Types Of Setae Research Articles

Leg Attachment Devices of Tiger Beetles (Coleoptera, Cicindelidae) and Their Relationship to Their Habitat Preferences.

The ability of many insects to adhere vertically or even upside down to smooth substrates is closely related to the morphology and distribution of the adhesive structures on their legs. During locomotion, the legs are in direct contact with different substrates, and it is hypothesized that the adhesive structures have been evolved as an adaption to smooth substrates in specific environments. To investigate whether there is a relationship between the presence of adhesive structures and the combined effects of different environments and mating behavior, we compared five species of tiger beetles belonging to two tribes living in arboreal and non-arboreal environments, respectively. In three non-arboreal species, we found a specific type of adhesive structure consisting of elongated spoon-like setae present on the protarsi of males but absent on the male meso- and metatarsi and on females. In Tricondyla pulchripes, an arboreal species living on stems, we found three types of adhesive setae on male protarsi, while only two types of setae were found on male meso- and metatarsi and on females. In Neocollyris linearis, an arboreal species living on leaves, we found three types of adhesive setae on male pro-, meso- and meta-tarsi but only two types of adhesive setae on females. The adaptive evolution of these adhesive structures was probably driven by the selective pressures of both mating behavior and the presence of smooth substrates in the respective environments. It is discussed that the adhesive structures in tiger beetles may be an adaptive evolutionary response to the plant surfaces and may play an important role in species differentiation.

Two- and Three-Dimensional Ultrastructures of the Micron-Scale Adhesive Setae of a Leaf Beetle Chrysochus chinensis (Coleoptera: Chrysomelidae)1

Abstract Chrysochus chinensis (Baly) (Chrysomelidae: Eumolpinae) is a phytophagous leaf beetle that excels in climbing on its host plants’ leaf surfaces and has well-developed adhesive setae on its feet. Using scanning electron microscopy, we examined the ultrastructure of the adhesive setae and recognized three types of setae, namely pointed, spatulate, and discoidal. The terminal plate areas of the three types of setae were 7.59 ± 1.76 μm2, 41.16 ± 1.46 μm2, and 63.65 ± 2.35 μm2, respectively. The three-dimensional topography of the terminal plates of three types of setae were imaged with an atomic force microscope. We found that the terminal plate of the discoidal seta had a concave center and a high circular edge, and the edge was 200–400 nm higher than the center. The ventral side of the spatulate seta was smooth with a 200-nm-high edge at two sides of the terminal plate. The results showed that the discoidal seta had the biggest terminal plate area (63.65 ± 2.35 μm2) and its topography can gather liquid and produce a 200- to 400-nm-thick fluid film between the terminal plate and smooth substrates. With the help of capillary force of the tarsal secretion, it can enhance adhesion force. The function of the discoidal seta, which is only present on male beetles, is hypothesized to serve for strong attachment force during mating.

Two new species of Hyalella (Amphipoda, Dogielinotidae) from the Humid Chaco ecoregion of Paraguay.

The freshwater amphipod genus Hyalella Smith, 1874 is widely distributed in the Neotropics, with several biogeographically restricted species and a high cryptic diversity throughout South America. Tens of species of Hyalella have been documented from nearby Brazil and Argentina, but no systematic record of the genus exists for Paraguay. Here we describe two new species of Hyalella: H.mboituisp. nov. and H.juliasp. nov. from the Ñeembucú wetlands of southwestern Paraguay. Hyalellamboituisp. nov. and H.juliasp. nov. are characterised by a dorsally smooth body, pigmented eyes, uropod 1 endopod with a curved seta, the dorsal margin of uropod 3 ramus without setae, and uropod 3 peduncle longer than wide and with six setae apically. The two species are distinguished by their diagnostic mouthparts, with a median serrated edge on the lacinia mobilis in H.mboituisp. nov. and two elongated lateral denticles with a serrated edge in H.juliasp. nov., and by the presence of a pronounced cup for the dactylus on gnathopod 2 in H.mboituisp. nov. In addition, they show differences in the number of articles on antennae 1 and 2, in the relative length of the pereiopods, and in the numbers and types of setae on their gnathopods and uropods 1-3. Hyalellamboituisp. nov. and H.juliasp. nov. represent the first taxonomically documented occurrence of Paraguayan freshwater amphipods. These new taxa attest to the largely unmapped species richness of freshwater invertebrates in the Humid Chaco of Paraguay. This potential biodiversity hotspot is currently under threat from land conversion, highlighting the need for more systematic studies and effective conservation of the local invertebrate biodiversity.

