ABSTRACT
Honeybee royal jelly is reported to have body-enlarging effects in holometabolous insects such as the honeybee, fly and silkmoth, but its effect in non-holometabolous insect species has not yet been examined. The present study confirmed the body-enlarging effect in silkmoths fed an artificial diet instead of mulberry leaves used in the previous literature. Administration of honeybee royal jelly to silkmoth from early larval stage increased the size of female pupae and adult moths, but not larvae (at the late larval stage) or male pupae. We further examined the body-enlarging effect of royal jelly in a non-holometabolous species, the two-spotted cricket Gryllus bimaculatus, which belongs to the evolutionarily primitive group Polyneoptera. Administration of royal jelly to G. bimaculatus from its early nymph stage enlarged both males and females at the mid-nymph and adult stages. In the cricket, the body parts were uniformly enlarged in both males and females; whereas the enlarged female silkmoths had swollen abdomens. Administration of royal jelly increased the number, but not the size, of eggs loaded in the abdomen of silkmoth females. In addition, fat body cells were enlarged by royal jelly in the silkmoth, but not in the cricket. These findings suggest that the body-enlarging effect of royal jelly is common in non-holometabolous species, G. bimaculatus, but it acts in a different manner than in holometabolous species.
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
A.M. and C.K. designed the study. A.M. and H.K. performed the experiments. A.M. and C.K. analyzed the data and prepared the figures. A.M., K.S., and C.K. wrote the manuscript.
Funding
This work was supported by Grants-in-aid for Scientific Research [26670025] and the Japan Society for the Promotion of Science research fellowships for young scientists [13J08664 to A.M.], and the Mishima Kaiun Memorial Foundation (to A.M.).
Supplementary information
Supplementary information available online at http://bio.biologists.org/lookup/doi/10.1242/bio.019190.supplemental
- Received April 21, 2016.
- Accepted April 27, 2016.
- © 2016. Published by The Company of Biologists Ltd
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