened cell walls, and a foot layer. Members of the A. pulcherrima complex have one of two distinct gland types: relatively small glands with a single-celled intermediate layer or larger glands that have a multicellular intermediate layer. Nectaries composed of small glands are patches of many (>50) glands, whereas those composed of large glands are patches of < 10 glands. Four outgroup species have bracteal nectaries of numerous small glands with pluricellular intermediate layers. Glands of all three types are initiated as single enlarged protodermal cells, and all undergo similar early periclinal divisions; the large-gland type shows greater subsequent enlargement with many more anticlinal divisions. The bracteal nectar glands are interpreted to be homologous with simpler glandular trichomes, and mark a monophyletic lineage within Aphelandra. Comparisons with outgroup species show that both nectary types in the A. pulcherrima complex have diverged from an ancestral condition of numerous small glands with pluricellular intermediate layers. Use of the ontogenetic criterion to polarize gland type within the A. pulcherrima complex would yield erroneous results because evolution has apparently involved a developmental truncation with loss of cell divisions in the intermediate layer of small glands. Comparable nectar glands in more distant taxa are interpreted as remarkable cases of convergent evolution, perhaps from similar trichome precursors.     

Active generation glands present in neonates of some Cordylid Lizards: A case study of Cordylus macropholis (Sauria: Cordylidae)

Generation glands are holocrine epidermal glands occurring on the ventral aspect of the thigh of cordylid lizards. In most species these glands seemingly start to differentiate with the onset of sexual maturity, but macroscopic signs of generation gland activity were noted in neonates of the large-scaled girdled lizard, Cordylus macropholis. The glands of neonatal, subadult, and adult individuals were examined microscopically using standard histological techniques. The glands of the five neonatal specimens examined, including both males and females, all had the same basic structure and displayed two layers of mature glandular material. In subadult and adult specimens, the number of layers varied from seven to nine. The structure of the generation glands of C. macropholis is similar to that of the few other Cordylus species that have been described to date. They are of the protruding kind with multiple mature glandular generations. Juveniles of an additional 12 cordylid species have been examined for the presence of active generation glands. Active glands were found to be present in neonates of C. tasmani and C. tropidosternum, both of which are, like C. macropholis, terrestrial species. In C. cordylus and C. coeruleopunctatus, active generation glands are absent in neonates, but differentiate soon after birth. In other cordylid species, generation glands apparently differentiate only with the onset of sexual maturity. J. Morphol. 235:177–182, 1998. © 1998 Wiley-Liss, Inc.     

Fine structure of reproductive glands in two primitive marine pulmonates (Basommatophora: Siphonariidae)

Within the clade Euthyneura the marine basommatophorans are particularly neglected. More morphological and molecular studies are needed because their phylogenetic relationships with other pulmonates remain unresolved. The present study examines the most conspicuous reproductive gland, the glandular complex in two marine limpets, Siphonaria capensis and S. serrata (Pulmonata: Basommatophora) at both gross and fine structural levels. These two sympatric species with different developmental modes were selected to compare the structure and function of this enormous glandular structure. In both S. capensis and S. serrata, the glandular complex shows an undifferentiated state composed of an acidophilic albumen gland and a basophilic mucous gland. The glands contain secretory cells and supporting cells (= ciliated cells) that are highly ciliated. When the histochemical properties of the glandular complex were compared with those of siphonariid egg masses (of each species) it could be established that the albumen gland was responsible for the production of perivitelline fluid whereas the mucous gland secreted substances that help in the assembly of mucous layers surrounding the egg capsules. We suggest that the presence of a single glandular complex comprised of two glands is the most primitive organization of reproductive glands in pulmonates. Furthermore, the histology, fine structure and histochemistry of these glands are very similar to those of the reproductive glands of opisthobranchs.     