Two new species of Caeculisoma (Trombidiformes: Erythraeidae) from Madagascar

Two new species of Caeculisoma are described and illustrated/photographed based on post-larval instars from Madagascar. Caeculisoma banari n. sp. has two different types of setae on dorsal idiosoma whereas C. madagascarensis n. sp. has one type of dorsal idiosomal setae but two different sizes. Details of different characters are presented in photographs and tables.

Mouthparts of the crab Goniopsis cruentata (Latreille, 1803) (Decapoda, Brachyura, Grapsidae): morphological variations associated with environment, sex and stage of development

Abstract Individuals and populations can display variations in distinct aspects of their life histories, which could be reflected in their morphological characteristics. This study analyzed the mouthpart morphology of the crab Goniopsis cruentata in relation to environment, sex and stage of development. Our results indicate differences in the number of setae between developmental stages and environments, as well as the interaction between developmental stages and environments. There were no differences in setae types between stages, sexes or environments. There were differences in the shape of the ischium between adults and juveniles, with a more homogeneous ischium in juveniles than adults. We also found differences in food content between developmental stages, as well as an interaction between developmental stages and environment. Our results support an association between diet and morphology of mouthparts in G. cruentata, and that these apparatuses vary according to ontogenetic development and the environmental conditions that species are exposed to. These associations should be considered in studies that use these characteristics to verify morphological responses to environmental variations.

The tight attachment achieved by the male discoidal setae is possibly a counter-adaptation to the grease layer on female integument surfaces in green dock beetles.

Green dock beetles Gastrophysa viridula exhibit sexual dimorphism in tarsal attachment setae: females have only pointed, lanceolate and spatula-like setae, while males additionally possess discoidal ones. The sexual dimorphism is probably attributed to the necessity of male discoidal setae to adhere to the smooth back of the female during copulation. We aimed to understand its possible mechanism of attachment with G. viridula. Pull-off forces of both females and males were measured on (i) alive females, (ii) dead and dried females, and (iii) resin replicas of fresh females. The attachment ability tended to increase on dead and replicated female surfaces in both sexes, which indicates that the epicuticular grease layer on the integument of alive intact beetles decreases the attachment. This tendency was prominent in females. The present study clearly showed that in G. viridula discoidal setae enable the males to adhere stronger to female surfaces. The divergent performance found between the sexes differing in their setal composition is probably caused by the stiffness difference between the setae types and by the specific shape of the setal tips. A peculiar reproductive biology in G. viridula is probably attributed to this remarkable divergence of labour in their attachment pads between the sexes.

Two new species of Hyalella Smith, 1874 (Malacostraca: Amphipoda: Hyalellidae) from the state of Santa Catarina, Brazil.

The genus Hyalella Smith, 1874 occurs exclusively in the Americas. In Brazil, the states of Santa Catarina and Rio Grande do Sul have the largest number of records with 20 species. This paper presents two new species for the state of Santa Catarina, Brazil. The serrate setae with accessory seta, a new type of seta, is registered for the genus and observed on gnathopods 1 and 2. Additionally, microtrichs are reported on articles, a detail that has not been mentioned in previous studies. Hyalella carsone sp. nov. is characterized by gnathopod 1 with comb-scales from the basis to the carpus, gnathopod 2 dactylus with proximal margin strongly serrated and the presence of serrate setae on the articles of gnathopods 1 and 2. Hyalella wangarie sp. nov. is characterized by gnathopod 2 palm not sinuous with margin inconspicuously serrated, peduncle and inner ramus of the pleopod with simple setae, presence of curved seta on uropod 1 of male and gnathopod 1 palm on female slightly serrated. In this work we expand the number of species from Brazil and increase the morphological knowledge of the genus Hyalella.

