Nymphal antennae and antennal sensilla in Aleurodicus dispersus (Hemiptera: Aleyrodidae)

Abstract

Whiteflies have distinct nymphal stages: their first stage is mobile, whereas the later immature stages are sessile. The developmental and structural changes of antennae and antennal sensilla in whiteflies during these stages have rarely been investigated. This paper describes the morphology of antennae and antennal sensilla in four nymphal stages of Aleurodicus dispersus based on scanning electron microscopy. There were significant differences found in shape and length of the antennae, and differences in type, number, morphological structure and distributional pattern of antennal sensilla in the four nymphal stages of A. dispersus. We found two types of sensilla on the antennae of first-instar nymph, three types on the third-instar nymphal antennae, four types on the second-instar and seven types on the fourth-instar nymphal antennae. Sensilla trichoidea (ST) and elevated sensilla placodea were found on the antennae of each nymphal stage, sensilla chaetica only occurred on the antennae of fourth-instar nymph. Sensilla furcatea occurred on the antennae of second- and third-instar nymphs, and sensilla basiconica were found on the antennae of second- and fourth-instar nymphs. In addition, there were sensilla campaniform and sensilla coeloconica found only on the antennae of fourth-instar nymph, whereas the ST of fourth-instar nymphs included sensilla trichoidea 1 and sensilla trichoidea 2. The possible functions of antennal sensilla are discussed. Our results contribute to a better understanding of the development of the olfactory system of whitefly nymphal stages, and provide a basis for further exploration of chemical communication mechanisms between whiteflies and host plants.

The structure and morphologic changes of antennae of Cyrtorhinus lividipennis (Hemiptera: Miridae: Orthotylinae) in different instars

“…lividipennis , male and female antennae were equipped with significantly more PLA than the nymphal antennae ( Table 7 ). The PLA were similar in appearance to those described for Aleurodicus dispersus [ 33 ]. Their specific functions were yet to be confirmed electrophysiologically because of lacking a multiple cuticular system.…”

“…They were the longest antennal sensilla in C . lividipennis as they would be the first sensilla to contact external objects, and may function as tactile mechanoreceptors [ 33 , 45 – 47 ]. CHA III occurred only on the Pe of adult male antennae, and was much more than CHA I and II in number ( Fig 5C , Table 5 ).…”

“…COE were found in many Hemiptera across several families, such as Pentatomidae [ 31 , 58 ], Pyrrochoridae [ 59 ], Dinidoridae [ 52 ], Tropiduchidae [ 32 ], Coreidae [ 60 ], Aleyrodidae [ 33 , 61 ]. According to Ruchty et al [ 62 ], COE serve as chemoreceptors that respond to air temperature changes in social insects.…”

“…They were found in many Hemiptera insects, including four Australian spittlebug species [ 75 ], Zema gressitti [ 32 ], A . dispersus [ 33 ], four genera of Pentatomidae [ 36 ], and S . furcifera [ 34 ].…”

Morphological characterization of antennae and antennal sensilla of Diaphorina citri Kuwayama (Hemiptera: Liviidae) nymphs

“…Classification of sensilla types in this work was based on the morphological characteristics of similar structures described previously [24][25][26][27][28][29][30][31][32].…”