Exploring a key synapomorphy: correlations between structure and function in the sternum V glands of Trichoptera and Lepidoptera (Insecta)

The sternum V glands are a key synapomorphy that unites Trichoptera with Lepidoptera, but their functional aspects have not been analysed from an evolutionary perspective. We examine phylogenetic trends and correlations between chemical and morphological features of these glands. The most likely ancestral gland compounds are heptan‐2‐ol, 4‐hepten‐2‐one and ‐ol, nonan‐2‐one, and 6‐nonen‐2‐one and ‐ol, making pheromone production a plausible ancestral function. The most widespread gland compounds (heptan‐2‐one and ‐ol and nonan‐2‐one and ‐ol) are not known from Apataniidae + Limnephilidae (Trichoptera), which in turn uniquely produce a number of methylated 3‐ketones and their corresponding alcohols, probably functioning as pheromones. We propose a functional connection between perforated patches on sternum IV in females and a scaly/dome‐covered area around the gland openings, as well as between perforated patches and lack of Trichoptera‐type opening muscles. We also propose a functional connection between the shape of the gland reservoirs and the presence of gland reservoir musculature. The perforated patches were significantly correlated with several gland compounds that had double bonds between carbon atoms: the double bonds may lower the viscosity of the compounds, facilitating secretion through the tiny pores of the perforated patches. The production of defensive substances in Pycnopsyche (Trichoptera: Limnephilidae) is probably connected to the presence of large, compartmentalized gland reservoirs. Large glands in male Hydropsyche (Trichoptera: Hydropsychidae) are probably linked to male aggregation pheromone production. The relative sizes of sternum V gland reservoirs and fenestral gland reservoirs in female philopotamids (Trichoptera) suggest a complementary function of the two structures. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 561–579.     

Ultrastructure of multicellular foregut glands in selected Solenogastres (Mollusca)

Foregut glands in Solenogastres are not only of importance in biological processes like feeding and digestion, but multicellular foregut glands also provide valuable characters for taxonomy and systematics. Here, the fine structure of four different types of foregut glands is investigated: the Meioherpia-type ventrolateral foregut gland of Meioherpia atlantica, the Simrothiella-type ventrolateral foregut gland of Simrothiella cf. margaritacea, and the Pararrhopalia-type ventrolateral foregut gland as well as the dorsal gland of Pararrhopalia pruvoti. Thereby, special focus is set on the arrangement of glandular and supporting cells within the glands, and on the characterization of glandular cells according to the size, shape and electron-density of their secretional vesicles. It is shown that the investigated glands are complex organs composed of non-glandular supporting cells and two to five glandular cell types producing discrete secretions.     

Multiple origins of Hawaiian drosophilids: Phylogeography of Scaptomyza Hardy (Diptera: Drosophilidae)

Scaptomyza is a highly diversified genus in the family Drosophilidae, having undergone an explosive radiation, along with the Hawaiian‐endemic genus Idiomyia in the Hawaiian Islands: about 60% of 269 Scaptomyza species so far described are endemic to the Hawaiian Islands. Two hypotheses have been proposed for the origin and diversification of Hawaiian drosophilids. One is the “single Hawaiian origin” hypothesis: Scaptomyza and Idiomyia diverged from a single common ancestor that had once colonized the Hawaiian Islands, and then non‐Hawaiian Scaptomyza migrated back to continents. The other is the “multiple origins” hypothesis: Hawaiian Scaptomyza and Idiomyia derived from different ancestors that independently colonized the Hawaiian Islands. A key issue for testing these two hypotheses is to clarify the phylogenetic relationships between Hawaiian and non‐Hawaiian species in Scaptomyza. Toward this goal, we sampled additional non‐Hawaiian Scaptomyza species, particularly in the Old World, and determined the nucleotide sequences of four mitochondrial and seven nuclear genes for these species. Combining these sequence data with published data for 79 species, we reconstructed the phylogeny and estimated ancestral distributions and divergence times. In the resulting phylogenetic trees, non‐Hawaiian Scaptomyza species were interspersed in two Hawaiian clades. From a reconstruction of ancestral biogeography, we inferred that Idiomyia and Scaptomyza diverged outside the Hawaiian Islands and then independently colonized the Hawaiian Islands, twice in Scaptomyza, thus supporting the “multiple origins” hypothesis.     