Morphology of the feeding apparatus of cave shrimps of the genus Typhlatya (Decapoda: Atyidae) from the Yucatán Peninsula and comparison with epigean species

The setal arrangement on the dactyl and propodus of pereopods 1 and 2, defined here as the feeding apparatus, of 3 species of cave shrimps of the genus Typhlatya (T. mitchelli, T. pearsei, T. dzilamensis) from the Yucatán Peninsula was studied using SEM micrographs. The setae were classified according to their morphology and position in the propodus and dactyl resulting in 6 main types. The 3 Typhlatya species differed slightly in the number of each type of setae and showed some morphological variations, especially in the central setae. A comparison of the setal arrangement of Typhlatya spp. with that of the epigean Potimirim mexicana and P. glabra, showed important differences probably driven by the specialization to specific habitats.

Suspension feeding in Copepoda (Crustacea) - a numerical model of setae acting in concert.

Suspension feeding via setae collecting particles is common within Crustacea. Even though the mechanisms behind it and the structures themselves have been studied for decades, the interplay between the different setae types and the parameters contributing to their particle collecting capacities remain partly enigmatic. Here, we provide a numerical modeling approach to understand the relationship among the mechanical property gradients, the mechanical behavior and the adhesion of setae, and the feeding efficiency of the system. In this context, we set-up a simple dynamic numerical model that takes all of these parameters into account and describes the interaction with food particles and their delivery into the mouth opening. By altering the parameters, it was unraveled that the system performs best when the long and short setae have different mechanical properties and different degrees of adhesion since the long setae generate the feeding current and the short ones establish the contact with the particle. This protocol can be applied to any system in the future as the parameters (i.e., properties and arrangement of particles and setae) can be easily altered. This will shed light on the biomechanical adaptations of these structures to suspension feeding and provide inspiration for biomimetics in the field of filtration technologies.

The tarantula Grammostola anthracina uses type IV urticating setae in passive defence: evidence from its presence on the ootheca

New World tarantulas present a unique and conspicuous defensive mechanism: the release of urticating setae. The morphological differentiation of the types of setae suggests their distinct use, with two defensive mechanisms proposed: active defence against potential predators and passive defence against other arthropods, through the incorporation of setae into the moulting mat and/or ootheca. Tarantulas from Uruguay present three types of urticating setae with different morphologies (types I, III, and IV). It has been proposed that type I is used in passive defence and that type III in active defence; however, the use of type IV remains enigmatic. This study aims to elucidate the use of the type IV urticating setae. For this, we analysed oothecae of Grammostola anthracina, a species that presents type III and IV setae, quantifying them, and comparing the proportions between each type. Differences were found in the number of setae incorporated into the ootheca: type IV urticating setae are present in a higher proportion compared to type III, which suggests their use mainly in passive defence. We also tested the effects of type IV urticating setae incorporated on oothecae on phorid larvae and ants.

Immature stages of Blepolenis bassus (C. Felder & R. Felder, 1867) (Lepidoptera: Nymphalidae: Satyrinae: Brassolini)

The Brassolini are among the most noticeable Neotropical butterflies. The adults have showy colorful wings with conspicuous eyespots on the ventral surface. Although Brassolini monophyly is recovered in recent phylogenies, some relationships among their genera remain uncertain and the shortage of information about the immature stages of the tribe probably contributes to the lack of understanding of its systematics. Blepolenis Röber, 1906 is a small brassoline genus and the morphology of its immature stages remains largely unknown. In order to provide new data on the morphology and natural history of Blepolenis and contribute to the systematics of the Brassolini, we here describe and illustrate the immature stages of Blepolenis bassus (C. Felder & R. Felder, 1867). The immatures of Blepolenis bassus show a general morphology similar to other Brassolini immatures. The first instar B. bassus head has two types of setae and the body bears filiform setae (F). The pupa lacks the lateral mirrored spot, seen on known pupae of closely related groups, such as Opsiphanes Doubleday, [1849]. B. bassus larvae feed on Saccharum villosum Steud. (Poaceae) remaining on their hostplant for about one year, and are univoltine, with adults flying in December and January.

