SYNOPSIS. Ontogenetic conflict arises when optima for alleles governing fitness variation differ between juveniles and adults or between adult sexes. Loci that govern development of alternative phenotypes in the sexes, hereafter termed morph-determining loci, mediate development through the endocrine system. Morphotypic selection is defined to be multivariate selection favoring discrete alterna...

Saltational changes may underlie the diversification of pheromone communication systems in insects, which are normally under stabilizing selection favoring high specificity in signals and signal perception. In orchid bees (Euglossini), the production of male signals depends on the sense of smell: males collect complex blends of volatiles (perfumes) from their environment, which are later emitte...

Round to oval, scalelike siliceous microstructures from cherts in Cambrian limestones of the western Yukon Territory suggest affinity with chrysophycean algae. At least six morphotypes present include porous forms with single branching processes and nonporous oval, ringlike forms. Partially dissolved specimens may indicate a contribution to contemporaneous or early diagenetic chert formation.

Selenidium is a genus of gregarine parasites that infect the intestines of marine invertebrates and have morphological, ecological, and motility traits inferred to reflect the early evolutionary history of apicomplexans. Because the overall diversity and phylogenetic position(s) of these species remain poorly understood, we performed a species discovery survey of Selenidium from tube-forming po...

Introduction: Density is one of the critical factors in echinoderm larvae for aquaculture purposes. Echinoplutei are very sensitive to overcrowding. High culture density can lead problems with bacteria or protozoa, decreasing survival and generating abnormal morphotypes. Objective: To evaluate effect on larval growth sea urchin Arbacia dufresnii. Methods: Two days after fertilization A. dufresn...