GLANDULAR LEAF STRUCTURE OF TRIPHYOPHYLLUM PELTATUM (DIONCOPHYLLACEAE): A “FLY-PAPER” INSECT TRAPPER

Certain leaves of Triphyophyllum peltatum (Hutch. & Dalz.) Airy Shaw (Dioncophyllaceae) have an extended, erect midrib covered with stalked and sessile glands exhibiting insect-trapping ability. The stalked glands secrete a sticky, acid mucilage to which numerous insects in various stages of decay were observed adhering. The morphology and anatomy of the glandular leaves were investigated with light and scanning electron microscopy. The midrib and the lamina in the lowermost part of the leaf bear stomata. Those of the midrib are transitional between actinocytic and cyclocytic in type. Parenchyma cells in mature and immature portions of the midrib and in the glands contain numerous crystals and amyloplasts. The anatomy of the stalked and sessile glands is remarkably similar to that of Drosophyllum lusitanicum (L.) Link. (Droseraceae). A distinct cuticle covers the gland head, but no pores are visible. Three distinct layers underlie the cuticle: a definite epidermal layer with irregularly thickened cell walls, and two layers of more loosely arranged cells. A fourth layer, endodermoid in nature with radially thickened cell walls, connects the head and stalk of the stalked glands and the head and midrib parenchyma of the sessile glands. Vascular elements (including helical and scalariform tracheary elements) reach the endodermoid layer. According to recent studies, Triphyophyllum and Drosophyllum have different phylogenetic origins; the morphological and anatomical similarities in the insect-trapping glandular leaves show more support for their convergent evolution rather than for an alliance of the Dioncophyllaceae with the Droseraceae.     

Gill‐derived glands in species of Astyanax (Teleostei: Characidae)

The presence of a gill‐derived gland is herein reported for the first time in males of species of Astyanax and related genera; they are described through histological cuts and SEM. The gill‐derived glands described for the Characidae, when fully developed, present a similar structure in different species. The main external feature of gill‐derived glands is the fusion of anteriormost gill filaments on the ventral branch of first gill arch. This fusion is caused by squamous stratified epithelial tissue that covers adjacent filaments, forming a series of chambers. In the region where the gill‐derived gland develops, the secondary lamellae of the gill filaments are much reduced or completely atrophied being characterized by the presence of glandular cells forming nests.     

Microscopic anatomy of the integument in the ribbon worm Micrura bella (Stimpson, 1857) (Pilidiophora,Nemertea)

The integument of ribbon worms in the order Heteronemertea is distinct from the integuments in the other taxa of nemerteans due to the presence of a special subepidermal glandular layer, the cutis. Among heteronemerteans, the ultrastructure of the cutis has been studied only in the Lineus ruber species complex. In the current study, ultrastructural (transmission electron microscopy) and histochemical studies of the epidermis and the cutis of Micrura bella from the basal Lineage A of the family Lineidae were performed. The epidermis consisted of ciliated and serous gland cells and is separated from the cutis by a layer of the subepidermal extracellular matrix; the basal lamina was not detected. The cutis comprised musculature, two types of mucous and four types of granular gland cells, and pigment cells with four types of granules. In the cutis of juvenile worms, type II granular gland cells and type II mucous cells were not observed. The integument of the caudal cirrus consisted of ciliated and serous gland cells and two intraepidermal lateral nerve cords; the cutis was absent. The compositions of the integument glands of M. bella and the L. ruber species complex are similar, except for the presence of type IV granular gland cells with narrow rod-shaped and lamellated granules exhibiting an alternating dark and light transverse layers and type II mucous cells found only in M. bella.     

Studies on silk secretion in the trichoptera (F. Limnephilidae): I. Histology,histochemistry, and ultrastructure of the silk glands

As part of a study on trichopteran silk secretion, the histology, histochemistry, and ultrastructure of the silk glands of two species of limnephilid trichopteran larvae, Pycnopsyche guttifer (Walk.) and Neophylax concinnus McL., were investigated. The silk glands consist of three anatomically distinct regions: a long, posterior silk-secreting region; a shorter, anterior conducting tube; and a terminal press/common duct. In Pycnopsyche, there is also a modified bulbous region between the secreting and conducting areas. Each anatomical region has a distinct cell type. There are two structurally and histochemically different components of the secretion in the glandular lumen: a core and a peripheral layer. Both components are produced all along the gland and are principally proteinaceous. However, the peripheral layer is also PAS and alcian blue (pH. 2.5) positive and shows β-metachromasia with toluidine blue (pH 3.5), indicating the presence of both neutral and acidic polysaccharides.     

