High juvenile hormone titre and abdominal activation of JH signalling may induce reproduction of termite neotenics

Termite castes are a key example of polyphenism, in which reproductive division of labour is clearly seen in colonies. The reproductive castes in termites include primary and neotenic reproductives; primary reproductives found a new colony whereas neotenics succeed them in the reproductive role when...

Full description

Saved in:
Bibliographic Details
Published in:Insect molecular biology 2015-08, Vol.24 (4), p.432-441
Main Authors: Saiki, R, Gotoh, H, Toga, K, Miura, T, Maekawa, K
Format: Article
Language:English
Subjects:
abdomen
Animals
caste determination
caste differentiation
Female
gene expression
Gene Expression Regulation, Developmental
genes
gonads
head
Isoptera - growth & development
Isoptera - physiology
juvenile hormone
juvenile hormones
Juvenile Hormones - metabolism
juveniles
Molting
neotenic reproductives
Nymph - physiology
nymphs
Reproduction
reproductives
Reticulitermes speratus
RNA Interference
senescence
Signal Transduction
termites
thorax
vitellogenin
Vitellogenins - biosynthesis
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Termite castes are a key example of polyphenism, in which reproductive division of labour is clearly seen in colonies. The reproductive castes in termites include primary and neotenic reproductives; primary reproductives found a new colony whereas neotenics succeed them in the reproductive role when the primary reproductives die or become senescent. Neotenics usually differentiate from nymphs or workers by developing functional gonads while retaining juvenile characteristics; however, the developmental mechanism during neotenic differentiation remains poorly understood. Juvenile hormone (JH) mediates a number of aspects of developmental regulation in caste differentiation in termites. In the present study we quantified JH titres in neotenic reproductives of Reticulitermes speratus, and compared these with other developmental stages. In addition, expression changes in JH signalling gene homologues (Methoprene‐tolerant [Met], Krüppel‐homolog1, Broad‐Complex) in the head, thorax and abdomen were investigated during neotenic differentiation. Finally, we examined the function of Met in reproduction of neotenics by RNA interference (RNAi). Our results showed that the JH titres of neotenics were significantly higher than those of nymphs and workers. JH signalling genes were highly expressed in neotenic abdomens, compared with those in workers and nymphs. Met RNAi resulted in the inhibition of vitellogenin gene expression in newly moulted neotenics. These results suggest that the fertility of neotenics might be controlled by a large increase of JH titres and body‐part‐specific activation of JH signalling pathways.
ISSN:0962-1075
1365-2583
DOI:10.1111/imb.12169