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Phylogeny of Trichoptera families and suborders Annulipalpia (A), ''Spicipalpia'' (B), and Hydropsychoidea (C).
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ABSTRACT Several orders of morphologically fourwinged
insects have evolved mechanisms that enforce a
union between the mesothoracic and metathoracic wings
(forewings and hindwings) during the wing beat cycle.
Such mechanisms result in a morphologically tetrapterous
insect flying as if it were functionally dipterous, and
these mechanisms have been d...
Contexts in source publication
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... and discussed. Annulipalpia currently comprises 4,605 of the 12,927 described caddisfly species (Morse, 2003(Morse, , 2009. While the monophyly of Annulipalpia was asserted previously on morpho- logical grounds alone, (e.g., Morse, 1997), recent molecular studies have clarified some internal rela- tionships [(Kjer et al., 2002;Geraci, 2007) Fig. ...
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... phylogenetic scheme adopted here is shown in Figure 1. The wings of Parapsyche apicalis Banks (Hydropsychidae: Arctopsychinae) are shown to highlight general wing morphology, and the forewing of Dolophilodes distincta (Walker) to show detail of the jugal lobe (Figs. 2, 3). ...
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... 1) Absence of a forewing jugal lobe; 2) Linear or slightly concave forewing ambient costa vein; 3) Forewing vein A1 parallel to ambient costa vein (Fig. 13C); 4) Forewing with a narrow and approximately parallel-sided anal cell [resulting from properties 2 and 3, contra Parapsyche apica- lis (Banks), Fig. 2]; 5) The forewing hamular setae are linearly arranged along a well-defined section of A1 (fwcs), with their bases projecting perpendic- ularly to the wing membrane or at a slight ...
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... 1) Costa is approximately linear in the region opposite forewing A1. The anterior mar- gin of the hind wing is parallel to the forewing A1 when the wings are coupled (e.g., Fig. ...
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... The socketed setae of Costa are apically directed, with the setae becoming progressively more recumbent. In cross section, the setae form a halo around Costa (Figs. 12, 29). 3) A distinct series of stout socketed setae forms a linear row along the dorsal edge of Costa. In the hindwing costal region corresponding to the forewing acanthae-forewing coupling setae, the setae assume a curved sinusoidal morphology with apically directed tips (Figs. 10, 11, 12). 4) The geometry of Costa is pro- gressively more ...
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... functional outcome of the following condi- tions, exemplified by Hydropsyche betteni Ross, is the following: The posterior forewing and anterior hindwing margins are spatially approximate when the wings are in the coupled position (Fig. 13C), and the halo of apically directed setae of Costa is retained by the fwcs on the forewing A1. The cos- tal sinusoidal setae on the off-set margin of the hindwing are positioned in the glabrous space on the forewing between the coupling setae on A1 and the anal-cell bed of acanthae. In vitro, this lin- ear row of setae can be made to ...
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... wing coupling apparatuses of the Macr- onematinae taxa Macrostemum sp. (see Fig. 14) and Oestropsyche vitrina (Hagen) are figured ( Figs. 27, 28, 30). Variation among taxa in compo- nents of the apparatus appears to be taxonomically informative. The Macronematinae theme involves cuticular modifications on the ventral forewing surface that engage with variously modified sock- eted setae on the hindwing Costa (or ...
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... putative synapomorphies include the following: 1) Absence of forewing jugal lobe. 2) Dif- fuse acanthae in the proximal (axillary) region of forewing anal cell [cf. microspines, (Schefter, 1996) progressively define a ridge-like structure [''file'' (Schefter, 1996); Figs. [15][16][17][18][19][20][21][22] in the forewing pos- terior to A1 (Figs. 14, 21, 22, 27F), but which in some taxa are nearly superimposed on A1. The cuticular ridge is adorned with acanthae of taxo- nomically and positionally variable morphology (Figs. 15-22, 27). The ridge is generally linear and parallel to the posterior margin of the forewing, but often assumes an anteriorly directed deflection in the apical section ...
