Abstract
In insects, juvenile hormone (JH) decreases or has any effect upon the phenoloxidase (PO) activity, and favors or decreases the Antimicrobial Peptides (AMPs) expression. Although there is no information about the differential effect of such hormone, two possibilities are that it depends on (a) the immune marker recorded and (b) sexual differences. Here, three commonly used immune markers, Phenoloxidase (PO), hydrogen peroxide (H2O2), and lytic activity, were measured 3, 6 and 24 hours after administration of methoprene (JHa, an analog of juvenile hormone) in male and female monarch butterflies (Danaus plexippus). At 3 and 6 h post-JHa administration, the PO activity increased in females but it only increased at 3 h in males, whereas H2O2 levels increased only in females at 3 h. For the remaining times the JHa had a null effect on POand H2O2. On the other hand, the JHa had a null effect for lytic activity in both sexes at 3, 6 and 24 h. To our knowledge, this is the first report of a positive effect of a JHa onPOand H2O2 and suggests that this effect is sex dependent.
Highlights
The endocrine system affects physiology, morphology, behavior and life history [1,2,3,4]
The General linear models (GLM) revealed that the effect of JHa on the expression of PO depended on the treatment (F = 23.96, P < 0.0001; Figure 1), the time elapsed after administration of the solution, and the interaction of time*gender (F = 8.63, P < 0.0001; Figure 1)
Under an evolutionary point of view, could not be adaptive that one molecule (JH in this case) may affect the overall immune response at the same time because animals could pay elevated cost of an increased immune response if they are exposed to autoimmune diseases or they could be exposed to parasites and pathogens if all their immune markers are decreased at the same time
Summary
The endocrine system affects physiology, morphology, behavior and life history [1,2,3,4]. For example in Tenebrio molitor [10] and Calopteryx virgo [11], the application of JH III or methoprene (JHa; an analogue of JH) respectively, diminished the production of Phenoloxidase (PO) This is a key enzyme for both the humoral (melanization) and cellular (encapsulation) response against pathogens, as well as wound repair and clotting after injury [12,13]. In Drosophila melanogaster, the application of two analogues of JH, methoprene and piriproxiphene, inhibited the expression of the genes that produce antimicrobial peptides (AMPs), one of the main components of the humoral response [16] This evidence suggests that JH could affect negatively the overall immune response. Why the response is not always immunosuppressed due to the JH application?
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
