Vol. 58, 2019
(update: 2019.03.29; 04.30)
Spiny but Subitaneous Eggs: Egg Morphology and Hatching in Acartia Copepods in the Tropics
Nakajima1,§,*, Teruaki Yoshida2,§, Sakiko O.
Sakaguchi1, Bin Haji Ross Othman3, and Tatsuki
Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushima,
Yokosuka, Kanagawa 237-0061, Japan. *Correspondence:
+81-(0)46-867-9686. E-mail: firstname.lastname@example.org,
email@example.com. E-mail: firstname.lastname@example.org (Sakaguchi)
and TY contributed equally to this work.
Received 23 October 2018 / Accepted 24
surface ornamentation, egg production rates, and hatching success of
two calanoid copepod species (Acartia pacifica and Acartia cf.
erythraea) were examined in a tropical coral reef of Tioman Island,
Malaysia, near the the equator (2°N). All observed females of A. pacifica
and A. cf. erythraea produced eggs with spines on the surface, either
short or long, which are common in resting eggs in temperate ecosystems
that hatch when environmental conditions are favorable or after a
certain refractory period. However, all of these spiny eggs in the
present study hatched within 48 hours when exposed to ambient seawater
temperature, suggesting that they were subitaneous eggs. Such spine
ornamentation has been thought to be an adaptive feature only for
resting eggs to survive during egg dormancy, but the presence of spines
on subitaneous eggs suggests further possible functions of these spines
such as reducing the risks of ingestion by predators.
Key words: Copepods, Subitaneous egg, Spiny, Tropics, Malaysia.
Nakajima R, Yoshida T, Sakaguchi SO, Othman BHR, Toda T. 2019. Spiny
but subitaneous eggs: egg morphology and hatching in Acartia copepods in the tropics.
Zool Stud 58:5.