TY - JOUR TI - Differential circadian behaviors in aquatic annelids DO - https://doi.org/doi:10.7282/T3S75D9J PY - 2013 AB - In aquatic annelids, locomotion has proven to be a perplexing phenomenon because of the intricacies with which it is regulated. These animals are capable of either swimming or crawling (or both) depending on species. Studies of Erpobdella punctata, a temperate aquatic leech, have shown that each of these locomotion methods are differentially regulated according to an innate circadian rhythm. Swimming occurrences are regulated by an internal oscillator resulting in predictable circadian patterns while crawling is not, resulting in time-independent crawling outputs. The difference in these output pathways seems implausible, but could possibly be caused by each method of locomotion having independent output pathways from a circadian oscillator. In this study, an automated motion capture experiment was designed to quantitatively evaluate various species of aquatic annelids for circadian-regulated crawling rhythms. Erpobdella punctata was used as a positive control for circadian behavior, but the experimental design used was unable to differentiate between swimming and crawling. To isolate crawling behaviors, a phylogenetic approach was utilized by analyzing species closely related to E. punctata for comparison. Helobdella robusta and Mesenchytraeus solifugus - both of which are obligate crawling annelids - were tested for innate rhythms to determine whether lack of crawling regulation is found in other species as well. Simultaneously, attempts were made to isolate circadian oscillatory genes from each of the three species in question via the Polymerase Chain Reaction. Comparisons were made of known Drosophila melanogaster circadian regulatory genes clock, cycle, doubletime and cryptochrome with the Capitella teleta genome in an attempt to find annelid circadian sequences. Amplified annelid sequences successfully showed no sequence similarity to any known genes in NCBI archives, nor in the Capitella teleta genome. However, H. robusta and E. punctata showed measurable crawling rhythm with close to a 24 hour period (while M. solifugus did not), implying future probing would be required to rule out the existence of a molecular oscillator in these species. The activity study also implies that lack of crawling rhythm in E. punctata is either unique to the species, or that previous studies regarding this behavior are flawed. KW - Biology KW - Annelida--Locomotion KW - Circadian rhythms KW - Annelida--Research LA - eng ER -