Species-specific sex pheromones secreted from new sexual glands in two sympatric fungus-growing termites from northern Vietnam, <Emphasis Type="Italic">Macrotermes annandalei</Emphasis> and <Emphasis Type="Italic">M. barneyi</Emphasis>

Summary Reproductive isolation in termites is not well known. Our study carried out on two sympatric species from northern Vietnam, Macrotermes annandalei and M. barneyi, showed that dispersal flights and sex pheromones were two important factors in their reproductive isolation. These fungus-growing termites were isolated, partially due to the timing of their respective dispersal flights. M. annandalei flew the first day after rain, while the flights of M. barneyi occurred the second day after rain. However, the flights can also be simultaneous in the two species. Sex pheromones of M. annandalei and M. barneyi were shown to be species-specific. In both species, they were secreted by females from two glandular sources, from tergal glands located on tergite 6 to 10 in M. annandalei and tergite 5 to 10 in M. barneyi, and from posterior sternal glands located on sternite 6 and 7 in both species. These posterior sternal glands, found for the first time in the Termitidae, were sex-specific glands. Although not fully identified, sex pheromones of M. annandalei and M. barneyi were clearly different from the trail-following pheromone secreted by the sternal gland stricto sensu located on the sternite 5. These results show that in termites, the sexual behaviour, the glandular origin of sex pheromones and their role in reproductive isolation greatly vary depending on the species and deserve to be more extensively studied.Received 8 April 2003; revised 1 September 2003; accepted 10 September 2003.     

MORPHOGENESIS OF CAPITATE GLANDULAR HAIRS OF CANNABIS SATIVA (CANNABACEAE)

The glandular secretory system in Cannabis sativa L. (marihuana) consists of three types of capitate glandular hairs (termed bulbous, capitate-sessile, and capitate-stalked) distinguishable by their morphology, development, and physiology. These gland types occur together in greatest abundance and developmental complexity on the abaxial surface of bracts which ensheath the developing ovary. Bulbous and capitate-sessile glands are initiated on very young bract primordia and attain maturity during early stages of bract growth. Capitate-stalked glands are initiated later in bract growth and undergo development and maturation on medium, to full sized bracts. Glands are epidermal in origin and derived, with one exception, from a single epidermal initial. The capitate-stalked gland is the exception and is of special interest because it possesses a multicellular stalk secondarily derived from surrounding epidermal and subepidermal cells. Glands differentiate early in development into an upper secretory portion and a subtending auxiliary portion. The secretory portion, depending on gland type, may range from a few cells to a large, flattened multicellular disc of secretory cells. The secretory portion produces a membrane-bound resinous product which caps the secretory cells. Capitate-stalked glands are considered to be of particular evolutionary significance because they may represent a gland type secondarily derived from existing capitate-sessile glands.     

The structure of the cutaneous pedal glands in the banded snail Cepaea hortensis (Müller, 1774)

Although gastropods have been crawling through the ocean and on the land for 60 million years, we still know very little about the sticky mucus produced in their foot. Most research has been focused on marine species in particular and, to a lesser extent, on the well‐known terrestrial species Arion vulgaris and Cornu aspersum. Within this study, we aim to characterize the foot anatomy of a smaller representative of the family Helicidae, the banded snail Cepaea hortensis. We are particularly interested in the microanatomy of the foot glands, their position, and the histochemical nature of their secretory content. Characterization of the dorsal foot region of Cepaea hortensis reveals four glands, differing in their size and in the granules produced. Histochemically, three of them react positively for sugars (PAS staining and lectin affinity tests for mannose, glucose and N‐acetyl‐d ‐glucosamine) and acidic proteins (positive Alcian blue and Toluidine blue staining), indicating the presence of acidic glycosaminoglycans. The fourth gland type does not react to any of these dyes. The ventral pedal region includes two different gland types, which are positive for the presence of acidic glycoproteins, with a lectin affinity for mannose only. A comparison with Helix pomatia indicates differences regarding the number of glands and their contents. In Helix, only three gland types are described in the dorsal region of the foot, which show a similar granular appearance but nevertheless differ in their chemical composition. Congruently, there are two gland types in the ventral region in both species, whereas in Helix an additional sugar moiety is found. This raises the question whether these differences between the pedal glandular systems of both helicid species are the result of protection or size‐related adaptations, as they occur in the same habitat.     