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... (Schefter, 1996) progressively define a ridge-like structure [''file'' (Schefter, 1996); Figs. [15][16][17][18][19][20][21][22] in the forewing pos- terior to A1 (Figs. 14, 21, 22, 27F), but which in some taxa are nearly superimposed on A1. The cuticular ridge is adorned with acanthae of taxo- nomically and positionally variable morphology (Figs. 15-22, 27). The ridge is generally linear and parallel to the posterior margin of the forewing, but often assumes an anteriorly directed deflection in the apical section before terminating (e.g., Mac- rostemum sp., Fig. 14A). In its morphologically most extreme form (e.g., O. vitrina, Fig. 27E), the cuticular ridge is essentially a pseudovein of ...
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... superimposed on A1. The cuticular ridge is adorned with acanthae of taxo- nomically and positionally variable morphology (Figs. 15-22, 27). The ridge is generally linear and parallel to the posterior margin of the forewing, but often assumes an anteriorly directed deflection in the apical section before terminating (e.g., Mac- rostemum sp., Fig. 14A). In its morphologically most extreme form (e.g., O. vitrina, Fig. 27E), the cuticular ridge is essentially a pseudovein of nearly circular cross-section. The position of the file relative to the posterior vein is also taxonomi- cally variable, with significant separation between the two of them in Leptonema boliviense Mosely, and very ...
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... cally variable, with significant separation between the two of them in Leptonema boliviense Mosely, and very little separation in O. vitrina. 3) Between the cuticular ridge (''file'') and A1 there is a region of glabrous wing membrane that defines a ''groove'' (Schefter, 1996). In examined taxa, A1 is always differentiable from this groove (Figs. 21, 22). 4) The forewing ambient Costa vein often bears a covering of stout socketed setae, but these are absent in some taxa. When present, they typically are quite small and distributed among vein-cover- ing acanthae. In some taxa (e.g., O. vitrina; Fig. 27B,F), the stout socketed setae become prom- inent apically and are involved in part ...
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... setae is restricted to Radius, and in Macrostemum sp. and Amphipsyche sp., there is no second row. In O. vitrina, Polymorphanisis sp. and Synoestropsis sp., a row of differentiated hook-tipped setae is present and suggestive of a role in wing engage- ment, and in O. vitrina, an intermediate series of lanceolate setae is present on Subcosta (Figs. 28D, 31, 32). The secondary setae of Polymorphanisus sp. and Synoestropsis sp. are similar both in mor- phology and distribution on the wing, and in both taxa the setae are in the membrane and not the vein, whereas in O. vitrina the setae are primarily on the vein, with only a few with sockets on the membrane (Figs. 31, 32). Barnard [(1980 ...
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... setae is present on Subcosta (Figs. 28D, 31, 32). The secondary setae of Polymorphanisus sp. and Synoestropsis sp. are similar both in mor- phology and distribution on the wing, and in both taxa the setae are in the membrane and not the vein, whereas in O. vitrina the setae are primarily on the vein, with only a few with sockets on the membrane (Figs. 31, 32). Barnard [(1980 indicated that the vein in question is ''. . .the stem of Rs (radius-sector),'' but his illustrations reveal a discrepancy with presumed homology of veins between O. vitrina and Polymorphanisus sp. and Synoestropsis sp. Two veins (or one vein and one neo-formation) are present between Costa and the stem of Rs. Subcosta ...
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... veins between O. vitrina and Polymorphanisus sp. and Synoestropsis sp. Two veins (or one vein and one neo-formation) are present between Costa and the stem of Rs. Subcosta is quite clear in all three taxa, but in O. vitrina, a vein (or neo-formation) visible only under dark-field lighting occurs between Subcosta and the stem of Radial-sector (see Fig. 31). In all three taxa the ''pseudo-vein'' cuticle is differentiable from the adjacent wing membrane, but it lacks evidence of either sock- eted-setae or the interior longitudinal nerve typi- cal of many ...
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... O. vitrina, the secondary row of setae on and adjacent to Radius of the hind wing also appears to be functionally engaged. Although the wings are coupled, this row is approximate to the stout setae on the forewing posterior vein (Figs. 28B, 31). The spacing is such that the recurved tips of the setae on and adjacent to the Radius could possibly engage the setae on the ambient ...
