Morphology and function of ovipositorial and tarsal sensilla of female Asian citrus psyllid

Abstract

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera:Psyllidae), is one of the most important pests of citrus plants worldwide, due to be the dominant vector of the devastating citrus disease Huanglongbing (HLB). Selection of suitable oviposition site is a crucial event of phytophagous insect life. Usually, the chemical and physical characteristics of a host plant were recognized by sensilla on the ovipositor and tarsi of a phytophagous insect after settling on a plant surface. In this study, the morphology, number, and distribution pattern of the ovipositorial and tarsal sensilla of adult female psyllids, were observed by scanning electron microscopy (SEM) techniques. The effect of these sensilla on oviposition was investigated by sensilla deactivation using hydrochloric acid (HCl). The results showed that sensilla trichoid (ST), sensilla chaetica (ChS) and sensilla basiconica (SB) were distributed on ovipositor, while sensilla trichoid (ST) were distributed on the external genitalia. Sensilla chaetica (ChS) and basiconica (SB) were mainly distributed on the end of the ovipositor back plate, and on the base of the sternum. On tarsus, sensilla trichoid (ST), sensilla chaetica (ChS), sensilla triangular (TeS) and sensilla ear ball (SE) were observed. However, whole tarsal segments were covered with Böhm's mane, which was arranged in a circular line. Oviposition assay revealed that a significantly lower number of eggs were laid on the Murraya paniculata seedlings confined by the psyllids with deactivated ovipositorial sensilla followed by protarsal sensilla, mesotarsal sensilla and hindtarsal sensilla. These results suggested that the ovipositorial and tarsal sensilla of citrus psyllid have an important role in the oviposition.

Host plant odours and their recognition by the odourant‐binding proteins of Diaphorina citri Kuwayama (Hemiptera: Psyllidae)

“…A recent study showed that there were a large number of sensilla on the ovipositor of female ACPs, including trichoid sensilla, which are related to chemical perception. When these sensilla were deactivated using HCl, an oviposition assay revealed the production of a significantly lower number of eggs than were produced by individuals that were treated with distilled water, and the results suggested that the ovipositor of the female ACP likely perceives odour to determine whether to lay eggs. Accordingly, in the ACP, DcitOBP6 is highly expressed in the ovipositor in addition to the antennae and mediates the recognition of β‐caryophyllene by females.…”

Evaluation of a push-and-pull strategy using volatiles of host and non-host plants for the management of pear psyllids in organic farming

“…Discriminating between host and nonhost species progresses through a series of behaviors, which begin with locating a potentially suitable plant, settling and probing, ingesting plant sap, and ovipositing. These behavioral components are regulated by plant-associated cues detected and evaluated by different types of sense organs or sensilla associated with varying structures of insects ( Ullman and McLean, 1986 ; Soroker et al., 2004 ; Liang et al., 2013 ; Zhang et al., 2019 ). Most of these behavioral processes and different sensilla functions are poorly understood.…”

“…Most of these behavioral processes and different sensilla functions are poorly understood. The initial component, locating the host from a distance, is likely governed by visual or olfactory cues detected by ocular organs and olfactory sensilla on the head and antennae ( Ullman and McLean, 1986 ; Soroker et al., 2004 ; Liang et al., 2013 ; Zhang et al., 2019 ). The importance of visual cues is shown by the attractiveness of specific colors to pear psyllids ( Adams et al., 1983 ; Krysan and Horton, 1991 ; Czarnobai De Jorge et al., 2022 ; Czarnobai De Jorge et al., 2023 ).…”