Location: Southern Insect Management ResearchTitle: Effects of the juvenile hormone mimic NC-184 on the development of the reproductive organs and mating behaviour of nymphs of the desert locust, Schistocerca gregaria (Orthoptera: Acrididae)
|HIROYOSHI, SATOSHI - International Centre Of Insect Physiology And Ecology|
|KOKWARO, ELIZABETH - Kenyatta University|
|METTUPALLI, SAI - Montana State University|
|MITSUNAGA, TAKAYUKI - National Agriculture And Food Research Organization (NARO), Agricultrual Research Center|
|YAGI, SHIGEMI - International Centre Of Insect Physiology And Ecology|
|Reddy, Gadi V.P.|
Submitted to: European Journal of Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2019
Publication Date: 12/13/2019
Citation: Hiroyoshi, S., Kokwaro, E., Mettupalli, S., Mitsunaga, T., Yagi, S., Reddy, G.V. 2019. Effects of the juvenile hormone mimic NC-184 on the development of the reproductive organs and mating behaviour of nymphs of the desert locust, Schistocerca gregaria (Orthoptera: Acrididae). European Journal of Entomology. 116:477–485. https://doi.org/10.14411/eje.2019.049.
Interpretive Summary: The desert locusts undergo drastic behavioral and morphological changes when they start swarming that has been extensively studied for many years. In the present study, application of this NC-184, a juvenile hormone mimic promoted ovarian development in female nymphs but not the development of internal reproductive organs in males. The result suggests that sensitivity to NC-184 differs between the induction of precocious mating behavior and maturation of reproductive organs and between the sexes. The present study strongly suggests that the effects of juvenile hormone on mating behavior are indeed direct and that the mechanisms underlying between mating behavior and internal reproductive development must be different.
Technical Abstract: The insect growth regulator NC-184, a juvenile hormone mimic, prevents molting to the adult stage in the desert locust, Schistocerca gregaria (Forsskål) (Orthoptera: Acrididae). Male nymphs treated with NC-184 exhibit precocious mating behavior in the final instar when treated in the penultimate or final instar nymphal stage. We examined whether application of this chemical affects the internal reproductive development in nymphs under crowded conditions. In treated males, both accessory glands and seminal vesicles were underdeveloped, and no sperm was found in the seminal vesicle, whereas these organs in controls greatly increased in size 10 days after treatment, when all the insects had molted to adults. Testis size in treated males was like that in controls, regardless of the smaller body size due to the inhibition of molting. Females treated with NC-184 showed development of oogenesis and spermatheca to some degree, but did not develop mature eggs in contrast to the controls. In conclusion, treatment of S. gregaria nymphs with NC-184 induced reproductive costs in box sexes.