Antennal sensillum morphology and electrophysiological responses of olfactory receptor neurons in trichoid sensilla of the diamondback moth (Lepidoptera: Plutellidae)
Keywords:
Plutella xylostella, olfaction, scanning electron microscopy, single sensillum recording, trichodea, volatile compoundsAbstract
Plant chemical signals are important olfactory cues for the survival and reproduction of phytophagous insects. The diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) is a Brassica spp. (Brassicales: Brassicaceae) specialist pest, with most of its life events occurring on Brassica spp. hosts. We conducted a scanning electron microscopy study on the morphology and distribution of antennal sensilla of male and female P. xylostella. Seven morphological types of sensilla were identified in the antennae of P. xylostella: 3 types of sensilla trichodea (Tr I, Tr II and Tr III), sensilla chaetica, sensilla coeloconica, sensilla auricillica and sensilla styloconica. One particular type of trichoid sensillum (Tr III) was present only in the males. The presence of numerous pores or deep longitudinal grooves on the surfaces of 5 morphological types of sensilla indicated that their major function is olfactory. Single sensillum recordings were also carried out on the trichoid sensilla of the female diamondback moth to identify the olfactory receptor neurons (ORNs) and to determine the response spectra of the ORNs, using a panel of 39 host and non-host volatile compounds. Based on the response profiles, 42 responsive trichoid sensilla could be segregated into 4 sensillum classes. Each sensillum appeared to contain 3 co-compartmentalized ORNs, and therefore a total of 12 classes of ORNs were identified from these sensilla. Each ORN class showed a narrow response spectrum, with some ORNs specialized for green leaf volatiles and (±)-linalool that are present in brassicaceous hosts, while several other ORNs responded to 2 non-host volatile sesquiterpenes, (E)-β-farnesene and germacrene D, as well as (E)-β-caryophyllene, a host-related sesquiterpene volatile. The sensitivity and selectivity of the female diamondback moth towards certain host plant volatiles warrants further investigation for potential behavioral manipulation to control this pest.
Resumen
Las señales químicas de las plantas son importantes señales olfativas para la sobrevivencia y reproducción de los insectos fitófagos. La polilla de la col, Plutella xylostella L. (Lepidoptera: Plutellidae) es una plaga especialista sobre Brassica spp. (Brassicales: Brassicaceae), que pasa la mayoría de los eventos de su vida sobre hospederos de especies de Brassica. Se realizó un estudio de microscopía electrónica de barrido sobre la morfología y distribución de la sensilla antenal del macho y la hembra de P. xylostella. Se identificaron siete tipos morfológicos de sensilla en las antenas de P. xylostella: 3 clases de sensilas trichodea (Tr I, II y Tr Tr III), sensilas chaeticas, sensilas coeloconicas, sensilas auricilicas y sensilas stiloconicas. Un tipo particular de sensila trichoid (Tr III) estaba presente sólo en los machos. La presencia de numerosos poros o ranuras longitudinales profundas en la superficie de 5 tipos morfológicos de sensilla indicó que su principal función es olfativo. También, se realizaron grabaciones individuales de la sensila en las sensilas trichoides de las hembras de la palomilla dorso de diamante para identificar las neuronas olfativas del receptor (NORs) y para determinar los espectros de respuesta de los NORs, utilizando un panel de 39 compuestos volátiles de hospederos y no hospederos. Basado en los perfiles de respuesta, 42 sensilas trichoides que respondieron podrían ser segregadas en 4 clases de sensilas. Cada sensila parecía contener 3 NORs co-compartimentada, y por lo tanto se identificaron un total de 12 clases de NORs de éstas sensilas. Cada clase de NOR mostró un espectro de respuesta estrecha, con algunas NORs especializados para sustancias volátiles de las hojas verdes y (±) -linalool que están presentes en los hospederos brassicaceosos, mientras que varios otros NORs respondieron a 2 no hospederos sesquiterpenos volátiles, (E) -β-farneseno y germacreno D, así como (E) -β-cariofileno, un volátil sesquiterpeno relacionado con el hospedero. La sensibilidad y la selectividad de las hembras de la polilla de la col hacia ciertos volátiles de las plantas hospederas justifica mas investigaciones adicionales para la manipulación potencial del comportamiento para control de esta plaga.
Downloads
Issue
Section
License
Copyright for any article published in Florida Entomologist is held by the author(s) of the article. Florida Entomologist is an open access journal. Florida Entomologist follows terms of the Creative Commons, Attribution Non-Commercial License (cc by-nc). By submitting and publishing articles in Florida Entomologist, authors grant the FOJ and Florida Entomologist's host institutions permission to make the article available through Internet posting and electronic dissemination, and to otherwise archive the information contained both electronically and in a hard printed version. When used, information and images obtained from articles must be referenced and cited appropriately. Articles may be reproduced for personal, educational, or archival purposes, or any non-commercial use. Permission should be sought from the author(s) for multiple, non-commercial reproduction. Written permission from the author(s) is required for any commercial reproduction.
