REGRESSION SHAPES HYDROID COLONIES

Physiological characterization of stolon regression in a colonial hydroid.

As with many colonial animals, hydractiniid hydroids display a range of morphological variation. Sheet-like forms exhibit feeding polyps close together with short connecting stolons, whereas runner-like forms have more distant polyps and longer connecting stolons. These morphological patterns are thought to derive from rates of stolon growth and polyp formation. Here, stolon regression is ident...

Causes and consequences of stolon regression in a colonial hydroid.

A cnidarian colony can be idealized as a group of feeding polyps connected by tube-like stolons. Morphological variation ranges from runner-like forms with sparse polyp and stolon development to sheet-like forms with dense polyp and stolon development. These forms have typically been considered in a foraging context, consistent with a focus on rates of polyp development relative to stolon elong...

Optimal Kernel Shapes for Local Linear Regression

Local linear regression performs very well in many low-dimensional forecasting problems. In high-dimensional spaces, its performance typically decays due to the well-known "curse-of-dimensionality". A possible way to approach this problem is by varying the "shape" of the weighting kernel. In this work we suggest a new, data-driven method to estimating the optimal kernel shape. Experiments using...

Colonial Responses of Hydroid Polyps

Hydroid Stolonal Contractions Mediated by Contractile Vacuoles

The growth and development of colonial hydroids is dependent upon a flow of gastrovascular fluid through a common vasculature. Gastrovascular flow is believed to be driven by polyp contractions, stolonal contractions and endodermal ciliation. In the athecate hydroid Hydr•actinia symbiolongicarpus we found that polyp contractions, stolonal contractions and gastrovascular flow were only weakly co...