The diversity, evolution, and development of setal morphologies in bumble bees (Hymenoptera: Apidae: Bombus spp.).

Bumble bees are characterized by their thick setal pile that imparts aposematic color patterns often used for species-level identification. Like all bees, the single-celled setae of bumble bees are branched, an innovation thought important for pollen collection. To date no studies have quantified the types of setal morphologies and their distribution on these bees, information that can facilitate understanding of their adaptive ecological function. This study defines several major setal morphotypes in the common eastern bumble bee Bombus impatiens Cresson, revealing these setal types differ by location across the body. The positions of these types of setae are similar across individuals, castes, and sexes within species. We analyzed the distribution of the two most common setal types (plumose and spinulate) across the body dorsum of half of the described bumble bee species. This revealed consistently high density of plumose (long-branched) setae across bumble bees on the head and mesosoma, but considerable variation in the amount of metasomal plumosity. Variation on the metasoma shows strong phylogenetic signal at subgeneric and smaller group levels, making it a useful trait for species delimitation research, and plumosity has increased from early Bombus ancestors. The distribution of these setal types suggests these setae may serve several functions, including pollen-collecting and thermoregulatory roles, and probable mechanosensory functions. This study further examines how and when setae of the pile develop, evidence for mechanosensory function, and the timing of pigmentation as a foundation for future genetic and developmental research in these bees.

The first zoeal stage of the deep-sea crab Tetraxanthus rathbunae (Brachyura: Pseudorhombilidae): a morphological description.

The description of the first zoea stage of Tetraxanthus rathbunae Chace, 1939, the third known zoea of Pseudorhombilidae and the first for Tetraxanthus, was carried out from laboratory hatched larvae. Their morphology differs from other pseudorhombilid species previously described primarily in the number and type of setae on the antennule, antennal exopod, maxilla, first maxilliped, and second maxilliped. These zoeae, however, share the same number of spines on the carapace (rostral, dorsal, and lateral), absence of the endopod on the antenna, long and well-developed spinose protopod, maxillary exopod with four marginal plumose setae and a robust posterior process, the absence of setae on the basis of the second maxilliped, and the presence of three lateral spines on each side of the furca. The results obtained in the present study are of great importance in being only the third known first stage pseudorhombilid zoea and the first for the Tetraxanthus, as well as in contributing to the identification of brachyuran planktonic zoea. Additionally, it also provides information that can help elucidate pseudorhombilid phylogeny.

Taxonomy of Two Psyllid Species of Cacopsylla genus (Hemiptera: Psyllidae) Associated with Prunus africana (Rosaceae) from Cameroon

Psyllids (Hemiptera: Psylloidea) are sap-sucking insects inducing serious damages to their host plants. Among the plants attacked by the psyllids in Cameroon, there is Prunus africana (Rosaceae), an important medicinal plant which is associated with two non-described psyllid species belonging to Cacopsylla genus. The two species induce necrosis of the leaves and stunt the growth of shoots of the host plant principally when it is in nursery. The aim of this survey is to describe and identify the two species of psyllids associated to P. africana. The specimens were captured with a sweep net of 0.5 mm mesh size and mouth aspirator. The fifth instar immatures and adults were described from the illustrated diagrams made with the aid of microscope as well as the morphological comparison with previously described species. The morphological examination shows that the two species share the nymph circumanal shape, but the abdomen distal margin bears different types of setae. In adult, the two species also share the head, forewing, and distal portion of aedeagus shape. They differ morphologically from the structure of paramere and female genitalia. When the two species of Cacopsylla described in this survey are compared to other species described elsewhere, they are morphologically different, notably the structure of paramere and female genitalia, the host plant species are also different. Then they are new species named Cacopsylla bamendae sp. nov. and C. messii sp. nov.

