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The mouthparts of the spoon-winged lacewing Nemoptera sinuata are adapted for the uptake of pollen and nectar. Form and function of the mouthparts are described, and the technique of food uptake is discussed in context with flower-visiting behaviour and floral architecture of the preferred flowers. The maxillae are the main organs for food uptake. The brush-shaped laciniae, galeae and maxillary palpi form a functional unit which can be extended by the action of the cardo-stipes joint. Video analyses of the mouthpart movements distinguished different patterns of maxillary motions which occur in nectar feeding or pollen collecting. The flower-visiting behaviour and the specialised mouthparts of the Nemopteridae are derived traits which probably evolved from predatory and biting/chewing mouthparts within the Neuroptera. [ABSTRACT FROM AUTHOR]

Abstract: The food canal of the proboscis of Lepidoptera serves for the uptake of nutrient fluids and the discharge of saliva. A valve was discovered at the entrance to the sucking pump in the head that separates these countercurrent flows in nymphalid butterflies. Three species of Nymphalidae were examined by dissections and light microscopic serial semithin sections. The sucking pump is a unit composed of three structures: (1) the oral valve, which is a projection of the epipharynx extending into the anterior cibarial lumen, (2) the expandable lumen, and (3) the posterior sphincter valve which controls influx into the oesophagus. Based on the microanatomical results, a functional model is presented to account for the uptake and swallowing of fluids and for the control of the salivary flow into the food canal of the proboscis. Dilator muscles of the sucking pump expand the lumen by pulling on the muscular dorso-anterior side. This opens the oral valve and fluid can be drawn into the lumen from the food canal of the proboscis. Circular compressor muscles which attach to both sides of the sclerotized ventro-posterior wall of the sucking pump reduce the size of the lumen; passively they close the oral valve and press fluid through the relaxed posterior sphincter opening into the oesophagus. According to this model saliva can be discharged into the food canal during the swallowing phase. The oral valve and pumping unit are similar in all studied species despite the fact that saliva presumably plays a special role in the derived pollen-feeding behaviour of one of them, viz. Heliconius melpomene. [Copyright &y& Elsevier]

Abstract: This review deals with the morphology and function of adult insect mouthparts modified to feed on nectar, pollen or petals. Specialization to nectar-feeding is evident in formation of proboscides of various lengths and designs. Proboscides of many Hymenoptera and Diptera function according to adhesion mechanisms that load nectar onto extensible apical mouthpart regions before fluid is conveyed along the food canal to the mouth by capillarity and suction. Predominantly suctorial proboscides evolved once in Lepidoptera, probably twice in Coleoptera, variously in some Hymenoptera and several times with similar design in Diptera. Many of them are particularly long and have sealed food tubes, specialized apical regions, new proboscis resting positions and modified feeding movements. Mouthparts of obligate pollen-feeding insects can be characterized by modified mandibles, specialized bristles for pollen manipulation and elaborate feeding movements. Often saliva is crucial for pollen retention and ingestion. In Coleoptera, intact pollen is gathered by sweeping movements of mouthparts; in Diptera, it is suspended in saliva prior to suction. Pollen is crushed by asymmetrical mandibles in aglossatan Lepidoptera and one group of basal Hymenoptera. Pollen-piercing mouthparts occur in Thysanoptera and one group of Diptera. Some butterflies and few Diptera extract nutrients from pollen by mixing it externally with saliva on their mouthparts. No mouthpart specializations to petal-feeding are reported in flower-visiting insects. [Copyright &y& Elsevier]

The morphology and functional anatomy of the mouthparts of pollen wasps (Masarinae, Hymenoptera) are examined by dissection, light microscopy and scanning electron microscopy, supplemented by field observations of flower visiting behavior. This paper focuses on the evolution of the long suctorial proboscis in pollen wasps, which is formed by the glossa, in context with nectar feeding from narrow and deep corolla of flowers. Morphological innovations are described for flower visiting insects, in particular for Masarinae, that are crucial for the production of a long proboscis such as the formation of a closed, air-tight food tube, specializations in the apical intake region, modification of the basal articulation of the glossa, and novel means of retraction, extension and storage of the elongated parts. A cladistic analysis provides a framework to reconstruct the general pathways of proboscis evolution in pollen wasps. The elongation of the proboscis in context with nectar and pollen feeding is discussed for aculeate Hymenoptera. [Copyright &y& Elsevier]

Abstract: The anatomy of the proboscis was studied in representatives of all major subfamilies of Papilionoidea and several outgroup taxa which included Hesperiidae, Hedylidae and Geometroidea. In all species the cross-sectional outline of the tapering proboscis continuously changes from proximal to the tip while the central food canal, formed by the concave medial galeal walls, retains its oval shape. Each galea contains three types of muscles, a branching trachea, nerves, sensilla, and at least one longitudinal septum. We focused on the varying arrangement and distribution of the intrinsic galeal muscles from the basal galeal joint to the tip region. The plesiomorphic condition of the galeal composition of Papilionoidea is regarded to include one basal intrinsic muscle in the basal joint region and two series of intrinsic muscles, i.e. the lateral intrinsic galeal muscles and the median intrinsic galeal muscles, both series extending from the proximal region to the tip region. The plesiomorphic arrangements of the intrinsic muscle series are found in all representatives of Papilionidae, in one species of Lycaenidae (sensu lato), in many Nymphalidae (sensu lato), and in all outgroup species. Three apomorphic character states are distinguished regarding the presence and extension of the median intrinsic galeal muscles. (1) Present up to 35% of the proboscis length and absent distally in Pieridae, Lycaeninae (Lycaenidae), Satyrinae (Nymphalidae), and Danainae (Nymphalidae). (2) Present in the proximal third of the proboscis and again near the tip between 80 and 90% of the proboscis length in the examined Heliconiinae (Nymphalidae). (3) Completely absent, as in one lycaenid species from the subfamily Riodininae. [Copyright &y& Elsevier]

Abstract: Few species of true butterflies (Lepidoptera: Papilionoidea) have evolved a proboscis that greatly exceeds the length of the body. This study is the first to examine the morphology of an extremely long butterfly proboscis and to describe how it is used to obtain nectar from flowers with very deep corolla tubes. The proboscis of Eurybia lycisca (Riodinidae) is approximately twice as long as the body. It has a maximal length of 45.6 mm (mean length 36.5 mm ± 4.1 S.D., N = 20) and is extremely thin, measuring only about 0.26 mm at its maximum diameter. The proboscis has a unique arrangement of short sensilla at the tip, and its musculature arrangement is derived. The flower handling times on the preferred nectar plant, Calathea crotalifera (Marantaceae), were exceptionally long (mean 54.5 sec ± 28.5 S.D., N = 26). When feeding on the deep flowers remarkably few proboscis movements occur. The relationship between Eurybia lycisca and its preferred nectar plant and larval host plant, Calathea crotalifera, is not mutualistic since the butterfly exploits the flowers without contributing to their pollination. We hypothesize that the extraordinarily long proboscis of Eurybia lycisca is an adaptation for capitalizing on the pre-existing mutualistic interaction of the host plant with its pollinating long-tongued nectar feeding insects. [Copyright &y& Elsevier]