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Additional Photos

cerata detail

underside

regenerating

food anemone

egg mass

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Berghia japonica (Baba, 1933)

Maximum size: 12 mm.
Identification:
Superficially,
this species is
similar to Berghia
major. However, it can be distinguished from that species by
the
fine branches of the digestive gland in the tips of the cerata as well
as the subterminal yellow and iridescent blue patches on the
dorsal surfaces of the cerata.
Natural history:
Berghia japonica
is
known from two animals found in Halimeda
kanaloana beds at a depth of 6-12 m (20-38 ft). It feeds on the anemone Bunodeopsis medusoides. (Note 1) A small
cream egg mass laid in a holding dish was similar in form to that of Berghia
salaamica rather than that
of B. major. It hatched in
about four
days.
Distribution:
Maui: widely distributed in the western & central Pacific.
Taxonomic notes:
This
species is listed by some authors as Baeolidia
japonica. It was first
recorded in Hawaii from Wahikuli, Maui by PF on Nov. 30, 2008.
Photo: CP: 12
mm; found by PF; Wahikuli, Maui; Nov. 30, 2008.
Observations and comments:
Note
1: In Oct., 2010, a 9 mm animal
was
observed repeatedly feeding on Bunodeopsis
medusoides in a holding dish over a period of
several days. The anemones were collected in the same sample as the
aeolid. Juvenile anemones (regurgitated, regenerating tentacles) were
"captured" with the oral tentacles and sucked in like spaghetti. Larger
animals were attacked from the base, after they released, with one or
two
bites taken per session. The mature anemones showed a strong aversive
response (releasing and swimming) on contact with the aeolid. However,
after attacking the mature anemones several times, the Berghia no longer showed interest
in doing so and appeared stressed. This may have been due to other
factors. But, I wonder if repeatedly attacked anemones might develop
antifeedent
chemicals in the manner of some plants under attack by insects? |
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