Evolution of venom delivery structures in madtom catfishes (Siluriformes: Ictaluridae)

The use of venom to subdue prey or deter predators has evolved multiple times in numerous animal lineages. Catfishes represent one of the most easily recognized, but least studied groups of venomous fishes. Venom glands surround spines on the dorsal and pectoral fins that serve as venom delivery structures. Species of madtom catfishes in the genus Noturus were found to each have one of four venom delivery morphologies: (1) smooth spine with no venom gland; (2) smooth spine with venom gland associated with shaft of spine; (3) serrated spine with venom gland associated with shaft of spine; and (4) serrated spine with venom gland associated with shaft of spine and posterior serrations. Analyses accounting for the phylogenetic history of Noturus species suggest that a serrated pectoral spine with a venom gland is the ancestral condition for the genus. The presence of serrations and a venom gland have been largely conserved among Noturus species, but sting morphology has changed at least five times within the genus. Four of these changes have resulted in a loss of morphological complexity, including the loss of posterior serrations, loss of venom glands associated with the posterior serrations, and one complete loss of the venom gland. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 115–129.     

Morphology of the fifth sternal glands of Neotropical social wasps (Hymenoptera,Vespidae, Polistinae)

Glands play a central role in the social behavior of insects, and comparative analysis of their structure may provide insights about their evolution and their role in insect social biology. Here, we describe the glands of the fifth metasomal sternite of ten polistine wasps with different social behaviors. The glands of foragers of these species were studied using semithin sections of Araldite‐embedded tissue, and scanning electron microscopy. The structure of the glands observed was mostly similar to what has previously been reported for independent‐founder and swarm‐founder species, respectively. Scale‐shaped modifications in the fifth sternite are reported for the first time for members of the genera Synoeca and Epipona. Two previously unreported glands in the fifth sternite are also described. A more restrictive definition of the name Richards' gland is proposed, applying to the class 3 cells associated with scale modifications of the fifth sternite, based on structural differences between the glands observed, homology requirements, and functional evidence. Previous phylogenetic reconstructions of this character suggest that it appeared early in the Vespidae and disappeared four times, with a single reappearance in the genus Vespula. The restricted definition of Richards' gland suggests that this structure is an exclusive trait of the Epiponini, with two reversals.     

Exocrine glands of Lepeophtheirus salmonis (Copepoda: Caligidae): Distribution,developmental appearance,and site of secretion

Exocrine glands of blood‐feeding parasitic copepods are believed to be important in host immune response modulation and inhibition of host blood coagulation, but also in the production of substances for integument lubrication and antifouling. In this study, we aimed to characterize the distribution of different types of salmon louse (Lepeophtheirus salmonis) exocrine glands and their site of secretion. The developmental appearance of each gland type was mapped and genes specifically expressed by glands were identified. Three types of tegumental (teg 1–3) glands and one labial gland type were found. The first glands to appear during development were teg 1 and teg 2 glands. They have ducts extending both dorsally and ventrally suggested to be important in lubricating the integument. Teg 1 glands were found to express two astacin metallopeptidases and a gene with fibronectin II domains, while teg 2 glands express a heme peroxidase. The labial glands were first identified in planktonic copepodids, with reservoirs that allows for storage of glandular products. The last gland type to appear during development was named teg 3 and was not seen before the preadult I stage when the lice become more virulent. Teg 3 glands have ducts ending ventrally at the host‐parasite contact area, and may secrete substances important for the salmon lice virulence. Salmon lice teg 3 and labial glands are thus likely to be especially important in the host‐parasite interaction. Proteins secreted from the salmon louse glands to its salmonid host skin or blood represents a potential interface where the host immune system can meet and elicit effective responses to sea lice antigens. The present study thus represents a fundamental basis for further functional studies and identification of possible vaccine candidates. J. Morphol. 277:1616–1630, 2016. © 2016 Wiley Periodicals, Inc.     

