Body-enlarging effect of royal jelly in a non-holometabolous insect species, Gryllus bimaculatus.

Atsushi Miyashita,Chikara Kaito,Hayato Kizaki,Kazuhisa Sekimizu

doi:10.1242/bio.019190

Abstract

ABSTRACTHoneybee 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.

Highlights

The size of living organisms is strictly regulated in each species
As a result we observed royal jelly-induced body enlargement in female pupae and adults, but not in larvae or male pupae (Fig. 1A-C, Table 1), and adult female moths administered royal jelly exhibited swollen abdomens (Fig. 1D). These findings confirmed that royal jelly enlarges body size in B. mori under these conditions and suggest that the effect of royal jelly depends on the developmental stage and sex
Effect of royal jelly in G. bimaculatus To examine whether royal jelly enlarges non-holometabolous species, we orally administered royal jelly to nymphs of cricket G. bimaculatus

Summary

Introduction

The size of living organisms is strictly regulated in each species. Artificial enlargement techniques are useful for elucidating the mechanisms involved in body size regulation, and could contribute to the development of methods to enlarge industrially important organisms. Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 3-1, 7-chome, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

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