Water fleas (Daphnia), a common zooplankton in lakes, go through a seasonal cycle of body forms called "cyclomorphosis
." In the presence of chemicals released by predators, each generation grows energetically expensive spines called "helmets." (35) Back on the land, entomologists have noticed that tree leaves will toughen, becoming distasteful after the plant has been fed upon by herbivorous insects.
We infer from this observation that this particular population experienced cyclomorphosis
in Daphnia lumholtzi induced by temperature.
The other side of cyclomorphosis
: why Daphnia lose their helmets.
Such traits include cyclomorphosis and other dimorphisms associated with protective structures ("protective" dimorphisms), paedomorphosis, diapause, some cases of sex determination (e.g., in many species of reptiles and some fish), trophic dimorphisms (e.g., cannibalistic versus herbivorous morphs), pupal color (swallowtail butterflies), dimorphic variation in "weaponry" (e.g., horns and forceps in insects, tentacles in some species of hydroids), body size (e.g., "jacking" in salmon), and wing dimorphism in insects (for a review of these and other types of dimorphic variation, see Roff 1996a).
Circulating chemicals have also been implicated in cyclomorphosis (Jacobs 1980) and wing dimorphism in insects.
Rotifer population in a Southeast Texas oxbow lake with empahsis on cyclomorphosis
of Keratella cochlearis.
1997), their morphological variations called cyclomorphosis
and adaptations (Wetzel 2001) and their ability to feed on different food type.
The nature and causes of cyclomorphosis
in a species of the Bosmina longirostris complex.
Cyclomorphosis in Daphnia galeata mendotae Birge and Daphnia retrocurva Forbes as a predator-inducedresponse.
Some aspects in the costs of cyclomorphosis in Daphnia cucullata.