Bohm Bristles Research Articles

Antennal Sensilla of Parthenogenetic and BisexualLissorhoptrus oryzophilus(Coleoptera: Curculionidae)

ABSTRACT Antennal sensilla were compared in parthenogenetic females and bisexual adults of rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), using scanning electron micrographs. The antenna of parthenogenetic females and of both sexes of bisexual reproductive weevils consisted of the scape, pedicel, and 6 flagellar segments. Females, regardless of mode of reproduction, had longer antennal segments than males. The 3 adult forms/genders can be correctly classified into their respective groups with a set of discriminant mathematical functions based on 4 morphological measurements of length or maximum width of segments of the antennae. For both sexes, 6 morphological sensilla types were found on the antennae, including hydrofuge scales I (hsI), trichoid sensilla (ts), 2 types of squamiform sensilla (ssI, ssII), tuft hairs (th), and Bohm bristles (Bb). No remarkable sexual differences in the types or distribution of sensilla were found on the antennae among parthenogenetic and b...

콜레마니진디벌(Aphidius colemani) 촉각에 분포하는 감각기의 종류 및 외부미세구조적 특징

Several species of the genus Aphidius are used in biological control programs against aphid pests throughout the world and their behavior and physiology are well studied. While the importance of sensory organs in their behavior is understood, their antennal structure remains largely unknown. In this study, the external morphology and distribution of the antennal sensilla on the antennal of both female and male adults of A. colemani were described using scanning electron microscopy (SEM). Generally, the filiform antennae of males () are longer than females (). Antennae of this species are made up of radicle, scape, pedicel and flagellomeres. Male and female antennae differed in the total number of flagellomeres as 15 in males and 13 in females. The result of SEM observation was characterization and grouping of seven types of receptors into morphological classcs: Bohm bristles, Sensilla placodea, 2 types of S. coeloconica and S. trichodea, and S. basiconica as with a tip pore and with wall pores. In addition, the possible functions of the above sensilla types arc discussed in light of previously published literature; mechanoreception (Bohm bristles, S, coeloconica I & II and S. trichodea) and chemoreception (S. placodea, S. basiconica type I & II).

Morphological changes induced in the antenna of cowpea beetle, Callosobruchus maculatus (Fabricius) (Coleoptera : Bruchidae) after treatment with lufenuron

The effect of a chitin synthesis inhibitor (Lufenuron) on the antennal segements and their sensilla of cowpea beetle, Callosobruchus maculatus(Fabricius) was studied by using scanning electron microscope. Seven types of sensilla were recognized on both untreated and treated antennae with 9 ppm of lufenuron, including Bohm bristles (BB), two types of sensilla trichodea (ST1, ST2), sensilla chaetica (SC), two types of sensilla basiconica (SB 1, SB2) and grooved peg (GP). The functions of these sensilla were discussed in relation to their position on the antenna. Significant difference in lengths of most segments of the antennae between untreated and treated beetles was observed. A significant difference in lengths and diameters of nearly all types of sensilla was recorded. The highest increase in length of sensilla was noticed for the sensilla chaetica followed by sensilla trichodea. These types are used by insects as mechanosensory, sex pheromone and gustatory receptors that help them to make a decision to select their food and oviposition sites.

Antennal Sensilla in Adult Helicoverpa assulta (Lepidoptera: Noctuidae): Morphology, Distribution, and Ultrastructure