Microsculpture and chaetotaxy of abdominal tergites of bark and ambrosia beetles (Coleoptera: Curculionidae, Scolytinae): morphology and nomenclature

The structure of the chaetom and the microsculpture of the abdominal tergites surface are analyzed for 60 species of Scolytinae from different tribes and genera. The typi¬fication and nomenclature of these structures are proposed for the first time. Eight types of microsculptural elements and five types of setae are recognized. The taxonomic significance of these structures is discussed.

Morphological Differentiation of Ventral Tarsal Setae and Surface Sculpturing of Theraphosids (Araneae: Theraphosidae) With Different Types of Lifestyles

Abstract The ventral surfaces of tarsi in spiders in the infraorder Mygalomorphae group play a key role in locomotion and burrow and nest construction. In our research, we analyzed the diversity of setae and patterns of sculpturing on tarsi in three species with different life strategies: a burrowing spider Brachypelma smithi (F. O. Pickard-Cambridge, 1897), a ground-dwelling spider, Pterinochilus murinus Pocock, 1897, and a arboreal spider, Poecilotheria regalis Pocock, 1899. We showed the presence of three types of setae on the ventral side of tarsi: plumose setae, short-haired spiniform setae, and spirally striated setae. Plumose setae were differentiated within a tarsus and their apical sections among the studied species, while the microtriched ensiform and spirally striated setae did not differ. All setae were characterized by a similar structure. Little differentiation was observed in the number and location of setae on the tarsi of the studied species. Spirally striated setae were absent in the burrowing spiders. In contrast, the shape and size of the sculpturing pattern varied among the studied species. The greatest differentiation was found in the burrowing and ground-dwelling spiders, while the smallest differentiation was found in the arboreal spider. We discuss our findings in relation to preferred habitats, the biology of the spiders, and adaptation of sculpturing and setae on spider feet to surface type. The morphology and diversity of setae and sculpturing patterns on the ventral side of tarsi in P. murinus was reported for the first time.

Setae and sensilla in the Iberian Myrmeleon Linnaeus, 1767 larvae (Insecta, Neuroptera: Myrmeleontidae)

Myrmeleon (tribe Myrmeleontini) is the most successful genus within Myrmeleontidae in number of species. This is probably due to its pit-building behavior, a famous adaptation of antlion larvae but present only in a few genera of the family. In the Iberian Peninsula, where only two other genera are able to construct these traps (Euroleon in tribe Myrmeleontini and Myrmecaelurus in tribe Myrmecaelurini), five species of Myrmeleon are present: M. formicarius, M. gerlindae, M. inconspicuus, M. almohadarum and M. hyalinus. There are some useful characters to tell apart the larvae of these species using optical microscope, including the disposition of digging setae or some color spots. In this work, we study the type of setae on these species in their larval stage using SEM. The type of bristles, digging setae, and the rest of sensilla found are not different in shape, surface or structure between species. All of these confer them a great equipment in their psammophilous lifestyle.

Morphology and distribution of antennal sensilla in the gall midge Gephyraulus lycantha (Diptera: Cecidomyiidae)

The gall midge Gephyraulus lycantha (Diptera: Cecidomyiidae) is a serious gall-forming pest that causes devastating damage in the wolfberry, Lycium barbarum (Solanaceae) in Northwest China. In the present study, the external morphology and ultrastructure of the antennae and the antennal sensilla of G. lycantha were examined by scanning electron microscopy. The results show that the moniliform antenna of G. lycantha consisted of a scape, pedicel, and flagellum, and exhibited obvious sexual dimorphism. The male antennae were significantly longer than those of females. Moreover, male flagellomeres were spheroidal nodes separated by slender internodes, whereas those of females were cylindrical with no obvious internodes. There were sex and individual differences in antennal segment number. Male antennae had 10 − 16 flagellomeres, most of which had 15, while female antennae consisted of 8 − 14 flagellomeres, most of which had 12. Moreover, a pair of antennae in the same individual had different numbers of flagellomeres. Four types of sensilla were observed along the surface of the antennae, including sensilla chaetica, sensilla trichodea, sensilla coeloconica, and sensilla circumfila. Among the types of sensilla, sensilla chaetica were the longest and most prominent sensilla discovered on the antennal flagellum in both sexes. Sensilla trichodea were widely distributed over the antennal surface, including the scape, pedicel, and flagellum. Sensilla coeloconica were categorized into four subtypes: sensilla coeloconica Ⅰ, sensilla coeloconica Ⅱ, sensilla coeloconica Ⅲ, and sensilla coeloconica IV; however, sensilla coeloconica IV was absent in females. Sensilla circumfila were found only on cecidomyiidae insect antennae and were attached to the surface by a series of stalks, forming loops around each flagellomere. The numbers of all four types of sensilla on the male antennal windward side were significantly higher than those on the leeward side. The probable biological functions of these sensilla were discussed herein based on their morphology and ultrastructure. These results provide an important basis for further research on chemical communication and strategies for the control of G. lycantha, and it will be able to serve future group Taxonomy studies (species of cecidomyiidae), providing new taxonomic characters (general ultrastructural morphology, number of sensilla and antennal segments, distribution of different types of setae, types and subtypes sensilla), which varies between species and subspecies.