Development and Structure of Internal Glands and External Glandular Trichomes in Pogostemon cablin

Pogostemon cablin possesses two morphologically and ontogenetically different types of glandular trichomes, one type of bristle hair on the surfaces of leaves and stems and one type of internal gland inside the leaves and stems. The internal gland originates from elementary meristem and is associated with the biosynthesis of oils present inside the leaves and stems. However, there is little information on mechanism for the oil biosynthesis and secretion inside the leaves and stems. In this study, we identified three kinds of glandular trichome types and two kinds of internal gland in the Pogostemon cablin. The oil secretions from internal glands of stems and leaves contained lipids, flavones and terpenes. Our results indicated that endoplasmic reticulum and plastids and vacuoles are likely involved in the biosynthesis of oils in the internal glands and the synthesized oils are transported from endoplasmic reticulum to the cell wall via connecting endoplasmic reticulum membranes to the plasma membrane. And the comparative analysis of the development, distribution, histochemistry and ultrastructures of the internal and external glands in Pogostemon cablin leads us to propose that the internal gland may be a novel secretory structure which is different from external glands.     

GLAND DISTRIBUTION AND CANNABINOID CONTENT IN CLONES OF CANNABIS SATIVA L.

The relationship between glandular trichomes and cannabinoid content in Cannabis sativa L. was investigated. Three strains of Cannabis, which are annuals, were selected for either a drug, a non-drug, or a fiber trait and then cloned to provide genetically uniform material for analyses over several years. The distribution of the number and type of glands was determined for several organs of different ages including the bract and its subtending monoleaflet leaf and the compound leaf on pistillate plants. Quantitation of glands on these structures was integrated with gas chromatographic analyses of organ cannabinoid profiles. A negative correlation was found between cannabinoid content and gland number for each of the three clones. Isolated heads of the capitate-stalked glands also were analyzed for cannabinoid content and found to vary in relation to clone and gland age. These studies indicate that cannabinoids may occur in plant cells other than glandular trichomes. The results of these studies emphasize the need for stringent sampling procedures in micromorphological studies on trichome distribution and analytical determinations of cannabinoid content in Cannabis.     

Distribution and structure of glandular tissue in the oropharynx and proximal esophagus of the emu (Dromaius novaehollandiae)

Crole, M.R., Soley, J.T. 2011. Distribution and structure of glandular tissue in the oropharynx and proximal esophagus of the emu (Dromaius novaehollandiae). —Acta Zoologica (Stockholm) 92 : 206–215. The glandular regions of the upper digestive tract in the emu were non‐pigmented (except for the tongue in most specimens) and invested by a non‐keratinised stratified squamous epithelium. The glands found in these regions were exclusively simple in nature and composed of tubular secretory units lined by Periodic Acid Schiff Stain‐positive mucus‐secreting cells. The naming of the various glandular fields was based on previously identified anatomical features and on nomenclature modified from previous studies on birds. The glands were classified into two main types, namely, simple tubular and simple branched tubular mucus‐secreting glands. Simple branched tubular glands were a feature of the regions exposed to the greatest amount of friction during feeding, whereas simple tubular glands were a feature of regions exposed to less friction. The saliva produced by the salivary glands in birds functions to moisturize and lubricate food boli. Mucins in saliva also protect mucosal surfaces from desiccation and mechanical damage, assist in maintaining cellular water balance, provide lubrication and have an antimicrobial action. This study suggests that, in addition to the role of specific gross anatomical features, the type and distribution of glandular tissue in the emu upper digestive tract supports the cranio‐inertial feeding method employed by this species.     

Neotropical harvestmen (Arachnida,Opiliones) use sexually dimorphic glands to spread chemicals in the environment

Sexually dimorphic glands have convergently appeared in animals and are often responsible for the production of pheromones. In the suborder Laniatores of the order Opiliones (Arachnida), glands of such type are widespread, but there is not a single paper on how they are used. Using Scanning Electron Microscopy and a behavioral approach, we describe glandular openings and how these glands are used, in the harvestmen Gryne perlata and Gryne coccinelloides (Cosmetidae). Males of these two species have glandular openings on the metatarsi of legs I and on the metatarsi IV. Males were shown rubbing the glands of the metatarsi I against their other legs, whereas glands on the metatarsi IV are gently touched on the substrate or rubbed either against other legs, or against the substrate. Not all behaviors were seen in both species.