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... humeral crossvein, and extends along the dorsal aspect of Costa approximately half the hindwing length; there is no well devel- oped setal cluster proximal to the humeral vein (Figs. 39, 40). The costal setae are longitudinally fluted but otherwise unremarkable except that the tapered apex of each becomes curved and assumes a hooked morphology (Fig. 41, Type 1). In S. dith- yra, a morphologically distinct class of setae inter- rupts the major row. These setae are shorter, nar- rower, straighter and have strongly recurved tips (Figs. 41, 42, Type 2). Collectively, the morphology of the hindwing Costa suggests a coupling ...
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... 39, 40). The costal setae are longitudinally fluted but otherwise unremarkable except that the tapered apex of each becomes curved and assumes a hooked morphology (Fig. 41, Type 1). In S. dith- yra, a morphologically distinct class of setae inter- rupts the major row. These setae are shorter, nar- rower, straighter and have strongly recurved tips (Figs. 41, 42, Type 2). Collectively, the morphology of the hindwing Costa suggests a coupling ...
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Citations
... In flight, the fore and hind wings of caddisflies act as a unified aerodynamic surface during the down stroke [34] and most species have physically coupled wings [37,38]. Thus, caddisflies have four true wings but are functionally two-winged during flight [39]. ...
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Findings: The results showed that butterflies use saliva to repair their proboscises via capillary adhesion, and theoretically supported the role of saliva in providing the necessary capillary forces to bring the galeae together. Tangential shear forces acting parallel to the galea at the tip of their separation are caused primarily by friction between the cuticular linking structures.
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... Up to now, researchers mainly focused on the morphology and material distribution of the coupling mechanism. Based on these two aspects, functional principles of an effective maintenance of the winglocking and synchronization of fore-and hindwing motion during insect flight have been elucidated (Scoble, 1995;Gorb, 2001;Gorb and Perez Goodwyn, 2003;Perez Goodwyn and Gorb, 2004;Stocks, 2010;Ma et al., 2015Ma et al., , 2017Ma et al., 2019aMa et al., , 2019bOgawa and Yoshizawa, 2018). For example, in Lepidopteran moths (Scoble, 1995;Gorb, 2001), a frenulum is situated at the leading edge of their hindwings, which is ventrally locked with one retinaculum (in males) or multiple retinacula (in females) at the trailing edge of forewings, forming a frenateretinacular coupling. ...
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... In butterflies, an enlarged humeral area extends from the costal margin of the hingwing base and overlaps with the trailing edge of the fore wing base (amplexiform coupling) [2]. In Hymenoptera (sawflies, ants, wasps and bees) and Trichoptera (caddisflies), fore and hind wings are connected by means of a rolled margin at the trailing edge of fore wings and a set of hooks at the leading edge of hind wings (hook-furrow coupling) [3,[12][13][14]. Another coupling mechanism, so called clamp-furrow coupling, occurs in Hemiptera and Homoptera, where fore and hind wings are coupled using a clamp-like structure at the fore wing trailing edge and a rolled margin at the hind wing costal margin [5,6,[15][16][17]. ...
... The wing coupling mechanism is of great importance for many four-winged insects with synchronized fore and hind wing flapping flight (so-called functional diptery). Most of the previous studies have been focused on the morphology and phylogeny of the coupling mechanisms in different insects including stink bugs (Heteroptera) [2,[4][5][6]13,[15][16][17]. However, the link between morphological characteristics and functionality of wing coupling of stink bugs still remains unclear. ...
