Structure and Sense Organs of Ovipositors of an Endoparasitoid Aprostocetus causalis and an Ectoparasitoid Quadrastichus mendeli in Leptocybe spp.

Abstract

Little is known of the olfactory mechanisms of host detection in the ovipositors of endoparasitoids and ectoparasitoids. An endoparasitoid Aprostocetus causalis La Salle & Wu (Hymenoptera: Eulophidae) and an ectoparasitoid Quadrastichus mendeli Kim & La Salle (Hymenoptera: Eulophidae: Tetrastichinae) are the two parasitoids of the eucalyptus gall wasp Leptocybe spp. Structures and sense organs of ovipositors of A. causalis and Q. mendeli were studied using scanning and transmission electron microscopy, which provided essential information for exploring the mechanism of host detection by endoparasitoid and ectoparasitoid. The ovipositors of two parasitoids consisted of the first and second valvulae and ended in a pointed tip. There were three types of microtrichia, two types of sensilla chaetica, and one type of sensilla campaniformia on the ovipositors of A. causalis and Q. mendeli. However, Q. mendeli has the fourth type of microtrichia on the ovipositor. The morphology, types, distribution, length, and width of these sensilla and microtrichia were described, and their possible functions are discussed in conjunction with the stinging, oviposition, and the host selection process.

Morphology and ultrastructure of antennal sensilla of the parasitic wasp Baryscapus dioryctriae (Hymenoptera: Eulophidae)

“…In addition, several studies have shown that the sensilla on ovipositor also plays a crucial role in the process of spawning in female wasps (Huang et al, 2019), which is synergistic with the function of antennae. Therefore, besides the functional verification test for antennae sensilla, meanwhile, the morphology and ultrastructure of ovipositor sensilla of the parasitic wasp B. dioryctriae need be investigated in our future study, in order to make an overall identify for the sensilla involved in host location and oviposition of B. dioryctriae .…”

Functional Ultrastructure of Hymenopteran Stingers: Devastating Spear or Delicate Syringe

“…Surprisingly, the stinger/ovipositor sensilla have been studied more in parasitic hymenopterans, where they have been classified as mechanoreceptors and chemoreceptors (and/or dual function mechano-chemosensors) as reported by Gal et al (2014) in Ampulex compressa , by Dweck et al (2008) in H. hebetor , and by Huang et al (2019) in Aprostocetus causalis and Quadrastichus mendeli .…”

“…Because the sensilla must be connected to the central nervous system via sensory neurones, the presence of the sensilla on honey bee lancets shows that they are not just simple cuticular needles, but live organs. Such an assumption appears reasonable, but it is surprisingly under-documented in the literature, with the majority of the evidence relating to the parasitoids indicated above (Dweck et al, 2008;Gal et al, 2014;Huang et al, 2019). This may be due to the difficult preparation of the hard stinger for TEM analysis: the bee stinger is a small, narrow hard tube through which fixation and other tissue-processing solutions for TEM are difficult to penetrate.…”

Cuticle protein gene LmCP8 is involved in the structural development of the ovipositor in the migratory locust Locusta migratoria

“…Among them, the ovipositor of hymenopteran insects comprises ventral and internal valves, among which the dorsal valve is wide and the ventral valve surface is concave to form an ovipositor sheath to contain it. The ovipositor of parasitic wasps is needle‐shaped (Huang et al, 2019), which lay eggs in plant tissues (Yang et al, 2014) or other insects (Gomez Duran & van Achterberg, 2011). The ovipositor of hemipteran insects (except aphids and scale insects) is mainly composed of dorsal and ventral valves, and the dorsal valve forms an ovipositor sheath to wrap around the ovipositor that stretches out and slides up and down when laying eggs, allowing its gradual insertion into the plant tissue to lay eggs (Zhong et al, 2017).…”