Premium
TESTING ADAPTIVE RADIATION AND KEY INNOVATION HYPOTHESES IN SPIDERS
Author(s) -
Bond Jason E.,
Opell Brent D.
Publication year - 1998
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1998.tb01641.x
Subject(s) - biology , spider , orb (optics) , adaptive radiation , thread (computing) , weaving , statistical hypothesis testing , phylogenetic tree , evolutionary biology , ecology , zoology , statistics , computer science , mathematics , artificial intelligence , genetics , gene , image (mathematics) , operating system
We combine statistical and phylogenetic approaches to test the hypothesis that adaptive radiation and key innovation have contributed to the diversity of the order Araneae. The number of unbalanced araneid clades (those whose species numbers differ by 90% or more) exceeds the number predicted by a null Markovian model. The current phylogeny of spider families contains 74 bifurcating nodes, of which 31 are unbalanced. As this is significantly more than the 14.8 expected unbalanced nodes, some of the diversity within the Araneae can be attributed to some deterministic cause (e.g., adaptive radiation). One of the more highly unbalanced (97%) bifurcations divides the orb‐weaving spiders into the Deinopoidea and the larger Araneoidea. A simple statistical model shows that the inequality in diversity between the Deinopoidea and the Araneoidea is significant, and that it is associated with the replacement of primitive cribellar capture thread by viscous adhesive thread and a change from a horizontal to a vertical orb‐web orientation. These changes improve an orb‐web's ability to intercept and retain prey and expand the adaptive zone that orb‐weaving spiders can occupy and are, therefore, considered to be “key innovations.”