Stink bugs have wing coupling mechanisms to synchronize flapping of their wings. The wing coupling is performed through a clamp-like structure on the fore wing (i.e., hemelytron) and a rolled margin on the hind wing. Here we used modern imaging techniques to investigate structural characteristics and material composition of the wing coupling of the stink bug Nezara viridula. We found that the surfaces of the clamp-like structure and the rolled margin are covered by highly-sclerotized microtrichia, which are expected to reduce friction between the wings during flapping flight. Micro-force measurements showed that fore and hind wings can be coupled only in certain angles ranging from 40.6° to 267.7°. The results further showed that the force required to uncouple fore and hind wings is maximal for a range of angles which they make with each other during flight (127.1° to 238.9°). In contrast to previous observations on some other insect species, the removal of the wing coupling in stink bugs led to complete loss of flight ability. In summary, we concluded that the shape, material composition and orientation of the coupling structure guarantee a robust fore wing to hind wing coupling during flight and a fast, easy uncoupling at rest.
... Trichoptera (Stocks, 2008(Stocks, , 2010a(Stocks, 2010bTillyard, 1918); (b) non-setal cuticular structures, often in the form of grooves, such as in various Hemiptera (D'Urso & Ippolito, 1994;Pesson, 1951b) and the jugum in Lepidoptera and Trichoptera (Stocks, 2010a(Stocks, , 2010bTillyard, 1918). ...
... Trichoptera (Stocks, 2008(Stocks, , 2010a(Stocks, 2010bTillyard, 1918); (b) non-setal cuticular structures, often in the form of grooves, such as in various Hemiptera (D'Urso & Ippolito, 1994;Pesson, 1951b) and the jugum in Lepidoptera and Trichoptera (Stocks, 2010a(Stocks, , 2010bTillyard, 1918). ...
Many four-winged insects have mechanisms that unite the forewings and hindwings in a single plane. Such an in-flight wing coupling apparatus may improve flight performance in four-winged insects, but its structure is variable among different insect groups. The wings of bark lice (Insecta: Psocodea: “Psocoptera”) also have an in-flight wing coupling apparatus, but to date, its morphology has not been studied in detail. In this study, we examined the wing-coupling structure in representative species of the three suborders of bark lice (Trogiomorpha, Troctomorpha, and Psocomorpha) and inferred its origin and transformation. We conclude that the main component of the psocodean wing coupling apparatus evolved once in the common ancestor via modification of cuticular structures at the apex of the forewing CuP vein. Morphological differences in components of the coupling structures are phylogenetically informative at the intraorder level and include an autapomorphy that characterizes Troctomorpha and a synapomorphy that supports a sister relationship between Troctomorpha and Psocomorpha.
... One pair of fore and hind wings were removed from each insect, mounted on a microscope slide and a digital image produced. Wings were oriented so that wing span or maximum wing length was horizontal and perpendicular to the longitudinal axis of the insect body (Fig. 1) and the hind wing was oriented in the coupled position (Stocks 2010). Wing measurements were carried out on digital images of coupled wing pairs in planform (the orientation of wings during the down stroke and the generation of lift forces) and using the software ImageJ 1.49 s (Rasband 1997(Rasband -2012. ...
Ecological traits that reflect movement potential are often used as proxies for measured dispersal distances. Whether such traits reflect actual dispersal is often untested. Such tests are important because maximum dispersal distances may not be achieved and many dispersal events may be unsuccessful (without reproduction). For insects, many habitat patches harbour 'resident' species that are present as larvae (sedentary) and adults (winged and dispersing), and 'itinerant' species present only as adults that have dispersed from elsewhere and fail to reproduce. We tested whether itinerancy patterns were temporally consistent, and whether itinerant and resident species differed in wing morphology, a strong correlate of flight capability. Over 3?years and at multiple locations in a 22?km stream length, we sampled larvae and adults of caddisflies in the genus Ecnomus to categorize species as residents or itinerants. Flight capacity was measured using wing size (length and area) and shape parameters (aspect ratio and the second moment of wing area). Three species of Ecnomus were residents and three species were itinerants, and patterns were consistent over 3?years. On average, itinerant species had larger wings, suggesting a greater capacity to fly long distances. Wing shape differed between species, but did not differ systematically between residents and itinerants. Wing morphology was associated with actual but not effective dispersal of some species of Ecnomus. Morphological traits may have weak explanatory power for hypotheses regarding the demographic connectedness of populations, unless accompanied by data demonstrating which dispersers contribute new individuals to populations.
