The presence of micropyles in the shells of developing and undeveloped eggs of the ladybird beetle Harmonia axyridis (Coleoptera: Coccinellidae)

• Main Authors: Naoya OSAWA, Arata YOSHINAGA
• Format: Article
• Language: English
• Published: Institute of Entomology, Biology Centre, Czech Academy of Science 2009-11-01
• Series: European Journal of Entomology
• Subjects: coccinellidae; harmonia axyridis; hatchability; infertile egg; morphology; scanning electron microscopy; sibling cannibalism; trophic egg
• Online Access: https://www.eje.cz/artkey/eje-200904-0019_The_presence_of_micropyles_in_the_shells_of_developing_and_undeveloped_eggs_of_the_ladybird_beetle_Harmonia_axy.php

In Hymenoptera and Heteroptera, the absence of micropyles is one criterion for categorizing an egg as trophic. Undeveloped eggs are observed in more than 90% of the egg clusters of the ladybird beetle Harmonia axyridis Pallas. Traditionally, these undeveloped eggs are regarded as "trophic eggs." The surfaces of the eggs of H. axyridis were examined using scanning electron microscopy and the presence of micropyles in the shells of developing and undeveloped eggs determined. Micropyles are circularly distributed around the top of eggs and present in both developing and undeveloped eggs. The number of micropyles in the shells of developing and undeveloped eggs did not differ significantly. Our results indicate that the undeveloped eggs of H. axyridis have micropyles, suggesting that the mechanisms regulating the production of undeveloped eggs in H. axyridis differ from those resulting in the production of trophic eggs by Hymenoptera and Heteroptera.