from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The property of crystallizing in three distinct forms.
- n. The coexistence among individuals of the same species of three distinct forms, not generally connected by intermediate gradations.
from the GNU version of the Collaborative International Dictionary of English
- n. The property of crystallizing in three forms fundamentally distinct, as is the case with titanium dioxide, which crystallizes in the forms of rutile, octahedrite, and brookite. See pleomorphism.
- n. The coëxistence among individuals of the same species of three distinct forms, not connected, as a rule, by intermediate gradations; the condition among individuals of the same species of having three different shapes or proportions of corresponding parts; -- contrasted with
polymorphism, and dimorphism.
from The Century Dictionary and Cyclopedia
- n. In crystallography, the property of crystallizing in three fundamentally different forms.
- n. In biology, existence under three distinct forms. It is not rare among insects.
- n. In botany, the occurrence of three distinct forms of flowers or other parts upon the same plant, or upon plants of the same species.
There are, also, cases of dimorphism and trimorphism, both with animals and plants.
Another twist to the story is that trimorphism is also known to exist in other animals - although it is extremely rare - and in these species the three different male forms are determined by inheritance of different alleles.
The study initially discovered male trimorphism in dung beetles.
Rowland and Emlen's ensuing studies of social interactions under facultative male trimorphism may thus provide additional new insights into these processes.
Once recognized, the research was expanded and trimorphism was found in other families of beetles as well, and in other weapon systems - which include head horns in dung beetles, mandibles in stag beetles and ventral spines in weevils.
"This likely means that facultative trimorphism operates by new and very different evolutionary rules than do 'genetic' trimorphisms - the latter of which have been intensively studied because of the insights they have provided about sexual selection," said Rowland.
However, male trimorphism in beetles appears to be facultative in nature.