Multiple‐Species Induction of Morphological Defenses in the Rotifer Keratella Testudo

  title={Multiple‐Species Induction of Morphological Defenses in the Rotifer Keratella Testudo},
  author={Richard S. Stemberger and John J. Gilbert},
Filtrates of cultures of 10 of 12 common freshwater zooplankton species induced posterior spines in the rotifer Keratella testudo. Filtrates of cultures of Asplanchna spp. and those of crustacean zooplankton, including cladocerans and cyclopoid and calanoid copepods, generally produced the strongest induction responses. The filtrates of Daphnia pulex cultures, at densities as low as 0.4 individuals/L, promoted significant posterior spine development. This is the first known case of a competitor… 
Predator-specific inducible defenses in the rotifer Keratella tropica
A Patagonian strain of Keratella tropica has very different induced morphological responses to two predators – the carnivorous rotifer Asplanchna brightwelli and the interference competitor Daphnia pulex, and the ratio of benefit to cost with daphniids may be highest for intermediate spine development.
A field and laboratory study on factors affecting polymorphism in the rotifer Keratella tropica
This is the first record of rotifer morphological change as an indirect effect of fish predation, and Morphological induction showed a direct relationship with the concentration of crustaceans, both under field and laboratory conditions.
Induction of different defences by two enemies in the rotifer Keratella tropica: response priority and sensitivity to enemy density
Keratella tropica has qualitatively distinct spine-development responses to kairomones released by the predatory rotifer Asplanchna and the cladoceran interference competitor Daphnia, leading to a coupling of exuberant and effective morphological defence with an unrivalled sensitivity to predator density.
Divergent developmental patterns of induced morphological defenses in rotifers and Daphnia: Ecological and evolutionary context
The type of developmental pattern associated with each induced defense appears to have been shaped by natural selection to effectively protect the animal, at minimal cost, from the specific kind of predation pressure to which it is commonly subjected.
Susceptibilities of Ten Rotifer Species to Interference From Daphnia Pulux
In natural zooplankton communities, Daphnia interference has the potential to impose high mortality rates on susceptible rotifer species and, therefore, to shift the species structure of rotifer assemblages in favor of resistant species.
The cost of predator-induced morphological defense in rotifers: experimental studies and synthesis
This review briefly discusses potential trade-offs associated with pronounced spine development, focuses on an evaluation and synthesis of experimental work comparing the reproductive potential of basic (non-induced) and Asplanchnainduced morphs and suggests areas for future research.
Escape response of the rotifer Keratella: Description, stimulation, fluid dynamics, and ecological significance
Keratel)a spp. sometimes exhibited escape responses when being contacted or closely approached by the predatory rotifer Asplanchna brightwefli, when enccmntering the inhalant currents of the
Developmental Polymorphism Induced by Intraspecific Predation in the Ciliated Protozoon Onychodromus quadricornutus
ABSTRACT. The hypotrich ciliate Onychodromus quadricornutus is remarkable in its potential for voluminous size (up to 900 μm in length), its possession of a unique set of four dorsal spines or horns,
Induction and inhibition of spine development in the rotifer Keratella tropica.: Evidence from field observations and laboratory experiments
The results support the idea that a major proportion of the phenotypic expression of K. tropica depends on the concentration of an inducing factor, which in turn depends upon the balance between release and decomposition rates of the chemical, and suggest an inverse relationship between spine length and growth rate.
The results suggest that phenotypic plasticity in Daphnia cucullata evolved as a ''dif- fuse'' coevolution against different invertebrate predators which selectively feed on small prey items.


Spine development in the rotifer Keratella cochlearis: induction by cyclopoid copepods and Asplanchna
The phenotypic variation of offspring produced from induced unspined Keratella females encompassed much of the variation reported for the taxon in North America and it is suggested that the North American morphotypes be identified because the presence of the posterior spine can greatly affect predator selectivity.
Asplanchna-induced polymorphism in the rotifer Keratella slacki1
Asplanchna releases into its environment a filterable factor which induces eggs of Keratella slacki to develop into individuals with slightly larger (x 15%) bodies, considerably longer (a 30%)
Predator induction of crests in morphs of the Daphnia carinata King complex
Temperature, turbulence, oxygen, and notonectid predators were studied experimentally as possible factors influencing crest growth in six different forms of the Daphnia carinata complex, indicating that predation was a potent factor influencing crest development, and the distribution and abundance of morphs.
Control of Keratella populations by interference competition from Daphnia1
Mechanical interference competition, described for the first time among zooplankton, may be very important in controlling natural populations of some rotifers.
Further Studies on Predator Induction of Crests in Australian Daphniaand the Effects of Crests on Predation
Results of predation experiments supported previously published indications that helmets reduce the efficiency of notonectid predation and showed that the presence of a crest was associated with reduced fecundity.
Chaoborus predation on typical and spined morphs of Daphnia pulex: Behavioral observations1
Results indicate that SM was clearly superior to TM in escaping the grasp of both third and fourth instar Chaoborus larvae and visible injuries to escapees were rare, while handling time of ingested SM longer than that of TM.
Embryological induction and predation ecology in Daphnia pulex
Results of laboratory experiments suggest that a water-soluble factor released into the environment by the predacious phantom midge larva Chaoborus americanus (Diptera: Chaoboridae) causes embryos of the waterflea Daphnia pulex Leydig 1860 emend to develop into a form called Daphnian minnehaha Herrick 1884.
Direct observations of the mechanisms of interference between Daphnia and Keratella cochlearis1
Direct observation was used to describe and quantify four types of interaction between Daphnia and the rotifer, Keratella cochlearis f.
Culture of Phytoplankton for Feeding Marine Invertebrates
The methods suffice for the most fastidious algae now routinely cultivable, and simplifications indicated for less demanding species are easily made; for example, omission of silicate for plants other than diatoms.
The Ecological Implications of Body Size
A mathematical primer: logarithms, power curves, and correlations, and a mathematical primer for allometric simulation models.