Effect of flufenoxuron on the antennal sensilla of Spodoptera littoralis (Lepidoptera: Noctuidae).

Abstract

In the present study, the effect of flufenoxuron on the sensory organ in the antenna of Spodoptera littoralis was showed after feeding of the 3 rd larval instars for 24 hrs. on treated castor been leaves with Lc 50 . Each adult antenna, male and female of untreated and treated group is divided into about 77-82 segment like annuli; and each segment is divided into a sensory region containing the olfactory sensilla and a largely non-sensory region containing scales and a very small number of sensory structures.Six types of sensilla were found on the antenna of adult S. littoralis: by scanning electron microscopy. These sensilla were trichoidae, chaetica, coeloconica, taste rod, sensilla auricillica and squamiforms.Two types of sexually dimorphic trichoidae were found; Type I is in the peripheral of the sensory field of the flagellar segments and present only on male antennae. This suggests that the sensillum may contain the receptor sites for the female sex pheromone. Type II is located within the ventromedial sensillar field of male and female where they are arranged without apparent pattern.Six mechanoreceptive sensilla chaetica on each segment of male and female were particularly abundant on the apical antennal segment.Each flagellar segment bears several sensilla coeloconica on the ventral surface of the antennae. Each sensillum consists of a depression surrounded by 15 to 17 teeth and one peg.There was a single sensillum taste rod on each segment. There is one of these sensilla at each segment in both male and female. On the terminal segment there were two sensilla joined.Sensilla auricillica were found on both male and female. These sensilla usually had a typical rabbit ear shape.The squamiform sensilla are found on both male and female on the dorsal part of the antenna among the scales.The study revealed that LC 50 of flufenoxuron caused the formation of abnormal antennae and effect the length and distribution of the sensilla.

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

“…Besides, some pores appeared in sensilla basiconica .These abnormalities may be attributed to the effect of insect growth regulator indirectly on the release of ecdysteroids, through interfering with the neuroendocrine sites responsible for the release of this hormone. In agreement with Zohry (2008) who revealed that LC 50 of flufenoxuron caused the formation of abnormal antennae and affect the length and distribution of the sensilla on Spodoptera littoralis. Similarly, Schmutterer et al, (1993) observed morphogenetic defects on antennae due to treatments of nymphs of desert locust, Schistocerca gregaria and the red locust, Nomadacris septemfasciata with neem oil.…”

Some factors affect the perception and production of pheromone and ultrastructure of antennae after treatment of Tribolium castaneum with Chlorfluazuron

“…On the other hand female adult antennae resulted from treated 4 th larval instar with LC 50 of Atabron showed antennae with highly confused segments without sensillae as shown in Plate (2-b) and the last three segments confused but without sensillae as shown in Plate (2-d). Similarily, obtained by Zohry (2008) who revealed that LC 50 of flufenoxuron on 3 rd larval instar of Spodoptera littoralis caused the formation of abnormal antennae and affect the length and distribution of sensillae.…”

Insight Into the Ultrastructure of Antennal Sensilla ofMythimna separata(Lepidoptera: Noctuidae)

“…1970 , Flower and Helson 1974 , Liu and Liu 1984 , Lavoie-Dornik and McNeil 1987 , Castrejón-Gómez et al. 1999 , Zohry 2008 , Diongue et al. 2013 ).…”

“…2013 ), and S. littoralis ( Seada 2015 ). Pores were observed on the tip indicated their chemoreceptor function, and in fact, Flower and Helson (1974) and Zohry (2008) called this sensillum as “taste rod.”…”