This study was done to elucidate structure and distribution of antenna and antennal sensilla in adult oriental tobacco budworm, Helicoverpa assulta (Guenee). The antenna consisted of scape, pedicel, and flagellum. The flagellum of both sexes had 6 major types of sensilla. The number of flagellar subsegments differed slightly between the 2 sexes. Sexual dimorphism was also noticed in the total number of sensilla and in the subtypes of sensilla trichodea. Sensilla chaetica were mechanical and contact chemoreceptors. All sensilla trichodea were thick-walled, multiporous sensilla with pitted surface characteristics typical of olfactory sensilla, and had 2-5 unbranched dendrites. These sensilla were further divided into different subtypes, which were not the same between the sexes. Subtypes I and II were divided by scanning electron microscopy, and subtypes A and B, which existed only in the male and may be pheromone-sensitive sensilla, by transmission electron microscopy. Sensilla basiconica were thin-walled, grooved, multiporous sensilla and had >10 dendritic branches. Sensilla auricillica were thin-walled, grooved, multiporous sensilla, flatter than sensilla basiconica and had >30 dendritic branches. Sensilla coeloconica were double-walled, grooved, multiporous sensilla and had spoked channels instead of pore tubules. The last subsegment of flagellum had 2-3 sensilla styloconica. Also, most of sensilla styloconica were distributed uniformly in the upper-middle region of each flagellar subsegment and another sensillum styloconicum was distributed randomly in each flagellar subsegment. The pedicel had 2 groups of Bohm bristles, sensilla basiconica, and the Johnston organ. The scape had 2 types of scales, 2 groups of Bohm bristles, and the scape muscles attached to cuticle of the pedicel. The antennal socket also had 2 groups of Bohm bristles.

Scanning Electron Microscopy of antennal sensilla of the Japanese tusser, Antheraea vamamai

Antennal surface structure of the Japanese tusser, Antheraea yamamai was observed by scanning electron microscope. The antennae of male and female were bipectinate with scape, pedicel and 33--37 flagellar segments. There were two pairs of equal long branch on eacli flagellar segment of male (Fig.1), but a pair of longer and a pair of shorter on female's (Fig.2).Seven types of sensillum, namely sensillum trichodeum, sensillum cheaticum, sensillum coeloconicum, sensillum campaniformlum, sensillum styloconicum, Bohm's bristle and sensillum squamiformium wer found on the antenna both of male and female. The sensillum trichodeum could be subdivided into long and short according to the shape and surface substructure. The long sensillum trichodeum had a diameter of 4.8μm at its base. It was reratively stright and slightly curved at the tip (Fig.3). The short sensillum trichodeum was 2.5--3.6 μm in diameter at the base. It was shorter, strongly bend down near its base and run parallel with the surface of the antenna (Fig.4). The surface of long and short sensilla trichodea were covered with annular ridges (Fig.5).

The antennal movement apparatus in the small tortoiseshell (Aglais urticae L., Insecta, Lepidoptera)

1. The club-shaped antenna ofAglais urticae L. consists of 34–37 segments (scape, pedicel, and flagellar segments; Fig. 1) covered by hairs and scales (Fig. 4a). Only the scape and the pedicel can be moved by muscles (Fig. 6). 2. The head-scape joint may be compared to a ball-and-socket joint. The scape can be moved in various directions by four muscles of the head (Fig. 6a). The scape-pedicel joint functions like a hinge joint, about which axis G3-G4 the pedicel together with the flagellum can be turned upwards by one muscle and downwards by two muscles of the scape (Figs. 6b and 7). This axis, when the antenna is in resting position, makes an angle of ca. 40° (pointing forwards) with the longitudinal body axis when projected into the horizontal plane (Fig. 14). 3. The pedicel-flagellum joint, as all the successive joints, is of almost radial symmetry (Fig. 2). The flagellar segments can only be moved passively by a relatively small amount. 4. Aglais has in its pedicel a highly developed Johnston's organ (Figs. 8–10), the sense cells of which can probably perceive passive movements of the flagellum in relation to the pedicel. The active movements of the antenna can be controlled by Bohm's bristles on the scape and the pedicel (Figs. 3–7). 5. The Johnston's organ, the Bohm's bristles and the antennal muscles are supplied by nerves which arise in the deutocerebrum (Figs. 11 and 12). 6. During flight the antennae are stretched forward almost horizontally (Fig. 1). The adjustment of this antennal flight position is discussed (Figs. 13 and 14).