Ecomorphological Adaptations of Second Maxilliped-setation: Insights from Three Species of Fiddler Crabs from Panama.

The functional morphology of maxilliped-setation in three species of fiddler crabs-Petruca panamensis, Leptuca terpsichores and L. beebei-collected from Panama were studied using a comparative ecomorphological approach. The coverage of spoon-tipped (ST) and plumose (P) setae on the inner surface of the second maxilliped were noted, and the abundance of each setal type was enumerated, with crab carapace width as the covariate. These attributes were then related to the sediment particle size characterization of their respective collection sites for an ecomorphological comparison. All three species have mixed setation, albeit in different proportions of coverage. For L. terpsichores, the ST:P coverage was consistently ca. 70%:30% whereas there was approximately equal coverage of both setal types (i.e., 50% ST:50% P) on the maxillipeds of L. beebei and P. panamensis. Analysis of Covariance (ANCOVA) results of setal counts between the sexes in each species showed that the number of ST and P setae did not differ significantly between males and females, indicating an absence of sexual dimorphism in mouthpart setae. When all three species were compared-sexes combined within each species-ANCOVA results reveal that for any crab of a given size, there were significantly more ST setae on the second maxilliped of L. terpsichores (sediment from sampling site classified as 'moderately-sorted medium sand') than L. beebei (sediment from sampling site classified as 'moderately-sorted fine sand') and P. panamensis (a rocky-habitat species); no significant difference was detected between ST abundance in the latter two species. Current results provide unequivocal quantitative evidence that the abundance of ST setae can be an indicator to differentiate habitats down to the level of different sand-grain size, i.e., medium sand versus fine sand habitats of L. terpsichores and L. beebei, respectively. Both L. beebei and P. panamensis had significantly fewer ST setae than L. terpsichores, possibly because the former two species' habitats have sediments with sand grains that are less coarse than the latter's. On rocks, P. panamensis does not produce pseudofecal pellets as they directly swallow food materials pinched from the rock surfaces without sorting, rendering the role of ST setae of secondary importance. The three species did not differ significantly in P setae abundance, suggesting that the adaptive function of this type of setae to habitat characteristics remains debatable. The significance of ST setae as an ecomorphological adaptation for efficient food extraction from sandy sediments is, thus, evident in L. terpsichores. As for other two species-L. beebei and P. panamensis-that live in environments with finer sediment grain sizes, the adaptive role of ST setae is of diminished functional importance. Fiddler crab species with mixed setal types may have greater potential to exhibit feeding plasticity should their habitats be threatened.

Redescription of the enigmatic Costa Rican spider Aenigmarachne sinapophysis Schmidt, 2005 (Araneae: Theraphosidae)

The Costa Rican theraphosine Aenigmarachne sinapophysisSchmidt, 2005 is redescribed and the problematic type locality given by Schmidt (2005) is discussed. Other inconsistencies were found in Schmidt (2005), including erroneous information on urticating setae types, and are addressed. The systematic placement of AenigmarachneSchmidt, 2005 in relation to other Mesoamerican theraphosine genera is briefly discussed, within the confines of the presently available data.